Manufacturing method of semiconductor device

Abstract

The invention provides a manufacturing method of a semiconductor device. The manufacturing method includes the following steps that: 1) a semiconductor device substrate including a semiconductor substrate, shallow trench isolation and a dielectric layer is provided, and a photolithographic mask with an etching window is manufactured on the back surface of the semiconductor substrate; 2) the semiconductor substrate is etched with first etching gas, and etching is performed until etching reaches a position which is located above the shallow trench isolation and is separated from the shallow trench isolation by a first distance; 3) the semiconductor substrate is further etched with second etching gas, and etching is performed until etching reaches a position which is located above the shallow trench isolation and is separated from the shallow trench isolation by a second distance; and 4) the semiconductor substrate is further etched with third etching gas until the shallow trench isolation and the dielectric layer located below the etching window are exposed, so that a trench for manufacturing a pad can be formed. With the manufacturing method of the semiconductor device of the invention adopted, the trench of which the surface is flat and of which the semiconductor substrate, the shallow trench isolation and the dielectric layer are not excessively etched, can be obtained, so that subsequent metal pad manufacture can be benefitted, and therefore, the performance of the device can be improved.

Description

technical field [0001] The invention relates to a method for manufacturing a semiconductor device, in particular to a method for manufacturing a semiconductor device. Background technique [0002] The back-illuminated CMOS sensor is a new type of sensor that has emerged in recent years. Compared with the existing surface-illuminated image sensor, the wiring layer is above the light-receiving surface, and the wiring layer will block part of the incident light. The back-illuminated image sensor The device adopts the design of reversing the wiring layer and the position of the light-receiving surface, which can efficiently receive incident light, greatly improving its light-sensing ability and signal-to-noise ratio, so that cameras and other equipment can achieve strong noise control capabilities at high ISO. [0003] In the manufacturing process of semiconductor devices such as back-illuminated image sensors (BSI), it is often necessary to etch trenches on the semiconductor su...

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Problems solved by technology

[0007] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a method for manufacturing a semiconductor device, which is used to solve the problem that the semiconductor substrate or oxide is easily over-etched in the etching method of the semiconductor device in the prior art. And other issues

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