Methods to reshape spacers for multi-patterning processes using thermal decomposition materials

1. A method to improve etch uniformity of an underlying layer for processing of microelectronic workpieces, the method comprising:

providing a substrate;

providing a material layer over the substrate;

performing a self-aligned multi-patterning (SAMP) process to form spacers on the material layer;

forming protective plugs between the spacers using a thermal decomposition material;

reshaping the spacers;

removing the thermal decomposition material using a thermal treatment; and

after removing the thermal decomposition material, etching one or more parts of the material layer;

wherein a rate for the removing is controlled by adjusting at least one of temperature or pressure for the thermal treatment.

2. The method of claim 1 , wherein a target level of etch uniformity is achieved in the etching.

3. The method of claim 1 , wherein the etching of said one or more parts of the material layer includes performing a plasma etch process.

4. The method of claim 1 , wherein the material layer is a hard mask layer formed on an additional material layer.

5. The method of claim 4 , wherein

a target level of gouging for the additional material layer is achieved in the etching.

6. The method of claim 1 , wherein the SAMP process comprises:

forming cores over the material layer;

depositing a spacer layer over the cores;

performing an etch back of the spacer layer to form the spacers as side wall structures adjacent the cores; and

performing a mandrel pull process to remove the cores and leave the spacers.

7. The method of claim 1 , wherein the thermal treatment has a temperature range from 100 to 450 degrees Celsius.

8. The method of claim 7 , wherein the thermal treatment comprises an anneal process.

9. The method of claim 1 , wherein

the thermal decomposition material has a depolymerizability characteristic such that it can be removed by a thermal treatment of 100 to 450 degrees Celsius.

10. The method of claim 1 , wherein the thermal decomposition material has a depolymerizability characteristic such that it can be removed by a thermal treatment of 250 to 450 degrees Celsius and such that it is stable from 150 to 215 degrees Celsius.

11. A method to improve etch uniformity of an underlying layer for processing of microelectronic workpieces, the method comprising:

providing a substrate;

providing a material layer over the substrate;

performing a self-aligned multi-patterning (SAMP) process to form spacers on the material layer;

forming protective plugs between the spacers using a thermal decomposition material;

reshaping the spacers;

removing the thermal decomposition material using a thermal treatment; and

after removing the thermal decomposition material, etching one or more parts of the material layer;

wherein the thermal decomposition material comprises at least one of urethane, polymethyl methacrylate (PMMA), or a monomer.

12. A method to improve etch uniformity of an underlying layer for processing of microelectronic workpieces, comprising:

providing a substrate with a material layer;

performing a self-aligned multi-patterning (SAMP) process to form spacers on the material layer;

forming protective plugs between the spacers using a thermal decomposition material;

reshaping the spacers; and

removing the thermal decomposition material using a thermal treatment, wherein the thermal decomposition material comprises an ashing-less coating (ALC) material.

13. The method of claim 12 , wherein the ALC material comprises a urea binding resin.

14. The method of claim 13 , wherein the urea binding resin comprises polyurea having depolymerizability characteristics such that it can be removed by a thermal treatment of less than 450 degrees Celsius.

15. A method to improve etch uniformity of an underlying layer for processing of microelectronic workpieces, the method comprising:

providing a substrate;

providing a material layer over the substrate;

performing a self-aligned multi-patterning (SAMP) process to form spacers on the material layer;

forming protective plugs between the spacers using a thermal decomposition material;

reshaping the spacers;

removing the thermal decomposition material using a thermal treatment; and

after removing the thermal decomposition material, etching one or more parts of the material layer;

wherein the forming of the protective plugs comprises:

forming a layer of the thermal decomposition material over the substrate, the material layer, and the spacers such that the spacers are covered by the layer of the thermal decomposition material; and

performing an etch back of a part of the layer of the thermal decomposition material such that top portions of the spacers are exposed above remaining parts of the layer of the thermal decomposition material, which remain after etching back the part of the layer of the thermal decomposition material, wherein the remaining parts of the layer of the thermal decomposition material form the protective plugs which are disposed between the spacers and above the material layer during the reshaping of the spacers, and wherein the reshaping of the spacers comprises reshaping of the exposed top portions of the spacers with an etch process.

16. The method of claim 15 , wherein the removing of the thermal decomposition material using the thermal treatment comprises, after the reshaping of the spacers, removing the remaining parts of the layer of the thermal decomposition material using the thermal treatment without performing an etch process.

17. The method of claim 16 , wherein the protective plugs reduce and/or suppress gouging during the removal of the part of the layer of the thermal decomposition material, and during the reshaping of the spacers, and further wherein gouging is also reduced and/or suppressed by the removal of the remaining parts of the thermal decomposition material without performing an etch process.