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CN-121985834-A - Processing method and structure of chip aluminum bonding pad in panel-level package

CN121985834ACN 121985834 ACN121985834 ACN 121985834ACN-121985834-A

Abstract

The invention discloses a processing method and a structure of a chip aluminum bonding pad in panel-level packaging, and relates to the technical field of panel-level packaging. The processing method of the chip aluminum bonding pad comprises the following steps of selecting a high temperature resistant film material, carrying out hollowed-out processing on the film material based on the distribution of the aluminum bonding pads on a wafer, attaching the hollowed-out film material to the surface of the wafer, coating conductive copper paste containing nano copper components on the surface of the wafer covered with the film material, filling the conductive copper paste on the surface of the aluminum bonding pad in a hollowed-out area, placing the wafer in an oven for pre-baking to enable the conductive copper paste to be primarily cured and bonded with the aluminum bonding pad, removing the film material, placing the wafer in a high temperature curing furnace for sintering processing to enable the surface of the aluminum bonding pad to form a compact copper layer, and realizing electrical interconnection of subsequent PLP packaging through the compact copper metal layer to finish panel-level packaging. The processing method provided by the invention can effectively reduce the cost, the process complexity and the time period in panel-level packaging.

Inventors

  • SHENG YAN
  • ZHANG BOWEI
  • LI JIAN

Assignees

  • 广东芯友微电子科技有限公司

Dates

Publication Date
20260505
Application Date
20251216

Claims (10)

  1. 1. The processing method of the chip aluminum bonding pad in the panel-level package is characterized by comprising the following steps of: selecting a high temperature resistant film material, wherein one side of the film material has viscosity, the other side has a release function, and the thickness of the film material is 20-50 mu m; Based on the distribution of the aluminum bonding pads on the wafer, carrying out hollowed-out treatment on the film material, wherein the hollowed-out areas on the film material correspond to the positions of the aluminum bonding pads on the wafer one by one; Attaching the hollowed-out film material to the surface of a wafer, wherein the adhesive surface of the film material faces the wafer and covers a non-aluminum welding disc area on the wafer; Coating conductive copper paste containing nano copper components on the surface of the wafer covered with the film material, filling the conductive copper paste on the surface of an aluminum welding disc in a hollowed-out area, and removing superfluous conductive copper paste on the surface based on the release function of the film material; the wafer coated with the conductive copper paste is placed in an oven for pre-baking, so that the conductive copper paste is primarily solidified and bonded with an aluminum welding disc; removing film materials on the surface of the wafer, and placing the wafer in a high-temperature curing furnace for sintering treatment so as to form a compact copper layer on the surface of the aluminum welding disk; And cutting the sintered wafer, and then sequentially carrying out carrier welding, large-size plastic packaging, laser perforating and metal interconnection to complete panel-level packaging.
  2. 2. The method for processing a chip aluminum pad in a panel-level package according to claim 1, wherein the high temperature resistant film material has a high temperature resistant range of 220 ℃ to 300 ℃.
  3. 3. The method of claim 1, wherein the wafer has a dimension of 4 inches, 6 inches, 8 inches, or 12 inches, and each die on the wafer has at least 1 aluminum pad in an active area on a front side of the die.
  4. 4. A method of handling die aluminum pads in a panel level package as recited in claim 3, wherein the size of individual aluminum pads is not less than 80 μm.
  5. 5. A method for processing a chip aluminum pad in a panel-level package according to claim 3, wherein the aluminum pad is made of aluminum, aluminum-silicon alloy or aluminum-silicon-copper alloy.
  6. 6. The method for processing the aluminum bonding pad of the chip in the panel-level package according to claim 1, wherein the process of hollowing out the film material comprises the following steps: And (3) carrying out hollowed-out treatment on the film material by adopting laser or blade equipment, hollowed-out the position of the aluminum bonding pad on the wafer chip, and matching the hollowed-out area with the size of the aluminum bonding pad.
  7. 7. The method for processing a chip aluminum pad in a panel-level package according to claim 1, wherein the process of coating the conductive copper paste containing the nano copper component on the surface of the wafer covered with the film material comprises: and coating liquid conductive copper paste containing nano copper components on the surface of a wafer covered with the film material, filling the conductive copper paste on the surface of an aluminum welding disc in a hollowed-out area through a spin coating scraper, and removing the conductive copper paste on the surface of the film material by combining the release function of the film material.
  8. 8. The method of claim 1, wherein the thickness of the dense copper layer formed on the surface of the aluminum pad is consistent with the thickness of the film material.
  9. 9. The structure of the chip aluminum bonding pad in the panel-level package comprises a wafer and is characterized in that the wafer comprises at least one chip body, an aluminum bonding pad arranged in an active area on the front surface of the chip body and a compact copper layer covered on the surface of the aluminum bonding pad, wherein the compact copper layer is formed by pre-baking and high-temperature sintering of nano copper conductive copper paste and completely covers the surface of the aluminum bonding pad.
  10. 10. The structure of claim 9, wherein the dense copper layer has a thickness of 20 μm to 50 μm.

Description

Processing method and structure of chip aluminum bonding pad in panel-level package Technical Field The invention relates to the technical field of Panel Level Packaging (PLP), in particular to a processing method and a structure of a chip aluminum bonding pad in panel level packaging. Background In the field of Panel Level Packaging (PLP), conventional processes require metal modification (e.g., copper plating, nickel-gold, etc.) of the aluminum pads (pads) on the chip surface by a redistribution layer (RDL) technique to improve its chemical resistance. The main reason that the aluminum welding disc needs to ensure the chemical resistance is that after the chip is subjected to die bonding and plastic packaging in the PLP packaging, the pad on the surface of the chip can be leaked out through the laser opening, the whole electric interconnection is performed, a product needs to enter a liquid medicine line body in the electric interconnection process, such as sodium permanganate, hydrogen peroxide, sulfuric acid and other chemical liquid medicine corrosion, aluminum is used as amphoteric metal acid-base intolerance, and effective interconnection cannot be formed, so that the aluminum welding disc needs to be treated. The traditional aluminum welding disk modification is basically chemical modification, namely, aluminum on the surface of a chip is replaced by NiAu, or copper surfaces or tin surfaces are electroplated on the surface of the aluminum welding disk through photoetching development electroplating and the like, and the whole process involves multiple photoetching, electroplating and etching procedures, so that the production cost is high, the process complexity is high and the period is long. Accordingly, there is a need to provide a solution to the above-mentioned problems. Disclosure of Invention The invention aims to provide a processing method and a structure of a panel-level packaged chip aluminum bonding pad, which solve the problems of high cost, complex process and long period caused by metal modification of an aluminum bonding pad by an RDL technology in the traditional method. The invention provides a processing method of a chip aluminum bonding pad in panel-level packaging, which adopts the following technical scheme: selecting a high temperature resistant film material, wherein one side of the film material has viscosity, the other side has a release function, and the thickness of the film material is 20-50 mu m; Based on the distribution of the aluminum bonding pads on the wafer, carrying out hollowed-out treatment on the film material, wherein the hollowed-out areas on the film material are in one-to-one correspondence with the positions of the aluminum bonding pads on the wafer; Attaching the hollowed-out film material to the surface of a wafer, wherein the adhesive surface of the film material faces the wafer and covers a non-aluminum welding disc area on the wafer; Coating conductive copper paste containing nano copper components on the surface of the wafer covered with the film material, filling the conductive copper paste on the surface of an aluminum welding disc in a hollowed-out area, and removing superfluous conductive copper paste on the surface based on the release function of the film material; the wafer coated with the conductive copper paste is placed in an oven for pre-baking, so that the conductive copper paste is primarily solidified and bonded with an aluminum welding disc; removing film materials on the surface of the wafer, and placing the wafer in a high-temperature curing furnace for sintering treatment so as to form a compact copper layer on the surface of the aluminum welding disk; And cutting the sintered wafer, and then sequentially carrying out carrier welding, large-size plastic packaging, laser perforating and metal interconnection to complete panel-level packaging. Optionally, the high temperature resistant temperature range of the high temperature resistant film material is 220 ℃ to 300 ℃. Optionally, the wafer has a size of 4 inches, 6 inches, 8 inches or 12 inches, and each chip on the wafer is provided with at least 1 aluminum bonding pad in an active area on the front surface of the chip. Optionally, the size of the single aluminum pad is not less than 80 μm. Optionally, the aluminum pad is made of aluminum, aluminum-silicon alloy or aluminum-silicon-copper alloy. Optionally, the process of hollowed-out treatment of the film material includes: And (3) carrying out hollowed-out treatment on the film material by adopting laser or blade equipment, hollowed-out the position of the aluminum bonding pad on the wafer chip, and matching the hollowed-out area with the size of the aluminum bonding pad. Optionally, the process of coating the conductive copper paste containing the nano copper component on the surface of the wafer covered with the film material comprises the following steps: and coating liquid conductive copper paste containing nano copper compon