Methods of forming diamond composite CMP pad conditioner
Methods of forming chemical-mechanical polishing/planarization pad conditioner bodies made from diamond-reinforced reaction bonded silicon carbide, with diamond particles protruding or “standing proud” of the rest of the surface, and uniformly distributed on the cutting surface. In one embodiment, the diamond particles are approximately uniformly distributed throughout the composite, but in other embodiments they are preferentially located at and near the conditioning surface. The tops of the diamond particles can be engineered to be at a constant elevation (i.e., the conditioner body can be engineered to be very flat). Exemplary shapes of the body may be disc or toroidal. The diamond particles can be made to protrude from the conditioning surface by preferentially eroding the Si/SiC matrix. The eroding may be accomplished by electrical discharge machining or by lapping/polishing with abrasive.
1 . A method of conditioning a chemical-mechanical planarization (CMP) pad, the method comprising:
forming a CMP pad conditioner including:
providing a composite, the composite including a plurality of diamond particles mixed within a Si/SiC matrix, the matrix comprising silicon carbide; and
preferentially eroding the Si/SiC matrix with respect to the plurality of diamond particles to expose a protruding portion of the diamond particles at a contacting surface such that the protruding portion of the diamond particles protrudes beyond a surface of the eroded Si/SiC matrix; and
contacting the protruding portion of the diamond particles at the contacting surface to a CMP pad.
2 . The method of claim 1 , wherein the eroding step is conducted via lapping the contacting surface.
3 . The method of claim 2 , wherein the lapping step comprises lapping the contacting surface with at least one of a cloth and a ceramic plate, each having a lapping abrasive applied thereon.
4 . The method of claim 1 , wherein the eroding step is conducted via electrical discharge machining (EDM).
5 . The method of claim 4 , wherein the matrix includes interconnected silicon.
6 . The method of claim 5 , wherein the matrix includes at least about 5-10% by volume of interconnected silicon.
7 . The method of claim 4 , wherein the CMP pad conditioner comprises about 60 volume % of the diamond particles; between about 30-40 volume % silicon, and no more than about 10 volume % in-situ formed silicon carbide.
8 . The method of claim 4 , wherein the eroding step comprises applying an electrical arc to the contacting surface via an electrode.
9 . The method of claim 1 , wherein the matrix is eroded such that the protruding portion protrudes from said matrix by a distance of at least 10 microns.
10 . The method of claim 9 , wherein the protruding portion protrudes from the matrix no more than about 50% of the size of the diameter of the diamond particles.
11 . The method of claim 1 , wherein providing a composite comprises forming the composite from a mixture comprising silicon carbide powder, the plurality of diamond particles, and an organic binder.
12 . The method of claim 11 , wherein forming the composite comprises placing the mixture into a mold and at least partially settling the diamond particles.
13 . The method of claim 11 , wherein forming the composite further comprises: heating the mixture to carbonize the organic binder; and reacting the mixture with silicon.
14 . The method of claim 1 , wherein a point on said portion of the diamond particles that is most distal from said matrix lies within about 50 microns of planar.
15 . The method of claim 1 , wherein another portion of said diamond particles, different than the exposed portion of the diamond particles, is entirely within the matrix.
16 . The method of claim 1 , wherein the matrix has a volume percentage concentration gradient of diamond particles that varies inversely with a distance from the contacting surface.
17 . The method of claim 1 , wherein the diamond particles have a diameter size in a range of 20 microns to 1000 microns.
18 . The method of claim 1 , wherein the matrix includes no more than about 10 volume percent in-situ formed silicon carbide.
19 . The method of claim 1 , wherein the Si/SiC matrix is preferentially eroded such that a distance of protrusion of the diamond particles from said matrix increases as a result of the eroding step.