KR20250043161A - Method For Controlling Thermocompression Bonding Head - Google Patents

Abstract

The present invention relates to a method for controlling a thermocompression bonding head, which performs bonding with a uniform pressing force while following a change in the height of a bonding head that pressurizes a semiconductor chip, and performs height control so that the bonding tool is raised by detecting the point in time when a bump is melted, thereby suppressing non-bonding and occurrence of a short circuit of a semiconductor chip, the method comprising: (a) a step of lowering the bonding head while a pressing portion presses the bonding tool with a preset force when a bonding tool having absorbed a semiconductor chip moves to the upper portion of a substrate; (b) a step of stopping the descent of the bonding head when it is determined that the semiconductor chip absorbed by the bonding tool is in contact with the substrate, and controlling the height of the bonding head while pressing the semiconductor chip while following a change in the height of the bonding tool and controlling the height of the bonding head so that a position value of a mover of the pressing portion when the preset force is applied is maintained constant when performing thermocompression bonding; (c) a step of cooling the bonding tool to a predetermined temperature while maintaining the height of the bonding head or raising the bonding head to a preset height when it is determined that the bump of the semiconductor chip has melted; and (d) a step of raising the bonding head from the substrate when the thermal compression is completed after a predetermined time has elapsed.

Description

{Method For Controlling Thermocompression Bonding Head}

The present invention relates to a method for controlling a thermal compression bonding head that applies heat while pressing a semiconductor chip having bumps formed on the lower surface onto a substrate.

A thermocompression bonding device is a device that separates individual semiconductor chips from a wafer, and applies heat and pressure to bond the semiconductor chips to a bonding target substrate using a thermocompression method while the thermocompression bonding head picks up the semiconductor chips with the lower surface (bump formation surface) of the chips facing downward.

A thermocompression bonding device that performs this type of thermocompression bonding is an essential bonding device for performing the through silicon via (TSV) package lamination process. The TSV package is an advanced lamination technique that forms electrodes by drilling tiny holes in semiconductor chips, vertically laminating multiple identical semiconductor chips, and filling the holes with copper, or by laminating multiple semiconductor chips filled with copper. The technique can laminate and bond semiconductor chips to a substrate by applying heat and pressure while bringing bumps into contact with the connection terminals of a processed bonding substrate using a thermocompression bonding head and performing thermocompression bonding.

The thermocompression bonding head performs the task of attaching (bonding) a semiconductor chip to a substrate by adsorbing the upper surface of a semiconductor chip having bumps formed on the lower surface and moving it onto a substrate and thermally compressing the semiconductor chip. At this time, the thermocompression bonding head can receive and adsorb a semiconductor chip on which flux has been applied to the bump formation surface, or can perform the task of dipping flux when adsorbing a semiconductor chip on which flux has not been applied. In addition, it is possible to bond to a substrate using a NCF (Non-Conductive Film) for thermocompression bonding without applying flux.

Thermocompression bonding using a conventional thermocompression bonding head controls the height of the thermocompression bonding head using parameters such as temperature and time required for thermocompression collected through testing. For example, when bonding a semiconductor chip, if it is heated and pressurized at a certain temperature, the heat of the thermocompression bonding head is transferred to the semiconductor chip, bump, substrate, etc., and one or more of these expands due to the heating, and if it is heated above the melting point of the bump, the expanded bump melts. When the bump melts, there is a problem that the thermocompression bonding head that was applying pressurization crushes the melted bump, causing a short circuit defect between adjacent bumps. In addition, it is very difficult to set a pressing force that does not crush the bump, and there is a problem that it takes time to control it with the pressing force.

In particular, as the density of semiconductor circuits has increased in recent years, the density of bump placement has increased, and there is a growing concern that the bumps will melt and come into contact with each other, causing a short circuit.

Considering these points, the existing thermocompression bonding head performs the task of raising the bonding head after a certain period of time when pressing the semiconductor chip to the substrate, assuming that the bump has melted.

However, since semiconductor chips based on the same wafer have different height change profiles due to melting of bumps, it is difficult to manage the gap between the bonding surface of the semiconductor chip and the substrate, and the shape of the generated bumps becomes inconsistent. This causes problems such as the occurrence of unbonded areas of the semiconductor chip or short circuits between bumps.

In addition, since the shrinkage and expansion height change rates are different for each semiconductor chip (material), there is a problem in that it is difficult to pressurize all materials to the desired gap and pressure.

Therefore, a method is required to pressurize the bump with a constant pressure during the bonding process and to uniformly control the mounting height of the semiconductor chip in order to minimize damage to the semiconductor chip and suppress the occurrence of non-bonding and short circuits.

Publication Patent No. 10-2009-0131863

In order to solve the above-described problems, the present invention provides a method for controlling a thermocompression bonding head that performs bonding with a uniform pressing force while following the change in height of a bonding head that pressurizes a semiconductor chip, and performs height control so that the bonding tool is raised by detecting the point in time when a bump is melted, thereby suppressing non-bonding and short-circuiting of a semiconductor chip.

In addition, the present invention aims to automatically detect the timing at which a bump is actually melted for each individual semiconductor chip, regardless of the type of semiconductor chip, the type of wafer, etc., and to improve bonding quality by controlling the height of a bonding head or the height of a mover.

In addition, the present invention aims to detect melting of a bump by tracking a change in the height of a bonding head according to melting of a semiconductor chip bump on which actual bonding is performed, and, when it is determined that the bump has melted, to prevent a short circuit by raising the bonding head or a mover so that the gap between the semiconductor chip and the substrate becomes the same mounting height.

In order to achieve the above-described object, a control method of a thermocompression bonding head according to an embodiment of the present invention is provided, wherein a control method of a thermocompression bonding head that applies heat while pressing a semiconductor chip having a bump formed on a lower surface to a substrate comprises: a step of lowering the bonding head while a pressure unit presses the bonding tool with a preset force when a bonding tool having a semiconductor chip adsorbed thereon moves to an upper portion of the substrate; a step of stopping the descent of the bonding head and heating the bonding tool to a preset temperature while pressing the semiconductor chip, while controlling the height of the bonding head while performing thermocompression so that a position value of a mover of the press unit when the preset force is applied is constantly maintained by following a change in the height of the bonding tool; a step of maintaining the height of the bonding head or cooling the bonding tool to a preset temperature while raising the bonding head to a preset height when it is determined that the bump of the semiconductor chip has melted; and a step of raising the bonding head from the substrate after a predetermined period of time has elapsed and the thermal compression is completed.

Meanwhile, a control method of a bonding head according to an embodiment of the present invention is a control method of a thermocompression bonding head that applies heat while pressing a semiconductor chip having a bump formed on a lower surface to a substrate, the method including: a step of lowering the bonding head while a pressure unit presses the bonding tool with a preset force when a bonding tool having a semiconductor chip absorbed moves to an upper portion of the substrate; a step of stopping the lowering of the bonding head and heating the bonding tool to a preset temperature while pressing the semiconductor chip, while controlling the height of the bonding head so that the position value of the movable part of the pressing unit when the preset force is applied is maintained constant in accordance with a change in the height of the bonding tool; a step of cooling the bonding tool to a preset temperature while switching the pressure unit to a position mode when it is determined that the bump of the semiconductor chip has melted; and a step of raising the bonding head from the substrate when thermocompression is completed after a preset time has elapsed.

In addition, in the step (b), it may be characterized in that when the position value of the actuator of the pressurizing part changes during the process of lowering the bonding head, it is determined that the semiconductor chip absorbed by the bonding tool has come into contact with the substrate.

In addition, in the step (b), it may be characterized in that the melting point is determined when the bonding head gradually rises and then no longer rises in height or when the movement direction of the bonding head changes from an upward direction to a downward direction.

In addition, a method for controlling a thermocompression bonding head according to an embodiment of the present invention may be characterized by determining the melting point of the bump when at least one condition among a preset heating temperature and a preset heating time of the bonding head is satisfied together.

In addition, in the step (c), if the movable part of the pressurizing part and the bonding tool are directly connected, it may be characterized in that the bonding head is raised to a preset height while the pressurizing part is switched to the position mode so that the position of the movable part of the pressurizing part does not change.

In addition, in the step (c), when the movable part of the pressurizing part and the bonding tool are directly connected, it may be characterized in that the height of the bonding head is maintained in a state where the pressurizing part is switched to the position mode so that the position of the movable part of the pressurizing part does not change.

In addition, in the step (c), when the movable part of the pressurizing part and the bonding tool are directly connected, it may be characterized in that the movable part of the pressurizing part is raised to a preset height while the pressurizing part is switched to the position mode.

In addition, in the step (c), when the movable part of the pressurizing part and the bonding tool are directly connected, it may be characterized in that the position of the movable part of the pressurizing part is maintained in a state where the pressurizing part is switched to the position mode.

The present invention has the effect of preventing excessive pressure from being applied to the semiconductor chip due to expansion of the semiconductor chip, bump, substrate, etc. by controlling the height of the bonding head so that the position value of the movable member of the pressing part is maintained constant so that the pressing part can press the bonding tool with a preset force while the semiconductor chip adsorbed on the bonding tool is pressed against the substrate.

In addition, there is an effect of preventing non-bonding and short circuit problems by judging the melting point of the bump through the change in the height of the bonding head and raising the bonding tool that pressurizes the bonding head or semiconductor chip.

In addition, the present invention can automatically detect the melting point of the bump for each individual semiconductor chip regardless of the type of semiconductor chip, the type of wafer, etc., and control the height of the bonding head in real time, and can secure bonding quality by following the change in the height of the bonding head according to the melting of the bump of each semiconductor chip actually bonded and then raising the bonding tool so that the mounting height of the individual semiconductor chips becomes the same after detecting the melting point.

FIG. 1 is a drawing showing a bonding device including a bonding head according to an embodiment of the present invention.
FIG. 2a and FIG. 2b are drawings showing the preparation steps in an embodiment of the present invention.
Figure 3a is a drawing showing a contact step in an embodiment of the present invention.
FIG. 3b, FIG. 3c and FIG. 4a are drawings showing a thermocompression step in an embodiment of the present invention.
Figure 4b is a diagram showing a cooling step in one embodiment of the present invention.
Figure 4c is a drawing showing a cooling step in another embodiment of the present invention.
FIG. 5a and FIG. 5b are drawings showing the preparation steps in an embodiment of the present invention.
Figure 6a is a drawing showing a contact step in an embodiment of the present invention.
Figures 6b, 7a and 7b are drawings showing a thermocompression step in an embodiment of the present invention.
Figure 7c is a drawing showing a cooling step in an embodiment of the present invention.
FIG. 8 is a drawing showing the height of the actuator of the pressurizing portion and the height of the bonding head when the control method of the thermocompression bonding head according to an embodiment of the present invention is performed.
FIG. 9 is a flow chart showing a method for controlling a thermocompression bonding head according to an embodiment of the present invention.

Those skilled in the art will be able to develop various devices that embody the principles of the invention and are included within the concept and scope of the invention, even though they are not explicitly described or illustrated in this specification. In addition, it should be understood that all conditional terms and embodiments listed in this specification are, in principle, expressly intended only for the purpose of making the concept of the invention understood, and are not limited to the embodiments and conditions specifically listed in this specification.

The above-described objects, features and advantages will become more apparent through the following detailed description of the invention in connection with the accompanying drawings, whereby a person skilled in the art in the art will be able to easily implement the technical idea of the invention.

The embodiments described in this specification will be described with reference to cross-sectional and/or perspective views, which are ideal examples of the present invention. The sizes of components depicted in these drawings may be exaggerated for effective explanation of the technical contents. The form of the exemplary drawings may be modified due to manufacturing techniques and/or tolerances.

When describing various embodiments, components that perform the same function will be given the same name and reference numerals for convenience even if the embodiments are different. In addition, the expression 'at least one of A, B, and C' means that it consists of one, two, or three of A, B, and C. Furthermore, the configuration and operation that have already been described in other embodiments will be omitted for convenience.

Meanwhile, in this specification, the width direction means the left-right direction and the ±x direction, the length direction means the front-back direction and the ±y direction, and the elevation direction means the ±z direction as the up-down direction (see Figure 1).

Hereinafter, a thermocompression bonding device (BD) (hereinafter, “bonding device”) including a thermocompression bonding head (60) (hereinafter, “bonding head”) according to an embodiment of the present invention will be described.

FIG. 1 is a drawing showing a bonding device (BD) including a bonding head (60) according to an embodiment of the present invention.

Referring to FIG. 1, the bonding device (BD) includes a flip-over picker (10) that picks up a semiconductor chip (1) on an adhesive film and flips it upside down, a die picker (20) that receives a semiconductor chip (1) from the flip-over picker (10), adsorbs it, and dips flux provided in a dipping plate (30) on the lower surface of the semiconductor chip (1), an up-looking vision (40) that photographs and inspects the lower surface of the semiconductor chip (1) adsorbed on the die picker (20) and the flux dipping state, a die block (50) on which the semiconductor chip (1) received from the die picker (20) is seated, a bonding head (60) that adsorbs the semiconductor chip (1) on the die block (50), transfers it to the upper surface of the substrate (3), and applies heat while pressurizing the semiconductor chip (1) to the substrate (3), a particle vision (100) that inspects whether there is any foreign matter on the substrate (3) to which the semiconductor chip (1) adsorbed on the bonding head (60) is to be bonded, and a substrate (3). It may include a slit vision (70) that photographs and inspects the alignment state between semiconductor chips (1) adsorbed on the bonding head (60). The bonding device (BD) may further include a control unit (90) that commands and operates at least one of the flip-over picker (10), the die picker (20), the up-looking vision (40), the die block (50), the bonding head (60), the particle vision (100), the up-looking vision (40), and the slit vision (70).

The bonding device (BD) can perform the task of transferring a semiconductor chip (1) to a substrate (3) using a bonding head (60) and bonding it by thermal compression. At this time, the bonding head (60) can be preset with the force required for bonding, that is, the force of the pressurizing portion (63) that presses the semiconductor chip (1) on the substrate (3).

The bonding head (60) is provided with a bonding tool (66) that absorbs a semiconductor chip (1) at the bottom, and a heater is built into the bonding tool (66) so that the semiconductor chip (1) can be heated to a preset temperature. In addition, a cooling air supply unit may be provided in the bonding tool (66) to cool the heater to a preset temperature. A pressurizing unit (63) that pressurizes the semiconductor chip (1) absorbed by the bonding tool (66) is provided at the top of the bonding tool (66), and the pressurizing unit (63) pressurizes the bonding tool (66) with a preset force so that the corresponding pressurizing force can be applied to the semiconductor chip through the bonding tool (66).

The bonding head (60) is provided so as to be able to be moved up and down and in the X-Y direction, so that when the bonding tool (66) has absorbed the semiconductor chip (1) and moved to the upper part of the substrate (3), the pressure unit (63) presses the bonding tool (66) with a preset force and lowers the bonding head (60) to contact the semiconductor chip (1) with the substrate (3). When contact is confirmed, the temperature of the bonding head (60) is increased to a preset temperature by the built-in heater, thereby heating the semiconductor chip (1) and compressing it, thereby transferring heat to the semiconductor chip (1). That is, the bonding head (60) can apply heat while the pressure unit (63) presses the bonding tool (66) with a preset force to thermally compress the semiconductor chip (1) to the substrate (3).

When the semiconductor chip (1) is heated, heat is also transferred to the bump (2) formed on the lower surface of the semiconductor chip (1), so that the bump (2) can be melted by the heating. The bonding head (60) heats the bump (2) at a preset temperature for a preset period of time to melt it, and when it is determined that the bump (2) of the semiconductor chip (1) has been melted, the operation of the heater is turned off and cooling air is supplied to the heater to cool the bump (2) to a preset temperature. Thereby, the semiconductor chip (1) can be bonded on the substrate (3) as the bump (2) solidifies. After a preset period of time has elapsed and the thermal compression is completed, the bonding head (60) is raised from the substrate (3), and the bonding head (60) can move to absorb the semiconductor chip (1) to be subsequently bonded.

Hereinafter, a method for controlling a bonding device (BD) and a thermocompression bonding head according to one embodiment of the present invention will be described.

First, one embodiment of the control method of the thermocompression bonding head of the present invention comprises: (a) a step of lowering the bonding head (60) while the bonding tool (66) adsorbing the semiconductor chip (1) moves to the upper portion of the substrate (3) and the pressurizing portion (63) presses the bonding tool (66) with a preset force; (b) a step of stopping the lowering of the bonding head (60) when it is determined that the semiconductor chip (1) adsorbed on the bonding tool (66) is in contact with the substrate (3), and pressing the semiconductor chip (1) while heating the bonding tool (66) to a preset temperature, controlling the height of the bonding head (60) so that the position value of the movable member (63b) of the pressurizing portion (63) is constantly maintained when the preset force is applied in accordance with the change in the height of the bonding tool (66), and performing thermocompression bonding; (c) a step of cooling the bonding tool (66) to a predetermined temperature while maintaining the height of the bonding head (60) or raising the bonding head (60) to a preset height when it is determined that the bump (2) of the semiconductor chip (1) has melted; and (d) a step of raising the bonding head (60) from the substrate (3) when the thermal compression is completed after a predetermined time has elapsed.

Another embodiment of the control method of the thermocompression bonding head of the present invention comprises: (a) a step of lowering the bonding head (60) while the bonding tool (66) adsorbing the semiconductor chip (1) moves to the upper portion of the substrate (3) and the pressurizing portion (63) presses the bonding tool (66) with a preset force; (b) a step of stopping the lowering of the bonding head (60) when it is determined that the semiconductor chip (1) adsorbed on the bonding tool (66) is in contact with the substrate (3), and pressing the semiconductor chip (1) while heating the bonding tool (66) to a preset temperature, controlling the height of the bonding head (60) so that the position value of the movable member (63b) of the pressurizing portion (63) is constantly maintained when the preset force is applied in accordance with the change in the height of the bonding tool (66), and performing thermocompression bonding; (c) a step of cooling the bonding tool (66) to a predetermined temperature while switching the pressurizing part (63) to the position mode when it is determined that the bump (2) of the semiconductor chip (1) has melted; and (d) a step of raising the bonding head (60) from the substrate (3) when the thermal compression is completed after a predetermined time has elapsed.

Hereinafter, a method for controlling a thermocompression bonding head of the present invention will be described in detail with reference to the drawings. FIGS. 2A and 2B are drawings showing a preparation step in an embodiment of the present invention. FIG. 3A is a drawing showing a contact step (S100) in an embodiment of the present invention. FIGS. 3B, 3C, and 4A are drawings showing a thermocompression step (S200) in an embodiment of the present invention. FIGS. 4B and 4C are drawings showing a cooling step (S300) in an embodiment of the present invention. FIG. 9 is a drawing showing a flowchart of a method for controlling a thermocompression bonding head according to an embodiment of the present invention.

Referring to FIG. 2a, the bonding head (60) may include a rotation motor (61) that rotates the bonding head (60), a bellows (62) provided at the lower portion of the rotation motor (61), a pressure unit (63) provided at the lower portion of the bellows (62), a load control unit (64) provided at the lower portion of the pressure unit (63), and a bonding tool (66) mounted at the lower portion of the load control unit (64) and adapted to absorb a semiconductor chip (1). At this time, the bonding head (60) is provided so as to be able to be raised and lowered by a separately provided raising and lowering unit, and is provided so as to be able to move on the X-Y plane.

In addition, the bonding head (60) is provided with a bellows (62), a pressure part (63), and a load control part (64) inside the head body (65), and the head body (65) may further be provided with a pressure measuring part (63c) for measuring the position value of the movable member (63b) whose position is changed by the pressure part (63). In addition, the bonding head (60) may further be provided with a load cell (67) provided between the pressure part (63) and the load control part (64) for measuring and verifying the load of the pressure part (63).

At this time, the rotary motor (61), bellows (62), pressurizing unit (63), load cell (67), load control unit (64), and bonding tool (66) can be directly connected to each other.

The pressurizing unit (63) can be directly connected to the bonding tool (66) through the central axis. The pressurizing unit (63) can pressurize the bonding tool (66) with a preset pressurizing force from the control unit (90). Here, the preset pressurizing force can be a value arbitrarily set by the operator before the preparation stage. The pressurizing unit (63) can include a pressurizing body (63a) fixed to the head body (65) and a mover (63b) that moves up and down relative to the pressurizing body (63a) according to the operation (or pressurizing force) of the pressurizing body (63a). That is, as the position of the movable member (63b) changes by the pressurizing member (63), the pressurizing force applied to the bonding tool (66) may change, and the fact that the position value of the movable member (63b) of the pressurizing member (63) is maintained constant may mean that the pressurizing force applied to the bonding tool (66) is constant.

The pressurizing unit (63) may preferably be composed of a motor. The pressurizing unit (63) may be directly connected to the central axis of the load control unit (65) through the central axis. The pressurizing unit (63) may tension or contract the movable member (63b) according to the control from the control unit (90), and may perform a pressurizing force control that applies a certain level of pressure to the bonding tool (66) from the bonding head (60). Accordingly, a corresponding force may be applied to the bonding tool (66) according to a value input to the control unit (90). At this time, the force applied by the pressurizing unit (63) may be measured and verified by a load cell (67) provided at the lower portion of the pressurizing unit (63), and the force measured by the load cell (67) may be a force provided to the semiconductor chip (1) adsorbed on the bonding tool (66).

The load control unit (64) provided in the bonding head (60) is configured to control the load. The load control unit (64) can reduce the self-weight of the bonding head (60) by applying a force in a direction opposite to the self-weight of the bonding head (60), that is, in an upward direction (in the direction of the pressurizing unit (63)), and can increase the self-weight of the bonding head (60) by applying a force in the same direction as the self-weight of the bonding head (60), that is, in a downward direction (in the opposite direction of the pressurizing unit (63)). In addition, the self-weight of the bonding head (60) can be used as a load required for bonding without increasing or decreasing the self-weight. The load control unit (64) can include a load control main body (64a) directly connected to the bonding tool (66) and a load control moving unit (64b) that moves relative to the load control main body (64a) and rises and falls according to the operation of the load control main body (64a).

The bonding tool (66) can absorb a semiconductor chip (1). The bonding tool (66) is directly connected to the movable member (63b) of the pressurizing portion (63) and can rise and fall together with the rise and fall of the movable member (63b).

Accordingly, since the bonding tool (66) is directly connected to the actuator (63b) of the pressurizing portion (63), the pressurizing portion (63) can control the torque that controls the force applied to the bonding tool (66), and since the height of the bonding tool (66) also rises and falls along with the rise and fall of the actuator (63b), position control is possible.

Referring to FIGS. 2A to 4C and FIG. 9, the control method of the thermocompression bonding head includes: a preparation step in which the pressurizing portion (63) presses the bonding tool (66) with a preset pressing force; a contact step (S100) in which the bonding head (60) is lowered to bring the semiconductor chip (1) and the substrate (3) into contact with each other with the bump (2) therebetween; a thermocompression step (S200) in which the bonding head (60) presses the bump (2) with a preset bonding force to heat the bump (2); and a cooling step (S300) in which the bonding tool (66) is cooled to a predetermined temperature while raising the movable member (63b) of the bonding head (60) or the pressurizing portion (63) to a preset height when melting of the bump (2) is detected. After a predetermined period of time has elapsed and the thermal compression is completed, a rising step (S400) may be included for raising the bonding head (60) from the substrate (3).

Referring to Fig. 2a, the bonding head (60) is moved to the upper part of the substrate (3) to be bonded, and checks the alignment status of the substrate (3) to be bonded and the semiconductor chip (1) adsorbed on the bonding tool (66) using a slit vision (70), and then performs a process of correcting the misalignment angle according to the alignment status check result. To this end, the pressurizing unit (63) is set to a position mode so that the bonding tool (66) can be rotated at a desired angle.

When alignment for the bonding tool (66) is completed, a preparatory step may be performed in which the pressurizing member (63) presses the bonding tool (66) with a preset force as shown in FIG. 2b. In the preparatory step, the pressurizing member (63) is switched to the torque mode, and in order to press the bonding tool (66) with the preset pressing force, the pressurizing body (63a) may lower the movable member (63b) to lower the bonding tool (66). That is, the bonding tool (66) may move downward relative to the head body (65) as shown in FIG. 2a.

The bonding head (60) is lowered while the pressurizing part (63) presses the bonding tool (66) with a preset force. During the process of lowering the bonding head (60), the bonding tool (66) is lowered together, and a contact step (S100) can be performed in which the semiconductor chip (1) and the substrate (3) are brought into contact with each other via the bump (2).

Therefore, the contact step includes a bonding head lowering step. At this time, in the contact step (S100), since the pressure part (63) presses the bonding tool (66) with a preset force while the bonding head (60) is lowered, if the position value of the movable member (63b) of the preset pressure part (63) changes, it is determined that the semiconductor chip (1) adsorbed on the bonding tool (66) is in contact with the substrate (3), and if it is determined that the semiconductor chip (1) adsorbed on the bonding tool (66) is in contact with the substrate (3), the lowering of the bonding head (60) is stopped.

Referring to Fig. 3a, when the bonding head (60) is lowered, the bonding tool (66) mounted at the bottom of the bonding head (60) is also lowered. The bonding head (60) can be lowered until the semiconductor chip (1) absorbed by the bonding tool (66) comes into contact with the substrate (3) and the bump (2) therebetween. The bonding head (60) can be lowered while the pressure unit (63) presses the bonding tool (66) with a preset pressure. At this time, the bonding head (60) can be raised and lowered by the lifting and lowering unit.

The control unit (90) can detect the state of the bonding force applied to the semiconductor chip (1) while pressurizing the semiconductor chip (1) through the pressure measuring unit (63c). When the bonding head (60) descends and the semiconductor chip (1) comes into contact with the substrate (3), the bonding head (60) can no longer descend, so the reaction force of the semiconductor chip (1) is applied to the bonding tool (66), causing the movable member (63b) of the bonding tool (66) to rise. Accordingly, the movable member (63b) of the preset pressure unit (63), which has been maintained at a constant level, rises to a position value for determining whether or not there is contact, and when the position value of the movable member (63b) of the pressure unit (63) becomes the position value for determining whether or not there is contact, it is determined that the semiconductor chip (1) adsorbed on the bonding tool (66) has come into contact with the substrate (3), and the bonding head (60) can stop descending. When contact is detected, the heater provided inside the bonding tool (66) can be used to heat the semiconductor chip (1) and bump (2) to a predetermined temperature.

Next, a thermocompression step (S200) may be performed in which the bonding head (60) heats the bump (2) while pressing the bump (2) with a preset bonding force. Here, the thermocompression step (S200) may include an expansion detection step in which the movable member (63b) of the pressurizing portion (63) rises due to an expansion force of at least one of the bump (2), the semiconductor chip (1), and the substrate (3), thereby detecting a change in the preset bonding force by changing the position value of the movable member (63b) of the pressurizing portion (63); and a bonding head rising step in which the bonding head (60) rises and returns the changed bonding force to the preset bonding force so that the position value of the movable member (63b) of the pressurizing portion (63) is maintained constant.

That is, the present invention can perform thermal compression bonding by heating the bonding tool (66) to a predetermined temperature and pressurizing the semiconductor chip (1) while controlling the height of the bonding head (60) so that the position value of the actuator (63b) of the pressurizing portion (63) is maintained constant.

Specifically, referring to FIG. 3b, the bonding head (60) can pressurize and heat the semiconductor chip (1) and the bump (2) with a preset bonding force. At this time, at least one of the semiconductor chip (1), the bump (2), and the substrate (3) can expand due to the heat and apply an expansion force to the bonding tool (66). The bonding tool (66) and the movable member (63b) of the pressurizing portion (63) directly connected to the bonding tool (66) can rise by an expansion length (L1) due to the expansion force.

The above expansion length (L1) may mean the difference in height between the top of the semiconductor chip (1) based on Fig. 3b and the top of the semiconductor chip (1) based on Fig. 3a.

The expansion force can raise the bonding tool (66) and the movable member (63b) of the pressurizing member (63), and the expansion force can change the preset position value of the movable member (63b) of the pressurizing member (63). That is, the expansion force can change the bonding force that pressurizes with the preset force. The pressure measuring member (63c) can detect the change in the bonding force by measuring the changed relative height (L1) of the bonding tool (66).

That is, the changed bonding force can be detected by measuring the changed relative height (L1) of the bonding tool (66) due to the expansion force.

Referring to FIG. 3c, the bonding head (60) can be raised so that the position value of the actuator (63b) of the pressurizing portion (63) is maintained constant, and the changed bonding force can be returned to the preset bonding force. Since the rise of the bonding head (60) is accompanied by the rise of the pressurizing portion (63), the bonding force applied by the bonding head (60) to the semiconductor chip (1) and the bump (2) can be adjusted by raising the pressurizing portion (63). At this time, the bonding head (60) can be raised by a height (L2) corresponding to the changed relative height (L1) of the bonding tool (66). At this time, the length of L1 and the length of L2 can be the same, and are not necessarily limited thereto.

The above height (L2) may mean the difference between the height of the top of the rotation motor (61) based on Fig. 3c and the height of the top of the rotation motor (61) based on Fig. 3b.

At this time, FIGS. 3b and 3c are performed sequentially, and the height of the bonding head (60) is controlled while following the change in height of the bonding tool (66) so that the position value of the actuator (63b) of the pressurizing portion (63) is maintained constant while pressurizing the semiconductor chip (1).

Referring to FIG. 4a, at least one of the semiconductor chip (1), the bump (2), and the substrate (3) may be additionally expanded by heat to apply additional expansion force to the bonding tool (66). The bonding tool (66) and the movable member (63b) of the pressurizing portion (63) may be raised by the expansion length (L3) due to the additional expansion force.

The above expansion length (L3) may mean the difference in height between the top of the semiconductor chip (1) based on Fig. 4a and the top of the semiconductor chip (1) based on Fig. 3c.

The additional expansion force can raise the bonding tool (66) and the movable member (63b) of the pressurizing member (63). The pressurizing measuring member (63c) can detect a change in the bonding force by measuring the position value of the movable member (63b) of the pressurizing member (63), and the load cell (67) can detect a change in the bonding force by measuring a change in the force received by the bonding tool (66).

That is, the changed bonding force can be detected by measuring the changed relative height (L3) of the bonding tool (66) due to the additional expansion force.

Referring to FIG. 4A, the bonding head (60) can be raised to return the changed bonding force to the preset bonding force. Since the raising of the bonding head (60) is accompanied by the raising of the pressure portion (63), the bonding force applied by the bonding head (60) to the semiconductor chip (1) and the bump (2) can be adjusted by raising the pressure portion (63). At this time, the bonding head (60) can be raised by a height (L4) corresponding to the changed relative height (L3) of the bonding tool (66). At this time, the length of L3 and the length of L4 can be the same, and are not necessarily limited thereto.

The above height (L4) may mean the difference between the height of the top of the rotation motor (61) based on Fig. 4a and the height of the top of the rotation motor (61) based on Fig. 3c.

For convenience of explanation, the expansion force and additional expansion force are explained separately, but the semiconductor chip (1), bump (2), and substrate (3) continuously expand in the thermal compression step (S200), and the bonding head (60) can gradually rise in real time in response to the expansion force or the change in the height of the bonding tool (66).

In the thermal compression step (S200), the bonding head (60) can detect the expansion of at least one of the semiconductor chip (1), the bump (2), and the substrate (3) and rise to heat the bump (2) while continuously maintaining a preset bonding force. At this time, the pressure measuring unit (63c) can detect the change in height of the bonding tool (66) due to the expansion of at least one of the semiconductor chip (1), the bump (2), and the substrate (3).

Conventional bonding heads pressurize and heat bumps (2) by controlling the height over time based on the profile of a sample material prepared in advance, and therefore cannot respond to various materials and types of semiconductor chips (1), bumps (2), and substrates (3), and when there is a height difference between individual semiconductor chips (1) due to reasons such as differences in the size of warpage or solder balls, non-bonding and short-circuiting problems may occur.

In an embodiment of the present invention, the bonding head (60) detects a change in the height of the bonding tool (66) due to expansion of at least one of the semiconductor chip (1), the bump (2), and the substrate (3), and rises so that the position value of the movable member (63b) of the pressurizing portion (63) is maintained constant, thereby enabling the bonding head to respond to various materials having different thermal characteristics and various types of semiconductor chips (1), bumps (2), and substrates (3), thereby preventing non-bonding and short-circuiting problems of the semiconductor chip (1).

Next, when it is determined that the bump (2) of the semiconductor chip (1) has melted, a cooling step (S300) may be performed in which the height of the movable member (63b) of the bonding head (60) or the pressurizing member (63) is maintained or raised to a preset height, and the molten bump (2a) is cooled to a preset temperature.

Here, the cooling step (S300) may include a melting detection step for detecting melting of the bump (2); and a maintenance step for maintaining the height of the bonding head (60) or raising the bonding head (60) to offset the lowering of the bonding tool (66) due to melting of the bump (2) and cooling the molten bump (2a) to a predetermined temperature while maintaining the preset height.

In addition, the cooling step (S300) may include a melting detection step for detecting melting of the bump (2); and a maintenance step for maintaining or raising the movable member (63b) of the pressurizing portion (63) so that the bonding tool (66) maintains or raises the height at the time of melting detection, thereby cooling the molten bump (2a) to a predetermined temperature while maintaining it at the preset height.

The bump (2) can melt when the thermocompression state continues and reaches the melting point. Detecting the melting of the bump (2) can be seen as detecting that the bump (2) has reached the melting point.

The bonding head (60) or the bonding tool (66) can be cooled while maintaining the height at which melting is detected so that the molten bump (2a) is not crushed, or while being raised to a preset height. The preset height can be set in advance. If the preset height is the height at which melting is detected, cooling can be performed while maintaining the height of the bonding head (60) without raising the bonding head (60) or the movable member (63b) of the pressurizing member (63), or while maintaining the height of the movable member (63b) of the pressurizing member (63).

If the height for forming the bump (2) is low due to the characteristics of the material as required, the preset height may be lower than the height at which melting is detected, and in this case, it is not excluded that the bonding head (60) is maintained or the movable member (63b) of the pressurizing portion (63) is slightly lowered without raising it. The preset height may be the height of the bump (2) or the distance between the semiconductor chip (1) and the substrate (3) when the semiconductor chip (1) is bonded to the substrate (3), and may be referred to as the molding height of the bump (2) at which the molten bump (2) is cooled, and is preset.

Accordingly, depending on the preset height, the height of the bonding head (60) (or the height of the movable member (63b) of the pressurizing portion (63)) at which melting is detected may be maintained, the height of the bonding head (60) (or the height of the movable member (63b) of the pressurizing portion (63)) may be increased, or the height of the bonding head (60) (or the height of the movable member (63b) of the pressurizing portion (63)) may be decreased. However, it is preferable to maintain or increase the height of the bonding head (60) (or the height of the movable member (63b) of the pressurizing portion (63)) at which melting is detected.

According to the control method of the thermocompression bonding head in the present invention, it is possible to automatically determine that the bump (2) of the semiconductor chip (1) is melted, and at this time, the detection of the melting point can be determined as the melting point when the bonding head (60) gradually rises due to the expansion of at least one of the semiconductor chip (1), the bump (2), and the substrate (3) and then the height of the bonding head (60) no longer rises, or when the movement direction of the bonding head (60) changes from the rising direction to the descending direction.

The bonding head (60) rises while following the change in height of the bonding tool (66) so that the position value of the movable member (63b) of the pressurizing portion (63) is kept constant due to the expansion of at least one of the semiconductor chip (1), the bump (2), and the substrate (3). In particular, just before melting, at least one of the semiconductor chip (1), the bump (2), and the substrate (3) is expanded to the maximum, and when the melting point is reached in the state of maximum expansion, the bump (2) is melted and the bonding tool (66) is lowered. Since the bonding head (60) also follows to keep the position value of the movable member (63b) of the pressurizing portion (63) constant, it is lowered together when the bonding tool (66) is lowered.

The bonding head (60) is provided with a separate height measuring unit for measuring the height of the bonding head (60) in the rising/falling section. The bonding head (60) height measuring unit detects that the height of the bonding head (60) no longer rises, which can be determined as the melting point. The bonding head (60), which was rising, is lowered by following the position value of the movable member (63b) of the pressurizing section (63), which can be determined as the melting point. In addition, the point at which the slope of the height change graph of the bonding head (60) becomes 0 can be determined as the melting point of the bonding head (60).

However, when determining the melting point using the above method, if a situation occurs in which the melting point is determined to be due to external factors such as vibration, it may result in bonding failure. Therefore, in order to solve the problem of incorrectly determining the melting point, it is determined whether at least one condition among the preset heating temperature and the preset heating time is met, and if both are met, it can be determined that it is the melting point of the bump (2).

The bonding head (60) can detect the melting point of the bump (2) when at least one of the preset heating temperature (first condition) and the preset minimum heating time of the bump (2) is satisfied.

The first condition, the preset heating temperature, can be set in advance as a temperature for heating the bump (2), and when the bonding tool (66) is heated to a predetermined temperature, if the temperature of the bonding tool (66) does not reach the preset heating temperature, it can be determined that the bump (2) has not melted, and the melting point of the bump (2) can be detected only when the preset heating temperature is reached.

The second condition, the preset minimum heating time of the bump (2), can be set in advance and can vary depending on the material or type of the bump (2). That is, when the semiconductor chip (1) absorbed by the bonding tool (66) comes into contact with the substrate (3), the bonding tool (66) is heated to a predetermined temperature. If the preset minimum heating time of the bonding tool (66) is not met, it can be determined that the bump (2) has not melted, and when the preset minimum heating time is met, the melting point of the bump (2) can be detected.

At this time, the bonding head (60) can recognize that the bump (2) reaches the melting point when at least one of the first condition and the second condition is satisfied. For example, the bonding head (60) may recognize that the bump (2) reaches the melting point when only the first condition is satisfied, but the bonding head (60) can recognize that the bump (2) reaches the melting point when both the first condition and the second condition are satisfied.

If the bump (2) reaches the melting point and melts, the force supporting the bonding tool (66) may be lost. The bonding tool (66) may be lowered momentarily to crush the melted bump (2a), thereby causing a short circuit in the semiconductor chip (1). In order to solve this problem, in the present invention, when the movable member (63b) of the pressurizing member (63) and the bonding tool (66) are directly connected, if it is determined that the bump (2) of the semiconductor chip (1) has melted, the pressurizing member (63) is switched from the torque mode to the position mode so that the position of the movable member (63b) of the pressurizing member (63) does not change, and the height of the bonding head (60) is maintained or the bonding head (60) is raised to a preset height. At this time, the position mode of the pressurizing unit (63) is a mode that maintains the pressurizing unit (63) at the current position, and by raising the bonding head (60) to a preset height, the position of the bonding tool (66) is also raised so that the semiconductor chip (1) and the substrate (3) can be maintained at a preset interval. At this time, the pressurizing unit (63) can hold the position of the mover (63b) at the point in time when melting is determined to be occurring in order to prevent further falling due to melting of the bump (2), or can adjust the position of the mover (63b) to a preset input value.

For reference, the case where the height of the bonding head (60) is maintained when melting is detected is not separately illustrated.

Referring to Fig. 4b, when the bonding head (60) detects melting of the bump (2), it can rise to offset the lowering of the bonding tool (66) due to melting of the bump (2). As the bonding head (60) rises, the bonding tool (66) can rise together to maintain the melted bump (2a) at a preset height. Accordingly, the bonding head (60) can cool the bonding tool (66) to a preset temperature while it is raised to the preset height to cool and form the bump (2).

Referring to Fig. 4c, when the bonding head (60) detects melting of the bump (2), the bonding tool (66) is cooled to a predetermined temperature while the pressurizing portion (63) is switched to the position mode. That is, when melting of the bump (2) is detected, the bonding tool (66) can maintain the position of the actuator (63b) at the time when melting is detected, or raise the actuator (63b) to a preset height to maintain the molten bump (2a) at the preset height. As a result, the bonding head (60) can cool the bump (2) to the preset height.

For reference, since the movable member (63b) of the pressurizing portion (63) and the bonding tool (66) are directly connected, the pressurizing portion (63) can be switched to the position mode to maintain the position of the movable member (63b) of the pressurizing portion (63) so that the position of the movable member (63b) of the pressurizing portion (63) does not change, or the movable member (63b) of the pressurizing portion (63) can be raised to a preset height to raise the bonding tool (66) together with the rise of the movable member (63b).

At this time, the position mode of the pressurizing unit (63) is a mode in which the position of the movable member (63b) of the pressurizing unit (63) is positioned at a set position, and the preset position value, i.e., the height, is input as a value for raising the position of the movable member (63b) to make the gap between the semiconductor chip (1) and the substrate (3) a constant height. If the position of the movable member (63b) at the time of determining melting is a height that can create an appropriate gap between the semiconductor chip (1) and the substrate (3), the movable member (63b) may not rise but may maintain the current position.

Accordingly, the bump (2) can be cooled and formed by cooling the bonding tool (66) to a predetermined temperature while raising or maintaining the movable member (63b) of the pressurizing portion (63) to a preset height without raising the bonding head (60).

If the preset position, i.e., the height set in advance, is the height at which melting is detected, cooling may be performed without raising the actuator (63b) of the pressurizing portion (63) and while maintaining the height of the actuator (63b) of the pressurizing portion (63) at which melting is detected.

Depending on the characteristics of the material, if the height for forming the bump (2) is low, the preset height may be lower than the height at which melting is detected, and in this case, it is not excluded that the movable member (63b) of the pressurizing member (63) is maintained or slightly lowered without being raised.

For reference, in this case, in the mode of raising the bonding head (60) to a preset height or in the mode of raising the actuator (63b) of the pressurizing portion (63) to a preset height, each preset height can be managed as the same value, and in this case, the preset height can be the desired gap between the substrate (3) and the semiconductor chip (1) with the bump (2) in between.

If the preset height is the same as the height at which melting is detected as described above, the bonding tool (66) may be cooled and forming may be performed while maintaining the height of the movable member (63b) of the pressurizing portion (63) or the height of the bonding head (60) at the time when melting is detected, or if the preset height is higher than the height at which melting is detected, the bonding tool (66) may be cooled and forming may be performed while raising the height of the movable member (63b) of the pressurizing portion (63) or the height of the bonding head (60) to the preset height at preset intervals.

Afterwards, the bonding head (60) is cooled to a predetermined temperature for a predetermined time, and when the thermal compression is completed, the bonding head (60) is raised from the substrate (3), and the bonding head (60) can be moved to absorb the semiconductor chip (1) to be subsequently bonded.

The present invention can be performed in a manner in which, when melting of a bump (2) of a semiconductor chip (1) is detected, the bonding head (60) rises and the bonding tool (66) rises together, or in a manner in which, when the movable member (63b) of the pressurizing member (63) rises, the bonding tool (66) itself, which is directly connected to the movable member (63b) of the pressurizing member (63), rises. When the bonding head (60) rises, the elevating/lowering member can move the bonding head (60) upward. In contrast, when the bonding tool (66) rises, the pressurizing member (63) can move the bonding tool (66) upward relative to the head body (65).

Since the conventional bonding head (60) uniformly applied height control over time by predicting the melting of the bump (2) based on the height change profile of the bonding head (60) according to the melting of the bump (2) prepared in advance, it could not respond to bumps (2) of various materials and shapes, and even if the semiconductor chips (1) belong to the same wafer, the melting profile of the bump (2) was different for each semiconductor chip (1), which could cause problems such as non-bonding and short circuiting of the semiconductor chips (1).

In an embodiment of the present invention, the bonding head (60) controls the height of the bonding head (60) so that the position value of the movable member (63b) of the pressurizing portion (63) is maintained constant when a preset force is applied by following the change in the height of the bonding tool (66), and automatically detects melting of the bump (2) through the change in the height of the bonding head (60), thereby maintaining the height of the bonding head (60) when melting is detected or raising the bonding head (60) to the preset height, or by maintaining the height of the movable member (63b) of the pressurizing portion (63) or raising the movable member (63b) of the pressurizing portion (63) to the preset height so that the bonding tool (66) is maintained or the bonding tool (66) is raised when melting is detected, thereby enabling the ability to respond to bumps (2) of various materials and shapes, thereby preventing non-adhesion and short-circuiting problems of the semiconductor chip (1).

Below, a method for controlling the height of a bonding device (BD) and a thermocompression bonding head (60) according to another embodiment of the present invention will be described.

Parts that can be applied in the same manner as the above-described embodiment of the present invention will be omitted for description.

According to the embodiments of FIGS. 2A to 4C, the movable member (63b) of the pressurizing member (63) and the bonding tool (66) are directly connected, so that when the movable member (63b) of the pressurizing member (63) rises, the bonding tool (66) also rises, so that the position of the bonding tool (66) can be controlled through the movable member (63b) of the pressurizing member (63). Accordingly, the pressurizing member (63) can implement not only the function of a torque mode that pressurizes the bonding tool (66) with a preset force, but also the function of a position mode that can control the position of the bonding tool (66).

On the other hand, according to the embodiments of FIGS. 5a to 7c, since the actuator (63b) of the pressurizing portion (63) and the bonding tool (66) are spaced apart, the pressurizing portion (63) can perform the function of a torque mode that pressurizes the bonding tool (66) with a preset force, but cannot control the position of the bonding tool (66). A method of controlling the thermocompression bonding head in this case will be described in detail with reference to the drawings.

FIG. 5a and FIG. 5b are drawings showing a preparation step in an embodiment of the present invention. FIG. 6a is a drawing showing a contact step (S100) in an embodiment of the present invention. FIG. 6b, FIG. 7a and FIG. 7b are drawings showing a thermocompression step (S200) in an embodiment of the present invention. FIG. 7c is a drawing showing a cooling step (S300) in an embodiment of the present invention.

Referring to FIG. 5, the bonding head (60) may include a head body (65) that is connected to a lifting/lowering unit and moves up and down in the lifting direction by the lifting/lowering unit, a pressure unit (63) provided on an inner upper surface of the head body (65), a load control unit (64) provided on an inner lower surface of the head body (65), and a bonding tool (66) that absorbs a semiconductor chip (1). In addition, the bonding head (60) may further include a pressure measuring unit (63c) that measures a position value of a mover (63b) of the pressure unit (63). In addition, the bonding head (60) may further include a load cell (67) provided on a lower portion of the pressure unit (63).

The pressurizing part (63) and the load cell (67) can come into contact with each other and the bonding tool (66) depending on the operating state of the pressurizing part (63), but since they are not directly connected, they can move up and down freely.

The pressurizing member (63) may be spaced apart from the bonding tool (66) and may come into contact with the bonding tool (66) to pressurize the bonding tool (66). The contact between the pressurizing member (63) and the bonding tool (66) includes the pressurizing member (63) and the bonding tool (66) coming into contact with each other with the load cell (67) therebetween. The pressurizing member (63) may pressurize the bonding tool (66) with a pressing force preset from the control unit (90). The pressurizing member (63) may include a pressurizing body (63a) fixed to the inner upper surface of the head body (65) and a mover (63b) that moves upward and downward relative to the pressurizing body (63a) according to the operation (or pressing force) of the pressurizing body (63a).

The load control unit (64) can reduce the dead weight of the bonding tool (66) by applying force in an upward direction to the horizontal portion of the bonding tool (66). The load control unit (64) can reduce the dead weight of the bonding tool (66) by applying force in an upward direction (in the direction of the pressurizing unit (63)).

The load control unit (64) may include a load control body (64a) fixed to the head body (65) and a load control moving unit (64b) that moves up and down relative to the load control body (64a) according to the operation of the load control body (64a).

The bonding tool (66) can absorb the semiconductor chip (1). The bonding tool (66) is provided so as to be spaced apart from and in contact with the pressurizing portion (63), and when the pressurizing portion (63) is set to the torque mode, the bonding tool (66) can descend together with the descent of the actuator (63b) by receiving a preset force. The bonding tool (66) can receive force from the semiconductor chip (1) and the bump (2), or rise together with the rise of the head body (65).

Referring to FIGS. 5A to 7C and FIG. 9, the control method of the thermocompression bonding head may include a preparation step in which the pressurizing unit (63) presses the bonding tool (66) with a preset pressing force; a contact step (S100) in which the bonding head (60) is lowered to bring the semiconductor chip (1) and the substrate (3) into contact with each other with the bump (2) therebetween; a thermocompression step (S200) in which the bonding head (60) presses the bump (2) with a preset bonding force to heat the bump (2); and a cooling step (S300) in which, when it is determined that the bump (2) of the semiconductor chip (1) has melted, the bonding tool (66) is cooled to a predetermined temperature while raising the bonding head (60) to a preset height to cool the molten bump (2a) to a preset height.

Referring to Fig. 5a, the load control unit (64) is in the off state and the weight of the bonding tool (66) is applied to the semiconductor chip (1) when lowered in the current state.

In order to bond a semiconductor chip (1) with a load smaller than the weight of the bonding tool (66), a preparatory step may be performed in which the load control unit (64) is operated as illustrated in FIG. 5b to raise the load control moving unit (64b) and the pressurizing unit (63) pressurizes the bonding tool (66) with a preset pressing force. In the preparatory step, the pressurizing unit (63) is set to the torque mode, and in order to pressurize the bonding tool (66) with the preset pressing force, the mover (63b) of the pressurizing unit (63) is lowered and the bonding tool (66) is raised by the load control unit (64), and the bonding tool (66) is pressed with the preset pressing force by the mover (63b) of the pressurizing unit (63) and the load control unit (64).

Referring to Fig. 5b, the pressurizing part (63) can pressurize the bonding tool (66) with a preset pressurizing force. The pressurizing body (63a) can lower the bonding tool (66) while the movable member (63b) is in contact with the bonding tool (66). That is, the bonding tool (66) can move relative to the head body (65).

Next, the bonding head (60) is lowered while the bonding tool (66) is pressed with a preset force. During the process of lowering the bonding head (60), the bonding tool (66) is lowered together, and a contact step (S100) can be performed in which the semiconductor chip (1) and the substrate (3) are brought into contact with each other via the bump (2).

Here, the contact step (S100) includes a bonding head lowering step. In the contact step (S100), since the pressure member (63) presses the bonding tool (66) with a preset force while the bonding head (60) is lowered, if the position value of the actuator (63b) of the preset pressure member (63) changes, it is determined that the semiconductor chip (1) adsorbed on the bonding tool (66) is in contact with the substrate (3), and if it is determined that the semiconductor chip (1) adsorbed on the bonding tool (66) is in contact with the substrate (3), the lowering of the bonding head (60) is stopped.

The position value can be confirmed by detecting a change in the position of the movable member (63b) of the pressurizing portion (63), or the position value of the movable member (63b) can be confirmed by detecting a change in the position of the bonding tool (66).

Referring to Fig. 6a, the bonding head (60) can be lowered along with the bonding tool (66). The bonding head (60) can be lowered until the semiconductor chip (1) adsorbed on the bonding tool (66) comes into contact with the substrate (3) with the bump (2) in between. The bonding head (60) can be lowered while the pressing part (63) presses the bonding tool (66) with a preset pressing force. At this time, the bonding head (60) can be raised and lowered by the raising and lowering part.

Referring to FIG. 6b, the bonding head (60) can be lowered until the height of the pressure measuring unit (63c) becomes a preset height. The control unit (90) can detect a state in which a preset bonding force is applied to the bump (2) through the load cell (67) and/or the pressure measuring unit (63c). When the pressure measuring unit (63c) becomes the preset height, the bonding head (60) can stop lowering. Thereafter, the bonding tool (66) can apply heat to the semiconductor chip (1) and the bump (2), and during the heating, the pressure measuring unit (63c) can maintain the height of the bonding tool (66) constant so that the bonding head (60) can heat the bump (2) while pressing the bump (2) with the preset bonding force, thereby performing a thermal compression step (S200). Here, the thermal compression step (S200) may include an expansion detection step for detecting a change in the preset bonding force due to an expansion force of at least one of the bump (2), the semiconductor chip (1) and the substrate (3); and a head elevation step for raising the bonding head (60) to return the changed bonding force to the preset bonding force.

Referring to Fig. 7a, the bonding head (60) can pressurize and heat the semiconductor chip (1) and bump (2) with a preset bonding force. The bonding tool (66) and/or the mover (63b) can rise by the expansion length (L5) due to the expansion force.

The above expansion length (L5) may mean the difference in height between the top of the semiconductor chip (1) based on Fig. 7a and the top of the semiconductor chip (1) based on Fig. 6b.

The pressure measuring unit (63c) can detect a change in bonding force by measuring the position value of the actuator (63b) of the pressure unit (63), and the load cell (67) can detect a change in bonding force by measuring a change in force received by the bonding tool (66).

That is, the changed bonding force can be detected by measuring the changed relative height (L5) of the bonding tool (66) due to the expansion force. The relative change between the head body (65) and the bonding tool (66) can be measured by measuring the position value of the movable member (63b) of the pressurizing portion (63) from the change in the scale displayed on the bonding tool (66).

The bonding head (60) can be raised to return the changed bonding force to the preset bonding force. Since the rising of the bonding head (60) is accompanied by the rising of the bonding tool (66), the bonding force applied by the bonding head (60) to the semiconductor chip (1) and the bump (2) can be adjusted by raising the bonding tool (66). At this time, the bonding head (60) can be raised by a height (L6) corresponding to the changed relative height (L5) of the bonding tool (66). At this time, the length of L5 and the length of L6 can be the same, and are not necessarily limited thereto.

The above height (L6) may mean the difference between the height of the top of the head body (65) based on Fig. 7a and the height of the top of the head body (65) based on Fig. 6b.

Referring to FIG. 7b, at least one of the semiconductor chip (1), the bump (2), and the substrate (3) may be additionally expanded by heat to apply additional expansion force to the bonding tool (66). The bonding tool (66) and/or the movable member (63b) of the pressurizing portion (63) may be raised by the expansion length (L7) due to the additional expansion force. At this time, the bonding head (60) may be raised by a height (L8) corresponding to the changed relative height (L7) of the bonding tool (66). At this time, the length of L7 and the length of L8 may be the same, but are not necessarily limited thereto.

The above expansion length (L7) may mean the difference in height between the top of the semiconductor chip (1) based on Fig. 7b and the top of the semiconductor chip (1) based on Fig. 7a.

The above height (L8) may mean the difference between the height of the top of the head body (65) based on Fig. 7b and the height of the top of the head body (65) based on Fig. 7a.

The semiconductor chip (1), bump (2), and substrate (3) continuously expand in the thermal compression step (S200), and the bonding head (60) can rise in real time in response to the expansion force or the change in the height of the bonding tool (66).

That is, the heat compression is performed by controlling the height of the bonding head (60) by following the change in height of the bonding tool (66) so that the position value of the actuator (63b) of the pressurizing portion (63) is maintained constant when a preset force is applied.

In an embodiment of the present invention, the bonding head (60) detects a change in the height of the bonding tool (66) due to expansion of at least one of the semiconductor chip (1), the bump (2), and the substrate (3) and rises by itself, thereby being able to respond to various materials with different thermal characteristics and various types of semiconductor chips (1), bumps (2), and substrates (3), thereby preventing non-bonding and short-circuiting problems of the semiconductor chip (1).

The height of the bonding head (60) gradually increases due to the expansion of at least one of the semiconductor chip (1), the bump (2), and the substrate (3), and when the height of the bonding head (60) no longer increases after rising, or when the movement direction of the bonding head (60) changes from an upward direction to a downward direction, or when the slope of the height change graph of the bonding head (60) becomes 0, the melting point can be automatically detected.

Of course, in order to solve the problem of misjudgment in the process of automatically detecting the melting point at this time, it is possible to determine that the melting point of the bump (2) is met by determining whether one or more conditions among the preset heating temperature and the preset heating time are met together.

When it is determined that the bump (2) of the semiconductor chip (1) has melted, a cooling step (S300) can be performed in which the bonding head (60) is raised to a preset height and the bonding tool (66) is cooled to a preset temperature to form the melted bump (2a) to a preset height.

For reference, if it is determined that the bump (2) of the semiconductor chip (1) has melted, a cooling step (S300) may be performed to cool the bonding tool (66) to a predetermined temperature while maintaining the height of the bonding head (60) to form the melted bump (2a) to a preset height, but this is not shown separately.

In an embodiment of the present invention, the cooling step (S300) may include a melting detection step for detecting melting of the bump (2); and a maintenance step for raising the bonding head (60) to offset the lowering of the bonding tool (66) due to melting of the bump (2) and cool the molten bump (2a) to the preset height.

Referring to Fig. 7c, when the bonding head (60) detects melting of the bump (2), it can rise to offset the lowering of the bonding tool (66) due to melting of the bump (2). At this time, the pressurizing unit (63) raises the bonding head (60) to a preset height while maintaining the torque mode for pressurizing the bonding tool (66). As the bonding head (60) rises, the bonding tool (66) can rise together to maintain the melted bump (2a) at the preset height. As a result, the bonding head (60) can cool the bump (2) to the preset height.

After the bonding head (60) is cooled to a predetermined temperature for a predetermined time and the thermal compression is completed, the bonding head (60) is raised from the substrate (3), and the bonding head (60) can be moved to absorb the semiconductor chip (1) to be subsequently bonded.

For reference, when the bonding head (60) detects melting of the bump (2), the height of the bonding head (60) can be maintained to offset the lowering of the bonding tool (66) due to melting of the bump (2). At this time, the bump (2) can be cooled while maintaining the position so that the height of the movable member (63b) of the pressurizing portion (63) does not change.

In an embodiment of the present invention, the bonding head (60) controls the height of the bonding head (60) so that the position value of the movable member (63b) of the pressurizing portion (63) is maintained constant by following the height change of the bonding tool (66) while the bonding tool (66) pressurizes the semiconductor chip (1), and the melting of the bump (2) is detected through the controlled height change of the bonding head (60), and the bonding head (60) is raised to prevent collapse during the melting process of the bump (2), so that it can respond to bumps (2) of various materials and shapes, thereby preventing non-bonding and short-circuiting problems of the semiconductor chip (1).

For reference, in the control method of the thermocompression bonding head according to another embodiment of the present invention, since the movable member (63b) of the pressurizing member (63) and the bonding tool (66) are spaced apart from each other, even if the movable member (63b) of the pressurizing member (63) is raised to a preset height, the bonding tool (66) cannot be raised, so the bonding head (60) has no choice but to be raised.

Hereinafter, the melting point in the control method of the thermocompression bonding head according to an embodiment of the present invention will be examined.

FIG. 8 is a drawing showing the height of the movable member (63b) of the pressurizing portion (63) and the height of the bonding head (60) when the control method of the thermocompression bonding head (60) according to an embodiment of the present invention is performed.

Referring to Fig. 8, it can be seen that 'expansion' of bumps (2), etc., occurs in the thermal compression step (S200). Here, since the 'bonding head height' is measured based on the scale, the decline in the graph illustrated in Fig. 8 means the rise of the bonding head (60). The bonding head height measuring unit is mounted on the bonding head elevating/lowering unit and is not separately indicated in the drawing. The "movable member (63b) height of the pressurizing unit (63)" means the position value of the movable member (63b) of the pressurizing unit (63).

Referring to Fig. 8, the height of the bonding head (60) is controlled so that the position value of the actuator (63b) of the pressurizing portion (63) is kept constant during the 'expansion stage', so that the height of the bonding head (60) gradually rises during expansion.

Fig. 8 is an example for explanation of the height of the bonding head (60) when following the height of the movable part (63b). The graph may appear in different forms depending on variables such as the detection speed of the height measuring part, the operation speed of the control part (90), and the responsiveness of various components.

The bonding tool (66) receives an expansion force (rising force) due to the expansion of at least one of the semiconductor chip (1), the bump (2), and the substrate (3), but the height of the bonding tool (66) can be maintained while raising the bonding head (60). That is, the height of the bonding head (60) rises in accordance with the change in the height of the bonding tool (66) so that the position value of the movable member (63b) of the pressurizing portion (63) is maintained constant during expansion.

Accordingly, the height measured by the pressure measuring unit (63c) can be maintained constant. Accordingly, the height of the bonding head (60) and the bonding tool (66) increases together in response to the expanded height of at least one of the semiconductor chip (1), the bump (2), and the substrate (3), while the position value of the actuator (63b) is maintained constant, so that a uniform bonding pressure can be applied to the bump (2) by the pressure unit (63).

In Fig. 8, when transitioning from 'expansion' to 'melting', the lowest point (MP) of the 'bonding head height' may mean the melting point (MP) of the bump (2). At this time, the height change slope of the bonding head (60) is the point where it becomes 0, and the bonding head (60) gradually rises and then no longer rises in height. In addition, this point is also the point where the movement direction of the bonding head (60) changes from an upward direction to a downward direction.

Accordingly, the present invention performs thermal compression bonding while controlling the height of the bonding head (60) so that the position value of the actuator (63b) of the pressurizing portion (63) is kept constant, and automatically detects the melting of the bump (2) of the semiconductor chip (1) through the height of the bonding head (60) as described above.

That is, the bonding head (60) automatically recognizes that the bump (2) has reached the melting point by using the change in height of the bonding head (60) due to melting of the bump (2) as an indicator, and maintains the height of the movable member (63b) of the bonding head (60) or the pressurizing portion (63) or raises it to a preset height to manage the gap between the semiconductor chip (1) and the substrate (3), thereby preventing the collapse of the molten bump (2). As a result, it is possible to cope with various materials having different thermal characteristics and various types of semiconductor chips (1), bumps (2), and substrates (3), thereby achieving the effect of preventing non-adhesion and short-circuiting of the semiconductor chip (1).

Accordingly, the present invention can automatically detect the melting point of the bump (2) for each individual semiconductor chip (1) regardless of the type of the semiconductor chip (1), the type of the wafer, etc., and control the height of the bonding head (60) in real time, and by following the change in the height of the bonding head (60) according to the melting of the bump (2) of each semiconductor chip (1) actually bonded and maintaining or raising the position of the bonding tool (66) to have the same mounting height after detecting the melting point, damage and short circuit of the semiconductor chip (1) can be prevented, thereby ensuring bonding quality.

As described above, the present invention has been described with reference to preferred embodiments thereof; however, it will be understood by those skilled in the art that various modifications or variations may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

BD: Thermocompression bonding device
1: Semiconductor chip
2 : Bump
3: Substrate
10: Flipover Picker
20: Die Picker
30: Dipping plate
40: Up-Looking Vision
50 : Die Block
60 : Bonding head
61 : Rotary motor
62 : Bellows
63 : Pressurized part
63b : Operator
63c: Pressure measuring section
64: Load control unit
65 : Head body
66 : Bonding tool
67 : Load cell
70 : Slit Vision
90 : Control Unit
100 : Particle Vision

Claims (9)

In a control method of a thermal compression bonding head that applies heat while pressing a semiconductor chip having a bump formed on the lower surface to a substrate,
(a) a step of lowering the bonding head while the bonding tool, which has absorbed the semiconductor chip, moves to the upper part of the substrate and the pressure part presses the bonding tool with a preset force;
(b) a step of performing thermal compression bonding while controlling the height of the bonding head so that when it is determined that the semiconductor chip absorbed by the bonding tool is in contact with the substrate, the lowering of the bonding head is stopped, the bonding tool is heated to a predetermined temperature and the semiconductor chip is pressed, and the position value of the pressurizing part is kept constant when the preset force is applied by following the change in the height of the bonding tool;
(c) a step of cooling the bonding tool to a predetermined temperature while maintaining the height of the bonding head or raising the bonding head to a preset height when it is determined that the bump of the semiconductor chip has melted; and
(d) A method for controlling a thermocompression bonding head, comprising the step of raising the bonding head from the substrate when thermocompression bonding is completed after a predetermined period of time has elapsed. In a control method of a thermal compression bonding head that applies heat while pressing a semiconductor chip having a bump formed on the lower surface to a substrate,
(a) a step of lowering the bonding head while the bonding tool, which has absorbed the semiconductor chip, moves to the upper part of the substrate and the pressure part presses the bonding tool with a preset force;
(b) a step of performing thermal compression bonding while controlling the height of the bonding head so that when it is determined that the semiconductor chip absorbed by the bonding tool is in contact with the substrate, the lowering of the bonding head is stopped, the bonding tool is heated to a predetermined temperature and the semiconductor chip is pressed, and the position value of the pressurizing part is kept constant when the preset force is applied by following the change in the height of the bonding tool;
(c) a step of cooling the bonding tool to a predetermined temperature while switching the pressurizing part to the position mode when it is determined that the bump of the semiconductor chip has melted; and
(d) A method for controlling a thermocompression bonding head, comprising the step of raising the bonding head from the substrate when thermocompression bonding is completed after a predetermined period of time has elapsed. In paragraph 1 or 2,
In step (b) above,
A control method for a thermal compression bonding head, characterized in that when the position value of the actuator of the pressurizing part changes during the process of lowering the bonding head, it is determined that the semiconductor chip absorbed by the bonding tool has come into contact with the substrate. In paragraph 1 or 2,
In step (b) above,
A control method for a thermocompression bonding head, characterized in that the melting point is determined when the bonding head gradually rises and then no longer rises in height or when the movement direction of the bonding head changes from an upward direction to a downward direction. In paragraph 4,
A control method for a thermocompression bonding head, characterized in that the melting point of the bump is determined when at least one condition among a preset heating temperature and a preset heating time of the bonding head is satisfied together. In the first paragraph,
In step (c) above,
A control method for a thermocompression bonding head, characterized in that when the movable part of the pressurizing part and the bonding tool are directly connected, the bonding head is raised to a preset height while the pressurizing part is switched to position mode so that the position of the movable part of the pressurizing part does not change. In the first paragraph,
In step (c) above,
A control method for a thermocompression bonding head, characterized in that when the movable part of the pressurizing part and the bonding tool are directly connected, the height of the bonding head is maintained in a state where the pressurizing part is switched to position mode so that the position of the movable part of the pressurizing part does not change. In the second paragraph,
In step (c) above,
A control method for a thermocompression bonding head, characterized in that when the movable part of the pressurizing part and the bonding tool are directly connected, the movable part of the pressurizing part is raised to a preset height while the pressurizing part is switched to position mode. In the second paragraph,
In step (c) above,
A control method for a thermocompression bonding head, characterized in that when the actuator of the pressurizing part and the bonding tool are directly connected, the position of the actuator of the pressurizing part is maintained while the pressurizing part is switched to the position mode.

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