CN-121985851-A - Method and device for laser massive ball implantation

Abstract

The invention provides a laser huge ball-planting method and device, the method comprises the steps of providing through hole glass, wherein the through hole glass is provided with a plurality of through holes penetrating through the upper surface and the lower surface, the upper part of the through hole is a conical hole with a big upper part and a small lower part, each through hole is provided with a solder ball, the plurality of through holes are arranged in a pattern mode, laser irradiates from the upper part of the through hole glass towards the upper surface of the through hole glass, the solder balls in the through holes are melted, the melted solder balls are transferred onto a substrate below the through hole glass under the pressure of inert gas, and a certain distance is reserved between the substrate and the through hole glass. By adopting the method, the tin balls after laser melting are transferred under the air pressure to implant the balls, the whole process is not contacted with the substrate, the ball implant and welding yield are greatly improved, and the substrate material is not limited by temperature.

Inventors

• LI ZHIGANG
• JIANG YIMING

Assignees

• 武汉帝尔激光科技股份有限公司

Dates

Publication Date

20260505

Application Date

20250122

Claims (15)

1. 1. A laser huge ball planting method is characterized by comprising the following steps: s1, providing through hole glass, wherein the through hole glass is provided with a plurality of through holes penetrating through the upper surface and the lower surface, the upper part of each through hole is a conical hole with a big upper part and a small lower part, each through hole carries one solder ball, and the through holes are arranged in a pattern; s2, irradiating laser from the upper side of the through hole glass towards the upper surface of the through hole glass, melting tin balls in the through hole, and transferring the melted tin balls to a substrate below the through hole glass under the pressure of inert gas; Wherein, a certain distance is arranged between the substrate and the through hole glass.
2. 2. The method for implanting a large amount of laser balls according to claim 1, wherein the inert gas pressure is 1-10 MPa.
3. 3. The method for implanting a large amount of laser balls according to claim 1 or 2, wherein the inert gas pressure is realized by providing a sealed laser transfer chamber, the through-hole glass is arranged at the bottom of the laser transfer chamber, the top of the laser transfer chamber is transparent, and inert gas is introduced into the laser transfer chamber to realize the inert gas pressure.
4. 4. The method of implanting a large amount of laser balls as set forth in claim 1, wherein the laser beam forms a spot covering at least one through hole to complete the transfer of solder balls covering the through holes, the spot is moved to the remaining through holes with respect to the through hole glass to complete the transfer of solder balls of the remaining through holes until the transfer of solder balls of all the target through holes is completed.
5. 5. The method for implanting a large amount of laser balls as set forth in claim 1, wherein the laser beam forms a spot covering all the through holes of the through hole glass, and the transfer of the solder balls of all the target through holes is completed by one irradiation.
6. 6. The method for implanting a large amount of laser balls according to claim 1, wherein an included angle between the side wall of the tapered hole and the normal line of the upper surface of the through hole is 0-45 °.
7. 7. The method for laser massive ball placement according to claim 1 or 6, wherein the relationship between the size of the tapered hole and the radius of the solder ball is as follows: Ds×cosθ/(2+2×sin2θ)< R<Ds×(cosθ)/2 wherein Ds is the diameter of the upper surface of the through hole, θ is the included angle between the side wall of the conical hole and the normal line of the upper surface of the through hole, and R is the radius of the solder ball.
8. 8. A method of laser macro ball placement according to claim 7 wherein each of the through holes carries a solder ball by dropping a solder ball into a through hole of the through hole glass by a screen ball in a screen tray and scraping off excess solder balls.
9. 9. The method of implanting a large amount of laser balls according to claim 1, wherein the lower portion of the through hole and the tapered hole at the upper portion of the through hole form an inverted cone, an hourglass shape or an upper cone and a lower straight shape.
10. 10. The method for implanting a large amount of laser balls as claimed in claim 1, wherein the through hole glass is silicate glass, sapphire, quartz glass or aluminosilicate glass, and the through hole is obtained by adopting a laser induced etching method.
11. 11. A laser macro ball mounting device for use in the laser macro ball mounting method according to any one of claims 1 to 10, comprising: A laser processing module; The laser transfer chamber is arranged below the laser processing module, through hole glass and an air inlet channel are arranged in the laser transfer chamber, and the air inlet channel is used for introducing inert gas; the substrate bearing table is arranged below the laser transfer chamber and used for bearing a substrate.
12. 12. The apparatus of claim 11, further comprising a laser scanning unit for moving the laser and the glass via relative to each other.
13. 13. The huge amount of laser ball planting device of claim 12, wherein the laser scanning unit is a galvanometer and a field lens arranged in a laser processing module, and/or a laser motion platform arranged on the laser processing module, and/or a transfer chamber motion platform arranged in a laser transfer chamber, and/or a substrate motion platform arranged on a substrate bearing platform; The laser motion platform, the transfer chamber motion platform and the substrate motion platform are two-dimensional motion platforms.
14. 14. The apparatus of claim 11, wherein the substrate stage is a chuck.
15. 15. The apparatus of claim 11, wherein the laser processing module comprises a laser, a beam expander set, a shaping mirror set, and a focusing mirror set.

Description

Method and device for laser massive ball implantation Technical Field The invention relates to the field of laser processing and ball-planting welding, in particular to a method and a device for laser massive ball-planting. Background In the process of electrically connecting the integrated circuit BGA package and the PCB, a large number of micron-sized solder balls are selectively and accurately moved to a target integrated circuit substrate and the PCB according to a required pattern through high-precision equipment to carry out tin-plating solder balls, so that good electrical connection and mechanical fixation are formed between the integrated circuit and the PCB, and finally, the mass production requirement of the electrical connection of the BGA package and the PCB is realized. Therefore, the importance of the ball planter is self-evident. Especially, at present, the use scene of the integrated circuit chip is more and more complex, the requirements on system integration are higher and higher, the requirements on chip threads and performance are higher and higher, the welding spots on the bonding pad of the integrated circuit show higher-density variation trend, the diameter of the solder ball is more and more miniaturized, the welding spots in unit area are more and more, and higher requirements on the precision and efficiency of ball planting equipment are provided. The current general mature scheme adopts 1) printing screen printing soldering flux, ball-planting net plate soldering tin ball implantation, and high-temperature heat treatment welding, 2) a laser solder ball welding machine transfers the solder balls in the container to a spray head through a special single-solder ball separating system, and then the solder balls arranged on the spray head are instantaneously melted by utilizing the high pulse energy of laser. And then, spraying the melted tin material on the surface of the welding spot by means of inert gas pressure to form an interconnection welding spot. The two processing modes have certain limitations, the substrate material is affected by adopting a screen plate mode, the substrate is required to be heated to more than 200 ℃ together in the later process, the melting point of the solder balls is reached, the substrate material which is sensitive to the temperature is not friendly, the substrate material is limited, the whole process is a contact process, the solder is easy to splash and stain, the short circuit and the open circuit are caused in the welding process, the screen plate is limited in the process, and the ball implantation and the welding of the smaller solder balls are difficult to carry out. The single-head laser solder ball welding machine is low in efficiency, the requirement of production beats is difficult to meet for a substrate with complex patterns and a large number of welding spots, the precision control difficulty is high, the precision is completely dependent on the motion precision of a platform, the precision is required to be calibrated for long-term motion, and the minimum solder ball diameter can only be about 70 mu m due to the limitation of the processing mode of the jet head, so that the subsequent requirement of processing welding spots with high density, small size and small space is difficult to meet. Disclosure of Invention The invention aims to solve the technical problem of providing a laser huge ball planting method and device which can improve ball planting and welding yield. The technical scheme adopted by the invention for solving the technical problems is as follows: as a first aspect of the present invention, the present invention provides a laser macro ball-implanting method, comprising: S1, providing through hole glass, wherein the through hole glass is provided with a plurality of through holes penetrating through the upper surface and the lower surface, the upper part of the through holes is a conical hole with a large upper part and a small lower part, and the through holes are arranged in a pattern manner; S2, irradiating laser from the upper side of the through hole glass towards the upper surface of the through hole glass to melt tin balls in the through hole, and transferring the melted tin balls to a substrate below the through hole glass under the pressure of inert gas; Wherein, a certain distance is arranged between the substrate and the through hole glass. According to the method, the air pressure of the inert gas is 1-10 MPa. According to the method, the inert gas pressure is realized by providing a sealed laser transfer chamber, the through hole glass is arranged at the bottom of the laser transfer chamber, the top of the laser transfer chamber is transparent, and inert gas is introduced into the laser transfer chamber to realize the inert gas pressure. According to the method, the light spot formed by the laser covers at least one through hole, so that the transfer of the solder balls covering the through holes is compl