CN102522363A

CN102522363A - Production method of deep groove isolation structure

Info

Publication number: CN102522363A
Application number: CN2011104357103A
Authority: CN
Inventors: 遇寒; 梅绍宁
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2011-12-22
Filing date: 2011-12-22
Publication date: 2012-06-27

Abstract

The invention discloses a production method of a deep groove isolation structure. After an epitaxial layer is grown, the method produces the deep groove isolation structure in the following steps: 1) growing silicon dioxide and silicon nitride in a furnace tube, and depositing silicon dioxide on silicon nitride; 2) performing exposure and development, and opening an area where a deep groove is to be etched in a dry etching mode; 3) utilizing silicon dioxide-silicon nitride-silicon dioxide formed by the step 1) to serve as an etching blocking layer, and forming the deep groove in the dry etching mode; 4) performing furnace pipe oxidation again, growing silicon dioxide, and fully oxidizing silicon below silicon nitride of a deep groove isolation area; 5) depositing silicon dioxide and sealing an opening of the deep groove; and 6) carrying out planarization of the surface of the deep groove. The method forms an ultra-thick field oxidation isolation layer by means of a deep groove etching and oxidation technology, and utilizes silicon nitride to serve as the blocking layer of planarization, thereby not only achieving isolation effect, but also greatly improving evenness in the surface and reducing difficulty of rear-end process.

Description

The manufacturing approach of deep groove isolation structure

Technical field

The present invention relates to semiconductor integrated circuit and make the field, particularly relate to a kind of manufacturing approach of deep groove isolation structure.

Background technology

RF LDMOS power device is because good electrology characteristic (for example, high linearity, high-gain; High-output power; High thermal stability, high working voltage, biasing circuit is simple; Input impedance is constant etc.) and with the favorable compatibility of existing CMOS integrated circuit technology, be widely used in wireless communication field at present.

General common STI (deep trench isolation) of employing of traditional LDMOS device and thick oxygen are isolated; This isolation technology can bring inner evenness poor, cause problems such as soup is residual easily, thereby limited the application of RF LDMOS device on the high-speed high frequency device to a certain extent.

Summary of the invention

The technical problem that the present invention will solve provides a kind of manufacturing approach of deep groove isolation structure, and it can improve the inner evenness of RF LDMOS device.

For solving the problems of the technologies described above, the manufacturing approach of deep groove isolation structure of the present invention may further comprise the steps:

1) at the silicon substrate growing epitaxial layers;

2) advance boiler tube grow up successively silicon dioxide and silicon nitride, deposit layer of silicon dioxide on silicon nitride again;

3) exposure is developed, and opens the zone of wanting the etching deep trouth with dry etching method;

4) with step 2) silicon dioxide-silicon nitride-silicon dioxide of forming is as etching barrier layer, and dry etching forms deep trouth;

5) furnace oxidation, growth silicon dioxide all oxidizes away the silicon below the silicon nitride in deep trench isolation zone;

6) deposit silicon dioxide is sealed the deep trouth opening;

7) deep trouth flattening surface.

The present invention is through deep plough groove etched and oxidation technology; Form ultra thick oxidation separator; Increase the barrier layer of silicon nitride simultaneously as flatening process; Thereby not only reached the effect of isolating, also improved the inner evenness of oxide layer greatly, effectively reduced the difficulty of the backend process that brings because of inhomogeneities in difference in height and the face and the hidden danger of device stability aspect.

Description of drawings

Fig. 1 is the manufacturing approach flow chart of embodiment of the invention deep groove isolation structure.

Description of reference numerals is following among the figure:

1: silicon substrate

2: epitaxial loayer

3,5,7,8: oxide layer (silicon dioxide)

4: silicon nitride

6: deep trouth

Embodiment

Understand for technology contents of the present invention, characteristics and effect being had more specifically, combine illustrated execution mode at present, to the manufacturing process flow of the deep groove isolation structure in the RFLDMOS device, details are as follows:

Step 1 is at silicon substrate 1 growing epitaxial layers 2, shown in Fig. 1 (a).

Step 2 is advanced furnace oxidation, and the layer thickness of growing up is the oxide layer 3 of 150～300 Ethylmercurichlorendimides; Advance the grow up silicon nitride 4 of a layer thickness 500～800 Ethylmercurichlorendimides of boiler tube then; Deposit forms the oxide layer 5 that a layer thickness is 2000～5000 Ethylmercurichlorendimides on silicon nitride 4 again, shown in Fig. 1 (b).

Step 3, exposure is developed, and with the method for dry etching, opens the zone of wanting the etching deep trouth, shown in Fig. 1 (c).

Step 4, as etching barrier layer, with the method for dry etching, etching forms trapezoid deep trouth 6, shown in Fig. 1 (d) with oxide layer 3, silicon nitride 4 and oxide layer 5.The angle of this trapezoid deep trouth 6 is 80～89 degree.

Step 5 is advanced furnace oxidation, growth oxide layer 7.Since there is oxide layer 3 below the silicon nitride 4, therefore, through the whole oxidations of SI post after the furnace oxidation that deep trouth is middle, shown in Fig. 1 (e).

Step 6 with chemical gaseous phase depositing process deposit layer of oxide layer 8, is sealed the opening of deep trouth 6, shown in Fig. 1 (f).

Step 7 is utilized flatening process, and with the deep trouth surface rubbing, the large-area deep groove isolation structure of the 5 μ m left and right sides degree of depth that complete is shown in Fig. 1 (g).Because the etching selection ratio of silicon nitride and silicon dioxide is very high, therefore, silicon nitride 4 can be used as the barrier layer; The difference in height of isolated area and active area is remained in 1000 Ethylmercurichlorendimides; Like this, both reach the effect of isolating, improved the inner evenness of oxide layer again; Effectively reduce the difficulty of the backend process that brings by inhomogeneities in difference in height and the face, guaranteed the stability of device.

Claims

1. the manufacturing approach of deep groove isolation structure is characterized in that, may further comprise the steps:

1) at the silicon substrate growing epitaxial layers;

6) deposit silicon dioxide is sealed the deep trouth opening;

7) deep trouth flattening surface.

2. method according to claim 1 is characterized in that step 2), the thickness of the silicon dioxide that boiler tube is grown up is 150～300 Ethylmercurichlorendimides.

3. method according to claim 1 is characterized in that step 2) thickness of the silicon nitride of growing up is 500～800 Ethylmercurichlorendimides.

4. method according to claim 1 is characterized in that step 2), the thickness of the silicon dioxide that deposit forms is 2000～5000 Ethylmercurichlorendimides.

5. method according to claim 1 is characterized in that, step 4), and said deep trouth is trapezoid.

6. method according to claim 5 is characterized in that, the angle of said trapezoid is 80～88 degree.

7. method according to claim 1 is characterized in that, step 4), the degree of depth of said deep trouth are 5 μ m.

8. method according to claim 1 is characterized in that, chemical gaseous phase depositing process is adopted in the deposit of silicon dioxide.