Method for reducing lithography pattern defects
View Patent ↗A preferred embodiment of the invention provides a semiconductor fabrication process. Embodiments include a method for removing contaminating particles from the surface of the wafer, such as in lithography. Embodiments also provide methods for repairing patterning defects caused by particles. The method comprises forming a resist layer over a substrate and a topcoat layer over the resist layer. The method further includes exposing the resist layer, and developing the resist layer a first time. Preferably, developing the resist layer the first time comprises dissolving a first portion of the topcoat layer in the developing solution. Embodiments further include spinning the substrate, developing the resist layer a second time after spinning the substrate. Preferably, developing the resist layer the second time comprises dissolving a second portion of the topcoat layer. Other embodiments provided include a topcoat layer that is insoluble in a developer solution, thereby requiring using a topcoat removal solution.
1. A semiconductor fabrication method, the method comprising:
forming a resist layer over a substrate and a topcoat layer over the resist layer;
exposing the resist layer to a radiation transmitted through an immersion liquid;
dissolving a first portion of the topcoat layer in a first topcoat remover solution, wherein a second portion of the topcoat layer under an impurity particle is not dissolved;
spinning the substrate to remove the impurity particle and the dissolved first portion of the topcoat layer; and
dissolving the second portion of the topcoat layer in a second topcoat remover solution wherein dissolving the second portion is performed after spinning the substrate to remove the impurity particle.
2. The method of claim 1 , further comprising dispensing a cleaning liquid onto the resist layer before dissolving the first portion of the topcoat layer, and spinning off the cleaning liquid.
3. The method of claim 2 , wherein the cleaning liquid comprises a material selected from the group consisting of water, acid, acetic acid, phosphorous acid, and combinations thereof.
4. The method of claim 1 , further comprising dispensing a cleaning liquid onto the resist layer before exposing the resist layer, and spinning off the cleaning liquid.
5. The method of claim 1 , wherein spinning the substrate comprises spinning the substrate about a rotational axis substantially perpendicular to a surface of the substrate at a rotational velocity up to about 3,000 rpm.
6. The method of claim 5 , wherein the rotational velocity is maintained for less than about 10 seconds.
7. The method of claim 1 , wherein the substrate comprises a partially fabricated integrated circuit on a semiconductor wafer.
8. The method of claim 1 , wherein the resist layer comprises a photoresist.
9. The method of claim 1 , wherein spinning the substrate comprises:
rotating the substrate in a first direction at a first rotational velocity; and
rotating the substrate in a second direction at a second rotational velocity, wherein the second direction is opposite the first direction.
10. The method of claim 9 , wherein a magnitude of the first rotational velocity and a magnitude of the second rotational velocity are substantially equal.
11. The method of claim 9 , further comprising:
maintaining the first rotational velocity for less than about 10 seconds; and
maintaining the second rotational velocity for less than about 10 seconds.
12. The method of claim 9 , further comprising repeating rotating the substrate at the first rotational velocity and rotating the substrate at the second rotational velocity a plurality of times.
13. The method of claim 1 , wherein the substrate comprises a material selected from the group consisting of Si, SiGe, GaAs, InP, GaN, silicon on insulator (SOI), and combinations thereof.
14. The method of claim 1 , wherein the impurity particle comprises silicon oxide or a metal-containing impurity.
15. A semiconductor fabrication method, the method comprising:
forming a resist layer over a substrate and a topcoat layer on the resist layer;
exposing the resist layer to a radiation transmitted through an immersion liquid;
dissolving a first portion of the topcoat layer in a first topcoat remover, wherein the resist layer is substantially insoluble in the first topcoat remover;
spinning off the first topcoat remover, wherein the spinning off removes an impurity particle disposed over the resist layer along with the dissolved first portion, thereby exposing a second portion of the topcoat layer;
dissolving the second portion of the topcoat layer in a second topcoat remover, after spinning off the first topcoat remover, the first and the second topcoat removers comprising a similar composition; and
developing the resist layer using a developing solution, wherein the developing solution and the first and the second topcoat removers comprise a different composition.
16. The method of claim 15 , further comprising dispensing a cleaning liquid onto the resist layer before exposing the resist layer and then spinning off the cleaning liquid.
17. The method of claim 16 , wherein spinning off the cleaning liquid comprises rotating the substrate at up to about 3,000 rpm.
18. The method of claim 15 , wherein the substrate comprises a partially fabricated integrated circuit on a semiconductor wafer.
19. The method of claim 15 , wherein spinning off the first topcoat remover comprises a series of steps, the series of steps comprising:
rotating the substrate in a first direction at a first rotational velocity; and
rotating the substrate in a second direction at a second rotational velocity, wherein the second direction is opposite the first direction.
20. The method of claim 19 , further comprising repeating the series of steps a plurality of times.
21. The method of claim 15 , wherein the impurity particle comprises silicon oxide or a metal-containing impurity.