JPH0237729A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce manufacturing equipment and manufacturing cost by using lead frame without an island part and performing wire bonding without performing chip bonding process of a semiconductor element (chip). CONSTITUTION:A lead frame 1 without an island carried to a wire-bonding position is fixed and heated. Then, a chip 12 on an adhesion sheet is picked up, is carried to a wire-bonding position, the chip 12 is directly mounted to a heating-block, and then is heated and fixed. Then, an internal connection part 9 of a lead frame 7 and a pad on the chip 12 are connected by a wire and the lead frame 1 without any island is carried by one pitch along with the chip 12 suspended by a wire. It allows die-bonding process of the chip 12 to be omitted, thus simplifying both the manufacturing device and process.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor device, and in particular, to a method for manufacturing a semiconductor device, in particular, a method for bonding a semiconductor element (hereinafter referred to as a chip) using a lead frame without an island portion. The present invention relates to a method for manufacturing a semiconductor device in which wire bonding is performed without any process.

[Prior Art] Traditionally, typical bonding methods of this type include the wire bonding method (TC method, TS method, US method) using a lead frame with an island, and the TAB method using a film carrier (for example, Showa 57-76850
The former involves die bonding the chip to the island of the lead frame and then connecting the internal connection part of the lead frame and the pad on the chip with a wire. The bumps on the chip are bonded to the leads, the chip with the leads is cut and separated from the film carrier, and then the leads are bonded to the lead frame or other mounting location.

[Problems to be Solved by the Invention] The above-described conventional wire bonding method using a lead frame with an island has the following drawbacks.

1, t5f After sealing with fat, moisture enters from the bonding interface between the resin and the island suspension lead, causing deterioration of the semiconductor device.

2. Due to the difference in linear expansion coefficient between the chip and the island portion, heating during the manufacturing process causes a difference in thermal expansion, which causes cracks in the chip due to thermal stress.

3. Since a chip bonding process is required, equipment and adhesives are required.

4. After resin encapsulation, due to the difference in linear expansion coefficient or elastic coefficient between the resin and the island, thermal stress due to heating during the resin encapsulation process and subsequent processing steps and during mounting on printed circuit boards, etc. Due to this action, cracks occur in the resin. This becomes especially noticeable when the chip size becomes larger than 10 m+e.

5. In a multi-pin lead frame with more than 100 leads, the island hanging lead has a width of 0.3 sm and a length of 1oII11 or more, and when heated during wire bonding, it thermally expands and the wire During bonding, the island portion becomes misaligned, resulting in bonding misalignment. In addition, the width of the hanging leads is also narrow, and when the island section is pressed down, the edges of the heating block used for bonding are also narrow, making alignment extremely difficult.

6. Since a chip adhesion process is required, defects (chip chipping, misalignment, adhesive stains, etc.) occur due to this process.

7. Chip heating during wire bonding is performed through the metal plate of the island portion, so the island portion and the heating block must be in close contact, resulting in poor thermal efficiency.

8. The lead frame design and manufacturing are limited by the island section, which requires more man-hours and makes the process more complicated.

9. The hanging lead in the island part causes natural vibration due to the rigidity of that part, which causes vibration relative to the lead side, resulting in defects such as wire breakage and loop abnormalities.

On the other hand, the conventional TAB method using a film carrier has the following problems.

1. The chip price is high because bumps for adhering leads are formed on the chip.

2. Since the leads on the film carrier are formed to match the bumps on the main surface of the chip, the film carrier needs to be changed according to the chip design, and the film carrier has poor versatility. 3. The number of connected leads is 100. When a large number of bottles is used, the width of the lead tip becomes 0.1 aug or less, which makes it easy to bend the internal connection lead portion and make bonding difficult.

4. Equipment costs are high because the bonding equipment is special.

[Means for Solving the Problems] The manufacturing method of the present invention includes: (1) fixing an island-less lead frame transported to a wire bonding position there and heating it; (2) picking up a chip on an adhesive sheet; Transport this to the wire bonding position. ■ Place the chip directly on a heating block, heat it, and fix it there. ■ Connect the internal connection part of the lead frame and the pad on the chip with a wire. , (1) Transporting only one pitch of a lead frame without an island along with a chip suspended by a wire.

[Example] Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a plan view of a lead frame without an island used in the present invention, and this lead frame 1 has a tie bar 8 between a pair of frames 7 and 7, similar to the conventional lead frame. A lead 10 having an internal connection portion 9 at its inner tip extends from the tie bar 8. However, this lead frame eliminates the island and island suspension leads required in conventional lead frames.

An embodiment of the present invention using this lead frame without islands will be described with reference to FIGS. 2(I) to (V) and FIG. 3.

(1) Lead frame conveyance process [see FIG. 2 (I)] The island-less lead frame 1 is gripped by the closing operation of the upper claw 2 and the lower claw 3 driven by an automatic feed positioning means (not shown). Then, after the heating block 4 is lowered by the heating block position up/down means 13 and the lead presser 28 is raised by a driving means (not shown), the upper claw 2
While holding the lead frame, the lower claw 3 is moved by one pitch of the lead frame to the right in the figure by the automatic feed positioning means.

(2) Lead frame fixing process [Figure 2 (■) 9] The internal connection part 9 of the island-less lead frame 1 is sent to the wire bonding position 6, and when the horizontal positioning is completed, the heating block 4 is raised. , the lead presser 28 is lowered, and the lead frame 1 is positioned and fixed. Then, the lead frame 1 is heated here,
Prepare for bonding. The temperature control of the heating block 4 is as follows:
As shown in FIG. 2(r), the signal from the thermocouple 5 inserted into the block 4 is input to the heating temperature control means 14,
Output current At! of this heating temperature control means 14! - by supplying a heater 15 embedded within the block. The upper claw 2 and lower claw 3 are shown in Fig. 2 (I
) to the left position shown in the figure.

3) Chip conveyance process [see Figures 2 (■) and 3] The chips 12, which have been positioned in advance, are vacuum-adsorbed by the chip suction nozzle 23 provided at the tip of the chip supply arm 22. , the chip 12 is carried above the wire bonding position 6 by the rotation of the chip supply arm 22, and lands at the bonding position 6 by the downward movement of the chip supply arm 22. A concave depression with a depth of about 0 to 1 mm is provided at the bonding position of the heating block 4. The bottom of this recess is precision-finished to ensure good adhesion with the chip. Further, the size of this depression is somewhat larger than that of chip 12,
In addition, the internal connection portion 9 of the lead frame 1 is set to a size that does not protrude above the recess.

When the chip 12 lands in this recess, the arm drive control means 17 issues a chip supply completion signal to the chip supply arm 22, and the vacuum guided to the chip suction nozzle 23 is cut off. Then, the chip supply arm 22 moves to a position where it does not interfere with the operation of the bonding device. Note that during the chip conveyance process, the bonding device is evacuated to the rear (toward the right side of the figure) as shown in FIG.

The chip supply arm 22 transfers the chips 12 to the heating block 4.
While the chip 12 is being transported, the position of the next chip 12 is corrected by the operation of the camera 19, the position correcting means 18, and the chip XY stage 27, and the chip suction nozzle 2
3 returns to the chip suction position, the position is controlled so that it is located at the center of the chip suction nozzle 23. Other chips are also arranged on the seat 24, which is fixed to the seat ring 25. And seat ring 2
5, a ring holder fixed to the chip xY stage 27 is fixed to the stand 26 with screws or the like.

(4) Chip heating/fixing process [see FIG. 2 (1)] When the chip 12 is transported to the bonding position Tt6 and the suction of the chip suction nozzle 23 is cut off, the signal is sent to the vacuum guiding means 16. The vacuum electromagnetic valve 15 is opened, whereby the chip 12 is vacuum-suctioned through the vacuum suction hole 11 and the pipe drilled in the heating block, and is fixed there. The chip 12 is then directly heated by the heating block 4.

(5) Wire bonding process [See Figure 2 (IV)] Next, the bonding device that had been evacuated to the position shown in 3I21 moves forward to perform wire bonding (moves to the left from the position shown in the figure). ), and the bonding device is applied to the chip 12 which is held at the wire bonding position 6 and is heated, and to the internal connection portion 9 of the lead frame 1 which is held and heated by the lead presser 28 and the heating block 4. , wire bonding is performed, in this case the bonding head 30
A camera 20 fixed to the chip 12 images two points on the chip 12 and transmits the image information to the recognition control means 21 . Then, the recognition control means calculates the amount of positional deviation of the chip based on the information and determines the bonding position. Based on the result, the XY stage control section 29 drives the χY stage 31. A bonding head 30 is fixed on the XY stage 31, and a bonding arm 37 is supported on the bonding head 30 so as to be movable up and down. A bonding tool 51 that performs the tensioning operation is fixed to the bonding arm 37. The vertical movement of the bonding tool 51 during the tensioning operation is performed by the bonding arm 37, and the movement on the horizontal plane is performed by the high-speed, high-precision movement of the XY stage 31.

When the predetermined wire bonding is completed, the vacuum electromagnetic valve 15 connected to the vacuum guiding means 16 is switched to return the vacuum in the vacuum suction hole 11 to normal pressure.

With this, one cycle of the embodiment of the present invention is completed. Thereafter, the process returns to the lead frame conveying step (1) again, and the island-less lead frame 1 is conveyed by a pitch of {circle around (1)}. At this time, as shown in FIG. 2(V), the wire-bonded chip 33 is transported together with the lead frame 1 while being supported by the wire loop 32.

Next, other embodiments of the present invention will be described.

FIG. 4 shows a heating block 36 having a wire support portion 52 formed around the periphery of the chip holder opening 34. As shown in FIG. This wire support portion 52 can prevent the wire loop 32 from being defective in shape and stabilize the state in which the bonded chip 33 is held.

FIG. 5(a) is a side view of yet another embodiment, and FIG.
Figure <b) is a sectional view taken along line A-A.

In this embodiment, the chip holding and fixing means of the previous embodiment is replaced with a mechanical chip pressing and fixing means, and a heating block 44, chip pressing claws 41 and 42, and a mechanical chip pressing unit 43 are used. . Figure 2 (I), (
Lead frame 1 without islands in the same manner as It)
After holding and fixing the internal connection part 9 of the chip with the lead presser 28,
The chip 12 held by suction by the heating block 44 is conveyed to the wire bonding position W45 of the heating block 44. Then, at the same time as it lands here, the chip pressing claws 41 and 42 approach the chip 12 so as to sandwich the sides thereof by the action of the mechanical pressing unit 43, and press and fix the chip 12 from both sides. Thereafter, wire bonding is performed in the same manner as in FIG. 2 (IV) and thereafter. In this embodiment, the center of the chip is not unheated due to the vacuum suction hole, which is advantageous when there is a connecting electrode in the center of the chip or when heating a small chip.

Still another embodiment will be described with reference to FIGS. 6(a) and (b). FIG. 6(a) is a diagram showing a state in the middle of chip transportation, and FIG. In this embodiment, the chip supply arm 22 is inserted between the island-less lead frame 1 and the heating block 4 that is lowered significantly downward to supply the chips. It was designed so that

In this embodiment, first, the internal connection portion of the island-less lead frame 1 is fed directly above the wire bonding position 48 by the same automatic feeding means as in the first embodiment. Simultaneously with or after this timing, the heating block position up/down means 47 lowers the heating block 4 by about 15 mm or more from the lower surface of the island-less lead frame 1 and maintains that state. Thereafter, the chips 12 are supplied to the recessed portion of the heating block 4 by the chip supply operation of the chip supply arm 22 in the same manner as in the previous embodiment.

After the chips 12 are aspirated there, the chip supply arm 2
2 and the chip suction nozzle 23 are avoided from above the heating block 4 as shown in FIG. 6(b). Thereafter, the heating block 4 is raised by the action of the heating block position up/down means 47, and at the same time the lead presser is lowered, resulting in a state similar to that shown in FIG. 2 ([).

Next, regarding the method of supplying the chips 12 onto the heating block 4, a method different from that illustrated in FIG. 3 will be explained.
This will be explained with reference to FIGS. 7 and 8. When transporting the chips 12 onto the heating block 4, the chip supply arm 22, bonding arm 37, and bonding tool 51
They may interfere with each other. In order to avoid this, in the example shown in FIG. 3, the entire bonding head 30 is moved back to the illustrated position (to the right in the figure), whereas in the example shown in FIG. A thin chip supply arm 38 and a thin chip suction nozzle 39 are used, and these are attached to the lead frame 1 and the bonding tool 51 when the bonding arm is lifted upwards.
It is designed to be thin, for example, 2.5a++*, so that it can fit between the two.

Further, in the example shown in FIG. 8, an XY stage vertical movement means 40 is provided below the XY stage 3, and thereby the bonding apparatus is retracted upward during the chip conveyance process.

In the present invention, the components shown in FIGS. 3, 7, and 8 may be combined to avoid interference between the bonding device and the chip supply arm 22.

Further, as for the wire bonding method, not only the TC method but also any commonly used bonding method may be used.

By the way, the drawbacks of using a lead frame without an island are: - During resin encapsulation, the chip position and wire loop change due to the resin flow;
(2) heat dissipation deteriorates, (2) it is impossible to heomicically bond the back surface of the substrate to the metal plate, etc. The inventors of the present invention have already found that the problem (2) can be overcome by controlling the resin flow rate during resin molding. Regarding (2), most IC chips today are die-bonded to islands using epoxy adhesive, so even if they do not use islands, they are superior in terms of heat dissipation compared to those that use them. There is no comparison. As for (2), there is no particular problem even if the island is removed, since conventionally the substrate and the island have often not been connected in an ohmic manner. Furthermore, if it is simply desired to keep the back surface of the chip at the same potential, this can be achieved by depositing AI or Au on the back surface of the substrate.

[Effects of the Invention] As explained above, according to the present invention, the process of die bonding of chips can be omitted. Therefore, manufacturing equipment and manufacturing costs are reduced as a whole.■ Chip chipping and cracking caused by the die bonding process are eliminated.■ Adhesives for die bonding are no longer required, and This has the effect of eliminating dirt on the chip and lead frame, and furthermore, by fixing the chip directly on the heating block and heating it, ■The chip is brought into close contact with the heating block and the chip is heated directly. ■Thermal efficiency is improved because uneven heating of the chip is eliminated, so bonding defects are reduced. ■During bonding, natural vibrations caused by the rigidity of the hanging leads of the island part are eliminated, so stable bonding is possible. It has the following effects: Furthermore, according to the present invention, it is possible to use a lead frame without an island, which makes designing and manufacturing the lead frame easier, and also makes positioning easier in the process of fixing the lead frame at the wire bonding position. It becomes easier. Further, according to the present invention, it is possible to manufacture a semiconductor device in which moisture does not enter from the hanging leads after resin molding and in which cracks in the resin due to islands do not occur.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a lead frame without an island used in the present invention; FIGS. 2(I) to (Vl) and FIG. 4 to 8 are diagrams for explaining other embodiments of the present invention, respectively. 1... Lead frame without island, 2... Upper claw, 3... Lower claw, 4. 36.44,... heating block, 6... wire bonding position, 9.
...Internal connection part, 11...Vacuum hole, 12...
Chip 22...Chip supply arm, 23...Chip suction nozzle, 27...Chip XY stage, 2
8... Lead holder, 30... Bonding head, 31... XY stage, 32... Wire loop, 33... Bonded chip, 37...
Bonding arm, 41.42...Chip pressing claw.

Claims (1)

[Claims] A lead that fixes and heats the part of the unit to be bonded in the current wire bonding process of the island-less lead frame consisting of a plurality of units, which has been transported to the bonding position and is transported to the bonding position. a frame fixing/heating process; a semiconductor element transport process for transporting the semiconductor element from its supply position to the bonding position; and at the bonding position, the transported semiconductor element is directly placed on a heating means and heated. And,
a semiconductor element heating and fixing process for fixing the semiconductor element; a wire bonding process for connecting the internal connection part of the island-less lead frame and the pad of the semiconductor element with a wire at the bonding position; A method for manufacturing a semiconductor device, comprising: a step of transporting a lead frame together with the semiconductor element suspended by a wire in units.