CN103137463A

CN103137463A - Solution for detect of needle shape in deep groove etching process

Info

Publication number: CN103137463A
Application number: CN2011103890586A
Authority: CN
Inventors: 黄志刚; 管军; 吴智勇
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2011-11-30
Filing date: 2011-11-30
Publication date: 2013-06-05

Abstract

The invention discloses a solution for the detect of a needle shape in a deep groove etching process. The method adds two processing steps of a dry method etching sleek etching step and a wet method repairing step before a step of removing residual polymer on the wafer in a wet method and after a photoresist ashing step of the existing deep groove hard mask dry method etching process. The method adds the dry method etching sleek etching step and the wet method repairing step in a cleaning step after the hard mask etching, improves the existing deep groove hard mask dry method etching process, basically eliminates the roughness of the surface of a substrate caused by the hard mask plasma etching, so that the needle shape defect appearing after the deep groove etching is effectively overcome.

Description

The solution of deep plough groove etched technique needle prick shape defective

Technical field

The present invention relates to semiconductor integrated circuit and make the field, particularly relate to the solution of the needle prick shape defective in deep plough groove etched technique.

Background technology

Deep plough groove etched technique (deep trench) is widely used in the processing procedure of the semiconductor device such as super-junction device (super junction), pressure-sensitive sensing element (MEMS) and high power device (power MOS).

Deep trench generally obtains by the method for dry etching.Because the degree of depth of deep trench is very dark, the etch period that needs is longer, if will realize by the single step etching technics etching of deep trench, needs to use hard mask dry etch process.

The flow process of existing hard mask dry etch process is as follows:

(1) plating one deck silica or silicon nitride on silicon substrate, the hard mask when deep plough groove etched is as shown in Fig. 1 (a);

(2) coating one deck photoresist on hard mask, and carry out exposure imaging;

(3) use plasma dry etch process, carve and open hard mask;

(4) photoresist being carried out ashing processes;

(5) wet method is removed the residual polymer of crystal column surface;

(6) carry out the etching of deep trench.

The defective of said method is, in the hard mask of step (3) etching, plasma is known from experience damage silicon substrate (substrate), cause substrate surface coarse, like this, carry out when deep plough groove etched follow-up, can be because little mask (micro-mask) effect forms the needle prick shape defective, as Fig. 1 (b), Fig. 2 and shown in Figure 3, thereby have influence on yield and the performance of devices of product.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of solution of deep plough groove etched technique needle prick shape defective, and it can avoid the needle prick shape defective occurring after deep plough groove etched.

For solving the problems of the technologies described above, the solution of deep plough groove etched needle prick shape defective of the present invention, after the photoresist ashing treatment step of the hard mask dry etch process of the deep trench of routine, wet method is removed before polymer step residual on wafer, increases successively two steps of the round and smooth etching of dry method and wet method renovation technique.

The present invention is by increasing the round and smooth etching of dry method and two processing steps of wet method renovation technique in the cleaning step after hard mask etching, improved the hard mask dry etch process of existing deep trench, substantially eliminated the silicon projection by the surface of silicon due to the plasma etching of hard mask, thereby avoided deep plough groove etched rear formation needle prick shape defective, and then improved the performance of yield and the semiconductor device of product.

Description of drawings

Fig. 1 is with existing hard mask dry etch process etching deep trench, the schematic diagram of needle prick shape defective occurs.Wherein, (a) be hard mask etching after, substrate surface forms the schematic diagram of silicon projection coarse structure; (b) be deep plough groove etched after, form the schematic diagram of needle prick shape defective.

Fig. 2 is SEM (scanning electron microscopy) figure of the needle prick shape defective of Fig. 1.

Fig. 3 is the distribution map of needle prick shape defective on wafer of Fig. 1.

Fig. 4 is introduce the method for the present embodiment in deep plough groove etched technique after, at the distribution map of deep plough groove etched rear formed needle prick shape defective on wafer.

Embodiment

Understand for technology contents of the present invention, characteristics and effect being had more specifically, existing details are as follows in conjunction with illustrated execution mode:

The solution of the deep plough groove etched technique needle prick shape defective of the embodiment of the present invention, after the photoresist ashing treatment step of the hard mask dry etch process of existing deep trench, before residual polyalcohol step on wet method removal wafer, sequentially increase following processing step:

(1) the round and smooth etching of dry method: with containing tetrafluoromethane (CF ₄) and oxygen (O ₂) hybrid plasma as etching gas, the silicon projection that forms when the hard mask etching with substrate surface waits tropism's etching reaction.Wherein, the flow of tetrafluoromethane is 10～80sccm, and oxygen flow is 5～40sccm.

This step dry method round and smooth etching technics is equivalent to roughly grind flat technique, and its substrate losses is less than 500 Ethylmercurichlorendimides, and has adopted plasma during due to etching, can improve the roughness of substrate surface.

(2) wet method reparation: the mixed liquor with ammoniacal liquor and hydrogen peroxide cleans substrate, utilizes tropism's etching reactions such as the mixed liquor of ammoniacal liquor and hydrogen peroxide and substrate silicon generation, further eliminates the roughness of substrate surface.Wherein, the proportioning of ammoniacal liquor and hydrogen peroxide is 1: 4～1: 1.

This step wet method renovation technique is equivalent to the flat technique of fine grinding, and its substrate losses is less than 30 Ethylmercurichlorendimides, and because it is wet-etching technology, does not need to use plasma, thereby has avoided the damage of plasma to substrate.

Comparison diagram 3 and Fig. 4 can see, after the method for using the present embodiment is improved deep plough groove etched technique, greatly reduces (as shown in Figure 4) in the needle prick shape defective of deep plough groove etched rear appearance.

Claims

1. the solution of deep plough groove etched technique needle prick shape defective, it is characterized in that, after the photoresist ashing treatment step of the hard mask dry etch process of the deep trench of routine, wet method is removed before polymer step residual on wafer, increases successively the round and smooth etching of dry method and wet method and repairs two processing steps.

2. method according to claim 1, is characterized in that, in the round and smooth etching technics step of described dry method, uses the hybrid plasma of tetrafluoromethane and oxygen as etching gas.

3. method according to claim 2, is characterized in that, the flow of described tetrafluoromethane is 10～80sccm, and the flow of described oxygen is 5～40sccm.

4. method according to claim 1, is characterized in that, in described wet method renovation technique step, uses the mixed liquor of ammoniacal liquor and hydrogen peroxide to clean silicon substrate.

5. method according to claim 4, is characterized in that, the proportioning of described ammoniacal liquor and hydrogen peroxide is 1: 4～1: 1.