Warping reduction in silicon wafers
Techniques for reducing stress in an integrated circuit wafer are disclosed. A silicon substrate may include multiple integrated circuit chips and multiple scribe regions situated between the one of the multiple integrated circuit chips. A particular scribe region includes a plurality of layers and a stress reduction structure that includes, at a particular layer of the plurality of layers, a material whose coefficient of thermal expansion of materials is greater than a coefficient of thermal expansion of the silicon wafer.
1. An integrated circuit wafer, comprising:
a silicon substrate that includes:
a plurality of integrated circuit chips; and
a plurality of scribe regions situated between ones of the plurality of integrated circuit chips, wherein a particular scribe region of the plurality of scribe regions has a total area and includes a plurality of vertically stacked layers, wherein the particular scribe region includes a stress reduction structure located on at least a particular layer of the plurality of vertically stacked layers, wherein the stress reduction structure includes, on the particular layer, a material, wherein a collective area of the material on the particular layer is at least 40 percent of the total area of the particular scribe region, and wherein the material is metal that is electrically isolated from one or more metal regions included in the plurality of integrated circuit chips adjacent to the particular scribe region, and has a coefficient of thermal expansion that is greater than a coefficient of thermal expansion of the silicon substrate.
2. The integrated circuit wafer of claim 1 , wherein the metal is arranged in a plurality of non-contiguous regions.
3. The integrated circuit wafer of claim 2 , wherein a space between a first and second of the non-contiguous regions corresponds to a minimum spacing specification for a semiconductor manufacturing process used to fabricate the plurality of integrated circuit chips.
4. The integrated circuit wafer of claim 1 , wherein the stress reduction structure further includes, on a different layer of the plurality of vertically stacked layers, the material, wherein a collective area of the material on the different layer is at least 40 percent of the total area of the particular scribe region.
5. The integrated circuit wafer of claim 4 , wherein the stress reduction structure further includes at least one via coupled to the material on the particular layer and the material on the different layer.
6. An apparatus, comprising:
a silicon substrate that includes:
a plurality of integrated circuit chips; and
a plurality of scribe regions situated between one of the plurality of integrated circuit chips, wherein a particular scribe region of the plurality of scribe regions includes:
a plurality of vertically stacked layers;
a stress reduction structure located on at least a particular layer of the plurality of vertically stacked layers, wherein the stress reduction structure includes, on the particular layer, a material, wherein a collective area of the material on the particular layer is at least 40 percent of a total area of the particular scribe region, and wherein the material is metal that is electrically isolated from one or more metal regions included in the plurality of integrated circuit chips adjacent to the particular scribe region, and has a coefficient of thermal expansion that is greater than a coefficient of thermal expansion of the silicon substrate;
a test circuit; and
one or more mask alignment targets.
7. The apparatus of claim 6 , wherein the metal within the particular layer is arranged in a plurality of non-contiguous regions.
8. The apparatus of claim 7 , wherein a space between a first and second of the non-contiguous regions corresponds to a minimum spacing specification for a semiconductor manufacturing process used to fabricate the plurality of integrated circuit chips.
9. The apparatus of claim 6 , wherein the stress reduction structure further includes on a different layer of the plurality of vertically stacked layers, the material, wherein a collective area of the material at the different layer is at least 40 percent of the total area of the particular scribe region.
10. The apparatus of claim 9 , wherein the stress reduction structure further includes at least one via coupled to the material on the particular layer and the material on the different layer.
11. The apparatus of claim 6 , wherein the material comprises copper.