CN101399218B

CN101399218B - Method for producing amorphous silicon isolated by deep groove

Info

Publication number: CN101399218B
Application number: CN200710094108A
Authority: CN
Inventors: 王剑敏
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2007-09-28
Filing date: 2007-09-28
Publication date: 2010-05-26
Anticipated expiration: 2027-09-28
Also published as: CN101399218A

Abstract

The invention discloses a preparation method of deep trench isolated amorphous silicon. The method comprises the following steps which are continuously carried out in deposition equipment: a first layer of amorphous silicon is deposited on a deep trench; gas pipelines and the deposition equipment are cleaned by nitrogen purging, afterward, a gaseous mixture of oxygen and argon is pumped into the equipment for purging, so that the surface of the first layer of amorphous silicon is oxidized to form silicon dioxide; a second layer of amorphous silicon is deposited on the silicon dioxide, thus finishing filling the deep trench. In the method, the stress brought from depositing the second layer of amorphous silicon is relieved by forming the silicon dioxide on the surface of the first layer of amorphous silicon; furthermore, the whole process is continuously carried out in the same deposition equipment, so that the total process time is relatively short; therefore, the production capacity of the deep trench isolated amorphous silicon technology is improved. The method is applicable for filling processes of deep trench isolated amorphous silicon in semiconductor preparations.

Description

The preparation method of amorphous silicon isolated by deep groove

Technical field

The present invention relates to a kind of preparation method of amorphous silicon isolated by deep groove.

Background technology

Deep trouth (being deep trench) at Bipolar or BiCMOS device is isolated in the making, adopts amorphous silicon as filling spacer medium usually.Because amorphous silicon need be deposited to certain thickness (10k

-20k

), so that deep trouth is filled up, but a deposit of amorphous silicon is too thick, will apply very large stress to silicon chip, is easy to like this cause the false sheet in goods or the stove because stress is excessive and cracked.Common method is that the amorphous silicon that deep trouth is filled is divided into twice deposit now, it is the amorphous silicon of a half thickness of the whole thickness of first deposit, come out of the stove then, under the normal temperature situation, place the regular hour, to eliminate certain stress, second half the amorphous silicon of thickness of deposit more subsequently, an overall deposit of stress ratio is little in the prepared like this amorphous silicon layer.But because whole deposition process is divided into twice, need comes out of the stove and go into stove again, and,, influence the production capacity for preparing amorphous silicon isolated by deep groove so greatly the expensive time again with being extracted into the needed pressure of si deposition in the body of heater.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of preparation method of amorphous silicon isolated by deep groove, and it can shorten the time of si deposition.

For solving the problems of the technologies described above, the preparation method of amorphous silicon isolated by deep groove of the present invention is included in and carries out following steps in the si deposition equipment continuously:

(1) deposit ground floor amorphous silicon on deep trouth;

(2) purge purge gas pipeline and described deposition apparatus with nitrogen, afterwards the mist of aerating oxygen and argon gas purges in described equipment, makes the oxidation of ground floor amorphous silicon surfaces form silicon dioxide;

(3) deposit second layer amorphous silicon on the silicon dioxide that step (2) forms.

Another preparation method of the present invention promptly uses laughing gas (N in above-mentioned steps (2) ₂O) mist of replace oxygen and argon gas.

Preparation method of the present invention is divided into twice deposit with the deep trouth amorphous silicon, in twice deposit, add oxidation step gas purging process, it is first deposit ground floor amorphous silicon, silane in the gas piping is purged clean with nitrogen earlier, the mist of aerating oxygen and argon gas or laughing gas in deposition apparatus then, make the surface oxidation of amorphous silicon form silicon dioxide, silicon dioxide can be alleviated the stress that amorphous silicon is brought when growing for the second time, and the stress that can avoid amorphous silicon isolated by deep groove one secondary growth to cause is excessive.This method is simple, and can utilize conventional device to carry out, and need not increase any attachment device.In addition, because oxidizing gas purges and si deposition is carried out in same equipment continuously, so the entire process time is shorter relatively.

Description of drawings

The present invention is further detailed explanation below in conjunction with accompanying drawing and embodiment:

Fig. 1 is preparation method's flow chart of the present invention;

Fig. 2 a is the structural representation after the ground floor si deposition in the preparation flow of the present invention;

Fig. 2 b is the structural representation after silicon dioxide forms in the preparation of the present invention;

Fig. 2 c is the structural representation after the second layer si deposition in the preparation of the present invention.

Embodiment

Preparation method of the present invention, in si deposition equipment, finish continuously, amorphous silicon isolated by deep groove is divided into the deposit (see figure 1) twice, in twice deposit, keep temperature-resistant in the deposition apparatus, add a step nitrogen and an oxygen blow process, the whole deep trouth of elder generation's deposit is filled 40%～60% thickness (being deposit ground floor amorphous silicon) of the whole thickness of needed amorphous silicon, with the residual reacting gas in the gas piping (for example, silane) purge totally with nitrogen, the mist of aerating oxygen and argon gas in deposition apparatus then, make the surface of ground floor amorphous silicon form silicon dioxide, the stress that this layer silicon dioxide is brought in the time of alleviating second layer si deposition.Twice deposition process of the present invention and the purge in twice deposition process are carried out in same deposition apparatus continuously, the deposition apparatus temperature the when temperature of deposition apparatus remains with si deposition identical (being about 500～600 degree).In the oxygen that adopts and the mist of argon gas, the molar percentage of oxygen is between 1%～2%.In concrete the enforcement, also can use N ₂O gas replaces the mist of oxygen and argon gas.

Fig. 2 a to Fig. 2 c is the silicon chip cross section structure schematic diagram in preparation method's process of the present invention, before carrying out the amorphous silicon filling, be coated with silicon dioxide around the deep trouth earlier, the ground floor si deposition (is seen Fig. 2 a), after deposit is intact, is kept temperature-resistant in the deposition apparatus on silicon dioxide, feeding nitrogen earlier purges with the silane gas in the purge gas pipeline, the mist of back aerating oxygen and argon gas purges deposition apparatus, makes the amorphous silicon of silicon chip surface be oxidized to silicon dioxide (seeing Fig. 2 b), is about 50

～100

In same equipment, carry out second layer si deposition at last to fill whole deep trouth (seeing Fig. 2 c).Si deposition equipment recited above can be the boiler tube in the LPCVD technology, also can be that other is used for the equipment of si deposition.

In concrete enforcement, the flow that the mist of oxygen and argon gas can be purged is 500sccm～1500sccm (a standard state ml/min), deposition apparatus pressure in the purge is controlled to be between 0.1Torr～1Torr (holder), and purge time is controlled to be 30s～240s.

Claims

1. the preparation method of an amorphous silicon isolated by deep groove is used for amorphous silicon is filled into deep trouth, it is characterized in that, is included in to carry out following steps in the si deposition equipment continuously:

(1) deposit ground floor amorphous silicon on deep trouth;

(3) deposit second layer amorphous silicon on the silicon dioxide that step (2) forms is finished the filling of described deep trouth.

2. according to the described preparation method of claim 1, it is characterized in that: the device temperature of the deposition apparatus temperature the when mist of described oxygen and argon gas purges during with si deposition is identical.

3. according to the described preparation method of claim 2, it is characterized in that: the flow of the mist of described oxygen and argon gas is 500sccm～1500sccm, pressure during described oxygen blow in the deposition apparatus is 0.1～1 holder, and the time that the mist of described oxygen and argon gas purges is 30 seconds～240 seconds.

4. according to the described preparation method of claim 1, it is characterized in that: the thickness of the silicon dioxide that forms in the described step (2) is

5. according to the described preparation method of claim 1, it is characterized in that: the thickness of described ground floor amorphous silicon be described deep trouth fill needed amorphous silicon thickness 40%～60%.

6. according to the described preparation method of claim 1, it is characterized in that: in the mist of described oxygen and argon gas, the mole percent level of oxygen is 1%～2%.

7. the preparation method of an amorphous silicon isolated by deep groove is used for amorphous silicon is filled into deep trouth, it is characterized in that, is included in to carry out following steps in the si deposition equipment continuously:

(1) in deposition apparatus, deposit ground floor amorphous silicon on deep trouth;

(2) purge purge gas pipeline and described deposition apparatus with nitrogen, the back feeds N in described equipment ₂O purges, and makes the oxidation of ground floor amorphous silicon surfaces form silicon dioxide;

8. according to the described preparation method of claim 7, it is characterized in that: the thickness of described ground floor amorphous silicon be described deep trouth fill needed amorphous silicon thickness 40%～60%.