JP3086125B2 - Method and apparatus for forming bump on semiconductor chip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a bonding bump on an electrode of a semiconductor chip when manufacturing a semiconductor device.

[0002]

2. Description of the Related Art In manufacturing a semiconductor device, bonding of an electrode of a semiconductor chip to an external lead portion via a bump is performed. For example, TAB (Tape Automate
In the d bonding method, as shown in FIG. 5, the inner leads 1 are aligned with the positions of the electrodes 5 on the semiconductor chip 4.
8 formed on a tape-shaped insulating film 19 are joined together by thermocompression bonding with a bump 20 made of Au or the like interposed therebetween.

Such bumps are formed in advance on a lead portion such as an electrode of a semiconductor chip or an inner lead of a TAB, and the semiconductor chip having the bump and the TAB are formed in advance.
B tape or the like or a semiconductor chip and a TAB tape having bumps or the like are overlapped and bonded by collective joining. At the time of bonding, in the case of the Au bump, the Au bump itself is compressed by thermocompression bonding to join them. There is also a method in which a bump having a low melting point metal such as solder is formed and joined by reflow (remelting). As means for forming the bumps, there are a vapor deposition method, a plating method, a metal ball method, and the like, and a metal ball method capable of forming a bump having a required thickness by a relatively simple means has attracted attention.

As a method of forming a bump by the metal ball method, Japanese Patent Application Laid-Open No. 62-25435 discloses a method in which a metal ball is set in a hemispherical concave portion formed at a predetermined position on a transparent plate, and a chip is mounted thereon. It is disclosed that a metal ball is fused to a predetermined portion of a chip by reflow.

[0005]

As the scale and density of integrated circuits such as LSIs and VLSIs increase, the number of electrodes on a semiconductor chip has increased dramatically, and the pitch between the electrodes has become narrower. Therefore, there are the following problems when bumps are formed on all the electrodes of such a semiconductor chip, or on all the lead portions of a TAB, a lead frame or a printed circuit board to be connected to the electrodes.

First, for a large number of electrodes of a semiconductor chip to be joined together as described above, the bumps must have a predetermined height and the height must be uniform. If the bump height is insufficient, the required bonding strength cannot be obtained, and if the height is not uniform, there is a risk of poor bonding at low bump locations and chip damage at high bump locations. is there. In this regard, the metal ball method is superior to the vapor deposition method and the plating method since a bump having a uniform predetermined height can be formed by selecting and using metal balls having a required diameter and a uniform size.

Next, the metal balls must be precisely arranged and joined to a large number of narrow-pitch electrodes and leads as described above. More specifically, alignment displacement accuracy of 5 μm or less is often required.
Japanese Patent Application Laid-Open No. Sho 62-25435 discloses a method in which metal balls are arranged on a transparent plate, a semiconductor chip is stacked thereon, and bumps are formed on the chip. It does not describe the alignment between the joint and the metal ball.

According to the present invention, a metal ball is arranged with high precision on a large number of electrodes having a narrowed pitch even if the integrated circuit such as an LSI or an VLSI is a large-scale and high-density semiconductor chip. Accordingly, it is an object of the present invention to provide a method and an apparatus for forming a bonding bump having a uniform predetermined height by collective bonding without defective bonding.

[0009]

According to the present invention, there is provided a method of forming a bonding bump on an electrode of a semiconductor chip, comprising a through-hole and a marker in the through-hole. Around the through holes of the array substrate in which the transparent reference plate is fitted, metal balls are arranged in the same array as the electrodes, the array substrate and the semiconductor chip are opposed to each other, and the semiconductor is passed through the transparent reference plate. Observe the chip, adjust the relative position of the semiconductor chip and the array substrate, after aligning the position of the electrode and the metal ball,
A method for forming a bump on a semiconductor chip, comprising pressing the array substrate and the semiconductor chip.

In order to achieve the above object, the present invention comprises two inventions. A first invention is an apparatus for forming a bonding bump on an electrode of a semiconductor chip.
A transparent reference plate having a marker is fitted into the through hole, an array substrate for arranging metal balls around the through hole, a goniometer for holding and adjusting the position of the array substrate, A semiconductor, comprising: a fixing head for holding the semiconductor chip in opposition to an array substrate; a microscope for observing the semiconductor chip through the transparent reference plate; and a pressing mechanism for pressing the semiconductor chip and the array substrate. This is an apparatus for forming bumps on a chip.

According to a second aspect of the present invention, there is provided an apparatus for forming a bonding bump on an electrode of a semiconductor chip,
A transparent reference plate having a marker is fitted in the through hole, and an array substrate on which metal balls are arranged around the through hole, and the semiconductor chip is held in opposition to the array substrate. It comprises a fixing head, a goniometer for holding and adjusting the position of the fixing head, a microscope for observing the semiconductor chip through the transparent reference plate, and a pressing mechanism for pressing the semiconductor chip and the array substrate. This is a device for forming bumps on a semiconductor chip.

[0012]

First, the method of the present invention will be described with reference to an example of the apparatus of the present invention shown in the drawings. 1 is a side view of an example of the first invention device, FIG. 2 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is a partially enlarged view of FIG.
FIG. 4 is a side view of the second invention apparatus example. In the method of the present invention, first, as shown in FIGS.
And the same arrangement as the arrangement of the electrodes 5 of the semiconductor chip 4. That is, the metal balls 1 and the electrodes 5 are arranged so as to overlap when the arrangement substrate 2 and the semiconductor chip 4 are adjusted to face each other. The array substrate 2 has a through hole 3 into which a transparent reference plate 7 having a marker 8 is fitted. Metal balls are arranged around the through hole 3 as described above. Then, the arrangement substrate 2 and the semiconductor chip 4 are opposed to each other, the semiconductor chip 4 is observed through the transparent reference plate 7, the relative position between the semiconductor chip 4 and the arrangement substrate 2 is adjusted, and the positions of the electrodes 5 and the metal balls 1 are aligned. After that, the array substrate 2 and the semiconductor chip 4 are pressurized, and the metal balls 1 are collectively joined to the electrodes 5 to form bumps.

In the method of the present invention, the arrangement of the metal balls 1 on the arrangement substrate 2 is performed by setting the suction port 13 at the position of the substrate 2 to be arranged.
Can be performed by a method such as adsorbing the metal ball 1 by using a microscope, and observation for position adjustment can be performed by the microscope 11. The metal balls 1 are aligned with the electrodes 5.
The relationship between the marker 8 of the transparent reference plate 7, for example, as shown in FIGS. 2 and 3, and the position on the semiconductor chip 4, for example, the specific position of the circuit pattern 6, is determined beforehand. The position of the array substrate 2 or the semiconductor chip 4 is adjusted such that

In FIG. 1 and FIG. 2, the metal ball 1 and the electrode 5 are shown greatly enlarged than other portions, and the circuit pattern 6 cannot be actually observed in the state of FIG. . Therefore, for example, the circle 11 in FIG. 2 is further enlarged with the microscope 11 and the circuit pattern 6 indicated by a broken line is observed as shown in FIG. I do. Enlarged positions such as circles in FIG. 2 are two (diagonal) to four. In the first invention device shown in FIG. 1, the array substrate 2 is placed on the goniometer 9 and, for example, five-axis adjustment (x direction,
y direction, z direction, θ rotation in xy plane, α inclination in xy plane)
I do. In the second invention device shown in FIG. 4, the semiconductor chip 4 is held and adjusted by the goniometer 9.

In the method of the present invention, when the metal ball 1 is pressed against the electrode 5 to form a bump, the control device 17 can control the pressing force to perform pressure bonding. Further, a heater may be built in the fixing head 12 and the temperature thereof may be controlled by the control device 17 to perform thermocompression bonding or fusion bonding. At the time of fusion joining, the suction of the suction port 13 is released,
The arrangement substrate 2 where the metal ball 1 comes into contact is made of a material that does not fuse. After the bumps are formed in this way, the suction of the suction port 13 of the array substrate 2 is released,
The process proceeds to the next bump formation. Further, as the marker 8 of the transparent reference plate 7, in addition to the grids shown in FIGS. 2 and 3, a marker having marks such as + and X arranged at appropriate positions can be used. The marker 8 can be formed, for example, on a glass plate by a photoresist method or the like. Further, a mark different from the circuit pattern 6 may be formed on the surface of the semiconductor chip 4 to be aligned with the marker 8.

Next, as shown in the example of FIG. 1, the first invention device of the present invention has a through hole 3, a transparent reference plate 7 having a marker 8 is fitted in the through hole 3, Around the hole 3, an array substrate 2 for arranging the metal balls 1, a goniometer 9 for holding and adjusting the position of the array substrate 2, a fixing head 12 for holding the semiconductor chip 4 in opposition to the array substrate 2,
The microscope 11 includes a microscope 11 for observing the semiconductor chip 4 through the transparent reference plate 7, and a pressing mechanism for pressing the semiconductor chip 4 and the array substrate 2. As the pressing mechanism, a pressing jig 15 fixed to the fixing head 12, its vertical movement guide 16 and a control device 17 can be adopted.

In the first invention device, the goniometer 9 is provided with a through-hole communicating with the through-hole 3 of the array substrate 2 so that the semiconductor chip 4 can be observed from below through the transparent reference plate 7. . After the bumps are formed, when moving to the next bump formation, the fixing head 1
2 and the semiconductor chip 4 is replaced with the next one, and the metal ball 1
Are arranged. At this time, the array substrate 2 can be removed from the goniometer 9 or moved together with the goniometer 9 by, for example, a guide rail (not shown).
Other functions are as described in the method of the present invention.

In the second invention, the position of the semiconductor chip 4 is adjusted as in the example of FIG. 4, and the goniometer 9 holds the fixing head 12 holding the semiconductor chip 4. And is fixed to the pressing jig 15.
No goniometer is provided on the array substrate. Therefore, the observation of the semiconductor chip 4 can be performed without passing through the goniometer 9, so that the goniometer 9 in the second invention device is used.
Has no through hole. Other configurations and operations are the same as those of the first invention device.

In the method of the present invention and the apparatus of the present invention, Au can be used as the metal ball, and a low melting point metal such as solder can also be used. The shape of the metal ball is selected according to the situation of the target semiconductor chip, such as an ellipse or a square, in addition to a sphere. The materials, shapes and dimensions of the metal balls are the same in the semiconductor chips to be joined together. When Au is used, bumps are formed by thermocompression bonding, and when low melting point metal such as solder is used, bonding can be performed by thermocompression bonding or melting.

According to the method of the present invention and the apparatus of the present invention, a bump can be formed by arranging and joining metal balls to a large number of electrodes provided on a semiconductor chip at a narrow pitch. Excellent in displacement accuracy, uniformity of bump height, and bondability.

[0021]

EXAMPLE A bonding bump was formed on an electrode of a semiconductor chip by the apparatus of the present invention as shown in FIG. As the metal ball 1, an Au fine wire for wire bonding (purity of 99.9% by weight or more) is cut to a fixed size, melted, and melted to a diameter of 7 mm.
A 0 μm sphere was used, and this was 150 μm
The electrodes were joined by thermocompression bonding to a total of 200 electrodes arranged at a pitch. As the transparent reference plate 7, a glass plate on which grids are marked by a photoresist process is used. As shown in FIGS. 2 and 3, the circuit pattern 6 of the semiconductor chip 4 is used.
And alignment. All of the formed bumps were free from bonding failure, were arranged with a high positional accuracy of 5 μm or less, and had a uniform bump height.

[0022]

According to the method and the apparatus of the present invention, metal balls are arranged with a positional deviation accuracy of 5 μm or less on a large number of electrodes provided on a semiconductor chip with a narrow pitch and high density. A bonding bump having a uniform height can be formed without bonding failure by bonding. Therefore,
The semiconductor chip on which bumps are formed according to the present invention is referred to as TA.
B, by bonding to a lead frame, a printed board, or the like, a highly reliable semiconductor device can be manufactured with high yield.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a first invention device of the present invention.

FIG. 2 shows an example of the first invention apparatus of the present invention, and FIG.
It is arrow A sectional drawing.

FIG. 3 shows an example of the first invention device of the present invention and is a partially enlarged view of FIG. 2;

FIG. 4 is a side view showing an example of the second invention apparatus of the present invention.

FIG. 5 is a cross-sectional view illustrating an example of a conventional semiconductor device using a TAB method.

[Explanation of symbols]

 1: Metal ball 2: Array substrate 3: Through hole 4: Semiconductor chip 5: Electrode 6: Circuit pattern 7: Transparent reference plate 8: Marker 9: Goniometer 10: Adjustment screw 11: Microscope 12: Fixing head 13, 14 : Suction port 15: Pressurizing jig 16: Vertical movement guide 17: Control device 18: Inner lead 19: Insulating film 20: Bump

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/60

Claims (3)

(57) [Claims] 1. A method of forming a bonding bump on an electrode of a semiconductor chip, comprising a through hole having a marker and a transparent reference plate fitted with a marker. Metal balls are arranged in the same arrangement as the arrangement of the electrodes, the arrangement substrate and the semiconductor chip are opposed to each other, the semiconductor chip is observed through the transparent reference plate, and the relative positions of the semiconductor chip and the arrangement substrate are determined. After adjusting the position of the electrode and the metal ball,
A method of forming a bump on a semiconductor chip, comprising pressing the array substrate and the semiconductor chip. 2. An apparatus for forming a bonding bump on an electrode of a semiconductor chip, comprising a through-hole, a transparent reference plate having a marker fitted into the through-hole, and a periphery of the through-hole. An array substrate for arranging metal balls, a goniometer for holding and adjusting the position of the array substrate, a fixing head for holding the semiconductor chip in opposition to the array substrate, a microscope for observing the semiconductor chip through the transparent reference plate, An apparatus for forming a bump on a semiconductor chip, comprising a pressure mechanism for pressing the semiconductor chip and the array substrate. 3. An apparatus for forming a bump for bonding on an electrode of a semiconductor chip, comprising a through hole, a transparent reference plate having a marker fitted into the through hole, and a periphery of the through hole surrounding the through hole. An array substrate for arranging metal balls, a fixing head for holding the semiconductor chip facing the array substrate, a goniometer for holding and adjusting the position of the fixing head, and a microscope for observing the semiconductor chip through the transparent reference plate An apparatus for forming a bump on a semiconductor chip, the apparatus comprising a pressing mechanism for pressing the semiconductor chip and the array substrate.