Spin coating process

• US 6,159,541 A
• Filed: 10/30/1998
• Issued: 12/12/2000
• Est. Priority Date: 10/31/1997
• Status: Expired due to Fees

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Nomura, Masafumi, Takamori, Hideyuki, Sakai, Mitsuhiro
• Primary Examiner(s): Beck, Shrive
• Assistant Examiner(s): CALCAGNI, JENNIFER A
• Application Number:
  US09/182,414
• Time in Patent Office: 774 Days
• Field of Search: 427/240, 427/425, 118/320, 118/52, 239/424.5
• US Class Current: 427/240
• CPC Class Codes: B05C 11/08 Spreading liquid or other fluent material by manipulating the work, e.g. tilting
• CPC Class Codes: B05D 1/005 Spin coating
• CPC Class Codes: G03F 7/162 Coating on a rotating support, e.g. using a whirler or a spinner
• CPC Class Codes: H01L 21/6715 Apparatus for applying a liquid, a resin, an ink or the like H01L21/67126 takes precedence

Abstract

A coating process comprises the steps of (a) holding a substrate using a spin chuck surrounded by inner and outer cups, such that the substrate can rotate, (b) rotating the substrate by rotating the spin chuck, and applying a coating liquid onto the substrate, thereby forming a coating on the substrate, (c) discharging, from the inner and outer cups, that part of the coating liquid which is scattered from the substrate while the substrate is rotated, (d) exhausting the inner and outer cups through a plurality of exhaust ports formed in outer peripheral portions of the outer cup, and (e) reducing, from a peripheral region of the substrate, the mist of the coating liquid which has occurred during the step (b), before the substrate stops rotation.

Claims

1. A process of forming a coating on a substrate within a cup section which has an upper opening and an exhaust port, comprising the steps of:

(a) carrying a substrate into the cup section through the upper opening, and holding the substrate by a spin chuck;

(b) applying a coating liquid to the substrate while exhausting the cup section through the exhaust port at a first amount of exhaustion Y1;

(c) rotating the spin chuck and the substrate while exhausting he cup section through the exhaust port at the first amount of exhaustion Y1, thereby diffusing the coating liquid applied to the substrate in the step (b) to form a coating on the substrate;

(d) decreasing the rotating seed of the spin chuck and increasing the exhausting amount of the cup section to a second amount Y2;

(e) stopping the rotation of the substrate and carrying the substrate with the coating out of the cup section.

2. A process according to claim 1, wherein in the step (c), a lid is mounted on the cup section to close the upper opening.

3. A process according to claim 2, further comprising the step (f1) of raising the substrate to cause the substrate to approach the lid.

4. A process according to claim 2, further comprising the step (f2) of raising the substrate to a level higher than the exhaust port.

5. A process according to claim 3, wherein the step (f1) is started when the amount of exhaustion is changed in the step (e).

6. A process according to claim 3, wherein the step (f2) is started after the amount of exhaustion is changed in the step (e).

7. A process according to claim 4, wherein the step (f1) is started when the amount of exhaustion is changed in the step (e).

8. A process according to claim 4, wherein the step (f2) is started after the amount of exhaustion is changed in the step (e).

9. A process according to claim 2, further comprising the step (g) of raising the substrate while raising the lid.

10. A process according to claim 9, wherein in the step (g), the raising speed of the substrate is higher than the raising speed of the lid.

11. A process according to claim 2, wherein in the step (e), the substrate is situated within the cup section or below the lid.

12. A process according to claim 1, wherein the cup section includes an inner cup which surrounds the substrate, and an outer cup which surrounds the inner cup, communicates with the inner cup and the exhaust port, and has a gas/liquid separating member;

and in the step (e), a drainage which contains a mist of the coating liquid exhausted from the inner cup is separated into a liquid component and a gas component by the gas/liquid separating member, and the drainage is exhausted through the exhaust port.

13. A process according to claim 12, wherein in the step (c), the inner cup is rotated in synchronism with the rotation of the substrate.

14. A process according to claim 1, wherein in the steps (b), (c) and (e), exhaustion of the cup section is performed through the exhaust port in a direction opposite to the direction of rotation of the substrate, and in a circumferential direction.

20. A process according to claim 1, wherein the cup section includes a rotary cup that surrounds the substrate, a stationary cup that surrounds the rotary cup, and a clearance adjusting mechanism having a projection projecting toward a lower edge portion of the rotary cut, the clearance suggesting mechanism adjusting a clearance formed between the rotary cup and the projection, further comprising:

at least before the step (b), moving the projection of the clearance adjusting mechanism toward the rotary cup to form a clearance therebetween, thereby suppressing entrance of the coating liquid in the form of mist into a lower middle portion of the rotary cup.

15. A process of forming a coating on a substrate within a cup section which has an upper opening and an exhaust port, comprising the steps of:

(a) carrying a substrate into the cup section through the upper opening, and holding the substrate by a spin chuck;

(b) applying a coating liquid to the substrate while exhausting the cup section through the exhaust port at a first amount of exhaustion Y1;

(c) rotating the spin chuck and the substrate while exhausting the cup section through the exhaust port at first amount of exhaustion Y1 thereby diffusing the coating liquid applied to the substrate in the step (b) to form a coating on the substrate;

(d) decreasing the rotational speed of the spin chuck and increasing the exhausting amount of the cup section to a second amount Y2;

(e) stopping the rotation of the substrate and carrying the substrate with the coating out of the cup section; and

(h) raising the substrate to a level higher than the exhaust port while rotating the substrate in the step (c).

16. A process according to claim 15, wherein in the step (c), a lid is mounted on the cup section to close the upper opening.

17. A process according to claim 16, wherein in the step (h), the substrate is raised while the lid is raised.

18. A process according to claim 17, wherein in the step (h), the raising speed of the substrate is higher than the raising speed of the lid.

19. A process according to claim 17, wherein in the step (h), the substrate is made to approach the lid to define therebetween a narrow clearance.