JP2005191460A - Semiconductor device manufacturing method and semiconductor device manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device having a process for bonding a solder bump provided on a semiconductor chip to a substrate, such that the solder bump is crushed or the adjacent solder bumps are in contact with each other at the time of bump bonding. The problem is to prevent it.
In a method of manufacturing a semiconductor device including a step of bonding a solder bump 4 disposed on a semiconductor chip 1 to an electrode 5 formed on a substrate 2, the semiconductor chip until the solder bump 4 contacts the electrode 5. 1 is moved toward the substrate 5, and after the solder bump 4 contacts the electrode 5, the movement of the semiconductor chip 1 is adjusted so that the distance between the semiconductor chip 1 and the electrode 5 is maintained at a predetermined distance.
[Selection] Figure 3

Description

  The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device having a process of bonding solder bumps provided on a semiconductor chip to a substrate.

  Generally, as a method of mounting a semiconductor chip on a substrate such as a mother board or other semiconductor substrate, a method of providing a solder bump on the semiconductor chip and bonding the solder bump to an electrode formed on the substrate (flip chip bonding method) Is frequently used. According to the flip chip bonding method, the number of terminals can be increased as compared with the wire bonding method using a wire, so that it is possible to cope with higher density (for example, see Patent Document 1).

  Conventionally, a semiconductor chip generally bonded to a substrate using a flip chip bonding method has 5000 bumps or less and a bump pitch between the bumps of 176 μm to 250 μm. The bump size used was about 80 μm to 120 μm in diameter and about 70 μm to 100 μm in height. A conventional method of joining this type of solder bump to an electrode of a substrate will be described with reference to FIG.

  FIG. 1A shows a state in which a semiconductor chip 1 and a substrate 2 to which the semiconductor chip 1 is bonded are mounted on a semiconductor manufacturing apparatus. This semiconductor manufacturing apparatus is a flip chip bonder, which is provided with a mounting tool 6 for mounting the semiconductor chip 1 and an upper heater 7 for heating the semiconductor chip 1, and a stage 8 for mounting the substrate 2 at the lower part. And the lower heater 9 which heats the board | substrate 2 is provided. The mounting tool 6 and the upper heater 7 are configured to be movable in the directions of arrows Z1 and Z2 in the drawing by a moving device (not shown). Note that the solder bumps 4 are disposed on the pads 3 formed on the semiconductor chip 1.

  In order to join the solder bump 4 to the electrode 5, first, the semiconductor chip 1 is mounted on the mounting tool 6 and the substrate 2 is mounted on the stage 8. Both the mounting tool 6 and the stage 8 are provided with suction means (for example, an air-type suction chuck). Therefore, the semiconductor chip 1 and the substrate 2 are mounted on the mounting tool 6 and the stage 8 by this suction chuck.

  When the semiconductor chip 1 is mounted on the mounting tool 6 and the substrate 2 is mounted on the stage 8, the solder bumps 4 are separated from the electrodes 5 as shown in FIG. In this state, the upper heater 7 and the lower heater 9 are energized for preheating, and preheating (for example, 200 ° C.) of the semiconductor chip 1 and the substrate 2 is started.

  When the semiconductor chip 1 and the substrate 2 are raised to a predetermined preheating temperature, the semiconductor chip 1 and the substrate 2 are positioned, and the semiconductor chip 1 is moved (downwardly moved) toward the substrate 2 by a moving device (not shown). ) As a result, the solder bump 4 approaches the electrode 5 and eventually the solder bump 4 and the electrode 5 come into contact with each other.

  FIG. 1B shows a state in which the solder bump 4 and the electrode 5 are in contact with each other. In this contact state, the energization amount to the upper heater 7 and the lower heater 9 is increased, whereby the semiconductor chip 1 and the substrate 2 are heated at a temperature higher than the preheating (for example, 260 ° C.). Is done. Further, even after the solder bump 4 contacts the electrode 5 as described above, the moving device controls the semiconductor chip 1 so as to press the semiconductor chip 1 toward the substrate 2 with a predetermined pressure (for example, 1 gf for one solder bump). Has been.

This state is maintained for a predetermined time (for example, 10 to 20 minutes). Thereby, the solder bump 4 is melted and joined to the electrode 5, and the semiconductor chip 1 and the substrate 2 are electrically connected. Subsequently, a cooling process is performed, and the solder bumps 4 are cooled. As a result, the solder bumps 4 are solidified, and the semiconductor chip 1 and the substrate 2 are mechanically fixed. Subsequently, the suction of the semiconductor chip 1 by the mounting tool 6 and the suction of the substrate 2 by the stage 8 are stopped, whereby the substrate 2 to which the semiconductor chip 1 is bonded is removed from the semiconductor manufacturing apparatus. In addition, the board | substrate 2 removed from the semiconductor manufacturing apparatus is put into a reflow furnace, and this heat processing is implemented.
JP 2000-33060 A (page 2-3, FIG. 2)

  By the way, in recent years, the density of the semiconductor chip 1 is further increased, and accordingly, the semiconductor chip 1 is reduced in size (for example, □ 16 mm × 24 mm) and the number of solder bumps provided on the semiconductor chip 1 is increased. ing. Specifically, the number of arranged bumps has reached 160,000, and accordingly, the bump pitch between the bumps is narrowed to 10 μm to 40 μm. Also, the size of the solder bump used is miniaturized with a diameter of 5 μm to 25 μm and a height of 3 μm to 20 μm.

  As described above, when the pitch between the bumps becomes narrower and the size of the solder bumps becomes finer, the bumps are crushed at the time of bonding in the conventional semiconductor device manufacturing method (bump bonding method), and adjacent bumps There was a problem that the space contacted.

  Specifically, as described above, in the conventional method, after the solder bump 4 and the electrode 5 are in contact with each other, the semiconductor chip 1 is pressed toward the substrate 2 with a predetermined pressure (for example, 1 gf / 1 Bump) while heating. Has been done. When the bump pitch is relatively wide and the bump size is large as in the prior art, the solder bumps 4 were not crushed even when the heating / pressurizing process was performed. However, if the pitch between bumps becomes narrower and the bump size becomes finer as in recent years, it cannot withstand the pressure and thermal expansion of the tool, and solder bumps 4 as shown in FIG. Will collapse and this will cause contact between adjacent bumps.

  The present invention has been made in view of the above points, and a method of manufacturing a semiconductor device and a semiconductor device capable of preventing a solder bump from being crushed or a contact between adjacent solder bumps being prevented during bump bonding. An object is to provide a manufacturing apparatus.

  In order to solve the above-described problems, the present invention is characterized by the following measures.

The invention described in claim 1
In a manufacturing method of a semiconductor device including a step of bonding solder bumps arranged on a semiconductor chip to an electrode formed on a substrate,
Move the semiconductor chip toward the substrate until the solder bump contacts the electrode,
After the solder bump contacts the electrode, the movement of the semiconductor chip is adjusted so that the distance between the semiconductor chip and the electrode is maintained at a predetermined distance.

  According to the above invention, after the solder bump contacts the electrode, the separation distance between the semiconductor chip and the electrode is maintained at a predetermined distance, so that an excessive load is not applied to the solder bump. Therefore, even if the solder bumps are miniaturized by increasing the density of the semiconductor chip, it is possible to prevent the solder bumps from being crushed at the time of bump bonding or from being contacted between adjacent solder bumps.

The invention according to claim 2
In the manufacturing method of the semiconductor device according to claim 1,
After the solder bump contacts the electrode, the tool used for bonding the solder bump is moved away from the electrode by a dimension corresponding to the amount of thermal expansion. It is a feature.

  According to the above invention, even if the heat treatment is performed to melt the solder bump at the time of joining, and the tool used for joining the solder bump is thermally expanded, the dimension corresponding to the thermal expansion amount of the tool. However, since the semiconductor chip is moved away from the electrodes, it is possible to prevent the solder bumps from being crushed during bump bonding or contact between adjacent solder bumps.

The invention according to claim 3
The method of manufacturing a semiconductor device according to claim 2.
The movement for separating the semiconductor chip from the electrode is started at the same time when heating is started with respect to the solder bump or before the start of heating. .

  According to the above-described invention, when the solder bump is softened by heating, the separation movement of the semiconductor chip with respect to the electrode is started, so that the solder bump can be reliably prevented from being crushed by the load.

The invention according to claim 4
A mounting jig for mounting a semiconductor chip provided with solder bumps and a heater for heating the semiconductor chip are provided, and the solder bumps are bonded to electrodes formed on a substrate mounted on a stage. In semiconductor device manufacturing equipment,
An inclination correction member for correcting an inclination of the semiconductor chip relative to the substrate is provided between the mounting jig and the semiconductor chip or between the heater and the mounting jig. is there.

The invention according to claim 5
A mounting jig for mounting a semiconductor chip provided with solder bumps and a heater for heating the semiconductor chip are provided, and the solder bumps are bonded to electrodes formed on a substrate mounted on a stage. In semiconductor device manufacturing equipment,
An inclination correction member for correcting an inclination of the semiconductor chip with respect to the substrate at the time of joining the solder bumps is provided on the stage mounting side of the stage.

  According to the fourth to fifth aspects of the present invention, by providing the inclination correction member for correcting the inclination of the semiconductor chip with respect to the substrate, all the solder bumps can be reliably bonded to the electrodes, and the semiconductor chip substrate It is possible to improve the bonding reliability with respect to.

  According to the present invention, even if the solder bumps are miniaturized by increasing the density of the semiconductor chip, it is possible to prevent the solder bumps from being crushed during bump bonding or contact between adjacent solder bumps. Moreover, since all the solder bumps can be reliably bonded to the electrodes, the bonding reliability of the semiconductor chip to the substrate can be improved.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 2 shows a semiconductor manufacturing apparatus 10A used for carrying out a semiconductor device manufacturing method according to an embodiment of the present invention. As is well known, a semiconductor device is manufactured through a number of processes, but this embodiment is characterized by a method of joining solder bumps 4 provided on a semiconductor chip 1 to electrodes 5 formed on a substrate 2. Other manufacturing processes use known processes. For this reason, in the following description, only the method of joining the solder bump 4 to the electrode 5 will be illustrated and described.

  Incidentally, the solder bumps 4 provided on the wafer 1 used in this embodiment are miniaturized with a bump size of 5 μm to 25 μm in diameter and 3 μm to 20 μm in height, and a bump pitch between the bumps of 10 μm to The pitch is reduced to 40 μm.

  The semiconductor manufacturing apparatus 10A used in the method of the present invention is a flip chip bonder, and roughly comprises a moving device 11, a control device 13, a mounting tool 16, an upper heater 17, a stage 18, a lower heater 19, and the like. The moving device 11 is provided with a mounting tool 16 and an upper heater 17 at the lower part thereof.

  The mounting tool 16 is provided with an air-type suction chuck, and the semiconductor chip 1 is mounted (fixed) on the mounting tool 16 by the suction action of the suction chuck. An upper heater 17 that integrally heats the semiconductor chip 1 is integrally provided on the mounting tool 16. The integrated mounting tool 16 and upper heater 17 can be moved by the moving device 11 in the directions of arrows Z1 and Z2 in the figure.

  A stage 18 and a lower heater 19 are provided below the mounting tool 16. The stage 18 and the lower heater 19 are fixed and are not moved in this embodiment. The stage 18 is provided with an air-type suction chuck, and the substrate 2 is mounted (fixed) on the stage 18 by the suction action of the suction chuck. A lower heater 19 for integrally heating the substrate 2 is integrally provided below the stage 18.

  The control device 13 is connected to the moving device 11 and the heaters 17 and 19. The control device 13 controls the vertical movement of the semiconductor chip 1 by the moving device 11 and also controls the temperature of the heaters 17 and 19.

  Next, a method for joining the solder bump 4 to the electrode 5 using the semiconductor manufacturing apparatus 10A described above will be described. In order to join the solder bump 4 to the electrode 5, first, the semiconductor chip 1 is mounted on the mounting tool 16 and the substrate 2 is mounted on the stage 18.

  When the semiconductor chip 1 is mounted on the mounting tool 16 and the substrate 2 is mounted on the stage 18, the solder bumps 4 are separated from the electrodes 5 as shown in FIG. In this state, energization for preheating is performed on the upper heater 17 and the lower heater 19, and preheating (for example, 200 ° C.) of the semiconductor chip 1 and the substrate 2 is started.

  When the semiconductor chip 1 and the substrate 2 are raised to a predetermined preheating temperature, the control device 13 causes the moving device 11 to perform a positioning process between the semiconductor chip 1 and the substrate 2. When this positioning process is completed, the control device 13 drives and controls the moving device 11 so that the mounting tool 16 and the upper heater 17 move downward. As a result, the semiconductor chip 1 is moved (moved downward) toward the substrate 2. As a result, the solder bump 4 approaches the electrode 5 and eventually the solder bump 4 and the electrode 5 come into contact with each other.

  FIG. 3B shows a state in which the solder bump 4 and the electrode 5 are in contact with each other. The control device 13 is configured to be able to detect that the solder bump 4 and the electrode 5 are in contact with each other by a sensor (not shown). A method of moving the semiconductor chip 1 after the solder bumps 4 and the electrodes 5 contact each other will be described below with reference to FIG.

  In FIG. 4, the horizontal axis represents time, the left vertical axis represents temperature, and the right vertical axis represents the amount of movement of the solder bump 4 (semiconductor chip 1). The characteristic indicated by the arrow A indicates the temperature of the mounting tool 16 and the stage 18 (this is equivalent to the temperature of the semiconductor chip 1 and the substrate 2), and the characteristic indicated by the arrow B indicates Z1, Z2 of the semiconductor chip 1 by the moving device 11. The amount of movement in the direction is indicated, and the characteristic indicated by the arrow C indicates the height of the mounting tool 16 relative to the stage 18 (this is equivalent to the height of the semiconductor chip 1 relative to the electrode 5).

  As described above, before the solder bumps 4 and the electrodes 5 contact each other, the semiconductor chip 1 and the substrate 2 are preheated, and the temperature thereof is, for example, 200 ° C. (in FIG. 4, an arrow T1). Show). On the other hand, when the solder bump 4 and the electrode 5 are in contact with each other (indicated by the arrow T2 in FIG. 4), the energization amount to the upper heater 17 and the lower heater 19 is increased, and thereby the semiconductor chip 1 and the substrate 2 are increased. On the other hand, for example, heating at 260 ° C., which is higher than the preheating, is performed (see arrow A). As a result, the solder bump 4 starts to melt.

  By the way, as described above, the heating temperatures of the upper heater 17 and the lower heater 19 rise after the solder bumps 4 and the electrodes 5 come into contact with each other. Thermal expansion (hereinafter, this thermal expansion is referred to as “thermal expansion after contact”) occurs in the mounting tool 16 and the stage 18 that are provided integrally with 19.

  This post-contact thermal expansion becomes a force for moving the semiconductor chip 1 in the direction of the arrow Z1 in the figure at the upper part with respect to the contact position between the solder bump 4 and the electrode 5. Further, in the lower part with respect to the contact position, it acts as a force for moving the substrate 2 in the direction of the arrow Z2 in the figure. Therefore, even if the moving device 11 is stopped, the force generated by the thermal expansion after contact acts in the direction of crushing the solder bump 4 from above and below, and thus the solder bump 4 is crushed.

  Therefore, in the present invention, after the solder bump 4 and the electrode 5 come into contact with each other, the control device 13 controls the moving device 11, and the mounting tool 16 and the upper heater 17 are moved in the Z2 direction, that is, the semiconductor chip 1 is placed on the electrode 5. In contrast, it is configured to move in the direction of separation (see the characteristic indicated by arrow B in FIG. 4). At this time, the movement amount (movement dimension) of the mounting tool 16 and the upper heater 17 in the Z2 direction is set to be a movement amount corresponding to the post-contact thermal expansion amount.

  By using this method, even if thermal expansion after contact occurs, the semiconductor chip 1 is separated from the electrode 5 by a dimension corresponding to the thermal expansion after contact, as shown by an arrow C in FIG. In addition, the separation position of the semiconductor chip 1 with respect to the electrode 5 is maintained and held at a fixed position. Therefore, by using the bonding method according to the present embodiment, even when the solder bumps 4 are miniaturized due to high density of the semiconductor chip 1, the solder bumps 4 are crushed or adjacent solder bumps are in contact with each other during the bump bonding. Can be prevented.

  In addition, as shown in FIG. 4, in this embodiment, the start time for moving the semiconductor chip 1 away from the electrode 5 is set to coincide with the heating start time T2 when the solder bump 4 starts to be heated. doing. Thereby, when the solder bump 4 is softened or melted by heating, the separation movement of the semiconductor chip 1 with respect to the electrode 5 is started, so that the solder bump 4 can be more reliably prevented from being crushed. The start time for moving the semiconductor chip 1 away from the electrode 5 does not necessarily have to be the same as the heating start time T2 for starting the heating of the solder bumps 4, and starts before the heating start time T2. It may be done.

  The process of keeping the separation distance between the semiconductor chip 1 and the electrode 5 by driving the moving device 11 controlled by the control device 13 constant is maintained for a predetermined time (for example, 10 to 20 minutes). FIG. 3C shows a state in which the distance between the semiconductor chip 1 and the electrode 5 is kept constant. As shown in the figure, in this state, the solder bumps 4 are not crushed and adjacent solder bumps are not in contact.

  Within this predetermined time, the solder bump 4 is bonded to the electrode 5 and the semiconductor chip 1 and the substrate 2 are electrically connected. Subsequently, a cooling process is performed, and the solder bumps 4 are cooled. As a result, the solder bumps 4 are solidified, and the semiconductor chip 1 and the substrate 2 are mechanically fixed. Subsequently, the suction of the semiconductor chip 1 by the mounting tool 16 and the suction of the substrate 2 by the stage 18 are stopped, whereby the substrate 2 to which the semiconductor chip 1 is bonded is removed from the semiconductor manufacturing apparatus 10A. In addition, the board | substrate 2 removed from 10 A of semiconductor manufacturing apparatuses is put into a reflow furnace, and this heat processing is implemented.

  Subsequently, a semiconductor manufacturing apparatus according to the present invention will be described. 5 to 7 show semiconductor manufacturing apparatuses 10B to 10D according to first to third embodiments of the present invention. Each of the semiconductor manufacturing apparatuses 10B to 10D has the same basic configuration as the semiconductor manufacturing apparatus 10A shown in FIG. For this reason, the same components as those of the semiconductor manufacturing apparatus 10A shown in FIG.

  The semiconductor manufacturing apparatuses 10B to 10D according to the first to third embodiments are characterized in that inclination correction members 15A to 15C for correcting the inclination of the mounted semiconductor chip 1 are provided. The correction members 15A to 15C are film-like or block-like members made of, for example, resin, and a material that can be elastically deformed is selected. Accordingly, the correction members 15A to 15C are elastically deformed when pressed, and are elastically restored to their original shapes when released.

  As shown in FIG. 5, the semiconductor manufacturing apparatus 10 </ b> B according to the first example has a configuration in which a correction member 15 </ b> A is provided on the side of the mounting tool 16 on which the semiconductor chip 1 is mounted. Further, the semiconductor manufacturing apparatus 10C according to the second embodiment is configured such that a correction member 15B is provided between the mounting tool 16 and the upper heater 17 as shown in FIG. Further, as shown in FIG. 7, the semiconductor manufacturing apparatus 10D according to the third embodiment has a configuration in which a correction member 15C is provided on the side of the stage 18 disposed at the lower side where the substrate 2 is mounted.

  With this configuration, the inclination of the semiconductor chip 1 with respect to the substrate 5 can be corrected, and the positions of the solder bumps 4 and the electrodes 5 can always be in a normal state (a state in which they are horizontally opposed). That is, in order to reduce the thickness of the semiconductor chip 1 in response to a demand for downsizing the semiconductor device, so-called back grinding is performed to polish the back surface 1a. After the back grinding, the back surface 1a of the semiconductor chip 1 may be inclined.

  When the tilted semiconductor chip 1 is mounted on the mounting tool 16, the back surface 1 a is mounted on the mounting tool 16, so that the surface on which the solder bumps 4 of the semiconductor chip 1 are formed is tilted with respect to the substrate 2. turn into. If the process of joining the solder bumps 4 to the electrodes 5 is performed in this state, a state in which all the solder bumps 4 do not come into contact with the electrodes 5 occurs, and thus a connection failure between the semiconductor chip 1 and the substrate 2 occurs. There is a risk that.

  However, the inclination of the semiconductor chip 1 relative to the substrate 5 is corrected by providing the inclination correction members 15A to 15C for correcting the inclination of the semiconductor chip 1 as in the semiconductor manufacturing apparatuses 10B to 10D according to the first to third embodiments. The positions of the solder bumps 4 and the electrodes 5 can always be in a normal state (a state in which they are horizontally opposed). Thereby, all the solder bumps 4 can be reliably bonded to the electrode 5, and the bonding reliability of the semiconductor chip 1 to the substrate 2 can be improved.

FIG. 1 is a diagram for explaining a conventional method for joining solder bumps to electrodes formed on a substrate. FIG. 2 is a diagram showing a semiconductor manufacturing apparatus used in a semiconductor device manufacturing method according to an embodiment of the present invention. FIG. 3 is a diagram for explaining a method of manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 4 is a diagram for explaining an example of control of the heater and the moving device. FIG. 5 shows a semiconductor manufacturing apparatus according to the first embodiment of the present invention. FIG. 6 is a view showing a semiconductor manufacturing apparatus according to the second embodiment of the present invention. FIG. 7 shows a semiconductor manufacturing apparatus according to the third embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor chip 2 Board | substrate 4 Solder bump 5 Electrode 10A-10D Semiconductor manufacturing apparatus 11 Movement apparatus 13 Control apparatus 15A-15C Correction member 16 Installation tool 17 Upper heater 18 Stage 19 Lower heater

Claims (5)

In a manufacturing method of a semiconductor device including a step of bonding solder bumps arranged on a semiconductor chip to an electrode formed on a substrate,
Move the semiconductor chip toward the substrate until the solder bump contacts the electrode,
A method of manufacturing a semiconductor device, comprising: adjusting the movement of the semiconductor chip so that a distance between the semiconductor chip and the electrode is maintained at a predetermined distance after the solder bump contacts the electrode. In the manufacturing method of the semiconductor device according to claim 1,
After the solder bump contacts the electrode, the tool used for bonding the solder bump is moved away from the electrode by a dimension corresponding to the amount of thermal expansion. A method of manufacturing a semiconductor device. The method of manufacturing a semiconductor device according to claim 2.
The movement of separating the semiconductor chip from the electrode is started at the same time when heating is started with respect to the solder bump, or before the start of heating. Production method. A mounting jig for mounting a semiconductor chip provided with solder bumps and a heater for heating the semiconductor chip are provided, and the solder bumps are bonded to electrodes formed on a substrate mounted on a stage. In semiconductor device manufacturing equipment,
An inclination correction member for correcting an inclination of the semiconductor chip with respect to the substrate is provided between the mounting jig and the semiconductor chip or between the heater and the mounting jig. manufacturing device. A mounting jig for mounting a semiconductor chip provided with solder bumps and a heater for heating the semiconductor chip are provided, and the solder bumps are bonded to electrodes formed on a substrate mounted on a stage. In semiconductor device manufacturing equipment,
An apparatus for manufacturing a semiconductor device, comprising: an inclination correction member that corrects an inclination of the semiconductor chip with respect to the substrate when the solder bumps are bonded to the side on which the substrate is mounted.

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