JPH07283224A - Bump forming method for semiconductor chip and device thereof - Google Patents

Abstract

PURPOSE:To form bonding bumps of uniform height by a method wherein metal balls are arranged around the through hole on an arrangement substrate whereon a transparent reference plate is fitted to the through hole, and the metal balls are arranged in a highly precise manner on a number of narrow-pitched electrodes by positioning them through the transparent reference plate. CONSTITUTION:A bonding bump is formed on the electrode 5 of a semiconductor chip 4. In that case, metal balls 1 are arranged around the through hole 3 of an arrangement substrate 2 where a transparent reference plate 7, having a marker 8 in the through hole in the same manner as the arrangement of the electrode 5, and the arrangement substrate and the semiconductor chip 4 are opposed. The semiconductor chip 4 is observed through the transparent reference plate 7, the relative position of the semiconductor chip 4 and the arrangement substrate 2 is adjusted, and after the electrode 5 and the metal balls 1 have been aligned, pressure is applied to the arrangement substrate 2 and the chip 4. For example, plate glass, on which cross stripes are marked by photoresist treatment, is used as the transparent reference plate 7.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In manufacturing a semiconductor device, electrodes of a semiconductor chip and external lead portions are bonded via bumps. For example, TAB (Tape Automate)
In the d-bonding method, as shown in FIG. 5, the inner lead 1 aligned with the position of the electrode 5 on the semiconductor chip 4 is used.
8 is formed on a tape-shaped insulating film 19 and bonded together by thermocompression bonding with a bump 20 made of Au or the like interposed.

Such a bump is 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 TA
B tape or the like is overlapped, or a semiconductor chip and a TAB tape or the like having bumps are overlapped and bonded by collective bonding. At the time of bonding, in the case of the Au bump, the Au bump is compressed by thermocompression to bond the both. There is also a method of joining by reflow (re-melting) using a bump formed of low melting point metal such as solder. As the bump forming means, 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 is drawing attention.

As a method of forming bumps by the metal ball method, Japanese Patent Laid-Open No. 62-25435 discloses that a metal ball is set in a hemispherical recess formed at a predetermined position on a transparent plate, and a chip is placed on the metal ball. Then, it is disclosed that the metal ball is fused to a predetermined portion of the chip by reflow.

[0005]

The number of electrodes of a semiconductor chip has dramatically increased and the pitch between electrodes has been narrowed due to the increase in the scale and density of integrated circuits such as LSI and VLSI. Therefore, when forming bumps on all the electrodes of such a semiconductor chip, or all the lead portions of the TAB, the lead frame, the printed circuit board or the like to be connected to the electrodes, there are the following problems.

First, the bumps must have a predetermined height and the heights must be uniform with respect to a large number of electrodes of the semiconductor chips that are collectively bonded as described above. If the bump height is insufficient, the required bonding strength will not be obtained, and if the height is uneven, there will be a risk of defective bonding at low bump locations and damage to the chip at high bump locations. is there. In this respect, the metal ball method is superior to the vapor deposition method and the plating method in that bumps having a uniform predetermined height can be formed by selecting and using metal balls of a uniform size having a required diameter.

Next, the metal balls must be accurately arranged and joined to the large number of electrodes or leads having a narrow pitch as described above. Specifically, in many cases, the positional displacement accuracy of the array is required to be 5 μm or less.
Japanese Patent Laid-Open No. 62-25435 discloses a method of arranging metal balls on a transparent plate, stacking a semiconductor chip on the metal balls, and forming bumps on the chip. There is no mention of the alignment of the joints and the metal balls.

According to the present invention, metal balls are arranged with high precision on a large number of electrodes with a narrowed pitch even in a semiconductor chip in which integrated circuits such as LSI and VLSI have become large-scale and high-density. Therefore, it is an object of the present invention to provide a method and apparatus for forming bonding bumps of uniform predetermined height by collective bonding without defective bonding.

[0009]

The method of the present invention for achieving the above object is a method for forming a bonding bump on an electrode of a semiconductor chip, wherein a through hole is provided and a marker is provided in the through hole. Around the through holes of the array substrate fitted with the transparent reference plate, metal balls are arrayed in the same array as the array of the electrodes, the array substrate and the semiconductor chip are opposed to each other, and the semiconductor is passed through the transparent reference plate. After observing the chip, adjusting the relative position of the semiconductor chip and the array substrate, after aligning the position of the electrode and the metal ball,
A method of forming bumps on a semiconductor chip is characterized by pressing the array substrate and the semiconductor chip.

The device of the present invention for achieving the above object comprises two inventions, and the device of the first invention is a device for forming a bonding bump on an electrode of a semiconductor chip.
A transparent reference plate having a through hole, in which a transparent reference plate having a marker is fitted, and an array substrate around which the metal balls are arrayed, a goniometer for holding and aligning the array substrate, A semiconductor comprising: a fixing head that faces the array substrate to hold the semiconductor chips, a microscope that observes the semiconductor chips through the transparent reference plate, and a pressing mechanism that presses the semiconductor chips and the array substrate. This is a bump forming device for a chip.

A second invention device of the present invention is a device for forming a bonding bump on an electrode of a semiconductor chip,
A transparent reference plate having a through hole, in which a transparent reference plate having a marker is fitted, an array substrate around which the metal balls are arrayed, and the semiconductor chip is held by facing the array substrate. It is characterized by comprising a fixing head, a goniometer for holding and adjusting 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. It is a bump forming device for 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. 2, and FIG.
FIG. 4 is a side view of an example of a second invention device. In the method of the present invention, as shown in FIG. 1 and FIG.
And the electrodes 5 of the semiconductor chip 4 are arranged in the same arrangement. That is, when the array substrate 2 and the semiconductor chip 4 are opposed to each other and the position is adjusted, the metal balls 1 and the electrodes 5 are arrayed so as to overlap each other. The array substrate 2 has the through holes 3, the transparent reference plate 7 having the markers 8 is fitted in the through holes 3, and the metal balls are arrayed around the through holes 3 as described above. Next, the array 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 positions of the semiconductor chip 4 and the array substrate 2 are 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 pressed to collectively bond the metal balls 1 to the electrodes 5 to form bumps.

In the method of the present invention, the metal balls 1 are arranged on the array substrate 2 at the suction port 13 at the position of the substrate 2 to be arrayed.
Can be performed by adsorbing the metal ball 1 and the like, and observation for position adjustment can be performed by the microscope 11. In addition, the metal ball 1 and the electrode 5
The relationship between the marker 8 of the transparent reference plate 7 such as the cross-cut shown in FIGS. 2 and 3 and the position on the semiconductor chip 4, for example, the specific position of the circuit pattern 6 when they overlap with each other is determined in advance, and the positional relationship is determined. The array substrate 2 or the semiconductor chip 4 is moved and the position is adjusted so that

In FIG. 1 and FIG. 2, the metal ball 1 and the electrode 5 are shown in a much larger scale than the other parts, and in the state of FIG. 2, the circuit pattern 6 cannot be actually observed. . Then, for example, by enlarging the circled part in FIG. 2 with the microscope 11, and observing the circuit pattern 6 shown by the broken line as in FIG. 3, fine alignment between the cross-shaped marker 8 and the circuit pattern 6 is performed. I do. The enlarged positions such as the circles in FIG. 2 are from 2 positions (diagonal positions) to 4 positions. In the apparatus of the first invention of FIG. 1, the array substrate 2 is placed on the goniometer 9 and, for example, 5-axis adjustment (x direction,
(y direction, z direction, θ rotation in xy plane, α inclination of xy plane)
I do. In the second invention device of FIG. 4, the semiconductor chip 4 is held by the goniometer 9 for adjustment.

In the method of the present invention, when the metal balls 1 are pressed against the electrodes 5 to form bumps, the pressure can be controlled by the control device 17 to perform pressure bonding. Further, it is also possible to incorporate a heater in the fixing head 12 and control the temperature thereof by the controller 17 to perform thermocompression bonding or melt bonding. At the time of fusion joining, the suction of the suction port 13 is released,
The portion of the array substrate 2 that is in contact with the metal balls 1 is made of a material that will not be fused. After forming the bumps 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. As the marker 8 of the transparent reference plate 7, in addition to the grid pattern as shown in FIGS. 2 and 3, it is possible to employ a marker having +, × marks, etc. arranged at appropriate positions. 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 aligned with the marker 8.

Next, the first invention device of the present invention has a through hole 3, and a transparent reference plate 7 having a marker 8 is fitted into the through hole 3 as shown in the example of FIG. An array substrate 2 for arranging the metal balls 1 around the holes 3, a goniometer 9 for holding and adjusting the position of the array substrate 2, a fixing head 12 for holding the semiconductor chips 4 facing the array substrate 2,
It comprises 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 pressurizing mechanism, a pressurizing jig 15 fixed to the fixing head 12, a vertical movement guide 16 thereof, and a controller 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 forming bumps, when moving to the next bump formation, the fixing head 1
The suction of the suction port 14 of 2 is released, the semiconductor chip 4 is replaced with the next one, and the metal balls 1 are attached to the array substrate 2.
Array. At that 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.

The device of the second invention is such that 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 for holding the semiconductor chip 4. Is fixed to the pressure jig 15,
No goniometer is provided on the array substrate. Therefore, since the semiconductor chip 4 can be observed without passing through the goniometer 9, the goniometer 9 in the second invention device can be observed.
Has no through hole. Other configurations and operations are similar to 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 balls, 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 the sphere. In the semiconductor chips to be collectively bonded, the metal balls have the same material, shape and size. When Au is adopted, the bumps can be formed by thermocompression bonding, and when a low melting point metal such as solder is adopted, the bumps can be bonded by thermocompression bonding or melting.

By the method and the apparatus of the present invention, bumps can be formed by arranging metal balls on a large number of electrodes provided on a semiconductor chip at a narrow pitch and bonding them together. Excellent positional deviation accuracy, bump height uniformity, and bondability.

[0021]

EXAMPLE A bonding bump was formed on an electrode of a semiconductor chip by the device of the present invention as shown in FIG. As the metal ball 1, an Au thin wire for wire bonding (purity of 99.9% by weight or more) is cut into a certain size and melted to have a diameter of 7
Use a spherical shape of 0 μm,
A total of 200 electrodes arranged at a pitch were joined by thermocompression bonding. As the transparent reference plate 7, a glass plate having a grid pattern marked by photoresist treatment is used. As shown in FIGS. 2 and 3, the circuit pattern 6 of the semiconductor chip 4 is used.
Was aligned with. The formed bumps did not cause any bonding failure, were highly accurately arranged with a positional deviation accuracy of 5 μm or less, and had a uniform bump height.

[0022]

According to the method of the present invention and the device of the present invention, metal balls are arrayed on a large number of electrodes provided on a semiconductor chip at a high density with a narrowed pitch with a positional deviation accuracy of 5 μm or less, and are collectively used. Bonding makes it possible to form bonding bumps having a uniform height without defective bonding. Therefore,
A semiconductor chip having bumps formed according to the present invention is
By bonding to B, a lead frame, a printed circuit board, etc., a highly reliable semiconductor device can be manufactured with high yield.

[Brief description of 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 a first invention device of the present invention, which is represented by A- in FIG.
FIG.

FIG. 3 is a partially enlarged view of FIG. 2, showing an example of a first invention device of the present invention.

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

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

[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: Adjusting 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

Claims (3)

[Claims] 1. A method of forming a bonding bump on an electrode of a semiconductor chip, comprising a through hole, and a transparent reference plate having a marker fitted in the through hole, around the through hole of an array substrate. The 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 position of the semiconductor chip and the arrangement substrate is determined. After adjusting and aligning the positions of the electrodes and the metal balls,
A method of forming bumps on a semiconductor chip, comprising pressing the array substrate and the semiconductor chip. 2. A device for forming a bonding bump on an electrode of a semiconductor chip, which has a through hole, and a transparent reference plate having a marker is fitted in the through hole, and the transparent reference plate is provided around the through hole. An array substrate for arranging the metal balls, a goniometer for holding and adjusting the position of the array substrate, a fixing head for holding the semiconductor chip facing the array substrate, a microscope for observing the semiconductor chip through the transparent reference plate, A bump forming device for a semiconductor chip, comprising a pressing mechanism for pressing the semiconductor chip and the array substrate. 3. A device for forming a bonding bump on an electrode of a semiconductor chip, which has a through hole, a transparent reference plate having a marker is fitted in the through hole, and the transparent reference plate is provided around the through hole. An array substrate on which metal balls are arrayed, a fixing head for holding the semiconductor chips facing the array substrate, a goniometer for holding and adjusting the position of the fixing head, and a microscope for observing the semiconductor chips through the transparent reference plate. An apparatus for forming bumps on a semiconductor chip, comprising: a pressing mechanism for pressing the semiconductor chip and the array substrate.