JPH0888250A - Tab tape and bonding method of tab inner lead - Google Patents

Abstract

PURPOSE: To provide a TAB inner lead bonding method and a TAB tape, wherein the inner leads are capable of being bonded uniform in bonding strength and narrowed in pitch. CONSTITUTION: A bump 8 of a 10mm square semiconductor device 21 is aligned with an inner lead 2, and the tip of the inner lead 2 is pressed by a clamper 23 with a pressure of 200gf/lead. Then, an ultrasonic horn 31 is made to descend, a bonding tool 32 is pressed against the inner lead 2, and the inner lead 2 comes into contact with the bump 8 of the semiconductor device 21. Then, ultrasonic vibrations 33 are applied in parallel with the direction of the ultrasonic horn 31, and the inner lead 2 and the bump 8 are bonded together at the heating temperature of 280 deg.C of the semiconductor device 21. At bonding, as a bonding load F of 60gf is applied to the bonding tool 32, an ultrasonic power of 100mW (amplitude:0.2μm) is applied. An above operation is carried out to all the inner leads 2 so as to bond them to the bumps 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TAB (Tape Automated Bo) used for mounting a semiconductor element.
The present invention relates to a bonding method and a TAB tape for bonding an inner lead of a tape carrier for a tape and an electrode of a semiconductor element.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a TAB tape is formed with a device hole 6 for mounting a semiconductor element and a support ring 4 for holding a Cu wiring electrode on a long tape carrier 1 made of polyimide. Has been done. At both ends of the width method of the tape carrier 1, sprocket holes 5 which are standardized at equal pitch intervals for tape positioning and transportation are previously formed by press working. The support ring 4 is formed with an inner lead 2 protruding inside the device hole 6 and an outer lead 7 outside for electrical connection with a substrate on which a TAB tape is mounted. All Cu wiring electrodes including inner leads and outer leads are plated with Au or Sn to a thickness of 0.5 to 1 μm by electrolytic plating or electroless plating.

FIG. 4 is a schematic view showing a conventional method of connecting inner leads in the TAB tape shown in FIG. Inner lead 2 of TAB tape and semiconductor element 21
In the single point bonding method in which the Al electrode portion of the semiconductor element 21 and the Al electrode portion of the TAB tape are sequentially bonded, a bump 8 is formed on either the Al electrode portion of the semiconductor element 21 or the tip of the inner lead 2 of the TAB tape. Bonding is performed by a bonding tool 32 via a method using both ultrasonic waves and heat. At this time, a load of 100 gf and an ultrasonic output of 150 mW are applied to the joint portion, and the semiconductor element 21 is heated to about 250 ° C. by the heating stage.

[0004]

In order to obtain a stable bonding strength by the single point bonding method using thermocompression bonding with ultrasonic wave, it is necessary to sufficiently remove the Sn natural oxide film existing in the Sn plating layer on the inner lead surface by ultrasonic vibration in order to obtain stable bonding strength. It is necessary to form a sufficient alloy layer of Sn on the surface of the inner lead and Au on the bump by thermal energy generated by the heating stage. Here, as shown in FIG. 4, the sides where the ends of the inner leads are arranged are perpendicular to the longitudinal direction of the tape carrier 1 as the first side H1 and the second side H2, and are parallel to the longitudinal direction of the tape carrier 1. When the different sides are the third side and the fourth side, the vibration direction 33 of the ultrasonic wave applied to the ultrasonic horn 31 is the longitudinal direction of the inner lead 2 with respect to the third side H3 and the fourth side H4. Parallel to the first side H
1, the direction perpendicular to the longitudinal direction of the inner lead 2 with respect to the second side H2.

When the ultrasonic vibration 33 is applied in the direction orthogonal to the longitudinal direction of the inner lead 2 like the first side H1 and the second side H2, the ultrasonic vibration 33 causes the inner lead 2 to move. The ultrasonic vibration 33 cannot be sufficiently transmitted to the bonding interface, and the Sn oxide film cannot be destroyed. Therefore, the bonding strength of the first side H1 and the second side H2 is
There is a problem that it is lower than the third side H3 and the fourth side H4.

Further, when the ultrasonic wave output is increased in order to reduce the variation in the bonding strength, the positional deviation of the inner leads increases and there is a risk of contact with the adjacent inner leads, which hinders the narrowing of the pitch. There was a problem.

Further, when the lead pitch is 100 μm or less, the lead width becomes as thin as 50 μm or less and the lead rigidity becomes small, so that the lead sags and the lead bend occurs during the production of the TAB tape, which causes a decrease in yield. It was

An object of the present invention is to solve such problems and realize a stable bonding with no variation in bonding strength.
An object of the present invention is to provide a TAB inner lead bonding method and a TAB tape capable of achieving a narrow pitch.

[0009]

SUMMARY OF THE INVENTION The present invention is a TAB tape having an inner lead having a wiring electrode protruding inside a support ring for mounting a semiconductor element, the base film holding a tip of the inner lead. It is characterized by

Further, the present invention is a method for joining the inner lead of the TAB tape and the electrode of the semiconductor element, wherein the inner lead and the electrode of the semiconductor element are aligned with each other, and a tip of the inner lead tip is provided by a clamper. Is pressed, and the bonding between the inner lead and the electrode is sequentially performed by a bonding tool.

[0011]

The TAB tape of the present invention prevents the lead from sagging and the pitch deviation caused by the bending of the lead, which is caused at the time of manufacturing the TAB tape, particularly when the inner lead is etched, by the lead holding film provided at the tip of the inner lead. Yield has been improved and the pitch can be narrowed.

Further, in the joining method of the present invention, the inner lead is suppressed by the clamper, so that the positional deviation of the lead due to ultrasonic vibration can be prevented, and the lead pitch can be joined at a narrow pitch. Furthermore, since ultrasonic vibrations are efficiently transmitted to the bonding interface, it is possible to bond with a low-power ultrasonic output,
Bonding stress on the semiconductor element has been reduced, enabling highly reliable bonding.

[0013]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a schematic view showing a TAB tape according to an embodiment of the present invention. As shown in FIG. 1, the TAB tape of the present invention has, for example, a thickness of 100 to 125 μm and a width of 35.
On a long tape carrier 1 made of polyimide of mm, a device hole 6 for mounting a semiconductor element and a thickness of, for example, 3
A support ring 4 for holding a Cu wiring electrode of 5 μm is formed. On both sides of the tape carrier 1 in the width direction, sprocket holes 5 standardized at equal pitch intervals are previously formed by pressing for tape positioning and transportation.

Outer leads 7 having a width of 100 μm and an arrangement pitch of 200 μm, for example, are formed on the outer side of the support ring 4 for electrical connection with the substrate on which the TAB tape is mounted. Inner leads 2 having a width of 60 μm and an arrangement pitch of 100 μm, for example, are formed inside the support ring 4 so as to protrude toward the device hole 6. In order to reinforce the inner lead 2 and prevent the lead position from being displaced due to ultrasonic vibration during bonding, the inner lead 2 is held at the tip from below, for example, a lead made of a polyimide of the same material as the tape carrier 1. The holding film 3 is formed.

All Cu wiring electrodes including the inner leads and the outer leads are plated with Sn, for example, to a thickness of 0.5 μm by electroless plating. The yield of the TAB tape was as high as 98% or more for the TAB tape having the lead arrangement pitch of 100 μm or less by providing the lead holding film 3.

Next, a method of bonding the inner leads in the TAB tape shown in FIG. 1 will be described.

FIG. 2 is a schematic view showing the inner lead bonding method of the present invention. As shown in FIG. 2, on the Al electrode 22 of the semiconductor element 21, by electrolytic plating,
For example, a bump 8 made of Au having a height of 20 μm and a diameter of 50 μm
Are formed.

First, after the bumps 8 of the 10 mm square semiconductor element 21 and the inner leads 2 are aligned, a clamper 23 is used to move the tip of the inner leads 2 onto, for example, 20
Pressurize with 0 gf / 1 lead.

Next, the ultrasonic horn 31 descends, the bonding tool 32 is pushed into the inner lead 2, and the inner lead 2 and the bump 8 of the semiconductor element 21 come into contact with each other. Further, the ultrasonic vibration 33 is applied in parallel to the direction of the ultrasonic horn 31, and the heating temperature of the semiconductor element 21 is 280 ° C.
Underneath, the inner leads 2 and the bumps 8 are joined. At the time of bonding, the bonding load is F = to the bonding tool 32.
With 60 gf applied, an ultrasonic output of 100 mW (amplitude width 0.2 μm) is applied.

The above operation was performed on all the inner leads 2 to join the bumps 8. After that, measure the joint strength,
Observe the amount of positional deviation between the inner lead 2 and the bump 8,
It was observed whether cracks were generated under the surface of the Al electrode 22. As a result, the pull strength was 30 gf / lead (δ = 5) on average on all sides, and it was possible to join with practically sufficient strength with little variation. Moreover, the inner lead 2 and the Al electrode 22
The amount of positional deviation between and was 10 μm or less, and could be reduced to about half that of the conventional joining method. Furthermore, Al
It was confirmed that no crack was generated under the surface of the electrode 22.

Further, in the inner lead bonding of the semiconductor element having the outer dimensions of 15 mm square and the electrode array pitch of 80 μm, by using the TAB tape and the bonding method of the present invention, reliable and stable bonding strength can be obtained, and It is possible to perform highly accurate bonding with a positional deviation amount of the inner leads of 10 μm or less, large-sized chips and narrow pitch TA.
B mounting becomes possible.

Furthermore, after joining the inner leads, a temperature / humidity cycle test (MIL-STD-883B) is performed as an environmental test.
According to the test method of 1). Environmental conditions are temperature 2
The temperature was 5 ± 2 ° C. to 65 ± 2 ° C., the humidity was 90 to 98%, and the number of cycles was 10 cycles (24 Hr / cycle). According to the pull strength test after the temperature and humidity test, the strength did not decrease.

In the present invention, the ultrasonic output can be reduced as compared with the conventional thermocompression bonding using ultrasonic waves.
It has been confirmed that the mechanical stress applied to the semiconductor element is reduced, and it is also effective for bumpless bonding in which the inner lead and the Al electrode are directly bonded without passing through the bump.

[0025]

As described above, according to the joining method of the TAB tape and the TAB inner lead of the present invention,
The lead-holding film can realize stable bonding with little variation in bonding strength, minimize the positional deviation between the inner lead and the electrode of the semiconductor element due to ultrasonic vibration, and realize large chip and narrow pitch TAB mounting. The effect is that you can do it.

Further, the transmission efficiency of ultrasonic vibration is improved, and the bonding can be performed at a low output, and the bumps and the inner leads of the semiconductor element can be bonded to the bumps and the inner leads of the semiconductor element with sufficient strength without causing damages under the electrode surface of the semiconductor element. Has the effect of joining with high reliability.

Further, the lead holding film provided at the tips of the inner leads can prevent pitch deviation due to lead sag and lead bending, and can improve the yield of the TAB tape, resulting in cost reduction.

[Brief description of drawings]

FIG. 1 is a schematic view showing a TAB tape of the present invention.

FIG. 2 is a schematic view showing a method for joining inner leads according to the present invention.

FIG. 3 is a schematic view showing a conventional TAB tape.

FIG. 4 is a schematic view showing a conventional TAB inner lead bonding method using bumps.

[Explanation of symbols]

 1 tape carrier 2 inner lead 3 lead holding film 4 support ring 5 sprocket hole 6 device hole 7 outer lead 8 bump 21 semiconductor element 22 Al electrode 23 clamper 31 ultrasonic horn 32 bonding tool 33 ultrasonic vibration direction H1 first side H2 first 2nd side H3 3rd side H4 4th side

Claims (4)

[Claims] 1. A TAB having an inner lead with a wiring electrode protruding inside a support ring for mounting a semiconductor element.
A TAB tape comprising a base film for holding the tips of the inner leads. 2. The TAB tape according to claim 1, wherein the base film holds the tips of the inner leads from below. 3. A method of bonding an inner lead of a TAB tape and an electrode of a semiconductor element to each other according to claim 1, wherein the inner lead and the electrode of the semiconductor element are aligned with each other, and a top of the inner lead tip portion is clamped by a clamper. A method of joining TAB inner leads, characterized in that the inner leads and the electrodes are sequentially joined by pressing with a bonding tool. 4. The method of joining TAB inner leads according to claim 3, wherein bumps are formed on the electrodes, and the inner leads and the electrodes are joined via the bumps.