Silicon film forming method, thin film forming method and cross-sectional shape control method

Patent metadata

Field	Value
Publication number	US-9758865-B2
Application number	US-201414447060-A
Country	US
Kind code	B2
Filing date	Jul 30, 2014
Priority date	Jul 31, 2013
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

The present disclosure provides a silicon film forming method for forming a silicon film on a workpiece having a processed surface, including: forming a seed layer by supplying a high-order aminosilane-based gas containing two or more silicon atoms in a molecular formula onto the processed surface and by having silicon adsorbed onto the processed surface; and forming a silicon film by supplying a silane-based gas not containing an amino group onto the seed layer and by depositing silicon onto the seed layer, wherein, when forming a seed layer, a process temperature is set within a range of 350 degrees C. or lower and a room temperature or higher.

First claim

What is claimed is:

1. A silicon film forming method for forming a silicon film on a workpiece having a processed surface, comprising:
forming a first seed layer by supplying a high-order aminosilane-based gas containing two or more silicon atoms in a molecular formula onto the processed surface and by having silicon adsorbed onto the processed surface;
forming a second seed layer by supplying a high-order silane-based gas containing two or more silicon atoms in a molecular formula and not containing an amino group onto the first seed layer and by depositing silicon onto the first seed layer; and
after the second seed layer is formed, forming a silicon film by supplying a silane-based gas not containing an amino group onto the second seed layer and by depositing silicon on the second seed layer,
wherein, when forming a first seed layer, a process temperature is set within a range of less than 300 degrees C. and more than 200 degrees C.,
wherein the silane-based gas not containing an amino group, which is used when forming a silicon film, is a silane-based gas having an order equal to or lower than the high-order silane-based gas not containing an amino group, which is used when forming a second seed layer, and
wherein a thickness of the second seed layer ranges from 2 nm to 4 nm.

2. The method of claim 1 , wherein the first seed layer is formed by having silicon adsorbed onto the processed surface, and an adsorption density of the silicon is controlled by adjusting the process temperature of forming a first seed layer is set within the range of less than 300 degrees C. and more than 200 degrees C.

3. The method of claim 1 , wherein the process temperature of forming a first seed layer is set within a range of less than 250±25 degrees C.

4. The method of claim 1 , wherein the high-order aminosilane-based gas containing two or more silicon atoms in a molecular formula is selected from gases containing at least one kind of silicon amino compound represented by a formula:
((R1R2)N) n Si X H 2X+2-n-m (R3) m   (A); and

((R1R2)N) n Si X H 2X-n-m (R3) m   (B),

where n is the number of amino groups, which is a natural number of 1 to 6, m is the number of alkyl groups, which is zero or a natural number of 1 to 5, R1, R2, and R3 are CH 3 , C 2 H 5 and C 3 H 7 , R1, R2 and R3 may be identical with each other or may not be identical with each other, R3 may be Cl, and X is a natural number equal to or greater than two.

5. The method of claim 4 , wherein the high-order aminosilane-based gas represented by the formula (A) is selected from a group consisting essentially of:
diisopropylaminodisilane (Si 2 H 5 N(iPr) 2 );
diisopropylaminotrisilane (Si 3 H 7 N(iPr) 2 );
diisopropylaminochlorodisilane (Si 2 H 4 ClN(iPr) 2 ); and
diisopropylaminochlorotrisilane (Si 3 H 6 ClN(iPr) 2 ).

6. The method of claim 4 , wherein the high-order aminosilane-based gas represented by the formula (B) is selected from a group consisting essentially of:
diisopropylaminocyclotrisilane (Si 3 H 5 N(iPr) 2 ); and
diisopropylaminochlorocyclotrisilane (Si 3 H 4 ClN(iPr) 2 ).

7. The method of claim 1 , wherein the high-order silane-based gas containing two or more silicon atoms in a molecular formula and not containing an amino group include a gas containing at least one selected from a group consisting essentially of:
Si 2 H 6 ;
silicon hydride which is represented by formula Si m H 2m+2 (where m is a natural number equal to or greater than 3); and
silicon hydride which is represented by formula Si n H 2n (where n is a natural number equal to or greater than 3).

8. The method of claim 7 , wherein the silicon hydride represented by the formula Si m H 2m+2 includes at least one selected from a group consisting essentially of:
Si 3 H 8 ;
Si 4 H 10 ;
Si 5 H 12 ;
Si 6 H 14 ; and
Si 7 H 16 , and

the silicon hydride represented by the formula Si n H 2n includes at least one selected from a group consisting essentially of:
Si 3 H 6 ;
Si 4 H 8 ;
Si 5 H 10 ;
Si 6 H 12 ; and
Si 7 H 14 .

9. The method of claim 1 , wherein the second seed layer is formed by vapor phase growth of silicon on the first seed layer.

10. The method of claim 1 , wherein the silane-based gas having an order equal to or lower than the high-order silane-based gas is SiH 4 or Si 2 H 6 .

11. A thin film forming method for forming a thin film on a workpiece having a processed surface and a hole or groove defined on the processed surface, comprising:
forming multiple seed layers including a first seed layer and a second seed layer on the processed surface according to the silicon film forming method of claim 1 ;
forming a silicon film at such a film thickness as not to close the hole or groove while leaving an opening portion corresponding to the hole or groove, by supplying a silane-based gas not containing an amino group onto the multiple seed layers and by depositing silicon on the multiple seed layers;
enlarging the opening portion of the silicon film corresponding to the hole or groove by partially etching the silicon film while leaving the silicon film along the hole or groove; and
forming an opening-portion-filling thin film on the silicon film whose opening portion is enlarged.

12. The method of claim 11 , wherein the silane-based gas not containing an amino group, which is used when forming a silicon film at such a film thickness as not to close the hole or groove while leaving an opening portion corresponding to the hole or groove, is a silane-based gas having an order equal to or lower than the high-order silane-based gas containing two or more silicon atoms in a molecular formula and not containing an amino group, which is used when forming multiple seed layers.

13. The method of claim 12 , wherein the silane-based gas having an order equal to or lower than the high-order silane-based gas is SiH 4 or Si 2 H 6 .

14. The method of claim 11 , wherein, when forming multiple seed layers, a source gas and a doping gas containing an impurity serving as a donor or an acceptor are simultaneously supplied at least during formation of the second seed layer.

15. The method of claim 11 , further comprising:
after forming multiple seed layers, doping an impurity serving as a donor or an acceptor on the multiple seed layers.

16. The method of claim 11 , wherein, when forming a silicon film at such a film thickness as not to close the hole or groove while leaving an opening portion corresponding to the hole or groove, the silane-based gas not containing an amino group and a doping gas containing an impurity serving as a donor or an acceptor are simultaneously supplied.

17. The method of claim 11 , further comprising:
after enlarging the opening portion of the silicon film corresponding to the hole or groove, doping an impurity serving as a donor or an acceptor on the silicon film whose opening portion is enlarged.

18. The method of claim 15 , wherein the impurity is doped by a vapor phase diffusion method.

19. The method of claim 11 , wherein, when controlling an in-hole or in-groove cross-sectional shape of the silicon film subjected to enlarging the opening portion of the silicon film corresponding to the hole or groove, the in-hole or in-groove cross-sectional shape of the silicon film is controlled by changing an aspect ratio of the opening portion, which corresponds to the hole or groove, of the silicon film subjected to forming a silicon film at such a film thickness as not to close the hole or groove while leaving an opening portion correspondin

Assignees

• Tokyo Electron Ltd

Inventors

• Hasebe Kazuhide
• Takahashi Kazuya
• Komori Katsuhiko
• Furusawa Yoshikazu
• Okada Mitsuhiro
• Hayashi Hiroyuki
• Kakimoto Akinobu

Classifications

• H10P14/416 Primary

  of highly doped semiconductor materials, e.g. polysilicon layers or amorphous silicon layers · CPC title

• H10P14/43

  Chemical deposition, e.g. chemical vapour deposition [CVD] · CPC title

• H10W20/0425

  comprising multiple stacked seed or nucleation layers · CPC title

• H10W20/056

  by filling conductive material into holes, grooves or trenches · CPC title

• H10W20/045

  for deposition from the gaseous phase, e.g. for chemical vapour deposition [CVD] · CPC title