A method for thinning bonded wafers

Abstract

The invention provides a bonded wafer thinning method. Before a device wafer is thinned, the edge of the wafer is ground first through a grinding wheel to remove the arc-shaped edge. According to the method, the bonded wafer is treated through the grinding wheel before the thinning process starts, and the arc-shaped edge of the device wafer is ground off, so the situation that sharp corners are formed on the bonded wafer in the thinning process is effectively avoided, the phenomenon of edge fractures of the device wafer is eradicated, the wafer can be thinned to less than 50 microns on the premise of guaranteeing that the edge of the device wafer does not fracture so as to meet the requirements of the follow-up preparation technology, and the performance of a semiconductor device manufactured later can be guaranteed. Compared with an existing thinning technology, the method has the advantages that no pollution will happen to a thinning machine platform and the follow-up technology, equipment adopted in the method is simple and easy to operate and concise in process, the production efficiency is greatly improved, and the production cost and equipment cost are lowered.

Description

technical field [0001] The invention relates to a semiconductor manufacturing process, in particular to a method for thinning bonded wafers. Background technique [0002] As integrated circuits have higher and higher requirements for ultra-thin chips, and in many semiconductor manufacturing fields, such as smart cards (Smart Card), micro-electromechanical systems (MEMS), LED chips, CMOS image sensor chips (CIS), Photovoltaic cells, stacked die, and multi-chip packages are all ultra-thin chips (chip thickness less than 50 μm), but these ultra-thin chips cannot be produced from ultra-thin wafer manufacturing processes. Obtained, but wafers obtained through conventional chip manufacturing processes, are achieved through a thinning process. Therefore, the wafer thinning process occupies an increasingly important position in the integrated circuit manufacturing process. [0003] refer to Figure 1a-1b As shown in , it gives a cross-sectional view of each step in the most common...

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Problems solved by technology

[0007] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a thinning method for bonded wafers, which is used to solve the problem of the edge in the prior art after the wafer is thinned to a certain thickness by using a conventional wafer thinning process. The problem of cracking, and the corresponding improvement in the thinning process, the pollution of the thinning machine and subsequent processes caused by the application of adhesive materials between the bonded wafers and the use of wet etching for the second thinning of the wafer The problems caused by the reduction of production efficiency and the increase of production cost and equipment cost

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