Method of wafer-level packaging using low-aspect ratio through-wafer holes
First Claim
1. A method of manufacturing wafer-level packages for integrated circuits, the wafer-level packages comprising a base wafer that is fixedly attached to and in operational association with a cap wafer having a through-wafer electrical interconnection, the method comprising:
- providing cavities having low-aspect ratio side-walls on both a front surface and a back surface of a polished semiconductor substrate;
providing an interconnection via between adjacent front surface cavities using a cavity disposed on the back surface;
applying a highly-electrically conductive metal/solder to surfaces of the interconnection via to provide through-wafer, low aspect ratio side-wall, electrical interconnections; and
fixedly attaching the cap wafer to the base wafer to form a composite wafer, wherein electrical contact points disposed on a front surface of the base wafer are electrically-coupled to the through-wafer, low aspect ratio side-wall electrical interconnections on the front surface of the cap wafer, and the through-wafer, low aspect ratio side-wall, electrical interconnections on the cap wafer are electrically-coupled to electrical contact points disposed on the rear surface of the cap wafer.
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Accused Products
Abstract
A wafer-level packaged IC is made by attaching a cap wafer to the front of an IC base wafer before cutting the IC base wafer, i.e. before singulating the plurality of dies on the IC base wafer. The cap wafer is mechanically attached and electrically connected to the IC base wafer, then the dies are singulated. Electrically conductive paths extend through the cap wafer, between wafer contact pads on the front surface of the cap and electrical contact points on the IC base wafer. Optionally, the cap wafer contains one or more dies. The IC base wafer can be fabricated according to a different technology than the cap wafer, thereby forming a hybrid wafer-level package. Optionally, additional “upper-level” cap wafers (with or without dies) can be stacked to form a “multi-story” IC. Optionally, a hermetically-sealed cavity headroom is provided.
40 Citations
19 Claims
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1. A method of manufacturing wafer-level packages for integrated circuits, the wafer-level packages comprising a base wafer that is fixedly attached to and in operational association with a cap wafer having a through-wafer electrical interconnection, the method comprising:
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providing cavities having low-aspect ratio side-walls on both a front surface and a back surface of a polished semiconductor substrate; providing an interconnection via between adjacent front surface cavities using a cavity disposed on the back surface; applying a highly-electrically conductive metal/solder to surfaces of the interconnection via to provide through-wafer, low aspect ratio side-wall, electrical interconnections; and fixedly attaching the cap wafer to the base wafer to form a composite wafer, wherein electrical contact points disposed on a front surface of the base wafer are electrically-coupled to the through-wafer, low aspect ratio side-wall electrical interconnections on the front surface of the cap wafer, and the through-wafer, low aspect ratio side-wall, electrical interconnections on the cap wafer are electrically-coupled to electrical contact points disposed on the rear surface of the cap wafer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of wafer-level packaging integrated circuit (IC) dies, comprising:
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providing an IC base wafer comprising a plurality of dies and at least one electrical contact point associated with each die; providing a first semiconductor cap wafer; forming electrically conductive side-wall paths having low aspect ratio portions through the first semiconductor cap wafer at positions corresponding to respective ones of the electrical contact points on the IC base wafer, such that each electrically conductive side-wall path extends from a first side of the first semiconductor cap wafer to a second side of the first semiconductor cap wafer and is insulated from at least a portion of the first semiconductor cap wafer; and before singulating the dies from the IC base wafer, attaching the first semiconductor cap wafer to the IC base wafer to form a composite wafer, such that the ends of the conductive paths on the first side of the first semiconductor cap wafer are electrically-coupled to the respective electrical contact points on the IC base wafer. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification