Abrasive, method of polishing target member and process for producing semiconductor device

• US 7,115,021 B2
• Filed: 01/11/2002
• Issued: 10/03/2006
• Est. Priority Date: 12/18/1997
• Status: Expired due to Term

• Current Assignee: Hitachi Chemical Company Limited (Resonac Holdings Corp.)
• Original Assignee: Hitachi Chemical Company Limited (Resonac Holdings Corp.)
• Inventors: Ootuki, Yuuto, Yoshida, Masato, Tanno, Kiyohito, Matsuzawa, Jun, Terazaki, Hiroki, Ashizawa, Toranosuke, Kurata, Yasushi
• Primary Examiner(s): Hail, III, Joseph J.
• Assistant Examiner(s): MCDONALD, SHANTESE L
• Application Number:
  US10/042,271
• Publication Number:
  US 20020090895A1
• Time in Patent Office: 1,726 Days
• Field of Search: 451/41, 513/07, 513/08, 513/09
• US Class Current: 451/41
• CPC Class Codes: C09G 1/02 containing abrasives or grinding agents abrasives as such C09K3/14; polishing of semi-conductors H01L
• CPC Class Codes: C09K 3/1409 Abrasive particles per se preparation of diamond C01B32/25
• CPC Class Codes: C09K 3/1463 Aqueous liquid suspensions
• CPC Class Codes: H01L 21/31053 involving a dielectric removal step

Abstract

To polish polishing target surfaces of SiO₂ insulating films or the like at a high rate without scratching the surface, the present invention provides an abrasive comprising a slurry comprising a medium and dispersed therein at least one of i) cerium oxide particles constituted of at least two crystallites and having crystal grain boundaries or having a bulk density of not higher than 6.5 g/cm³ and ii) abrasive grains having pores. Also provided are a method of polishing a target member and a process for producing a semiconductor device which make use of this abrasive.

Claims

1. An abrasive comprising cerium oxide particles, said particles having a crystal grain boundary and having a maximum diameter of not large than 3000 nm.

2. The abrasive of claim 1, wherein a crystallite of said cerium oxide particles has a maximum diameter of not larger than 600 nm.

3. The abrasive of claim 1, wherein said cerium oxide particles have pores.

4. The abrasive of claim 1, wherein said cerium oxide particles have a porosity of from 10 to 30% as determined from the ratio of a true density measured with a pycnometer to a theoretical density determined by X-ray Rietvelt analysis.

5. The abrasive of claim 1, wherein said cerium oxide particles have a pore volume of from 0.02 to 0.05 cm³/g as measured by B.J.H. method.

6. The abrasive of claim 1, wherein said cerium oxide particles have a bulk density not higher than 6.5 g/cm³.

7. The abrasive of claim 1, further comprising a medium, wherein said medium is water.

8. The abrasive of claim 1, further comprising a dispersant.

9. The abrasive of claim 8, wherein said dispersant is at least one selected from a water-soluble organic polymer, a water-soluble anionic surfactant, a water-soluble nonionic surfactant and water-soluble amine.

10. An abrasive as claimed in claim 9, wherein said dispersant is a polyacrylic acid type polymer.

11. The abrasive of claim 1, wherein cerium oxide particles with a diameter not smaller than 1 μ

m occupies at least 0.1% by weight of the total weight of the cerium oxide particles.

12. The abrasive of claim 1, wherein said cerium oxide particles having said crystal grain boundary have a property of polishing a target member while collapsing.

13. The abrasive of claim 1, wherein said cerium oxide particles having said crystal grain boundary have a property of polishing a target member while forming new surfaces not coming into contact with any medium.

14. The abrasive of claim 1, wherein a content of the cerium oxide particles having a particle diameter not smaller then 0.5 μ

m after polishing, measured by centrifugal sedimentation after polishing a predetermined target substrate, is in a ratio of not more than 0.8 with respect to that content before polishing.

15. The abrasive of claim 1, wherein cerium oxide particle diameter at D90% by volume measured by laser diffraction after a target substrate has been polished is in

a ratio of from 0.4 to 0.9 with respect to that particle diameter before polishing.

16. An abrasive comprising cerium oxide particles, wherein a crystallite of said cerium oxide particles has a crystal grain boundary and has a maximum diameter not larger than 600 nm.

17. A method of polishing a predetermined substrate, comprising polishing said substrate using an abrasive comprising cerium oxide particles, said particles having a crystal grain boundary and having a maximum diameter of not larger than 3000 nm.

18. The method of polishing a predetermined substrate as claimed in claim 17, wherein strength of the substrate is larger than the breaking strength of grain boundary of the cerium oxide particles.

19. The method of polishing a predetermined substrate as claimed in claim 17, wherein said predetermined substrate is a semiconductor chip with a silica film formed thereon.

20. A manufacturing method of a semiconductor device comprising the step of polishing a semiconductor chip having a silica film formed thereon with an abrasive comprising cerium oxide particles, said particles having a crystal grain boundary and having a maximum diameter of not larger than 3000 nm.