JPH0758723B2 - Film carrier tape - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film carrier system (TapeAutomated) which is one of surface mounting of ICs and LSIs.
The present invention relates to a film carrier tape used for Bonding (abbreviated as TAB method).

[0002]

2. Description of the Related Art Conventionally, as a structure of a film carrier tape, an upper surface of a copper foil as a material is directly plated with Au over the entire surface, or an upper surface of the copper foil is plated with Ni over the entire surface. After that, commercially available products are those that are Au plated over the entire surface, or film carrier tapes that are Sn plated directly over the entire surface of the copper foil. However, it has become necessary to improve the reliability and stability of the bonding of the outer lead portion during the connection operation with the external circuit, so in recent years, the outer lead portion has been tin-lead solder alloy plated. Demand for products with the required specifications is increasing.

[0003]

In order to satisfy the product structure based on the above specifications, for example, as shown in FIG. 3, after the Au plating 15 is applied over the entire upper surface of the copper foil 14, the outer lead portion 12 is formed. Tin lead solder plating on top 1
The manufacturing method of applying 6 has been often used. However, in this case, Au is used as the base of the tin-lead solder plating 16.
Since the plating 15 exists, a diffusion phenomenon occurs between the gold plating 15 and the tin-lead solder plating 16 when a heat treatment that is unavoidable in the IC manufacturing process is performed, resulting in When the outer lead part is connected to the external circuit by the Au-Sn alloy layer formed on the
There has been presented a problem that the bondability and wettability of the outer lead portion are remarkably deteriorated, which easily leads to defective connection.

Further, when the tin lead solder plating 16 is applied to the outer lead portion 12, the tin lead solder plating 16 is applied even to the test pad portion 13 for the purpose of simplifying the work procedure. Since the electrical contact resistance of the plated surface 16 increases significantly, as a result, there remains a problem in reliability when inspecting the electrical characteristics of the film carrier tape 1 and stability of product characteristics.

[0005]

As a means for solving the above situation, the present invention provides an outer lead portion 12
Even in the case of applying the tin-tin-lead solder alloy plating 16, the surface of the Au plating 15 is exposed in the test pad portion 13,
Moreover, the present invention provides a film carrier tape in which the tin-lead solder alloy plating 16 area is not adjacent to the Au plating 15 area.

[0006]

The present invention exposes the Au plating 15 on the upper surface of the test pad portion 13 before the tin lead solder plating 16 is applied to the outer lead portion 12.
By arranging the tin-lead solder alloy plating 16 region so as not to be adjacent to the plating 15 region, even if the heat treatment that is unavoidable in the IC manufacturing process is performed, the gold-plating 15 and the tin lead A diffusion phenomenon does not occur between the solder plating 16 and the Au-Sn alloy layer is eventually formed, so that the bonding property and wettability of the outer lead portion 12 are not significantly reduced. Not only that, since the electric contact resistance in the test pad portion 13 can be prevented from significantly increasing, the electric characteristic inspection after the IC and LSI are formed in addition to the electric contact inspection after the film carrier tape is manufactured. In addition to improving its reliability, it has also become possible to improve the stability of product quality.

[0007]

Example 1 As shown in the structure of FIG. 1, a base copper foil 10 having a thickness of 35 μm
Gold plating on the entire surface of the lead pattern obtained by processing
5 is applied to 2 μm, and then tin lead solder plating 16 having a composition of 9: 1 is applied to the outer lead portion 12 to a thickness of 8 μm.
Further, a film carrier tape 1 having a 2 μm-thick Au plating 15 region applied to the test pad portion 13 without adjoining the tin-lead solder plating 16 region was produced. In the figure, 2 is a sprocket hole, 3 is an inner lead hole, 4 is an outer lead hole, 5 is an inner lead,
Reference numeral 6 is an outer lead, 7 is a test pad, 8 is a wiring for plating, 13 is a test pad portion, and 17 is a polyimide substrate. This film carrier tape 1 was subjected to a heat treatment at 175 ° C. for 24 hours, and the zero cross time was measured by a solder checker [SAT-2000 manufactured by Resca Co., Ltd.]. It was found that the Au-Sn alloy layer was not formed.

Further, in order to inspect whether the contact phenomenon between the leads of the film carrier tape 1 has occurred, a dedicated needle is pressed against the test pad portion 13 to inspect the contact phenomenon between the leads. When the spring pin type probe inspection was carried out, a sufficient inspection result of 100% reproducibility could be obtained with a load of 40 g.

Comparative Example 1 As shown in FIG. 3, 2 μm of gold plating 15 is applied to the entire surface of a lead pattern obtained by treating a copper foil 14 having a thickness of 35 μm, and the outer lead portion 12 and the test pad portion 1 are left as they are.
The film carrier tape 1 obtained by applying 8 μm of the tin-lead solder plating 16 having a composition of 9: 1 to 3 was subjected to the same heat treatment as in Example 1, and the same zero cross time was measured. 3.5 seconds, and in this case, the fragile Au—Sn alloy layer has been formed on the surface of the outer lead portion 12, so that the wettability of the surface of the outer lead portion 12 is inferior. Became clear.

Further, in the same manner as in Example 1, in order to inspect whether the contact phenomenon between the leads of the film carrier tape 1 has occurred, a dedicated needle is pressed against the test pad portion 13 to lead each lead. When the probe test of the spring pin system for inspecting the contact phenomenon between the two was performed, only an insufficient test result of reproducibility of 85% at a load of 40 g could be obtained.

[0011]

According to the present invention, when the tin lead solder plating is applied to the outer lead portion, the tin lead solder plating is separated from the Au plating area of the test pad area adjacent to the outer lead portion. It is possible to supply a film carrier tape which does not reduce the bonding property and wettability of the outer lead part, and the Au plating is applied to the upper surface of the test pad part. Even if the probe test of the spring pin method for inspecting the contact phenomenon between the leads is performed, it is possible to obtain highly accurate inspection results.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a schematic view of constituent materials seen in a cross section of one embodiment of the present invention.

FIG. 3 is a schematic view of constituent materials seen in a cross section of Comparative Example 1.

[Explanation of symbols]

 1. Film carrier tape 2. Sprocket hall 3. Inner lead hole 4. Outer lead hole 5. Inner lead 6. Outer lead 7. Test pad 8. Wiring for plating 10. Dough (Cu foil) 11. Inner lead part 12. Outer lead part 13. Test pad section 14. Cu foil 15. Au plating 16. Sn-Pb plating 17. Polyimide substrate

Claims (1)

[Claims] 1. An Au plating is applied to an upper surface of a test pad portion connected to an outer lead portion which is plated with a tin-lead solder alloy plating, and the Au-plated region and the tin-lead solder alloy plated region are isolated from each other. A film carrier tape characterized by being used.