JPH03204949A - Bonding of ic chip - Google Patents

Abstract

PURPOSE:To enable the parallelism of an IC chip to a thermocompression bonding face to be easily adjusted in a short time by a method wherein the bonding face of a thermocompression bonding head is pressed against the upside of a swingable chip stage table, and the upside of the chip stage is adjusted in position to be substantially parallel with the bonding face of the thermocompression head. CONSTITUTION:An IC chip 7 is placed on the upside of a chip stage table 6, a tape carrier 12 is arranged thereon, the IC chip 7 is inserted into an opening 16 of the tape carrier 12, and finger leads 13 are positioned to bumps 15 respectively. When gas is introduced into a cavity 9 through an intake path 5 of a stage base 1 to make the pressure of the cavity 9 equal to an atmospheric pressure, the chip stage table 6 can be made swingable in an optional direction in a mounting recess 2. In this state, a thermocompression bonding head 11 of a bonding device is made to descend, and a thermocompression bonding face 14 is pressed against the IC chip 7 through the intermediary of the finger leads 13. The chip stage table 6 is made to swing in the mounting recess 2 so as to align with the plane of the thermocompression bonding face 14. In result, the upside of the chip stage table 6 is adjusted in parallelism to the thermocompression bonding face 14 so as to enable the bonding face 14 to bear uniformly against the bumps 15 of the IC chip 7.

Description

[Detailed description of the invention] [Industrial Application Field J The present invention relates to an IC chip bonding method.

[Conventional technology] Conventionally, in IC chip mounting technology, TAB (tape carrier) is used as a method for mounting an IC chip on a tape carrier.
e Automated Bonding) method is known. In this TAB method, first, a large number of finger leads made of metal foil such as copper are patterned on a tape carrier, and the surfaces of the finger leads are soldered.Then, the tape carrier is placed on a chip stage table. 2 Inga leads are placed on a large number of bumps provided on the IC chip in correspondence with each other. In this state, the thermocompression bonding head attached to the bonding device so as to be movable up and down is lowered from above the tape carrier, and each finger lead is heated and pressurized at once with the thermocompression bonding surface to bond each finger lead to each bump of the IC chip. ing.

[Problem to be Solved by the Invention J] In the above-described IC chip bonding method, if the bump surface of the IC chip and the thermocompression bonding surface of the thermocompression bonding head are not parallel, the thermocompression bonding surface will hit the IC chip unevenly, and the IC chip will be damaged. Since each bump and each finger lead cannot be reliably bonded, it is necessary to adjust the parallelism between the bump surface of the IC chip and the thermocompression bonding surface of the thermocompression bonding head.

This adjustment method includes, for example, adjusting the part where the thermocompression bonding head is attached to the bonding device to adjust the parallelism between the thermocompression bonding surface and the top surface of the chip stage table, or polishing the thermocompression bonding surface of the thermocompression bonding head. Constructed from possible materials,
There is a method of polishing this thermocompression bonding surface to adjust the parallelism between the thermocompression bonding surface and the top surface of the chip stage table.

However, in the former method, the part where the thermocompression bonding head is attached to the bonding device must be mechanically adjusted, making it difficult to adjust the parallelism between the thermocompression bonding surface and the top surface of the chip stage table. There is a problem in that the work requires skill and takes a long time. In addition, in the latter method, it is necessary to place a polishing plate on the chip stage table on which the IC chip is placed and polish the thermocompression bonding surface of the thermocompression bonding head to adjust the parallelism, which makes the polishing work troublesome.
Not only is the process time-consuming, but since the thermocompression head is made of a polishable material, there is a problem in that the thermocompression head wears out quickly.

The object of the present invention is to provide an IC that can easily adjust the parallelism of an IC chip and a thermocompression bonding surface in a short time without requiring a skilled person, and that can bond an IC chip and a finger lead reliably and accurately. An object of the present invention is to provide a method for bonding chips.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a chip stage that is capable of lowering a thermocompression head attached to a bonding device so as to be movable up and down, and swinging the thermocompression bonding surface. IC placed directly on the top surface of the stand or on the chip stage stand
GL with parallel chips and front and back surfaces! After adjusting the top surface of the # chip stage base to a position where it is substantially parallel to the thermocompression bonding surface of the thermocompression bonding head, the IC chip and fingers placed on the chip stage base are pressed together using a 1 m tool. This is to bond with the lead. In this case, the parallelism between the thermocompression bonding surface of the thermocompression bonding head and the top surface of the cheap stage table may be adjusted every time the XC chip and the finger leads are bonded. After bonding a number of times,
The polishing may be performed every time the thermocompression bonding surface of the thermocompression bonding head is polished.

[effect j The operation of this invention is as follows.

When bonding an IC chip to a finger lead, first lower the thermocompression head of the bonding device,
Without heating, the thermocompression bonded surface is pressed onto the top surface of the chip stage table directly or via an IC chip or an adjustment jig whose front and back surfaces are parallel. Then, the chip stage
Since it is pushed by the thermocompression bonding surface and swings in correspondence with the thermocompression bonding surface, the upper surface of the chip stage base is adjusted to a position where it is substantially parallel to the thermocompression bonding surface of the thermocompression bonding head. After this, the IC chip placed on the chip stage and the finger leads are heated and pressed with the thermocompression bonding surface of the thermocompression bonding head to perform thermal bonding, so that the thermocompression bonding surface does not touch the IC chip unevenly. To.

Bonding can be performed accurately and precisely.

[Example J The present invention will be described in detail below with reference to one drawing.

! FIG. 1 shows a first embodiment of bonding an IC chip to a finger lead using a bonding device suitable for the bonding method of the present invention. First, in FIG. This stage base l is made of a material with high mechanical strength. In the center of the top is #,! ! Four parts 2 are provided, and an intake passage 3 and an exhaust passage 4 are provided in the central part so as to penetrate from the bottom surface of the mounting recess 2 to the lower surface of the stage base 1.

The mounting recess 2 has a circular shape as a whole, and the inner peripheral wall surface 5 is formed into a recessed spherical curved surface that gradually widens from the bottom to the top. Further, a chip stage base 6 is arranged in the mounting recess 2. The chip stage base 6 is a portion on which the IC chip 7 is placed, is made of the same material as the stage base l, and is formed into a disk shape. Its upper surface is formed into a highly flat plane, and the lower peripheral edge portion 8 is formed into a convex spherical curved surface that closely contacts the inner peripheral wall surface 5 of the placement recess 2 through line contact. As a result, the chip stage base 6
A space 9 is formed between the lower part of the stage base 1 and the mounting recess 2 of the stage base 1.

Therefore, when a gas such as air is introduced into the space IIA9 from the air intake path 3 and the pressure within the space 9 becomes equal to or higher than atmospheric pressure, the chip stage base 6 can be operated at any position within the mounting port 1IAZ. It becomes possible to swing in the direction. Conversely, when the air intake path 3 is closed and the gas in the space 9 is discharged through the exhaust path 4, and the inside of the space 9 becomes a negative pressure state close to a vacuum state, the chip stage table 6 is fixed to the mounting recess 2. be done. Note that a recess 10 is provided on the lower surface of the chip stage base 6 to enlarge the space 9 and increase negative pressure.

On the other hand, above the chip stage base 6 is a thermocompression bonding pad 11.
is located. The thermocompression bonding head 11 heats and presses each finger lead 13 of the tape carrier 12, which will be described later, on the IC chip 7 on the chip stage table 6, and its lower end surface is similar to the upper surface of the chip stage table 6.
It is formed on a thermocompression bonding surface 14 with high flatness. Note that the thermocompression bonding head 11 is attached to a movable arm (not shown) of a bonding device, and can be moved up and down by this movable arm.

By the way, the IC chip 7 is formed in the shape of a square plate, and a large number of bumps 15 are provided on the upper surface of the IC chip 7 so as to protrude upward. Further, an opening 16 into which the IC chip 7 is inserted is formed at a predetermined location in the tape carrier 12, and each bump 15 of the IC chip 7 is formed on the upper surface of the opening 16.
A large number of finger leads 13 corresponding to . . . are patterned so as to protrude inward from the edge of the opening 16.

Note that solder plating (not shown) is applied to the surface of each finger lead 13.

Next, a case will be described in which the finger leads 13 are bonded to the IC chip 7 using the above-described bonding apparatus.

First, the parallelism between the upper surface of the chip stage base 6 and the thermocompression bonding surface 14 of the thermocompression bonding head 11 is adjusted. In this case, the IC chip 7 is placed on the upper surface of the cheap stage 6 in advance, the tape carrier 12 is placed on the IC chip 7, and the IC chip 7 is placed in the opening 16 of the tape carrier 12.
are inserted, and the finger leads 13 are made to correspond to each bump 15 of the IC chip 7. Then, gas is introduced into the space 9 through the air intake path 3 of the stage base l to bring the pressure inside the space 9 to a state equivalent to atmospheric pressure.

Then, since the lower peripheral edge 8 of the chip stage base 6 is in close line contact with the inner circumferential wall surface 5 of the mounting recess 2, it becomes possible to swing in any direction within the mounting recess 2. In this state, the RAD 11 is lowered to the thermocompression bonding unit of the bonding apparatus, and the thermocompression bonding surface 14 of the thermocompression bonding head 11 is pressed against the IC chip 7 via the finger doors 3 . At this time, the heater (not shown) of the thermocompression bonding head 11 is turned off so that the heating by the rad 11 is not performed on the thermocompression bonding. Then, since the chip stage base 6 is in a state where it can swing in any direction within the mounting recess 2, it swings within the mounting recess 2 so as to correspond to the plane of the thermocompression bonding surface 14. As a result, the top surface of the chip stage base 6 is
The parallelism to the thermocompression bonding surface 14 is adjusted so that the thermocompression bonding surface 14 evenly contacts each bump 15 of the chip 7. After this, the intake passage 3 of the stage base l is closed and the exhaust passage 4 is closed.
When the gas inside the space 9 is exhausted and the inside of the space 9 is brought into a negative pressure state close to vacuum, the chip stage table 6 is moved to the mounting recess 2.
Fixed. Thereby, the parallelism between the upper surface of the chip stage base 6 and the thermocompression bonding surface 14 of the thermocompression bonding pad 11 can be easily adjusted in a short time without requiring a skilled person.

In this state, after raising the thermocompression bonding head 11,
The rad 11 is lowered to the thermocompression bonding again, and the finger leads 13 are pressed against the bumps 15 by the thermocompression leakage 14. At this time, the heater of the rad 11 is turned on to heat and pressurize the thermocompression bonding. Then, since the parallelism between the upper surface of the chip stage base 6 and the thermocompression bonding surface 14 of the thermocompression bonding head 11 is adjusted, the thermocompression bonding surface 14 does not hit the IC chip 7 unevenly, and the fingers are reliably and precisely attached. Leads 13... and bumps 15... can be bonded.

By the way, the above-mentioned adjustment of the parallelism between the thermocompression bonding surface 14 of the thermocompression bonding pad 11 and the top surface of the chip stage base 6 can be adjusted every time the IC chip 7 and the finger leads 13 are bonded. It is possible to absorb variations in the bonding temperature and perform bonding with extremely high precision. However, it is not efficient, so it is usually only necessary to perform bonding once every several thousand times. In reality, if bonding is repeated about 50 times, Since solder etc. adheres to the thermocompression bonding surface 14 of the thermocompression bonding surface 14 and prevents bonding, the thermocompression bonding surface 1
It is necessary to remove solder etc. from the surface by polishing 4, and the parallelism may be adjusted at this time.

FIG. 2 shows a second embodiment in which the parallelism between the upper surface of the chip stage 6 and the thermocompression bonding tool 4 of the thermocompression bonding head 11 is adjusted by using a parallelism adjustment jig 17 instead of the above-mentioned IC chip 7. The parallelism adjustment jig 17 shown is formed in the same shape as the standard size of the IC chip 7, and a bump portion 19 is provided on the upper surface of the main body portion 18. When adjusting the parallelism using this parallelism adjustment jig 17, first, with the chip stage base 6 swingably arranged in the mounting recess 2, place the parallelism adjustment jig on the chip stage base 6. The tool 17 is placed, and as in the embodiment described above, the Rad 11 is lowered to the thermocompression bonding surface 14 so that the bump portion 1 of the parallelism adjustment jig 17 is lowered.
If you press it on top of 9, the Cheap Stage 6 will become the loading port!
12 to adjust the parallelism between the upper surface of the chip stage base 6 and the thermocompression bonding surface 14 of the thermocompression bonding head 11. After the adjustment, bonding can be performed in the same manner as described above by fixing the chip stage base 6 in the mounting recess 2 and removing the parallelism adjustment jig 17.

In this adjustment method, the parallelism adjustment jig F is
Since it is formed in a standard size, it can always be adjusted to a constant state. Therefore, stable bonding can be achieved at all times without being affected by manufacturing variations in the IC chips 7 by making adjustments only once every several thousand times. In addition, parallelism adjustment jig 1
7 does not necessarily have to have the same shape as the IC chip 7, and may be a plate or the like whose front and back surfaces are parallel.

Figure 3 shows Ws in which the thermocompression bonding surface 14 of the thermocompression bonding head 11 is pressed directly against the top surface of the chip stage base 6 to adjust the parallelism.
Embodiment 3 is shown. In this case, with the chip stage base 6 swingably arranged in the mounting recess 2, the thermocompression bonding surface 14 is simply pressed directly onto the top surface of the chip stage base 6.
Similarly to the above, the upper surface of the chip stage base 6 and the thermocompression bonding surface 1
Since the parallelism with 4 can be adjusted, the adjustment can be made efficiently. In this case, since the thermocompression bonding surface 14 and the top surface of the chip stage base 6 are in surface contact, in order to avoid this, the above-mentioned parallelism adjustment jig 17 is used.
Alternatively, only the protrusion portion corresponding to the bump portion 19 may be fixed to the upper surface of the chip stage base 6 with an adhesive or the like, and the parallelism may be adjusted in the same manner as described above.

Note that the IC chip bonding method of this invention is based on T.
It can be applied not only to the AB method but also to face-down bonding. In this case, the substrate is placed on the top surface of the chip stage 6 which is adjusted parallel to the thermocompression bonding surface 14 of the thermocompression bonding pad 11 as described above. Then, an IC chip may be mounted on this substrate with its electrodes facing the substrate side and bonded.

[Effects of the Invention] As described in detail above, according to the present invention, the thermocompression bonding head is lowered and the thermocompression bonding surface is placed directly or on the top surface of the swingable chip stage table. The placed IC chip is pressed through a plate whose front and back surfaces are parallel, and the upper surface of the chip stage table is adjusted to a position where it is substantially parallel to the thermocompression bonding surface of the thermocompression bonding head, so a skilled person is not required. First, the parallelism between the IC chip and the thermocompression bonding surface can be easily adjusted in a short time, and then the IC chip placed on the chip stage table and the finger leads are bonded. The IC chip and the finger leads can be bonded reliably and accurately without the surface touching the IC chip unevenly.

[Brief explanation of drawings]

! Figure 1 is a sectional view of a main part of a first embodiment in which an IC chip is bonded to a finger lead using a bonding apparatus suitable for the bonding method of the present invention, FIG. 2 is a sectional view of a second embodiment, and FIG. FIG. 3 is a cross-sectional view of the third embodiment. 1...Stage base, 6...Chip stage base, 7...IC chip, 11...
・Thermocompression bonding head, 13...Finger lead, 1
4...Thermocompression bonding surface, 17...Parallelism adjustment jig.

Claims (3)

[Claims] (1) The thermocompression bonding head attached to the bonding device so as to be movable up and down is lowered, and the thermocompression bonding surface is placed on the top surface of the swingable chip stage base directly or on the IC chips mounted on the chip stage base. The top surface of the chip stage base is adjusted to a position substantially parallel to the thermocompression bonding surface of the thermocompression bonding head by pressing through an adjustment jig whose front and back surfaces are parallel, and then placed on the chip stage base. An IC chip bonding method characterized by bonding an IC chip and finger leads. (2) In claim 1, the parallelism between the thermocompression bonding surface of the thermocompression bonding head and the top surface of the chip stage table is adjusted every time the IC chip and the finger leads are bonded. Features of IC chip bonding method. (3) In claim 1, the parallelism between the thermocompression bonding surface of the thermocompression bonding head and the top surface of the chip stage table is adjusted by performing bonding at least a predetermined number of times using the thermocompression bonding head, and An IC chip bonding method characterized in that the bonding method is performed each time the thermocompression bonding surface of the IC chip is polished.