JPH03265150A - Bump transferring method and device - Google Patents

Abstract

PURPOSE:To make each bump joint correctly to a prescribed position on a target lead and to make possible mass production of a tab tape with bumps by a method wherein when ideal spherical bumps are jointed to lead point parts on the tab tape, the bumps are once temporarily fixed in through hole parts in flat plates utilizing a vacuum suction force. CONSTITUTION:A polygonal vacuum suction chamber 1 is constituted using thin flat plates 2 with a plurality of through holes provided therein and fixing elements for taking charge of suction and temporary fixing of a set of bumps to be aligned are respectively constituted of each of the flat plates 2. This chamber 1 is mounted to a bonding pad part of a bonding machine and is rotated around an axis part 4 which is used in combination as a vacuum suction port. A bump feeding mechanism part which is made to position under the lower part of the chamber 1 is constituted of a saucer 5 with the bumps 6 placed thereon and an automatic bump replenishing machine 20 and every time the chamber 1 is rotated, the bumps are picked up by the hole parts 3 and are temporarily fixed on the flat plates 2. After that, when the plates 2 oppose to a bonding tool over the chamber 1, a tape 11 is aligned to the plates 2 and the bumps are transferred and jointed to leads 10.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a bumped TA used in the TAB method, which is a type of connection method between an electrode of an IC chip and an external lead.
In the production of B tape, when transferring the metal that will become the bumps to the lead tip of the TAB tape, the bumps are automatically arranged according to a predetermined arrangement pattern, and then the TAB tape is
The present invention relates to a bump transfer method and apparatus for bonding to the lead end of a tape.

[Conventional technology]

T A B (Tape Automated bong)
The ding (ding) method connects lead wires to the electrodes of an IC chip by connecting metal protrusions called bumps between the tips of the leads patterned on TAB tape and the electrodes of the IC chip. This is a method of joining through the

The bump should be placed on the lead side of the TAB tape or on the IC.
Attach it to either electrode side of the chip and press TAB.
The tape and the IC chip are bonded by applying heat and pressure using a bonding machine.

The method of forming bumps on the lead side of the TAB tape rather than on the IC chip side has become widely used in recent years because there is no fear of damaging the IC chip during bump bonding. The manufacturing method for TAB with bumps is to make the leads thicker, leave only the part that will become the bump, and scrape off the rest by a method such as etching, or make the bumps by plating them on a substrate such as glass in advance. is usually transferred to the tip of the lead. However, in the bumped TAB tapes produced by these methods, the bumps have a nearly rectangular shape, which is not necessarily suitable for bonding with the electrodes of an IC chip.

The inventors of the present application previously proposed a new method for forming spherical bumps on the lead tips of TAB tapes in Japanese Patent Application No. 1-239.
The application was filed as No. 917. In this method, vacuum is applied to the back side of a mold with through holes arranged in alignment with the positions where the bumps are to be arranged, and the metal balls that will become the bumps are attracted to the through holes and temporarily fixed, and then TAB tape is applied. The lead and the temporarily fixed metal ball are overlapped and transfer-bonded.

[Problem to be solved by the invention]

Spherical bumps are easier to deform than conventional rectangular bumps formed by plating on glass substrates, etc., and are advantageous from the viewpoint of bonding.

However, when forming bumps by plating, it is possible to form bumps by specifying the predetermined positions to be arranged from the beginning, whereas spherical bumps are made in pieces, so it is difficult to arrange them in the predetermined positions. The big problem is whether they can be arranged efficiently and furthermore, how they can be easily transferred to the lead portion on the TAB tape.

An object of the present invention is to further develop the previous application and provide an efficient bump transfer method and apparatus suitable for mass production.

[Means to solve the problem]

The present invention provides: (1) A vacuum suction chamber equipped with a flat plate having a plurality of through holes of a predetermined size formed on the upper surface according to a predetermined pattern corresponding to the arrangement of bumps, at the position of the bonding cradle of a TAB bonding machine. The bumps are sucked into the through hole part of the upper flat plate using the suction action of the vacuum suction chamber.
A method for transferring bumps, which is characterized in that after temporary fixation, the bumps are transferred to the leading ends of the aligned TAB tapes by thermocompression bonding.

(2) At the position of the bonding pedestal of the TAB bonding machine, install a vacuum suction chamber equipped with a flat plate having a plurality of through holes of a predetermined size formed on the upper surface according to a predetermined pattern corresponding to the arrangement of bumps, and After the vacuum suction chamber was temporarily removed from the bonding machine body, the bump was suctioned and temporarily fixed in the through-hole part of the flat plate, and then the vacuum suction chamber was pulled back again to a specific position on the top of the bonding cradle of the bonding machine and fixed. A bump transfer method characterized by repeatedly carrying out the series of steps described above in which the bumps are transferred to the lead tips on the aligned TAB tape by thermocompression bonding.

(3) It is possible to rotate a drum-shaped vacuum suction chamber in which a plurality of flat plates are arranged on the circumference and are formed according to a predetermined pattern corresponding to the bump positions where a plurality of through holes of a predetermined size are to be arranged. It is installed so that the upper surface corresponds to the bonding pedestal of the TAB bonding machine, and each flat plate on the circumference of the rotating vacuum suction chamber has the lower part i! ! After the bump is suctioned and temporarily fixed in the through-hole part of the flat plate until it reaches the upper part, the vacuum suction chamber rotates further and the flat plate with the bump temporarily fixed reaches the upward position, and the positioning is performed. A bump transfer method characterized by repeatedly carrying out a series of steps of transferring the bumps to the lead tips on the TAB tape by thermocompression bonding.

(4) a bonding tool having a heating and pressurizing part;
A flat plate in which a plurality of through holes of a predetermined size are formed according to a predetermined pattern corresponding to the arrangement of the bumps, and a vacuum suction mechanism that generates a suction force for temporarily fixing the bumps on the front side of the through holes of the flat plate is provided. A bump suction/temporary fixing part on the back side of the flat plate, a bump supply mechanism part for arranging and temporarily fixing the bumps on the flat plate having a through hole for the bump suction/temporary fixing part, and a TAB tape lead. A bump transfer device characterized by comprising a bump alignment adjustment mechanism section.

It is.

That is, the present invention provides a method and apparatus for manufacturing a TAB tape with bumps, and the TAB tape with bumps manufactured by the method or apparatus according to the present invention is manufactured by bonding the leads of the TAB tape using a TAB bonding machine. After the alignment between the IC chip and the IC chip is performed automatically or manually, the bonding tool heats and presses the bonding tool to bond it to the electrode portion of the IC chip. The TAB tape itself has a structure in which many frames are continuously formed on the tape, with one frame being a portion on which one IC chip is mounted. Usually, the leads are copper plated with gold or tin, and these leads are arranged in a certain pattern on an insulating tape made of polyimide or the like. Generally, this tape is obtained wound on a reel, and each reel is attached to a bonding machine. When one frame of tape unwound from the reel is placed on the bonding stage, it is aligned with the IC chip. Upper joining is performed.

-a, since bumps are often formed on the IC chip side, the lead portion of the TAB tape usually does not have bumps. On the other hand, the idea behind a TAB with bumps is to use one without bumps on the IC chip side, and instead form bumps in advance on the lead portion of the TAB tape. The present invention relates to the production of TAB tape with bumps, and the method for joining bumps to the lead portion of the TAB tape is based on the above-mentioned lead and IC.
As in the case of bonding between the chip and the electrodes, it is convenient to use the thermocompression bonding effect by pressing a heated bonding tool, so we decided to utilize this. That is, the TAB tape before the bumps are bonded is loaded into a bonding machine as a reel, and the spherical bumps are bonded to the lead tips at the bonding stage.

The bonding stage section of a punching machine usually consists of a bonding pedestal on which an IC chip is temporarily placed and a frame-shaped fixture that holds down the TAB tape.
Correcting the relative positional deviation between the two 8! structure is combined. In order to effectively utilize the mechanism of the bonding machine to bond bumps onto the TAB tape lead, which is the aim of the present invention, the bonding stage part, especially the bonding pedestal on which the IC chip is mounted, must be It is necessary to remove it and place bumps arranged to match the lead pattern of the TAB tape. Conversely, as long as bumps arranged according to a certain pattern can be realized on this bonding pedestal, the bumps can be transferred and bonded onto the TAB tape lead using the mechanism of the bonding machine as is. It is thought that it will be possible to do so.

FIG. 1 is a schematic diagram for explaining the basic idea of the present invention. FIG. 1(a) shows a vacuum suction chamber 1 corresponding to a bump suction/temporary fixing section installed in a bonding pedestal section. The upper surface of the vacuum suction chamber 1 has a thin flat plate 2 provided with through holes 3 at positions where bumps are to be arranged. The through hole 3 passes through the vacuum suction chamber 1 and is connected to the vacuum suction port 4, as shown in the cross-sectional view on the side of the figure.

In the same cutaway diagram, only the through hole is hollowed out and the tunnel is connected to the vacuum suction port, but if the flat plate with the through hole is thick and there is no risk of deformation during thermocompression bonding, the vacuum suction chamber 1 There is no problem in having a box-like structure with the inside cut out with the letters remaining, and a thin flat plate 2 with a through hole attached to the top surface. The material for the flat plate 2 needs to be a material that provides a uniform plane, allows for the processing of fine through holes, and is resistant to deterioration due to heat and pressure during bonding. Suitable materials include thin plates made of stainless steel, nickel, etc., and ceramics.

Next, as shown in FIG. 1(b), the vacuum suction chamber 1, which has been evacuated through the vacuum suction port 4, is moved through a large number of bumps 6.
The bump is brought close to the bump supply mechanism constituted by the receiving tray 5 on which the bump is placed, and the bump is sucked and temporarily fixed into the through hole 2 as shown in FIG. In this process, the schematic diagram shows a method in which the bumps are sucked up by inverting the vacuum suction chamber and approaching it from above, but the vacuum suction chamber is held facing upward or diagonally and the bumps are sprinkled onto the surface. It is also possible to use methods.

After the bump has been suctioned and temporarily fixed, the vacuum suction chamber 1 is installed in the bonding pedestal part of the bonding machine as shown in Figure 1 (c), and the positioning adjustment mechanism (not shown in the schematic diagram) is installed in the vacuum suction chamber 1. Positioning between the TAB tape 10 on which the leads 11 are formed on the film base 12 made of an insulating material such as polyimide is performed using the parts 9.
When the alignment is completed, the bumps temporarily fixed to the through-hole portion of the vacuum suction chamber are transferred to the lead portion 11 of the TAB tape by applying a constant load using the bonding tool 7 heated to an appropriate temperature.・Joined.

The vacuum suction chamber 1 where the bumps have been copied returns to the state shown in Figure 1 (b) where it sucks the bumps again, and at the same time, the TAB tape is fed one frame on the bonding machine and the bumps are transferred and bonded in the same way as before. By placing the next frame of the TAB tape in the standby position, the process described above provides an efficient method of successively joining bumps one after another for each frame of the TAB tape that is rewound from the reel. You can see that it will be provided.

FIG. 2 schematically shows a more preferred embodiment of the invention. A plurality of thin flat plates 2 having through-holes 3 are arranged on the circumference of a vacuum suction chamber 1 configured to have a polygonal shape, and constitute a bump suction/temporary fixing section. Each of the flat plates 2 serves as a bump fixing element for sucking and temporarily fixing bumps for one string to be arranged. The vacuum suction chamber 1 is attached to the bonding pedestal portion of the bonding machine, and its upper surface replaces the original position of the bonding pedestal.

Although the vacuum suction chamber 1 is illustrated as being composed of eight bump fixing elements in the schematic diagram, this number can of course be freely increased or decreased as required.

By rotating the polygonal vacuum suction chamber 1 around a shaft portion 4 that also serves as a vacuum suction port, the bump supply 1! The structure, in this example, the tray 5 on which the bumps 6 are placed and the automatic replenishment of the bumps [920] When passing through the part where the bumps are placed, the bumps are sucked into the through hole and temporarily fixed on the flat plate. When the upper bonding position is reached by rotation, alignment with the TAB tape 11 is performed.
A bump is transferred and bonded to the lead 10. When the transfer and bonding of bumps for one frame of TAB tape is completed, the vacuum suction chamber rotates one unit and the TAB tape is also fed one frame. At the same time, bumps are supplied from an automatic supply device,
By performing a series of continuous operations, TAB
Transferring and bonding bumps to the lead portion of the tape can be performed extremely efficiently.

[Effect]

In the method of the present invention, a vacuum suction chamber having through holes is used in a portion where bumps necessary for one frame of TAB tape are arranged in a predetermined pattern. A major feature of the bumps is that they can be arranged naturally and easily by the action of a vacuum, unlike soft metal balls that tend to get crushed or dirty, resulting in defects in their function as bumps.

In addition, by using the main parts of the TAB bonding machine as is and replacing only the bonding pedestal with a vacuum chamber, it is possible to bond bumps to the lead tips of TAB tapes accurately and efficiently. It has become possible.

Further, the apparatus according to the present invention exhibits an optimal function in appropriately performing the above-described process of bonding bumps to the lead portion of the TAB tape.

〔Example〕

Example 1 A vacuum suction chamber as shown in 1 in FIG. 1 was made of stainless steel. A flat plate 2 having a through hole 3 attached to the top surface of this box was made of stainless steel with a thickness of 30 μm, and the through hole was made by an etching method.

The diameter of the through holes is 60 μmφ, -50 per hole,
A total of 200 through holes on all four sides are formed to form approximately 10 fi square.

As the bump 6, a gold ball having a diameter of 80 μmφ was used. A large number of gold balls were stored on a plate 5, and the vacuum suction chamber was brought close to the plate to suction and temporarily fix the gold balls to the through-hole portion.

The TAB tape 10 has the tips of its leads positioned so as to match the arrangement of through holes in a flat plate, and has a gold-plated copper glue 11 formed on a polyimide film 12. Each reel of this tape is loaded in advance in the TAB inner lead bonding machine, and one frame of the tape is loaded on the bonding stage. Next, the vacuum suction chamber 1 with the bump 6 temporarily fixed in the through hole 3 was moved to the bonding pedestal part of the bonding machine while continuing to be vacuumed. After adjusting the lead position of the TAB tape so that it matches the position of the gold ball on the vacuum suction chamber, the bonding tool 7 heated to 450"C is lowered and heated to 3K.
Bonding was performed for 0.5 seconds with a load of gf (15 gf per 1 lead).

As a result, all of the gold balls that had been temporarily fixed in the through holes of the flat plate were accurately transferred and bonded one by one to the lead tips of the TAB tape. After bonding, the bonding strength of the gold balls was measured using the Shear test method for the TAB tape after bonding. It was found that each lead stably held a weight of 1.5 g or more per lead, and was provided with sufficient strength to function as a bumped TAB tape.

Example 2 An octagonal vacuum suction chamber as shown by 1 in FIG. 2 was prepared. The size and arrangement of the through holes 3 for each bump fixing element were all the same as in Example 1. However, flat plate 2 with through holes, plate 30 made by electroforming method.
Made of μm thick nickel. The vacuum suction chamber is built into a bonding pedestal portion of an inner lead bonding machine for TAB, and a vacuum suction port 4 which also serves as a rotating shaft is connected to a vacuum pump. At the bottom of the vacuum suction chamber, a tray 5 is installed which is replenished with a large number of 80 μmφΦ gold balls 6 that serve as bumps, and when the gold balls on this tray are used and the number decreases, they are automatically replenished from the supply device 20. It has a mechanism that allows The upper part of the vacuum suction chamber corresponds to the bonding pedestal part, and rotates intermittently at an angle of 45 degrees. No matter where it rotates and stops, its upper surface is adjusted to be exactly parallel to the plane of the tip of the bonding tool 7.

As in the first embodiment, a piece of TAB tape 10 having a portion 11 that matches the arrangement pattern of the through holes in the flat plate is set on the bonding stage. T.A.
The leads of tape B were made of copper and plated with gold in this example as well. When the vacuum suction chamber begins to be evacuated, the gold ball on the plate is attracted to the through hole at the bottom of the Bonx and temporarily fixed. Next, the vacuum suction chamber is rotated by an angle of 45 degrees corresponding to one pitch, and the gold ball is sucked and temporarily fixed into the through hole of the second element. When a total of four pitches of rotation are applied in the same manner, the element to which the gold ball was first temporarily fixed is sent to the normal position of the bonding pedestal. In this state, align the lead of the TAB tape and bond with the bonding tool 7 heated to 450"C for 0.5 seconds under a load of 3Kgf. The gold balls that were temporarily fixed were all made with one TAB tape lead and one lead.
Transfer and bonding was performed in the designated position of the book.

In this example as well, the bonding strength between the bonded gold balls and leads was stably maintained at 1.5 gf or more, and it was found that the function as a bumped TAB tape was sufficiently satisfied.

Example 3 In Example 2, a tin-plated copper lead was used as the TAB tape. All bonding conditions were the same as in Example 2 except that the heating temperature of the bonding tool was 300'C.

In the case of this example as well, the gold balls were reliably transferred and bonded to the lead tips of the TAB tape. The strength of the joint was slightly lower than that of gold menki tape, but it was 0.7 gf.
More stable bonding strength was achieved.

Example 4 A hexagonal vacuum suction chamber as shown by l in FIG. 3 was used. The material and size of the flat plate 2 and the size and arrangement of the through holes 3 for each bump fixing element were all the same as in Example 2.

The bump supply mechanism section is different from any of the previous embodiments, and includes a bump supply port 8 and a bump receptacle 9 in FIG. The bottom of the tank was destroyed. With these devices, bumps were sprinkled from the bump supply port 8 onto a flat plate located diagonally above the vacuum suction chamber.

The sprinkled bumps 6 are caught in the through holes on the flat plate and temporarily fixed, but after all the through holes are covered with bumps, the extra bumps flow down and are stored in the bump receiver 9 provided below. These are then delivered to the bump supply port 8 again.

When using a large polygonal vacuum suction chamber as in the case of this embodiment, in the method of Embodiment 2, the vacuum chamber becomes open after the bump is transferred and before the next bump is sucked. Vacuum leakage occurs from the through holes in the flat plate, which may weaken the bump suction force. Since the through-hole is small, if the vacuum pump has sufficient capacity, even if the through-hole is partially open, it is possible to generate enough suction force to cause no trouble in the bump suction section. However, if the capacity of the pump becomes small or the drum of the vacuum suction chamber becomes large, the vacuum leakage from the open through hole becomes impossible to ignore. In such cases, use an elastic belt such as rubber.
Although it is effective to close the through hole in the open state as shown in FIG. 4 using the pulley 22 and pulley 22, sufficient bump adsorption can also be achieved by placing the bump supply mechanism at the bottom of the tank as shown in this embodiment. It was confirmed that the power could be maintained.

〔Effect of the invention〕

In the method of the present invention, an ideal spherical bump is TA
When bonding to the tip of the lead on the B tape, the bump is temporarily fixed in the through hole of the flat plate using vacuum suction, allowing for accurate and efficient bonding to the desired position on the target lead. Therefore, it is suitable for mass production of bumped TAB tapes with excellent performance. Further, the device according to the present invention provides the above-mentioned bumped T.
This is optimal for continuous and efficient production of AB tape.

[Brief explanation of drawings]

Figure 1 (a) is a diagram showing the concept of a vacuum suction chamber, Figure 1 (b)
, (C) is a diagram showing a state in which metal particles that will become bumps are temporarily fixed using a vacuum suction chamber, and (d) of the same figure shows a state in which the vacuum suction chamber with the bumps temporarily fixed is placed in an inner lead bonding machine for TAB and bonding 2 is a diagram conceptually showing a more desirable embodiment B of the present invention, and FIG. Schematic perspective view of the chamber,
Figure 3(b) shows an example of a bonder for bump transfer and bonding of bumped TAB tapes by incorporating and integrating a vacuum suction chamber into a TAB inner lead bonding machine. FIG. 4 is a diagram showing an example of a more desirable embodiment of the present invention, similar to FIG. It is a figure which shows an example of the mechanism which can measure the stabilization of a bump suction effect by combining with a figure. 1...Vacuum suction chamber 1,...Flat plate with through holes,...Through holes for temporarily fixing bumps,...Vacuum suction port 2,...Dish for storing bumps,... Metal particles that become bumps, ... bonding tool, ... bump supply port, 9 ... bump receiver, 0 ... T
AB tape, 1...TAB tape lead, 2...TAB tape head film, 0...bump automatic supply machine, 1...bump return device, 2...pulley 23..., belt.

Claims (4)

[Claims] (1) At the position of the bonding pedestal of the TAB bonding machine, install a vacuum suction chamber equipped with a flat plate having a plurality of through holes of a predetermined size formed on the upper surface according to a predetermined pattern corresponding to the arrangement of bumps. Using the suction action of the vacuum suction chamber, the bumps are sucked into the through-hole part of the upper flat plate.
A method for transferring bumps, which is characterized in that after temporary fixation, the bumps are transferred to the leading ends of the aligned TAB tapes by thermocompression bonding. (2) At the position of the bonding pedestal of the TAB bonding machine, install a vacuum suction chamber equipped with a flat plate having a plurality of through holes of a predetermined size formed on the upper surface according to a predetermined pattern corresponding to the arrangement of bumps, and After the vacuum suction chamber was temporarily removed from the bonding machine body, the bump was suctioned and temporarily fixed in the through-hole part of the flat plate, and then the vacuum suction chamber was pulled back again to a specific position on the top of the bonding cradle of the bonding machine and fixed. A bump transfer method characterized by repeatedly carrying out the series of steps described above in which the bumps are transferred to the lead tips on the aligned TAB tape by thermocompression bonding. (3) It is possible to rotate a drum-shaped vacuum suction chamber in which a plurality of flat plates are arranged on the circumference and are formed according to a predetermined pattern corresponding to the bump positions where a plurality of through holes of a predetermined size are to be arranged. It is installed so that the upper surface corresponds to the bonding pedestal of the TAB bonding machine, and each flat plate on the circumference of the rotating vacuum suction chamber passes through the lower part and reaches the upper part. After the bumps are suctioned and temporarily fixed in the through-holes of the flat plate, the vacuum suction chamber rotates further until the flat plate with the bumps temporarily fixed reaches an upward position, and then thermocompression is applied to the lead tips on the aligned TAB tape. A bump transfer method characterized by repeatedly performing a series of steps leading to transfer of bumps by action. (4) a bonding tool having a heating and pressurizing part;
A flat plate in which a plurality of through holes of a predetermined size are formed according to a predetermined pattern corresponding to the arrangement of the bumps, and a vacuum suction mechanism that generates a suction force for temporarily fixing the bumps on the front side of the through holes of the flat plate is provided. A bump suction/temporary fixing part on the back side of the flat plate, a bump supply mechanism part for arranging and temporarily fixing the bumps on the flat plate having a through hole for the bump suction/temporary fixing part, and a TAB tape lead. A bump transfer device characterized by comprising a bump alignment adjustment mechanism section.