CN103094117B

CN103094117B - Technique method of manufacturing bottom thick grate oxide layer groove metal oxide semiconductor (MOS)

Info

Publication number: CN103094117B
Application number: CN201110340498.2A
Authority: CN
Inventors: 金勤海; 沈浩峰; 袁秉荣
Original assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2011-11-01
Filing date: 2011-11-01
Publication date: 2015-06-03
Anticipated expiration: 2031-11-01
Also published as: CN103094117A

Abstract

The invention discloses a technique method of manufacturing a bottom thick grate oxide layer groove metal oxide semiconductor (MOS). The technique method of manufacturing the bottom thick grate oxide layer groove MOS comprises the following steps. The first step is that an epitaxial layer grows on a heavily-doped silicon substrate, and a first lightly-doped epitaxial layer is formed; the second step is that silicon dioxide grows on the first lightly-doped epitaxial layer; the third step is that a photoresist pattern is formed; the fourth step that the silicon dioxide which is unblocked by photoresist is etched cleanly, so that the first lightly-doped epitaxial layer except the photoresist is exposed, and then the photoresist is eliminated; the fifth step is that a second epitaxial layer grows selectively; the sixth step is the silicon dioxide is etched backward to required thickness through wet process or dry process etching technology, and a groove and a thick grate oxide layer at the bottom of the groove are formed. According to the technique method of manufacturing the bottom thick grate oxide layer groove MOS, selectively epitaxial growth is adopted to form the groove, the oxide layer inside the groove is etched backward to the required thickness so as to serve as the thick grate oxide layer at the bottom of the groove. According to the technique method of manufacturing the bottom thick grate oxide layer groove MOS, the structure of the bottom thick grate oxide layer groove MOS is enabled to be easily formed and controlled.

Description

Make the process of bottom thick grating oxide layer groove MOS

Technical field

The present invention relates to a kind of manufacture method of semiconductor device, be specifically related to a kind of process making bottom thick grating oxide layer groove MOS.

Background technology

Bottom thick grating oxide layer (thickness is 500 ~ 10000 dusts) MOS (metal-oxide semiconductor (MOS)) can make electric capacity between device gate-drain greatly reduce.Existing technique forms groove by etching, but this method makes the formation of bottom thick grating oxide layer very difficult.Further, existing technique generally only has one deck extension in heavy doping, and when needing two-layer outer time delay, the relative position controlling of prior art processes to extension and groove is accurate not, therefore makes the Comparision difficulty optimizing epi dopant and device performance.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of process making bottom thick grating oxide layer groove MOS, and it can make the formation of the bottom thick grating oxide layer of groove MOS become easily realization and control.

For solving the problems of the technologies described above, the technical solution that the present invention makes the process of bottom thick grating oxide layer groove MOS is comprise the following steps:

The first step, at heavily doped silicon Grown epitaxial loayer, forms the first light dope epitaxial loayer;

Second step, the first light dope epitaxial loayer grows silicon dioxide;

The thickness of the silicon dioxide formed is equal to, or greater than the follow-up gash depth that will be formed.

3rd step, adopts photoetching process, on silica gluing, photoetching, forms photoetching offset plate figure;

4th step, etching, by clean for the silicon dioxide etching do not blocked by photoresist, exposes the first light dope epitaxial loayer beyond photoresist; Then photoresist is removed;

5th step, selective growth second epitaxial loayer; At the superficial growth second light dope epitaxial loayer of the first light dope epitaxial loayer exposed;

The thickness of the second light dope epitaxial loayer formed is the gash depth that will be formed.

6th step, adopts wet method or dry etching technology, returns and carves silicon dioxide to required thickness, form the thick grating oxide layer of groove and bottom thereof.

The technique effect that the present invention can reach is:

The present invention adopts selective epitaxial growth to form groove, and the oxide layer of returning in ditch groove is to the thickness needed, to serve as the thick grating oxide layer of channel bottom.

The present invention can make bottom thick grating oxide layer trench MOS structure easily be formed and control, and accurately can control the position of the epitaxial loayer opposed channels of two-layer epitaxial groove MOS, thus by controlling the doping content of two-layer extension respectively, puncture voltage and the on state resistance of optimised devices can be come.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation:

Fig. 1 to Fig. 5 is the structural representation that each step of the process making bottom thick grating oxide layer groove MOS to the present invention is corresponding;

Fig. 6 is the schematic cross-section of the bottom thick grating oxide layer groove MOS device adopted made by the present invention.

Embodiment

The present invention makes the process of bottom thick grating oxide layer groove MOS, comprises the following steps:

The first step, as shown in Figure 1, at heavily doped silicon Grown epitaxial loayer, forms the first light dope epitaxial loayer; Heavy doping bulk concentration is 10 ¹⁸/ cm ³above;

Second step, as shown in Figure 1, the first light dope epitaxial loayer grows silicon dioxide, its thickness is equal to, or greater than the follow-up gash depth that will be formed;

3rd step, as shown in Figure 2, adopts photoetching process, on silica gluing, photoetching, forms photoetching offset plate figure;

4th step, as shown in Figure 3, etching, by clean for the silicon dioxide etching do not blocked by photoresist, exposes the first light dope epitaxial loayer beyond photoresist; Then photoresist is removed;

5th step, as shown in Figure 4, selective growth second epitaxial loayer; At the superficial growth second light dope epitaxial loayer of the first light dope epitaxial loayer exposed, and silicon dioxide does not grow;

The thickness of the second light dope epitaxial loayer is the gash depth wanting to be formed;

6th step, as shown in Figure 5, adopts existing wet method or dry etching technology, returns and carves silicon dioxide to required thickness, namely form the thick grating oxide layer of groove and bottom thereof;

The silicon dioxide remained is namely as the thick grating oxide layer of channel bottom;

Adopt the present invention, groove MOS device as shown in Figure 6 can be made.

Claims

1. make a process for bottom thick grating oxide layer groove MOS, the thickness of described bottom thick grating oxide layer is 500 ~ 10000 dusts; It is characterized in that, comprise the following steps:

Second step, the first light dope epitaxial loayer grows silicon dioxide;

2. the process making bottom thick grating oxide layer groove MOS according to claim 1, it is characterized in that, the thickness of the silicon dioxide that described second step is formed is equal to, or greater than the follow-up gash depth that will be formed.

3. the process making bottom thick grating oxide layer groove MOS according to claim 1 and 2, it is characterized in that, the thickness of the second light dope epitaxial loayer that described 5th step is formed is the gash depth that will be formed.