Thinning and dicing of semiconductor wafers using dry etch, and obtaining semiconductor chips with rounded bottom edges and corners
First Claim
1. A method for obtaining one or more chips from a semiconductor wafer, the method comprising:
- forming one or more openings in a first side of the semiconductor wafer along a boundary of the one or more chips, wherein the one or more openings do not go through the wafer; and
placing the wafer into a non-contact wafer holder and thinning the wafer with a dry etch to remove material from an entire second side of the wafer at least until the one or more openings become exposed on the second side, wherein the dry etch rounds one or more of the edges and/or coners obtained on the second side of the wafer at a location of the one or more openings when the one or more openings become exposed.
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Accused Products
Abstract
A semiconductor wafer is diced before thinning. The wafer is diced only part of the way through, to form grooves which are at least as deep as the final thickness of each chip to be obtained from the wafer. Then, the wafer is placed into a non-contact wafer holder, and the wafer backside is blanket etched with a dry etch, for example, atmospheric pressure plasma etch. The wafer is thinned until the grooves are exposed from the backside. The dry etch leaves the chip'"'"'s backside smooth. After the grooves have been exposed, the dry etch is continued to remove damage from the chip sidewalls and to round the chips'"'"' bottom edges and coners. As a result, the chip becomes more reliable, and in particular more resistant to thermal and other stresses.
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Citations
28 Claims
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1. A method for obtaining one or more chips from a semiconductor wafer, the method comprising:
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forming one or more openings in a first side of the semiconductor wafer along a boundary of the one or more chips, wherein the one or more openings do not go through the wafer; and
placing the wafer into a non-contact wafer holder and thinning the wafer with a dry etch to remove material from an entire second side of the wafer at least until the one or more openings become exposed on the second side, wherein the dry etch rounds one or more of the edges and/or coners obtained on the second side of the wafer at a location of the one or more openings when the one or more openings become exposed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for obtaining one or more chips from a semiconductor wafer, the method comprising:
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forming one or more openings in a first side of the semiconductor wafer along a boundary of the one or more chips, wherein the one or more openings do not go through the wafer; and
thinning the wafer with a dry etch to remove material from an entire second side of the wafer at least until a through hole is formed at a location of each of the one or more openings, wherein the dry etch rounds one or more of the edges and/or coners obtained on the second side of the wafer during the etch at a location of the one or more through holes. - View Dependent Claims (17, 18, 19)
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20. A method for obtaining one or more chips from a semiconductor wafer, the method comprising:
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forming one or more openings in a first side of the semiconductor wafer along a boundary of the one or more chips, wherein the one or more openings do not go through the wafer; and
thinning the wafer with a dry etch to remove material from an entire second side of the wafer at least until a semiconductor sidewall of at least the one or more openings is exposed on the second side, such that at some time during the dry etch, the semiconductor sidewall has a portion spaced from the second side but reachable from the second side through the opening. - View Dependent Claims (21, 22)
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23. A method for obtaining one or more chips from a semiconductor wafer, the method comprising:
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forming one or more openings in a first side of the semiconductor wafer along a boundary of the one or more chips, wherein the one or more openings do not go through the wafer; and
etching an entire second side of the wafer with a dry etch at least until the one or more openings become exposed on the second side, wherein the dry etch rounds one or more of the edges and/or coners obtained on the second side of the wafer at a location of the one or more openings when the one or more openings become exposed. - View Dependent Claims (24, 25, 26, 27, 28)
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Specification