Process sequence for photoresist stripping and/or cleaning of photomasks for integrated circuit manufacturing
View Patent ↗A method and system for cleaning and/or stripping photoresist from photomasks used in integrated circuit manufacturing comprising a process and means of introducing a mixture of sulfuric acid and ozone (or a mixture of sulfuric acid and hydrogen peroxide) to the surface of a photomask while applying megasonic energy. The invention also comprises method and system comprising a process and means of introducing ozonated deionized water and/or a low temperature dilute aqueous solution (dAPM) to the surface of photomasks while applying megasonic energy. The process and apparatus also remove post plasma ashed residues and other contaminants from photomask surfaces.
1. A system for cleaning and/or photoresist stripping of photomasks comprising:
a source of a mixture comprising sulfuric acid and ozone (SOM);
a source of a dilute aqueous solution of ammonium hydroxide and hydrogen peroxide (dAPM);
first means for supplying the SOM to a photomask;
second means for supplying the dAPM to the photomask;
means for supplying acoustical energy to the photomask; and
a controller adapted to activate the SOM supply means and the acoustical energy supply means so as to supply acoustical energy to the photomask during supply of SOM to the photomask, and subsequent to completing the supply of the SOM and acoustical energy to the photomask, activate the dAPM supply means and the acoustical energy supply means so as to supply acoustical energy to the photomask during supply of dAPM to the photomask.
2. The system of claim 1 wherein the source of dAPM has a temperature less than 30° C.
3. The system of claim 1 further comprising:
a source of ozonated deionized water (DIO 3 ); and
means for supplying the DIO 3 to the photomask.
4. The system of claim 1 further comprising a plurality of process chambers, the SOM supply means located in a first process chamber and the dAPM supply means located in a second process chamber.
5. The system of claim 1 further comprising a process chamber, the SOM supply means and the dAPM supply means located in the process chamber.
6. The system of claim 1 further comprising means for dissolving ozone gas into the sulfuric acid.
7. The system of claim 1 wherein the source of SOM is at a temperature less than 90° C. and is free of bubbles.
8. The system of claim 1 further comprising:
a source of deionized water;
a source of ozonated deionized water (DIO 3 );
means for supplying the deionized water to the photomask;
means for supplying the DIO 3 to the photomask; and
wherein the controller is adapted to sequentially (i) activate the SOM supply means and the acoustical energy supply means so as to supply acoustical energy to the photomask during supply of SOM to the photomask, (ii) deactivate the SOM supply means, (iii) activate the deionized water supply means so as to rinse the photomask with the deionized water, (iv) deactivate the deionized water supply means, (v) activate the DIO 3 supply means so as to supply DIO 3 to the photomask, (vi) deactivate the DIO 3 supply means; (vii) activate the dAPM supply means and the acoustical energy supply means so as to supply acoustical energy to the photomask during supply of dAPM to the photomask, (viii) deactivate the dAPM supply means, and (ix) activate the deionized water supply means so as to rinse the photomask with the deionized water.
9. The system of claim 1 further comprising moans for supplying hydrogen peroxide to the SOM prior to the mixture being supplied to the photomasks.