CN101106087A

CN101106087A - Technique method for forming local metal silicide

Info

Publication number: CN101106087A
Application number: CNA2006100288531A
Authority: CN
Inventors: 张斌; 章宇翔; 岩垂史
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2006-07-12
Filing date: 2006-07-12
Publication date: 2008-01-16

Abstract

The invention discloses a technical method to form partial metal silicide, which includes the following steps: form structures such as shallow groove separation, poly-silicon grid, side wall, and source/drain electrode on a semiconductor silicon surface with the traditional technical method, and then deposit the silicon dioxide film layer, medium film layer, and photosensitive chemical; form photosensitive chemical pictures and remove medium film layer with the dry etching method; remove gel; remove the silicon dioxide film layer not protected by the medium film layer with the method wet corrosion; spatter metal layer and heat treatment; and remove residual metal and medium film with the wet method. Since the new technique slides over the step that the prior art has to deliver photosensitive chemical and pre-deposited silicon dioxide layer into the acid groove for wet corrosion after forming photosensitive chemical pictures, thus effectively avoiding the phenomena that some photosensitive chemicals under the prior art, particularly deep ultraviolet and below, are likely to generate peeling in acid groove, so as to enhance the precision and reliability of shifting photosensitive pictures.

Description

Be used to form the process of local metal silicide

Technical field

The present invention relates to a kind of process of semiconductor integrated circuit, relate in particular to a kind of process that is used to form local metal silicide.

Background technology

As shown in Figure 1; when at present existing technology is used to form local metal silicide; generally at silicon substrate on deposit one silicon dioxide layer 6; through a photoetching process with after forming required photoresist 5 figures; adopt dry etching to add the wet method corroding method and remove the silicon dioxide layer 6 that exposes to shift litho pattern; because existing technology is with the protective layer of photoresist 5 as corrosion in wet etching course; thereby may generating unit divide photoresist 5 especially deep ultraviolet (DUV) and following photoresist thereof photoresist stripping glue phenomenon (Peeling) 8 takes place in acid tank, thereby reduced the accuracy and the reliability of transfer litho pattern.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of in forming local metal silicide figure process, avoids producing the new process of photoresist stripping glue, improves the accuracy and the reliability that shift litho pattern.

For solving the problems of the technologies described above, the invention provides a kind of process that is used to form local metal silicide, it comprises following steps: the semiconductor silicon chip surface adopt traditional process form shallow trench isolation from, polysilicon gate, after side wall and the source/structures such as drain electrode, the deposit silica coating, media coating, and photoresist applies; Form photoresist figure and dry etching and remove media coating; Remove photoresist; Wet etching is removed the silica coating without the media coating protection; Splash-proofing sputtering metal layer and heat treatment; Wet method is removed kish and deielectric-coating.

The present invention needs the silicon dioxide layer of photoresist and deposit is in advance entered the step preface that acid tank carries out wet etching behind the formation photoresist figure owing to having avoided in the existing technology, thereby effectively avoided existing technology lower part photoresist especially deep ultraviolet and following photoresist thereof in acid tank, be easy to generate the phenomenon of stripping glue, improved the accuracy and the reliability that shift litho pattern.

Description of drawings

Fig. 1 is process design sketch behind wet etching that prior art forms local metal silicide;

Fig. 2 is process design sketch behind wet etching that the present invention forms local metal silicide;

Fig. 3 is the flow chart that the present invention forms the process of local metal silicide;

Fig. 4-Fig. 9 is the flow chart that the present invention forms the process of local metal silicide.

Wherein, 1 be shallow trench isolation from; 2 is grid; 3 is side wall; 4 is source/drain electrode; 5 is photoresist; 6 is silicon dioxide layer; 7 is media coating; 8 are photoresist stripping glue phenomenon; 9 do not have stripping glue phenomenon for photoresist; 10 is metal level; 11 is local metal silicide.

Embodiment

The present invention is further detailed explanation below in conjunction with accompanying drawing.

The local metal silicide structure can reduce semiconductor device active area-place, source/drain region-grid produces the probability of electric leakage, having the function that prevents Electrostatic Discharge simultaneously. the present invention has newly proposed a kind of process that can be used for forming local metal silicide, it comprises (1): form shallow trench isolation from (STI) at the semiconductor silicon chip surface by traditional process, polysilicon gate (Gate), after side wall (Sidewall) and the source/drain electrode structures such as (S/D), elder generation's deposit one silicon dioxide layer (SiO2), deposit one and silicon dioxide have high wet etching and select the media coating of ratio (for example Poly/Si3N4/SiON etc.) again; (2). expose the zone that needs form metal silicide (Silicide) selectively by a photoetching process, utilize dry etching to remove the media coating that exposes; (3). after removing photoresist, utilize deielectric-coating and silicon dioxide to have the advantages that high wet etching is selected ratio, adopt wet etching to remove the silicon dioxide layer of protecting without media coating; (4). deposited metal, through promptly forming a local metal silicide structure behind Technology for Heating Processing and wet etching removal kish and the deielectric-coating.The present invention compares with the traditional handicraft that forms local metal silicide, avoided in the existing technology and needed the silicon dioxide layer of photoresist and deposit is in advance entered the step preface that acid tank carries out wet etching behind the formation photoresist figure, thereby effectively avoided existing technology lower part photoresist especially deep ultraviolet (DUV) and following photoresist thereof in acid tank, be easy to generate the phenomenon of stripping glue (Peeling), improved the accuracy and the reliability that shift litho pattern.

The present invention is a kind of new process that is used to form local metal silicide (Silicide), its concrete execution mode is to arrive shown in Figure 9 as Fig. 3: at first, as shown in Figure 4, at a surface of silicon deposit one silica coating 6, deposit one has high wet etching and selects the media coating 7 of ratio and apply photoresist 5 with it on silica coating 6; Secondly, as shown in Figure 5, utilize dry etching to remove the media coating 7 that after a photoetching, exposes; Once more, as shown in Figure 6, after removing photoresist; As shown in Figure 7, adopt the method for wet etching, utilize the media coating 7 and the high wet etching of silicon dioxide layer 6 to select the silicon dioxide layer 6 that exposes than removing, thereby form the required figure of local metal silicide; As shown in Figure 8, deposited metal 10 is removed kish layer 10 and media coating 7 back formation one local metal silicide structure 11 through Technology for Heating Processing and wet method as shown in Figure 9.

Claims

1. a process that is used to form local metal silicide is characterized in that, comprises following steps:

A. adopt traditional process to form shallow trench isolation at the semiconductor silicon chip surface from, polysilicon gate, after side wall and the source/structures such as drain electrode, deposit silica coating, media coating, and photoresist coating;

B. form photoresist figure and dry etching and remove media coating;

C. remove photoresist;

D. wet etching is removed the silica coating without the media coating protection;

E. splash-proofing sputtering metal layer and heat treatment;

F. wet method is removed kish and deielectric-coating.

2. the new process that is used to form local metal silicide according to claim 1 is characterized in that: described media coating comprises polysilicon, silicon nitride, silicon oxynitride for having the rete that high wet etching is selected ratio with silicon dioxide.