Alleviation of the corrosion pitting of chip pads
View Patent ↗Methods for processing a metal pad of a chip and chip structures including a chip with a metal pad. A surface modification agent is applied to the metal pad on the chip. The surface modification agent is effective to increase the hydrophobicity of the metal pad and may involve silylation.
1. A method for processing a chip having a first metal pad in the chip region and a second metal pad in the kerf region, the method comprising:
silylating a metal oxide comprising a surface layer on the first metal pad and on the second metal pad by replacing hydroxyl groups at binding sites over at least a portion of a top surface of the surface layer with siloxyl groups so as to increase hydrophobicity and decrease pitting corrosion;
after the metal oxide is silyated, removing the surface layer from the first metal pad;
after the surface layer is removed from the first metal pad, contacting the first metal pad with a probe of a wafer prober;
testing the chip for a functional defect with a test signal communicated from the probe to the first metal pad; and
after the chip is tested for the functional defect, installing the chip in an end product with the surface layer on the second metal pad.
2. The method of claim 1 wherein the surface modification agent comprises hexamethyldisilazane.
3. The method of claim 1 further comprising:
placing the chip into a holder configured to deliver the chip to an end user,
wherein the end user installs the chip in the end product.
4. The method of claim 1 wherein the chip is an integral portion of a wafer, and further comprising:
placing the wafer into a holder configured to deliver the wafer to an end user
wherein the end user installs the chip in the end product.
5. The method of claim 1 further comprising:
mounting the chip to a chip carrier.
6. The method of claim 5 further comprising:
establishing an electrical connection between the second metal pad on the chip and a metal pad on the chip carrier.
7. The method of claim 1 wherein removing the surface layer from the first metal pad comprises:
performing a desilylation reaction to exchange the silyl groups for protons.
8. The method of claim 1 further comprising:
forming the first metal pad and the second metal pad,
wherein lithography steps are absent after the first metal pad and the second metal pad are formed.