Method of manufacturing a semiconductor device

• US 7,223,643 B2
• Filed: 08/10/2001
• Issued: 05/29/2007
• Est. Priority Date: 08/11/2000
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ohnuma, Hideto, Uehara, Ichiro
• Primary Examiner(s): Booth; Richard A.
• Application Number:
  US09/925,512
• Publication Number:
  US 20020025591A1
• Time in Patent Office: 2,118 Days
• Field of Search: 438151-166, 438948-949, 257/E21.561
• US Class Current: 438/163
• CPC Class Codes: H01L 2029/7863 with an LDD consisting of more than one lightly doped zone or having a non-homogeneous dopant distribution, e.g. graded LDD
• CPC Class Codes: H01L 21/28114 characterised by the sectional shape, e.g. T, inverted-T
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/32139 using masks
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1288 employing particular masking sequences or specially adapted masks, e.g. half-tone mask
• CPC Class Codes: H01L 29/42384 for thin film field effect transistors, e.g. characterised by the thickness or the shape of the insulator or the dimensions, the shape or the lay-out of the conductor
• CPC Class Codes: H01L 29/66598 forming drain [D] and lightly doped drain [LDD] simultaneously, e.g. using implantation through the wings a T-shaped layer, or through a specially shaped layer
• CPC Class Codes: H01L 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate
• CPC Class Codes: H01L 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78627 with a significant overlap between the lightly doped drain and the gate electrode, e.g. GOLDD
• CPC Class Codes: Y10S 438/949 Energy beam treating radiation resist on semiconductor

Abstract

Formation of LDD structures and GOLD structures in a semiconductor device is conventionally performed in a self aligning manner with gate electrodes as masks, but there are many cases in which the gate electrodes have two layer structures, and film formation processes and etching processes become complex. Further, in order to perform formation of LDD structures and GOLD structures only by processes such as dry etching, the transistor structures all have the same structure, and it is difficult to form LDD structures, GOLD structures, and single drain structures separately for different circuits. By applying a photolithography process for forming gate electrodes to photomasks or reticles, in which supplemental patterns having a function of reducing the intensity of light and composed of diffraction grating patterns or translucent films, are established, GOLD structure, LDD structure, and single drain structure transistors can be easily manufactured for different circuits through dry etching and ion injection process steps.

Claims

1. A method of manufacturing a semiconductor device, the method comprising:

forming a conductive film over a semiconductor with an insulating film therebetween;

forming a resist pattern over the conductive film by using one of a photomask having a light shielding portion and a translucent film and a reticle having a light shielding portion and a translucent film, wherein the translucent film is adjacent to the one of the photomask and the reticle, and wherein a thickness of an edge portion of the resist pattern is smaller than a thickness of a middle portion of the resist pattern;

forming a gate electrode by etching using the resist pattern, wherein a thickness of an edge portion of the gate electrode is smaller than a thickness of a middle portion of the gate electrode; and

introducing an impurity element into the semiconductor with the gate electrode as a mask to form a first impurity region and a second impurity region in the semiconductor, wherein the first impurity region is not overlapped with the gate electrode and the second impurity region is overlapped with the edge portion of the gate electrode.

2. The method of manufacturing a semiconductor device according to claim 1, wherein a phase of an exposure light is shifted by one wavelength by passing through the translucent film portion, the exposure light being a single wavelength light.

3. The method of manufacturing a semiconductor device according to claim 1, wherein the edge portion of the resist pattern has a tapered configuration.

4. The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor is a semiconductor layer formed on an insulating surface.

5. The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor is a semiconductor substrate.

6. The method of manufacturing a semiconductor device according to claim 1, wherein the etching is dry etching.

7. The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is incorporated into an electronic device selected from the group consisting of a video camera, a digital camera, a projector, a head mounted display, a navigation system, a car stereo, a personal computer, a portable information terminal.

8. A method of manufacturing a semiconductor device comprising the steps of:

forming a conductive film over a semiconductor with an insulating film therebetween;

forming a resist pattern over the conductive film by using one of a photomask having a light shielding portion and a translucent film and a reticle having a light shielding portion and a translucent film, wherein the translucent film is adjacent to the one of the photomask and the reticle, and wherein a thickness of an edge portion of the resist pattern is smaller than a thickness of a middle portion of the resist pattern;

forming a gate electrode by etching using the resist pattern, wherein a thickness of an edge portion of the gate electrode is smaller than a thickness of a middle portion of the gate electrode; and

introducing an impurity element into the semiconductor with the gate electrode as a mask to form a first impurity region and a second impurity region in the semiconductor, wherein the second impurity region is in contact with a channel forming region, and the first impurity region is in contact with the second impurity region.

9. The method of manufacturing a semiconductor device according to claim 8, wherein a phase of an exposure light is shifted by one wavelength by passing through the translucent film portion, the exposure light being a single wavelength light.

10. The method of manufacturing a semiconductor device according to claim 8, wherein the edge portion of the resist pattern has tapered configuration.

11. The method of manufacturing a semiconductor device according to claim 8, wherein the semiconductor is a semiconductor layer formed on an insulating surface.

12. The method of manufacturing a semiconductor device according to claim 8, wherein the semiconductor is a semiconductor substrate.

13. The method of manufacturing a semiconductor device according to claim 8, wherein the etching is dry etching.

14. The method of manufacturing a semiconductor device according to claim 8, wherein the semiconductor device is incorporated into an electronic device selected from the group consisting of a video camera, a digital camera, a projector, a head mounted display, a navigation system, a car stereo, a personal computer, a portable information terminal.

15. A method of manufacturing a semiconductor device comprising the steps of:

forming a conductive film over a semiconductor with an insulating film therebetween;

forming a resist pattern over the conductive film by using one of a photomask and a reticle having a light shielding portion and a translucent film, wherein the translucent film is adjacent to the one of the photomask and the reticle, and wherein a thickness of an edge portion of the resist pattern is smaller than a thickness of a middle portion of the resist pattern; and

forming a gate electrode by etching using the resist pattern, wherein a thickness of an edge portion of the gate electrode is smaller than a thickness of a middle portion of the gate electrode.

16. The method of manufacturing a semiconductor device according to claim 15, wherein a phase of an exposure light is shifted by one wavelength by passing through the translucent film portion, the exposure light being a single wavelength light.

17. The method of manufacturing a semiconductor device according to claim 15, wherein the edge portion of the resist pattern has tapered configuration.

18. The method of manufacturing a semiconductor device according to claim 15, wherein the semiconductor is a semiconductor layer formed on an insulating surface.

19. The method of manufacturing a semiconductor device according to claim 15, wherein the semiconductor is a semiconductor substrate.

20. The method of manufacturing a semiconductor device according to claim 15, wherein the etching is dry etching.

21. The method of manufacturing a semiconductor device according to claim 15, wherein the semiconductor device is incorporated into an electronic device selected from the group consisting of a video camera, a digital camera, a projector, a head mounted display, a navigation system, a car stereo, a personal computer, a portable information terminal.

22. A method of manufacturing a semiconductor device comprising:

forming a conductive film over a semiconductor film with an insulating film therebetween;

forming a photoresist layer over the conductive film;

disposing a mask over the photoresist layer, the mask having a first mask portion which substantially blocks light and a second mask portion which partially passes light;

exposing the photoresist layer to light by using the mask;

patterning the photoresist layer after exposing the photoresist layer to form a photoresist pattern which includes a first pattern portion and a second pattern portion with a smaller thickness than the first pattern portion;

etching the conductive layer using the photoresist pattern as a mask to form a gate electrode over the semiconductor film, the gate electrode having a first electrode portion and a second electrode portion with a smaller thickness than the first electrode portion;

forming a first impurity region in the semiconductor film by introducing an impurity into a region of the semiconductor film not overlapped by the gate electrode;

forming a second impurity region in the semiconductor film by introducing a second impurity through the second electrode portion such that a concentration of the second impurity in the second impurity region is smaller than a concentration of the first impurity in the first impurity region.

23. The method of manufacturing a semiconductor device according to claim 22 wherein the second electrode portion has a tapered configuration.

24. The method of manufacturing a semiconductor device according to claim 22 wherein the mask is a photomask.

25. The method of manufacturing a semiconductor device according to claim 22 wherein the mask is a reticle.

26. The method of manufacturing a semiconductor device according to claim 22 wherein the second mask portion includes a diffraction grating pattern.

27. The method of manufacturing a semiconductor device according to claim 22 wherein the second mask portion includes a translucent film.

28. The method of manufacturing a semiconductor device according to claim 22 wherein the first impurity is the same material as the second impurity.

29. The method of manufacturing a semiconductor device according to claim 22 wherein transparency of the second mask portion monotonically increases as a distance from the first mask portion increases.

30. A method of manufacturing a semiconductor device comprising:

forming a conductive film over a semiconductor substrate with an insulating film therebetween;

forming a photoresist layer over the conductive film;

disposing a mask over the photoresist layer, the mask having a first mask portion which substantially blocks light and a second mask portion which partially passes light;

exposing the photoresist layer to light by using the mask;

patterning the photoresist layer after exposing the photoresist layer to form a photoresist pattern which includes a first pattern portion and a second pattern portion with a smaller thickness than the first pattern portion;

etching the conductive layer using the photoresist pattern as a mask to form a gate electrode over the semiconductor substrate, the gate electrode having a first electrode portion and a second electrode portion with a smaller thickness than the first electrode portion;

forming a first impurity region in the semiconductor substrate by introducing an impurity into a region of the semiconductor substrate not overlapped by the gate electrode;

forming a second impurity region in the semiconductor substrate by introducing a second impurity through the second electrode portion such that a concentration of the second impurity in the second impurity region is smaller than a concentration of the first impurity in the first impurity region.

31. The method of manufacturing a semiconductor device according to claim 30 wherein the second electrode portion has a tapered configuration.

32. The method of manufacturing a semiconductor device according to claim 30 wherein the mask is a photomask.

33. The method of manufacturing a semiconductor device according to claim 30 wherein the mask is a reticle.

34. The method of manufacturing a semiconductor device according to claim 30 wherein the second mask portion includes a diffraction grating pattern.

35. The method of manufacturing a semiconductor device according to claim 30 wherein the second mask portion includes a translucent film.

36. The method of manufacturing a semiconductor device according to claim 30 wherein the first impurity is the same material as the second impurity.