CN-122013116-A - Follow-up pressing jig for vapor deposition of high-warpage silicon wafer and vapor deposition process

CN122013116ACN 122013116 ACN122013116 ACN 122013116ACN-122013116-A

Abstract

The invention relates to the technical field of high-warpage silicon wafers and discloses a follow-up pressing jig for vapor deposition of the high-warpage silicon wafers and a vapor deposition process, which comprise a flat plate body matched with the size of the silicon wafers to be processed, wherein the flat plate body is made of a high-temperature-resistant Wen Lvzhi material, the lower surface of the flat plate body is a high-precision polished surface, the surface roughness Ra of the high-precision polished surface is less than or equal to 0.1 mu m, the follow-up pressing jig is extremely simple in structure, free of complex moving parts, low in machining and polishing preparation difficulty and low in manufacturing cost, the adopted aluminum alloy material has excellent wear resistance, high temperature resistance and corrosion resistance, can be repeatedly recycled for thousands of times after being cleaned, can be used for a long time, is extremely low in operation and maintenance cost, and meanwhile, the breakage rate is greatly reduced, the loss of expensive wafer raw materials is remarkably reduced, the production cost is improved, and the industrial popularization and application value is extremely high.

Inventors

CAI MENGLIN
ZHENG WENQUAN
CHEN LIAN

Assignees

重庆凌芯微电子有限公司

Dates

Publication Date: 20260512
Application Date: 20260407

Claims (7)

1. The follow-up tabletting jig for the vapor deposition of the high-warpage silicon wafer comprises a flat plate body matched with the size of the silicon wafer to be processed, and is characterized in that the flat plate body is made of a high-temperature-resistant Wen Lvzhi material, the lower surface of the flat plate body is a high-precision polished surface, the surface roughness Ra of the high-precision polished surface is less than or equal to 0.1 mu m, the high-precision polished surface is used for being attached to a front circuit area of the high-warpage silicon wafer, the flat plate body can restrain the warpage deformation of the high-warpage silicon wafer through self-gravity pressing, so that the silicon wafer is kept in a flat state, and the flat plate body can synchronously complete the whole flow procedures of feeding, lantern ring and vapor deposition along with the silicon wafer.
2. The follow-up pressing jig for vapor deposition of high-warpage silicon wafers according to claim 1, wherein the flat plate body is a circular flat plate with a thickness of 1.5mm, and the diameter of the circular flat plate is equal to that of the silicon wafers to be processed.
3. The high warp wafer vapor deposition follow-up wafer jig according to claim 2, wherein the edge of the circular flat plate is provided with a chamfer structure, and the upper surface of the circular flat plate is provided with a handle structure and/or a positioning feature which are convenient for taking and placing.
4. A high warp silicon wafer evaporation process, which is characterized in that the process is realized based on the follower pressing jig according to any one of claims 1 to 3, and comprises the following steps: S1, a preparation procedure, namely sleeving a plating ring at the bottom of a cylindrical auxiliary jig, and placing a high-warpage silicon wafer to be processed on a top center platform of the cylindrical auxiliary jig with the right side upwards; s2, flattening and restraining, namely taking a follower pressing jig, downwards covering the high-precision polishing surface of the follower pressing jig on the front surface of the Gao Qiaoqu silicon wafer, and pressing the high-warpage silicon wafer by the dead weight of the follower pressing jig to keep the high-warpage silicon wafer in a flat state to form a silicon wafer-jig combination; S3, a lantern ring fixing procedure, namely keeping the continuous pressing constraint of the follow-up pressing jig on the silicon wafer, vertically and stably pushing a plating ring at the bottom of the cylindrical auxiliary jig upwards, completely sleeving the silicon wafer-jig combination into the plating ring, and finishing fixing; S4, assembling a pot-filling procedure, namely covering a plating cover on the upper surface of the follow-up pressing jig to form an integrated assembly of a plating ring, a silicon wafer, the follow-up pressing jig and the plating cover from bottom to top, transferring the integrated assembly into an evaporation plating pot, and feeding the evaporation plating pot into evaporation equipment; s5, vapor plating and post-treatment steps, namely, after the metal vapor plating operation on the back surface of the silicon wafer is finished, taking out the integrated assembly from vapor plating equipment, and sequentially removing the plating cover and the follower pressing jig to finish vapor plating processing of the high-warpage silicon wafer.
5. The high warp silicon wafer vapor deposition process according to claim 4, wherein in S1, the warp degree of the high warp silicon wafer to be processed is 10mm to 50mm.
6. The process according to claim 4, wherein in step S3, the accommodating thickness of the plating ring is adapted to the total thickness of the silicon wafer and the follower fixture, and the inner profiling surface of the plating ring contacts the back edge of the silicon wafer during the lifting process of the plating ring, and the lifting process is continued until the sleeving and fixing of the silicon wafer-fixture assembly are completed.
7. The process of claim 4, wherein in S5, the removed follower pressing jig is cleaned and recycled.

Description

Follow-up pressing jig for vapor deposition of high-warpage silicon wafer and vapor deposition process Technical Field The invention relates to the technical field of high-warpage silicon wafers, in particular to a follow-up pressing jig for vapor deposition of a high-warpage silicon wafer and a vapor deposition process. Background The invention belongs to the technical field of manufacturing of rear ends in semiconductors, and particularly relates to a technology for processing high-warpage silicon wafer back metal vapor deposition after thinning the back of a wafer. In the back end fabrication and advanced packaging processes in semiconductors, wafer back side thinning and back side vacuum evaporation are core processes. For mainstream products such as power semiconductor devices, IGBT, MEMS devices, radio frequency devices and the like, the thickness of a silicon wafer is thinned from the conventional 700-775 mu m to the level of tens of micrometers to 200 mu m through a back thinning process, so that the on-resistance of the device is reduced, the heat dissipation performance is improved, the packaging thickness requirement is met, and after the thinning is finished, a metal stacking layer is prepared on the back of the silicon wafer through a vacuum evaporation process, so that the core functions such as ohmic contact, electrode extraction, heat dissipation enhancement and the like are realized. After the wafer is thinned on the back, serious internal stress mismatch exists among the device structure on the front side, the dielectric layer and the silicon substrate thinned on the back, and meanwhile, additional stress is introduced in the thinning process, the UV photoresist stripping process and the photoresist stripping process, so that serious buckling deformation occurs after the photoresist stripping of the silicon wafer. Especially when the silicon wafer is thinned to be less than 150 mu m, the warping amount can reach 10-50mm, so that a commonly-called pot cover plate in industry is formed, and the subsequent evaporation processing of the high-warping silicon wafer becomes one of core pain points in the back surface process of a semiconductor. For the back surface vapor plating processing of high-warpage silicon wafers, a manual feeding process is mainly adopted in the industry, wherein the silicon wafers are fixed in a special vapor plating ring, then covered and plated to form an integrated assembly, and then the integrated assembly is placed into a plating pot of vapor plating equipment to complete the back surface vapor plating operation. At present, manual feeding operation of a high-warpage silicon wafer is generally completed by adopting a cylindrical auxiliary jig, and the specific process steps are that firstly, a plating ring for vapor plating is sleeved at a bottom step of the cylindrical auxiliary jig, the high-warpage silicon wafer is placed on a top platform of the cylindrical auxiliary jig with the right side upwards, then an operator manually pushes the plating ring upwards along the cylindrical jig, tries to clamp the edge of the silicon wafer in a warpage state into a limit groove of the plating ring, completes collar fixing of the silicon wafer, and then covers a plating cover above the silicon wafer, and the whole assembly is placed into a vapor plating pot for vapor plating operation. Above-mentioned prior art scheme only can realize the preliminary location of high warpage silicon chip, can't solve the series core problem that high warpage brought, has following defect that is difficult to overcome: First, the risk of ring link fragmentation is extremely high. In the process of pushing up the sleeve by the plating ring, the silicon wafer is always in a high-warpage free state, the edge of the plating ring is extremely easy to scratch and collide with the edge of the silicon wafer tilted, the edge of the silicon wafer is broken and hidden to crack if the edge of the silicon wafer is light, the silicon wafer is broken if the edge of the silicon wafer is heavy, meanwhile, the warped silicon wafer cannot be completely clamped into the limit structure of the plating ring, the problem that the warpage part is exposed easily occurs, the subsequent plating cover cannot be closed, and normal evaporation operation cannot be completed. Secondly, the cover plating link is easy to cause irreversible damage. Even if the silicon wafer is barely completed and the buckling deformation of the collar is not restrained effectively, the buckling bulge is still higher than the upper surface of the plating ring, the downward pressing action of the plating cover can directly collide with the buckling bulge of the silicon wafer in the process of covering the plating cover, so that the silicon wafer is easy to crack and break, if the buckling amount of the silicon wafer is too large, the plating cover can be directly caused to be incapable of being normally closed, and when an operator is forced to