CN103576466A

CN103576466A - Photoetching method

Info

Publication number: CN103576466A
Application number: CN201210258708.8A
Authority: CN
Inventors: 徐春云
Original assignee: Wuxi CSMC Semiconductor Co Ltd
Current assignee: Wuxi CSMC Semiconductor Co Ltd
Priority date: 2012-07-24
Filing date: 2012-07-24
Publication date: 2014-02-12

Abstract

The invention relates to a photoetching method. The method comprises following steps: coating a wafer with hexamethyldisilazane; forming an antireflective coating on the wafer and baking; coating on the wafer with a photoresist which is a positive photoresist; performing soft baking to the coated photoresist; exposing the coated photoresist; baking the coated photoresist after exposure; developing the photoresist after exposure; and performing hard baking to the developed photoresist. Therefore, compared to traditional technology, the photoetching method improves the critical dimension (CD) of a product, and increases the yield of the product.

Description

Photoetching method

Technical field

The present invention relates to semiconductor technology, particularly relate to a kind of photoetching method.

Background technology

Photoetching process is to utilize the photonasty of photoresist and corrosion stability on silicon based material or metal film, to run off the geometric figure completely corresponding with mask plate.Photoetching need to first form one deck photoresist film through gluing, then through overexposure, the figure on mask plate is transferred on photoresist.As being an AZ630, after exposure, the photosensitive region of photoresist can react with developer solution and dissolve, and through the part of illumination, does not react.Again will be at SiO after developing ₂on the dielectric layers such as/metal/polysilicon, form and the identical photoetching offset plate figure of mask plate patterns.Photoetching need to be controlled the characteristic parameters such as the line size of glue and glue pattern.

Positive photoresist adopts traditional process conditions, and the final glue pattern forming is poor, as shown in Figure 1.Can affect like this critical size (CD), and the graphics request after etching, may cause that PCM parameter inefficacy etc. is abnormal.

Summary of the invention

Based on this, being necessary, for the poor problem of pattern after positive photoresist photoetching in traditional handicraft, provides a kind of photoetching method.

, comprise the following steps: to apply HMDS on wafer; On described wafer, form antireflecting coating baking; On described wafer, apply photoresist, described photoresist is positive photoresist; The photoresist applying is carried out to soft baking; Photoresist to described coating exposes; Photoresist is carried out to postexposure bake; Photoresist after exposure is developed; Photoresist after developing is dried firmly.

In an embodiment, the described photoresist to coating carries out in the step of soft baking therein, and baking temperature is 105 ~ 115 degrees Celsius, and baking time is 60 seconds.

Therein in an embodiment, the baking temperature in described step of the photoresist applying being carried out to soft baking is 112 degrees Celsius.

Therein in an embodiment, in described step of photoresist being carried out to postexposure bake, baking temperature is 105 ~ 115 degrees Celsius, and baking time is 60 seconds.

Therein in an embodiment, the baking temperature in described step of photoresist being carried out to postexposure bake is 112 degrees Celsius.

In an embodiment, in the described step that photoresist after developing is carried out firmly drying, baking temperature is 95 ~ 105 degrees Celsius therein, and baking time is 60 seconds.

In an embodiment, the described baking temperature that photoresist after developing is carried out in hard step of drying is 100 degrees Celsius therein.

In an embodiment, described positive photoresist is AZ6130 therein.

Adopt the positive photoresist after above-mentioned photoetching method photoetching, with respect to traditional handicraft, can obtain better pattern.Therefore, with respect to conventional art, improve the critical size (CD) of product, improved the yield of product.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of photoetching method in an embodiment;

Fig. 2 is positive photoresist cross sectional photograph under the microscope after employing photoetching method photoetching of the present invention;

Fig. 3 is positive photoresist cross sectional photograph under the microscope after the traditional photoetching process condition photoetching of employing.

Embodiment

For object of the present invention, feature and advantage can more be become apparent, below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in detail.

Fig. 1 is the process flow diagram of photoetching method in an embodiment, comprises the following steps:

S11 applies HMDS (HMDS) on wafer.

To after liquid HMDS vaporization, evenly be sprayed on crystal column surface.

S12 forms antireflecting coating (ARC) baking on wafer.

Use anti-reflective coating layer process, the impact that can lower standing wave effect.Antireflecting coating is formed at the surface of wafer in the present embodiment, and the bottom of photoresist, can form by depositing technics.

S13 applies photoresist on wafer, this photoresist be positive photoresist, and the optional AZ6130 of positive photoresist.

S14, carries out soft baking to the photoresist applying.

Soft baking is mainly for by a part of solvent evaporates in photoresist.In certain processing range, improve the volatile quantity that baking temperature has increased photoresist internal solvent, reduced molecule and flowed, increased adhesion, thereby can improve the pattern of photoresist, but excess Temperature may cause the charing of photoresist.The baking temperature of this step is 105 ~ 115 degrees Celsius, is preferably 112 degrees Celsius, and baking time is preferably 60 seconds.

S15, exposes to the photoresist applying.

S16, carries out postexposure bake to photoresist.

Through postexposure bake (Post Exposure Bake, PEB), the emulsion of non-exposed area can spread to exposure region, thereby forms average exposure effect on the border of exposure region and non-exposed area, can reduce the impact of standing wave effect.Adopt higher baking temperature, can strengthen the effect of diffusion, thereby reduce the impact of standing wave effect, but excess Temperature may cause the charing of photoresist.The baking temperature of this step is 105 ~ 115 degrees Celsius, is preferably 112 degrees Celsius, and baking time is preferably 60 seconds.

S17, develops to the photoresist after exposure.

After PEB completes, photoresist is developed.

S18, dries firmly to the photoresist after developing.

Hard baking can be removed remaining solvent in photoresist, strengthens the adhesion of photoresist to silicon chip surface, improves corrosion stability and the protective capability of photoresist in the processes such as etching and Implantation simultaneously.But too high baking temperature can make photoresist due to the increase of inner tensile stress, make on the contrary the adhesion of photoresist decline.The baking temperature of this step is 95 ~ 105 degrees Celsius, is preferably 100 degrees Celsius, and baking time is preferably 60 seconds.

Fig. 2 is positive photoresist cross sectional photograph under the microscope after employing photoetching method photoetching of the present invention.Can find out, its pattern with respect to Fig. 3 is improved.Therefore, the present invention has improved the critical size (CD) of product with respect to conventional art, has improved the yield of product.

The above embodiment has only expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.

Claims

1. a photoetching method, comprises the following steps:

On wafer, apply HMDS;

On described wafer, form antireflecting coating baking;

On described wafer, apply photoresist, described photoresist is positive photoresist;

The photoresist applying is carried out to soft baking;

Photoresist to described coating exposes;

Photoresist is carried out to postexposure bake;

Photoresist after exposure is developed;

Photoresist after developing is dried firmly.

2. photoetching method according to claim 1, is characterized in that, the described photoresist to coating carries out in the step of soft baking, and baking temperature is 105 ~ 115 degrees Celsius, and baking time is 60 seconds.

3. photoetching method according to claim 2, is characterized in that, described baking temperature is 112 degrees Celsius.

4. according to the photoetching method described in any one in claim 1-3, it is characterized in that, in described step of photoresist being carried out to postexposure bake, baking temperature is 105 ~ 115 degrees Celsius, and baking time is 60 seconds.

5. photoetching method according to claim 4, is characterized in that, the baking temperature in described step of photoresist being carried out to postexposure bake is 112 degrees Celsius.

6. photoetching method according to claim 1 or 5, is characterized in that, described photoresist after developing is carried out in hard step of drying, and baking temperature is 95 ~ 105 degrees Celsius, and baking time is 60 seconds.

7. photoetching method according to claim 6, is characterized in that, the described baking temperature that photoresist after developing is carried out in hard step of drying is 100 degrees Celsius.

8. photoetching method according to claim 1, is characterized in that, described positive photoresist is AZ6130.