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CN-122002929-A - Wafer bonding process

CN122002929ACN 122002929 ACN122002929 ACN 122002929ACN-122002929-A

Abstract

The application discloses a wafer bonding process which comprises the steps of providing a top wafer and a bottom wafer to be bonded, activating bonding surfaces of the top wafer and the bottom wafer by taking first gas as a plasma gas source, cleaning the surfaces of the top wafer and the bottom wafer by taking the first gas as a gas with a Joule Thomson coefficient smaller than 0, and bonding the top wafer and the bottom wafer under the condition that the atmosphere environment is the first gas. By the aid of the scheme, the problem that bubble defects are generated in the wafer edge area after bonding in the related technology can be solved.

Inventors

  • CAO MIN
  • ZHAO ZHENGYUAN
  • ZHANG SHUO
  • YANG LINLIN
  • HUI KESHI
  • LI YUANHAO
  • WANG RANRAN
  • LI CHUANYU
  • TAN JUAN
  • ZHANG SHOULONG

Assignees

  • 华虹半导体制造(无锡)有限公司
  • 华虹半导体(无锡)有限公司

Dates

Publication Date
20260508
Application Date
20260122

Claims (5)

  1. 1. A wafer bonding process comprising: Providing a top wafer and a bottom wafer to be bonded; Activating the bonding surface of the top wafer and the bottom wafer by using a first gas as a plasma gas source, wherein the first gas is gas with a Joule Thomson coefficient smaller than 0; surface cleaning is carried out on the top layer wafer and the bottom layer wafer; And carrying out a bonding process on the top wafer and the bottom wafer under the condition that the atmosphere environment is the first gas.
  2. 2. The wafer bonding process of claim 1, wherein the first gas is helium or neon.
  3. 3. The wafer bonding process according to claim 1, wherein in the step of activating the bonding surface of the top wafer and the bottom wafer by using the first gas as a plasma gas source, the low-frequency rf power of the plasma generator is 35 to 45w and the high-frequency rf power of the plasma generator is 50 to 60w.
  4. 4. The wafer bonding process according to claim 1, wherein in the step of performing the activation treatment on the bonding surface of the top wafer and the bottom wafer using the first gas as a plasma gas source, a duration of the activation treatment is 5 to 60 seconds.
  5. 5. The wafer bonding process according to claim 1, wherein in the step of surface cleaning the top and bottom wafers, the cleaning solution used is deionized water.

Description

Wafer bonding process Technical Field The application relates to the technical field of integrated circuit manufacturing, in particular to a wafer bonding process. Background In the backside illuminated (BSI, back Side illuminated) process, the photosensitive element is located above the metal line, so that the photosensitive efficiency is improved, and for the backside illuminated process, the effect of the bonding process for bonding the Device wafer and the Carrier wafer together is important. Currently, the bonding process uses an atmosphere, typically air, and is activated using a nitrogen plasma. During bonding, air between the wafers escapes from the center of the wafer, moves toward the wafer edge, and expands under the influence of ambient atmospheric pressure. When the pressure suddenly drops, the temperature of the air drops by a few degrees and supersaturation of water vapor is caused, and the water vapor is easily condensed into water drops at the edge of the wafer, so that bubble defects are generated in the edge area of the wafer, and the product yield is affected. Disclosure of Invention The application provides a wafer bonding process which can solve the problem that bubble defects are generated in the edge area of a wafer after bonding in the related technology. The embodiment of the application provides a wafer bonding process, which comprises the following steps: Providing a top wafer and a bottom wafer to be bonded; Activating the bonding surface of the top wafer and the bottom wafer by using a first gas as a plasma gas source, wherein the first gas is gas with a Joule Thomson coefficient smaller than 0; surface cleaning is carried out on the top layer wafer and the bottom layer wafer; And carrying out a bonding process on the top wafer and the bottom wafer under the condition that the atmosphere environment is the first gas. In some embodiments, the first gas is helium or neon. In some embodiments, in the step of activating the bonding surface of the top wafer and the bottom wafer by using the first gas as a plasma gas source, the low-frequency rf power of the plasma generator is 35-45 w and the high-frequency rf power of the plasma generator is 50-60 w. In some embodiments, in the step of performing the activation treatment on the bonding surface of the top wafer and the bottom wafer by using the first gas as the plasma gas source, the duration of the activation treatment is 5 to 60 seconds. In some embodiments, in the step of performing surface cleaning on the top wafer and the bottom wafer, the cleaning solution used is deionized water. The technical scheme of the application at least comprises the following advantages: 1. The bonding surface of the top-layer wafer and the bottom-layer wafer is activated by using the first gas with the Joule Thomson coefficient smaller than 0 as a plasma gas source, so that the surface state of the bonding surface is changed, and the bonding process is performed on the top-layer wafer and the bottom-layer wafer under the condition that the atmosphere environment is the first gas with the Joule Thomson coefficient smaller than 0 in the subsequent bonding process, so that the formation of water vapor at the edge of the wafer in the bonding process can be reduced, and the possibility of bubble defects is reduced. Drawings In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present application, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art. FIG. 1 is a flow chart of a wafer bonding process provided in an exemplary embodiment of the present application; FIG. 2 is a prior art bubble defect detection pattern using an ultrasonic scanning microscope in accordance with an exemplary embodiment of the present application; Fig. 3 is a graph of bubble defect detection after using the wafer bonding process of the present application using an ultrasonic scanning microscope, according to an exemplary embodiment of the present application. Detailed Description The following description of the embodiments of the present application will be made more apparent and fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the application are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application. In the description of the present application, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based