Correction of fabricated shapes in additive manufacturing using sacrificial material
A method of fabricating a polishing pad using an additive manufacturing system includes depositing a first set of successive layers onto a support by droplet ejection. Depositing the first set of successive layers includes dispensing a polishing pad precursor to first regions corresponding to partitions of the polishing pad and dispensing a sacrificial material to second regions corresponding to grooves of the polishing pad. A second set of successive layers is deposited by droplet ejection over the first set of successive layers. The second set of successive layers corresponds to a lower portion of the polishing pad. The first set of successive layer and the second set of successive layers provide a body. The body is removed from the support. Removing the sacrificial material from the body provides the polishing pad with a polishing surface that has the partitions separated by the grooves.
1. A method of fabricating a polishing pad using an additive manufacturing system, the method comprising:
depositing onto a support a first plurality of successive layers by droplet ejection, wherein depositing the first plurality of successive layers includes
dispensing a polishing pad precursor to first regions corresponding to partitions of the polishing pad, and
dispensing a sacrificial material to second regions corresponding to grooves of the polishing pad;
depositing a second plurality of successive layers by droplet ejection over the first plurality of successive layers, the second plurality of successive layers corresponding to a lower portion of the polishing pad, the first plurality of successive layer and the second plurality of successive layers providing a body;
removing the body from the support; and
removing the sacrificial material from the body to provide the polishing pad comprising a polishing surface having the partitions separated by the grooves.
2. The method of claim 1 , comprising curing the polishing pad precursor.
3. The method of claim 2 , comprising curing the sacrificial material.
4. The method of claim 3 , wherein the polishing pad precursor comprises a first polymer precursor and the sacrificial material comprises a second polymer precursor of different composition.
5. The method of claim 1 , wherein depositing the second plurality of successive layers comprises dispensing the polishing pad precursor.
6. The method of claim 5 , wherein the second plurality of successive layers correspond to a lower portion of a polishing layer of the polishing pad.
7. The method of claim 1 , comprising depositing a third plurality of successive layers by droplet ejection over the second plurality of successive layers, the third plurality of successive layers having a different composition than the second plurality of successive layers.
8. The method of claim 7 , wherein the third plurality of successive layers correspond to a sub-pad of the polishing pad.
9. The method of claim 7 , wherein depositing the third plurality of successive layers comprises droplet ejection of the polishing pad precursor and curing the third plurality of successive layers with a different wavelength or intensity of light than the second plurality of successive layers.
10. The method of claim 7 , wherein depositing the third plurality of successive layers comprises droplet ejection of a polymer precursor of different composition than the polishing pad precursor.
11. The method of claim 1 , wherein the second plurality of successive layers span both the first regions and the second regions.
12. The method of claim 1 , wherein removing the sacrificial material comprises etching.
13. The method of claim 1 , wherein removing the sacrificial material comprises lifting the polishing pad off the sacrificial material.