JPH0482184B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for bonding chips, and in particular, to electrically connect bump contacts formed on one side of a chip, such as a flip chip, to leads of a board, and at the same time connect the chip to a board. This relates to a method for joining chips that are fixed to

BACKGROUND ART Conventionally, various bonding methods using metal-to-metal bonding have been proposed as methods for bonding chips having bump contacts. For example, the present applicant has previously proposed a joining method as shown in FIG. That is, the chip 41 is held with the adhesive film 42 with its bump contacts facing upward, and the adhesive film 42 is positioned by the positioning device 44 via the wafer ring 43, and the chip 41 is held by suction (not shown). Using a transfer device equipped with a collet, the chip is transferred onto the mounting surface 46 of a pressing body 45 that is movable up and down and configured to vacuum-adsorb the chip, and the chip is positioned upward on the mounting surface 46. The position of the pressing body 45 is detected by the position detection device 47, and the position of the pressing body 45 is corrected by the positioning device 48 according to the position detection, and the substrate 51 is further moved on a horizontal plane above the pressing body 45 by the substrate positioning device 52. At the same time, the position of the substrate 51 is detected by the substrate position detection device 53, and the chip bonding position of the substrate 51 is positioned directly above the chip 41 on the mounting surface 46, and then the pressing body 45 is raised to place the chip on the substrate 51. Chip 41
By pressurizing and applying heat or ultrasonic waves,
A method of bonding the bump contacts of the chip 41 to the leads of the substrate 51 was proposed.

Problems to be solved by the invention By the way, in the above chip joining method,
Metal-to-metal bonding is performed by applying heat or ultrasonic waves while applying pressure to the bonding surfaces, and the chips are fixed and electrically bonded at the same time, so heat and ultrasonic waves must be applied to the substrate and chips. In addition to this problem, there was also the problem that reliable bonding may not be possible even due to slight differences in conditions.

In view of the above-mentioned conventional problems, the present invention provides a chip bonding method that can reliably fix the chip to the board while the bump contacts and leads are electrically connected by pressing the chip against the board. The purpose is to

Means for Solving the Problems In order to achieve the above object, the present invention includes a chip table on which a chip is placed, and a substrate support that supports a transparent substrate with leads arranged opposite to the chip table and on which leads are formed. A chip bonding method in which the leads and bumps on the transparent substrate are electrically connected using a table and a work table on which an adhesive coating device and an ultraviolet irradiation device are installed in parallel, the bump contacts of the chip are placing the chip on the chip table so as to face the transparent substrate; applying ultraviolet curable adhesive to the surface of the chip on which bump contacts are formed using the adhesive applicator of the work device; a step of applying pressure between the chip and the substrate so that the bump contacts of the chip come into pressure contact with the leads of the transparent substrate; and a step of moving the working device to apply the agent on the joint between the chip and the substrate. a step of positioning an ultraviolet irradiation device, and using the ultraviolet irradiation device to irradiate the bonding portion with ultraviolet rays from the back side of the transparent substrate to cure the adhesive and electrically connect the bump contact and the lead; The method is characterized by a step of fixing the chip to the substrate.

Function Since the present invention has the above-mentioned configuration, an adhesive is used to bond a chip having bump contacts to a substrate, and there is no need to apply heat or ultrasonic waves, so the device can be easily constructed. In addition, the chip can be easily and reliably fixed to the board, and since the bump contacts are pressed against the leads to ensure electrical connection, the adhesive is cured and bonded. After the mechanical bonding is completed by curing, even if the pressure is removed, the bump contacts are pressed against the leads by their elastic restoring force and the electrical connection is maintained, ensuring a reliable mechanical and electrical bond. can.

Furthermore, by adjusting the parallelism between the chip and the substrate when pressurizing them, the bonding surfaces can be reliably pressed against each other, and a highly reliable electrical bonding state can be obtained.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

In Figure 5, 1 is a chip such as an IC chip,
A bump contact 2 is provided protruding from one side thereof, and this bump contact 2 is electrically connected to a lead 4 formed on the chip adhesion surface of the substrate 3.
The chips 1 are transferred from the chip supply section onto the pressure table 5a at the upper end of the chip table 5 by a transfer device (not shown). The chip table 5 includes an X table 6 that moves in the X-axis direction from below, a Y table 7 that moves in the Y-axis direction perpendicular to the X-axis, and a Z-axis that rotates around the Z-axis that is perpendicular to the X and Y axes. A θ table 8, a Z table 9 that moves in the Z-axis direction,
It is composed of a parallel adjustment table 10 that can swing around an axis parallel to the X-axis and the Y-axis. On the other hand, the substrate 3 is made of a transparent glass substrate, and a reference mark (not shown) for positioning is provided at an appropriate position on the chip mounting surface. This board 3
is held by a holder 12 in a substrate moving device 11 disposed above the chip table 5 with the chip mounting surface facing downward. This substrate moving device 11 is movable between a position above the chip table 5 and a position evacuated to the side thereof, and moves the held substrate 3 to an arbitrary position at the center of the pressurizing table 5a of the chip table 5. When the substrate moving device 11 is located at the retracted position, the substrate 3 is supplied by a substrate supply/take-out device (not shown) and the substrate 3 on which the chip 1 is mounted is taken out. It is configured as follows.
Further, through holes 13 are bored in the support plate 11a against which the back surface of the substrate 3 of the substrate moving device 11 comes into contact, corresponding to the placement position of the reference mark provided on the substrate and the chip mounting position. Reference numeral 14 denotes a workbench disposed above the substrate moving device 11, which includes a microscope 15 with a focus detection device equipped with a CCTV camera, an adhesive applicator 16 consisting of a dispenser that drips adhesive, and an ultraviolet irradiator 17. are arranged in parallel, and are configured to be movable in the Z-axis direction and movable in the arrangement direction of each of the above devices. The ultraviolet irradiator 17 includes a mercury lamp 18 having a shutter.
The ultraviolet rays are guided through the optical fiber 19. Further, the microscope 15 with a focus detection device is attached to a movable table 20 that is movable in the Z-axis direction with respect to the workbench 14.

The movable table 20 and the microscope 1 with a focus detection device
5 is constructed as shown in FIG. The image of the top surface of the chip 1 or the mark on the chip mounting surface of the substrate 3, which is verified by the illumination device 21, is captured by the objective lens 22.
The light is focused on the image pickup tube of the CCTV camera 23, but part of the light passes through the beam splitter 24.
The light is taken out laterally by a beam splitter and a total reflection prism 25 to form two images on a CCD line sensor 26 as straight light and a light beam with a longer optical path. 27 is a focus determination device, which determines the focus position direction from the contrast difference between two images on the CCD line sensor 26, and drives a motor 29 by a motor driver 28.
is driven, and the movable base 20 is moved and driven by the ball screw 30. The height position of the movable base 20 is monitored by a central control unit (hereinafter abbreviated as CPU) using a displacement detector 31 and a counter 32. The image signal of the CCTV camera 23 is sent via the camera control unit 33 to a pattern matching type position reading device 34 and a monitor television 35, and the position reading result is transmitted to the CPU.

In the above configuration, the operation of mounting the chip 1 at a predetermined position on the board 3 will be explained with reference to FIGS. 1 and 2. First, the substrate 3 is supplied to the substrate moving device 11, which has been moved to the retracted position in advance, by a substrate supply/take-out device (not shown), and the chip 1 is transferred onto the pressure table 5a of the chip table 5 by a transfer device (not shown). Place and hold. Next, the substrate moving device 11 is moved to a position above the chip table 5, and
The workbench 14 is lowered to a predetermined position, and then the first
As shown in FIG. The height position of the movable table 20 is measured by a displacement detector 31 and a counter 32.
The height of each of the three points on the substrate 3 is detected. Thereby, the position and inclination of the chip mounting surface of the board 3 can be detected. Next, after moving the substrate moving device 11 to the retracted position, the work table 14 is further lowered to a predetermined position as shown in FIG. The position of the chip 1 is detected from the image, the X table 6, the Y table 7, and the θ table 8 are operated to position the center of the chip 1 at a predetermined position. are sequentially positioned directly below the microscope 15 with a focus detection device, and the movable base 20 is moved to perform an automatic focusing operation.The height position of the movable base 20 at the focused point is read in the same manner as above, and Detect the height of three points on the top surface,
The upper surface position and inclination of chip 1 are detected. Then,
Based on the above detection results, the parallel adjustment table 10 is operated so that the top surface of the chip 1 is parallel to the chip mounting surface of the board 3. Next, as shown in FIG. 1c, the work table 14 is moved laterally and the chip 1
The adhesive applicator 16 is placed oppositely above and discharges the adhesive 36, thereby applying the adhesive 36 to the upper surface of the chip 1, as shown in FIG. 3a.
Subsequently, after raising the workbench 14, the substrate moving device 11 is moved to a position above the chip table 5, the position where the chip 1 is to be bonded is positioned directly above the chip 1, and the Z table 9 is raised. As shown in FIG. 1d and FIG. 3b, the chip 1 is pressed against the substrate 3, and the chip 1 is
The bump contacts 2 are brought into pressure contact with the leads 4 of the substrate 3. At this time, each bump contact 2 has one side, for example.
Since it is generally small, about 0.1 mm, the adhesive 36 is completely removed from between the bump contact 2 and the lead 4 by the pressure applied, and the bump contact 2 digs into the surface of the lead 4, as shown in FIG. They are pressed together and elastically to ensure electrical connection. At the same time, the workbench 14 moves laterally so that the ultraviolet ray irradiation tool 17 is located directly above the chip 1, and the workbench 14 is lowered, allowing the ultraviolet ray irradiation tool 17 to pass through the through hole in the substrate 3, as shown in FIG. 1e. The adhesive 36 is irradiated with ultraviolet light through the adhesive 13 and the transparent substrate 3 to cure it, thereby fixing the chip 1 to the substrate 3. During this time, by maintaining the pressure contact state between the bump contact 2 and the lead 4, when the adhesive 36 hardens, the pressure contact state is maintained even when the pressure on the chip 1 is released, and the bump contact 2 and The electrical connection of the leads 4 is reliably maintained. When bonding of one chip is completed in this way, the substrate moving device 11 is retracted, and new chips 1 are sequentially transferred onto the pressure table 5a of the chip table 5, and are attached and fixed to the substrate 3 in the same manner as above. When all the chips 1 are mounted and fixed, the substrate moving device 11 is retracted to the retracted position and taken out by the substrate supplying and unloading device, and
A new substrate 3 is supplied and the above operation is repeated.

In the above embodiment, parallel adjustment was performed by detecting the positions of the three points of the board 3 and the chip 1. However, if the board 3 is reliable as a reference surface, only the position of the chip 1 can be adjusted at 3 points.
Parallel adjustment may be performed by detecting point positions, and in cases where the degree of parallelism between the two is high, or when the pressurizing table 5a has a built-in spherical bearing or the like and has a parallel adjustment function with respect to the substrate 3. In this case, the parallel adjustment step can also be omitted. Further, the adhesive may be applied not to the chip 1 side but to the substrate 3 side. Furthermore, although the above embodiment shows an example in which a transparent substrate is used as the substrate 3, it can also be applied to an opaque substrate by detecting the three positions of the substrate 3 and irradiating the ultraviolet rays from the chip mounting surface. It is possible.

Effects of the Invention According to the chip bonding method of the present invention, a chip having bump contacts is bonded to a substrate using an adhesive as described above, and there is no need to apply heat or ultrasonic waves, so the device can In addition to being simple, it is also possible to easily and reliably fix the chip to the board, and since the bump contacts are pressed against the leads and the electrical connection is secured, the adhesive is cured and bonded. After the mechanical bonding is completed due to curing of the agent, even if the pressure is removed, the bump contact is pressed against the lead by its elastic restoring force and the electrical connection is maintained, ensuring mechanical and electrical bonding. I can do it.

In addition, in the second invention, since the chip and the substrate are adjusted in parallel when they are pressurized, it is possible to ensure that all bonding surfaces are in pressure contact and obtain a highly reliable electrical bonding state. be effective.

[Brief explanation of drawings]

Fig. 1 is a process diagram of an embodiment of the present invention, Fig. 2 is a flowchart of the same, Figs. 3 a and b are enlarged front views of the state of adhesive application and the state of pressure contact of the chip, and Fig. 4 is a bump. FIG. 5 is a partially sectional front view showing the general configuration of the bonding device; FIG. 6 is a diagram showing the principle of construction of a microscope with a focus detection device; FIG. 7 is a diagram of the conventional device. FIG. 2 is a front view showing a schematic configuration. 1... Chip, 2... Bump contact, 3... Board, 4... Lead, 5... Chip table, 5a
...Pressure table, 10...Parallel adjustment table, 15...
...Microscope with focus detection device, 16...Adhesive coating device, 17...Ultraviolet irradiation tool.

Claims (1)

[Claims] 1. A chip table on which a chip is placed, a substrate support stand placed opposite to the chip table and supporting a transparent substrate on which leads are formed, and a workbench on which an adhesive coating device and an ultraviolet irradiation device are installed in parallel. A chip bonding method for electrically connecting leads and bumps on the transparent substrate using
placing the chip on the chip table so that the bump contacts of the chip face the transparent substrate; and using the adhesive application device of the working device on the surface of the chip on which the bump contacts are formed. a step of applying an ultraviolet curable adhesive, a step of pressurizing the chip and the substrate so that the bump contacts of the chip come into pressure contact with the leads of the transparent substrate, and a step of moving the working device to connect the chip and the substrate. a step of positioning the ultraviolet irradiation device on the bonding portion, and using the ultraviolet irradiation device, irradiating the bonding portion with ultraviolet rays from the back side of the transparent substrate to harden the adhesive and electrically connect the bump contact and the lead. A method for bonding chips, comprising the step of fixing the chips to a substrate while connected to the substrate.