TWI715485B - Circuit structure for improving pin glass strength in cof-ic packaging process - Google Patents

Abstract

The invention provides a circuit structure for improving the peeling strength of a pin in a COF-IC packaging process, including a copper wire, a flexible substrate and an IC chip, the copper wire is attached to the flexible substrate, and the pins of the IC chip are connected with The pins of the copper wire are fixedly connected. The pins of the copper wire are located at the ends of the copper wire. The pins of the copper wire include a long pin and a short pin. The long pin and the short pin are arranged at intervals, and the long pin and the short pin The shape and structure of the legs are different from copper wires. The present invention improves the single bonding area of the copper wire pin and the flexible substrate by changing the edge shape of the connection point between the copper wire pin and the flexible substrate by crimping the IC chip pin and the copper wire pin External loads, temperature stresses, and residual stresses cause plastic deformation, excessive stress concentration and uneven structure caused by crack sources.

Description

A circuit structure for improving the peeling strength of pins during COF-IC packaging

The present invention relates to the technical field of flip-chip films, and in particular to the technical field of circuit structures for improving the peel strength of pins in the COF-IC packaging process.

COF-IC packaging refers to the use of internal pin pressure welding equipment to pressure welding the ultra-fine circuit lines on the carrier tape and the pins of the display driver chip under specific conditions to achieve COF-IC packaging.

During processing, on the one hand, the line width of the ultra-fine line is less than 10 microns, which results in the limited contact area between the line and the flexible substrate. At the same time, the line width cannot be adjusted due to the influence of space. On the other hand, the chip pin spacing is small and dense. The bonding strength with the chip pins is limited; it will also be affected by the side corrosion phenomenon during the circuit processing. The wire ends in the copper wire welding area are often irregular or severely side corroded, which damages the adhesion of the copper wire to the flexible substrate after pressure welding , Resulting in a decrease in yield, a decrease in product life and a decrease in electrical performance indicators; it is easily damaged by mechanical factors, chemical factors and physical factors during the processing of the carrier tape line and the pressure welding process. This damage is likely to occur on the copper wire and the substrate. The edge part of the connection occurs, especially the lead part. The stress concentration in the lead part and the edge area often leads to excessive surface energy of the tip, which makes the lead of the copper wire in this area easy to crack between the base material and the inner part. The migration of the copper wire will eventually cause the copper wire to break or the copper wire to peel off the substrate, which in turn causes the circuit to be broken or short-circuited.

In order to overcome the problem that the copper wire in the prior art has low adhesion strength to the flexible substrate, and is easily affected by subsequent processing, the copper wire is broken or the copper wire peels off the substrate, which causes the circuit to be broken or short-circuited, the present invention discloses a method for improving COF- Circuit structure of pin peel strength during IC packaging.

The present invention achieves the above objectives through the following technical solutions: a circuit structure for improving the peeling strength of pins in the COF-IC packaging process, which includes copper wires, flexible substrates and IC chips. The copper wires are attached to the flexible substrate and the IC chips The pins of the copper wire are fixedly connected to the pins of the copper wire by pressure welding. The pins of the copper wire are located at the end of the copper wire. The pins of the copper wire include long and short pins, and the distance between long and short pins Layout, the shape and structure of the long pin is different from that of the copper wire. The shape and structure of the long pin and the short pin are the same.

The circuit structure for improving the peeling strength of the pins in the COF-IC packaging process, wherein a wire reel is fixed at the upper end of the long pin or/and the short pin, and the wire reel is round, oval, long, and block-shaped One or more of the structures.

The circuit structure for improving the peeling strength of the pins in the COF-IC packaging process, wherein a wire reel is arranged on the upper part of the copper wire in the crimping area of the long IC pin, and the wire reel is round, oval, long, and block One or more of the shape structure.

In the circuit structure for improving the peeling strength of the pins in the COF-IC packaging process, the long pins have a wave-shaped structure.

In the circuit structure for improving the peeling strength of the pins in the COF-IC packaging process, the long pins have a segmented block structure.

In the circuit structure for improving the peeling strength of the pins in the COF-IC packaging process, the long pins have a dot matrix structure.

In the circuit structure for improving the peel strength of pins in the COF-IC packaging process, the long pins are multiple parallel wave-shaped structures.

In the circuit structure for improving the peeling strength of the pins during the COF-IC packaging process, the long pins have a "feng" structure extending outward on both sides.

Compared with the prior art, the present invention has the beneficial effects that: the present invention improves the shape of the edge of the joint between the copper wire pin and the flexible substrate by crimping the IC chip pin and the copper wire pin. The single bonding area of the lead of the copper wire and the flexible substrate is caused by external load, temperature stress, residual stress, plastic deformation, excessive stress generated by the crack source, and uneven structure; the copper wire is further strengthened by setting the wire reel The bonding strength between the head of the pin and the flexible substrate; enhances the adhesion strength between the circuit and the flexible substrate; improves the product yield of the packaging process; enhances the product life; at the same time, the copper wire pins and wire reels are designed into Different shapes and different combinations provide different design schemes to meet different line bonding strength requirements.

1: Copper wire

2: Flexible substrate

3: Long pin

4: Bobbin

31: short pin

Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention; Figure 2 is a schematic structural diagram of Embodiment 2 of the present invention; Figure 3 is a schematic structural diagram of Embodiment 3 of the present invention; Figure 4 is a schematic structural diagram of Embodiment 4 of the present invention; Figure 5 Fig. 6 is a schematic structural diagram of Embodiment 6 of the present invention; Fig. 7 is a schematic structural diagram of Embodiment 7 of the present invention; Fig. 8 is a schematic structural diagram of Embodiment 8 of the present invention; A schematic structural diagram of Embodiment 9 of the present invention; FIG. 10 is a schematic structural diagram of Embodiment 10 of the present invention; 11 is a schematic structural diagram of Embodiment 11 of the present invention; FIG. 12 is a schematic structural diagram of Embodiment 12 of the present invention; FIG. 13 is a schematic structural diagram of Embodiment 13 of the present invention; FIG. 14 is a schematic structural diagram of Embodiment 14 of the present invention.

The following describes the present invention in further detail in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not used to limit the present invention.

Example 1, as shown in Figure 1, the copper wire 1 is attached to the flexible substrate 2, the pins of the IC chip are fixedly connected to the pins of the copper wire 1 through pressure welding, and the pins of the copper wire 1 are located on the copper wire 1. At the end of the copper wire 1, the pins of the copper wire 1 include long pins 3 and short pins 31. The long pins 3 and the short pins 31 are arranged at intervals. The long pins 3 have the same structure as the copper wire 1, and are long; The pin 31 has the same structure as the copper wire 1 and is a long strip; the upper end of the long pin 3 is fixedly provided with a wire reel 4, and the wire reel 4 is oval.

In Embodiment 2, as shown in Figure 2, the copper wire 1 is attached to the flexible substrate 2, and the pins of the IC chip are fixedly connected to the pins of the copper wire 1 through pressure welding, and the pins of the copper wire 1 are located on the copper wire 1. At the end of the copper wire 1, the pins of the copper wire 1 include long pins 3 and short pins 31. The long pins 3 and the short pins 31 are arranged at intervals; the short pins 31 have the same structure as the copper wire 1, and are long; The pin 3 has a "feng"-shaped structure extending outward on both sides, and the extension part is an oval shape.

Embodiment 3, as shown in FIG. 3, the main structure of Embodiment 3 is the same as Embodiment 2, except that the long pin 3 is a wave-shaped structure.

Embodiment 4, as shown in FIG. 4, the main structure of Embodiment 4 is the same as Embodiment 2, except that the long pin 3 is a segmented block structure.

Embodiment 5, as shown in FIG. 5, the main structure of Embodiment 5 is the same as Embodiment 2, except that the long pin 3 is a dot matrix structure.

Embodiment 6, as shown in FIG. 6, the main structure of Embodiment 6 is the same as Embodiment 2, except that the long pin 3 is a plurality of parallel wave-shaped structures.

Embodiment 7, as shown in FIG. 7, the main structure of embodiment 7 is the same as that of embodiment 2, except that: the long pins 3 and the short pins 31 are both extended outwards with a "feng" structure. It is oval.

Embodiment 8, as shown in FIG. 8, the main structure of Embodiment 8 is the same as that of Embodiment 7, except that the long pins 3 and the short pins 31 are both wave-shaped structures.

Embodiment 9, as shown in FIG. 9, the main structure of embodiment 9 is the same as that of embodiment 7, except that the long pins 3 and the short pins 31 are both segmented block structures.

In Embodiment 10, as shown in FIG. 10, the main structure of Embodiment 10 is the same as that in Embodiment 7, except that the long pins 3 and the short pins 31 are both dot matrix structures.

In Embodiment 11, as shown in FIG. 11, the main structure of Embodiment 11 is the same as that in Embodiment 7, except that the long pins 3 and the short pins 31 are both parallel wave-shaped structures.

Embodiment 12, as shown in FIG. 12, the main structure of Embodiment 12 is the same as that of Embodiment 8, except that a wire reel 4 is fixedly arranged at the upper end of the long pin 3, and the wire reel 4 has an elliptical structure.

Embodiment 13, as shown in FIG. 13, the main structure of embodiment 13 is the same as that of embodiment 7, the difference is: the short pin 31 is a "feng"-shaped structure extending outward on both sides, and the extension part is oval; The legs 3 have a "bundance"-shaped structure extending outward on both sides, and the extension part is a long strip, and the upper end of the long pin 3 is fixedly provided with a wire reel 4, which has an oval structure.

Embodiment 14, as shown in FIG. 14, the main structure of embodiment 14 is the same as that of embodiment 11, except that: the upper end of the long pin 3 is fixedly provided with a wire reel 4, which has an oval structure; the upper end of the short pin 31 is fixed A cable reel 4 is provided, and the cable reel 4 has a block structure.

In summary, because the IC chip protrudes from the flexible substrate 2, the IC chip is often easily affected by various external factors (processing, transportation, etc.) during the packaging process. After being affected by external forces, it will be in line with the IC chip's pins. The leads of the crimped copper wire 1 are often peeled off the flexible substrate 2. It can be seen from Table 1 that the present invention changes the line structure of the long lead 3 and the short lead 31 so that the edges of the long lead 3 and the short lead 31 are no longer straight lines. When the long lead 3 or the short lead 31 and When cracks appear at the joints of the flexible substrate 2, on the one hand, the irregular edges cause the cracks to bifurcate, alleviating the stress concentration at the crack tip, and on the other hand, the irregular edges disperse the external force received during the packaging process. Thus, the peeling strength of the copper wire 1 and the flexible substrate 2 is improved.

The above description shows and describes the preferred embodiments of the present invention. As mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as the exclusion of other embodiments, but can be applied to various other embodiments. Combinations, modifications and environments can be modified through the above description or technology or knowledge in related fields within the scope of the inventive concept described herein. The modifications and changes made by those skilled in the art do not depart from the spirit and scope of the present invention, and should fall within the protection scope of the attached patent application of the present invention.

1: Copper wire

2: Flexible substrate

3: Long pin

4: Bobbin

31: short pin

Claims (7)

A circuit structure for improving the peeling strength of pins in the COF-IC packaging process, which includes: a copper wire, a flexible substrate and an IC chip, the copper wire is attached to the flexible substrate, and the pins of the IC chip It is fixedly connected to a pin of the copper wire by pressure welding. The pin of the copper wire is located at the end of the copper wire. The pin of the copper wire includes a long pin and a short pin. The pins and the short pins are arranged at intervals, the shape and structure of the long pins are different from the shape and structure of the copper wire, and the shapes and structures of the long pins and the short pins are the same. The circuit structure for improving the peeling strength of the pins in the COF-IC packaging process as described in claim 1, wherein the upper end of the long pin or/and the short pin is fixedly provided with a wire reel, the wire reel is round, One or more of oval, long strip, and block structure. The circuit structure for improving the peeling strength of the pins in the COF-IC packaging process as described in Claims 1 to 2, wherein the long pins have a wavy structure. The circuit structure for improving the peeling strength of pins in the COF-IC packaging process as described in Claims 1 to 2, wherein the long pins have a segmented block structure. The circuit structure for improving the peeling strength of pins in the COF-IC packaging process as described in Claims 1 to 2, wherein the long pins have a dot matrix structure. The circuit structure for improving the peeling strength of pins in the COF-IC packaging process as described in Claims 1 to 2, wherein the long pins are a plurality of parallel wave-shaped structures. The circuit structure for improving the peeling strength of the pins in the COF-IC packaging process as described in Claims 1 to 2, wherein the long pins are in the shape of "Feng" extending outward on both sides.

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