Target and process for its production, and method for forming a film having a high refractive index

• US 6,334,938 B2
• Filed: 12/05/2000
• Issued: 01/01/2002
• Est. Priority Date: 08/23/1995
• Status: Expired due to Term

• Current Assignee: AGC Flat Glass North America Incorporated (AGC, Inc.)
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Sasaki, Kenichi, Hayashi, Atsushi, Oyama, Takuji, Mitsui, Akira, Osaki, Hisashi, Kida, Otojiro, Suzuki, Eri
• Primary Examiner(s): Nguyen, Nam
• Assistant Examiner(s): VerSteeg, Steven H.
• Application Number:
  US09/729,102
• Publication Number:
  US 20010020586A1
• Time in Patent Office: 392 Days
• Field of Search: 204/192.15, 204/192.22, 204/192.23, 204/298.12, 204/298.13, 427/453, 427/454
• US Class Current: 204/298.13
• CPC Class Codes: C23C 14/083 of refractory metals or yttrium
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: C23C 4/02 Pretreatment of the material to be coated, e.g. for coating on selected surface areas
• CPC Class Codes: C23C 4/11 Oxides

Abstract

A sputtering target comprising a substrate and a target material formed on the substrate, wherein the target material comprises a metal oxide of the chemical formula MO_x as the main component, wherein MO_x is a metal oxide which is deficient in oxygen as compared with the stoichiometric composition, and M is at least one metal selected from the group consisting of Ti, Nb, Ta, Mo, W, Zr and Hf, a process for its production, and a method for forming a film having a high refractive index.

Claims

1. A method for forming a film, the method comprising sputtering a target, wherein

the sputtering target comprises a substrate and a target material formed on the substrate;

the target material comprises as the main component an oxygen deficient oxide;

the oxygen deficient oxide comprises a metal oxide of a chemical formula TiO_x that is deficient in oxygen as compared with a stoichiometric composition of the metal oxide; and

1<

x<

2.

2. The method according to claim 1, wherein the sputtering is DC sputtering.

3. The method according to claim 1, wherein the target has a resistivity of at most 10 Ω

cm.

4. The method according to claim 1, wherein the target has a resistivity of at most 1 Ω

cm.

5. The method according to claim 1, wherein the target further comprises an oxide of at least one metal selected from the group consisting of Cr, Ce, Y, Si, Al and B.

6. The method according to claim 5, wherein the target contains the oxide of at least one metal in an amount of at most 20 wt %.

7. The method according to claim 1, wherein the sputtering is carried out in an argon atmosphere or in a mixed atmosphere of argon and oxygen.

8. The method according to claim 7, wherein the mixed atmosphere of argon and oxygen comprises at most 30 vol % oxygen.

9. The method according to claim 1, further comprising forming a film having a refractive index of 2.4.

10. A sputtering target comprising

a substrate;

a target material formed on the substrate; and

an undercoat of a metal or alloy between the target material and the substrate, wherein

the target material comprises as the main component an oxygen deficient oxide;

the oxygen deficient oxide comprises a metal oxide of a chemical formula TiO_x that is deficient in oxygen as compared with a stoichiometric composition of the metal oxide; and

1<

x<

2.

11. The sputtering target according to claim 10, wherein the undercoat has a thermal expansion coefficient between a thermal expansion coefficient of the target material and a thermal expansion coefficient of the substrate.

12. The sputtering target according to claim 11, wherein the thermal expansion coefficient of the undercoat is from 12×

10<sup>−

6</sup> to 15×

10<sup>−

6</sup>/°

C.

13. The sputtering target according to claim 10, wherein the undercoat comprises

a first layer, which is adjacent to the substrate and which has a thermal expansion coefficient between the thermal expansion coefficient of the target material and the thermal expansion coefficient of the substrate; and

a second layer, which is adjacent to the target material and which has a thermal expansion coefficient within a range of ±

2×

10<sup>−

6</sup>/°

C. of a thermal expansion coefficient of the target material.

14. The sputtering target according to claim 10, wherein the undercoat comprises a material selected from the group consisting of Mo, Ti, Ni, Nb, Ta, W, Ni—

Al, Ni—

Cr, Ni—

Cr—

Al, Ni—

Cr—

Al—

Y and Ni—

Co—

Cr—

Al—

Y.

15. The sputtering target according to 10, wherein the undercoat has a thickness of from 30 to 100 μ

m.

16. The sputtering target according to claim 10, wherein the undercoat has a thermal expansion coefficient within a range of ±

2×

10<sup>−

6</sup>/°

C. of a thermal expansion coefficient of the target material.

17. The sputtering target according to claim 16, wherein the thermal expansion coefficient of the undercoat is from 4×

10<sup>−

6</sup> to 11×

10<sup>−

6</sup>/°

C.

18. The sputtering target according to claim 10, wherein the target material has a thickness of from 2 to 10 mm.

19. The sputtering target according to claim 10, wherein the target has a resistivity of at most 10 Ω

cm.

20. The sputtering target according to claim 10, wherein the target has a resistivity of at most 1 Ω

cm.

21. The sputtering target according to claim 10, wherein the target material further comprises an oxide of at least one metal selected from the group consisting of Cr, Ce, Y, Si, Al and B.

22. The sputtering target according to claim 21, wherein the oxide of at least one metal is contained in an amount of at most 20 wt. %.

23. A method of making a sputtering target, the method comprising

providing an undercoat on a substrate;

depositing a target material on the undercoat; and

forming the sputtering target of claim 10.

24. The method of claim 23, wherein the depositing comprises plasma spraying.

25. A method of using a sputtering target, the method comprising sputtering the sputtering target of claim 10.