Method of patterning photoresist on a wafer using a reflective mask with a multi-layer ARC
View Patent ↗A patterned reflective semiconductor mask uses a multiple layer ARC overlying an absorber stack that overlies a reflective substrate. The absorber stack has more than one layer and an upper layer of the absorber stack has a predetermined metal. The multiple layer ARC overlying the upper layer of the absorber stack has layers of nitrogen, oxygen and nitrogen combined with the predetermined metal of the upper layer of the absorber stack. The oxygen layer in the ARC has less metallic properties than the nitrogen layers therein. In one form, an overlying dielectric layer is positioned on the multiple layer ARC to increase light interference. The ARC provides wide bandwidth inspection contrast for extreme ultra-violet (EUV) reticles.
1. A semiconductor mask comprising:
a substrate;
a reflecting layer overlying the substrate for reflecting light from the semiconductor mask;
an absorber stack selectively formed overlying the reflecting layer, the absorber stack having a plurality of layers, an upper layer of the absorber stack that is opposite the reflecting layer comprises a predetermined metal; and
a multiple layer anti-reflective coating overlying the upper layer of the absorber stack, the multiple layer anti-reflective coating comprising adjoining layers that respectively have nitrogen, oxygen and nitrogen combined with the predetermined metal of the upper layer of the absorber stack.
2. The semiconductor mask of claim 1 wherein the multiple layer anti-reflective coating further comprises:
an overlying dielectric layer adjacent the multiple layer anti-reflective coating comprising a predetermined material, the overlying dielectric layer providing additional destructive interference of light for a wider bandwidth of inspection wavelengths.
3. The semiconductor mask of claim 2 wherein the predetermined dielectric material comprises one of silicon oxygen nitride, silicon nitride or silicon oxide.
4. The semiconductor mask of claim 1 wherein the predetermined metal further comprises one of tantalum, chromium, tungsten, tantalum silicide, tantalum boride and oxides and nitrides thereof.
5. The semiconductor mask of claim 1 wherein the multiple layer anti-reflective coating comprising adjoining layers respectively having nitrogen, oxygen and nitrogen respectively comprise tantalum silicon nitride, tantalum silicon oxide and tantalum silicon nitride.
6. The semiconductor mask of claim 1 wherein the multiple layer anti-reflective coating further comprises a concentration of nitrogen and oxygen that is greater than any nitrogen or oxygen in the predetermined metal of the upper layer of the absorber stack.
7. The semiconductor mask of claim 1 wherein a layer of the adjoining layers having oxygen has less metallic properties than remaining layers of the adjoining layers.
8. The semiconductor mask of claim 1 wherein an inspection contrast of the semiconductor mask is greater than seventy percent (70%) at multiple inspection wavelengths.
9. The semiconductor mask of claim 1 wherein the reflectivity of the multiple layer anti-reflective coating is less than ten percent (10%) at multiple inspection wavelengths.
10. A method of providing a semiconductor mask comprising:
providing a substrate;
forming a reflecting layer overlying the substrate for reflecting light from the semiconductor mask;
forming an absorber stack selectively formed overlying the reflecting layer, the absorber stack having a plurality of layers, an upper layer of the absorber stack that is opposite the reflecting layer comprises a predetermined metal; and
forming a multiple layer anti-reflective coating overlying the upper layer of the absorber stack, the multiple layer anti-reflective coating comprising adjoining layers that respectively have nitrogen, oxygen and nitrogen combined with the predetermined metal of the upper layer of the absorber stack.
11. The method of claim 10 further comprising:
forming an overlying dielectric layer comprising a predetermined material, the overlying dielectric layer providing additional destructive interference of light for a wider bandwidth of inspection wavelengths.
12. The method of claim 11 further comprising forming the predetermined material from one of silicon oxygen nitride, silicon nitride or silicon oxide.
13. The method of claim 10 further comprising forming the predetermined metal from one of tantalum, chromium, tungsten, tantalum silicide, tantalum boride and oxides and nitrides thereof.
14. The method of claim 10 further comprising forming the multiple layer anti-reflective coating comprising adjoining layers respectively from tantalum silicon nitride, tantalum silicon oxide and tantalum silicon nitride.
15. The method of claim 10 further comprising forming the multiple layer anti-reflective coating from a concentration of nitrogen and oxygen that is greater than any nitrogen or oxygen in the predetermined metal of the upper layer of the absorber stack.
16. The method of claim 10 further comprising forming the multiple layer anti-reflective coating from a layer of oxygen within the adjoining layers, the layer of oxygen having less metallic properties than the remaining adjoining layers.
17. The method of claim 10 further comprising forming the multiple layer anti-reflective coating having physical characteristics so that an inspection contrast of the semiconductor mask is greater than seventy percent (70%) at multiple inspection wavelengths.
18. The method of claim 10 further comprising forming the mask with materials in the multiple layer anti-reflective coating having physical properties so that a reflectivity of the multiple layer anti-reflective coating is less than ten percent (10%) at multiple inspection wavelengths.
19. The method of claim 10 further comprising:
forming a semiconductor pattern in both the predetermined metal of the upper layer of the absorber stack and the multiple layer anti-reflective coating with a same process etch step.