Chips with wafer scale caps formed by molding
First Claim
1. A method of applying a plurality of caps to a plurality of microfabricated devices at the wafer stage, the method including:
- a) forming a plurality of hollow molded caps, as an array, from a layer of thermoplastic material which is placed in a mold, the mold having first and second mold halves which are brought together to form the caps, each cap having a central portion and a perimeter wall;
b) retaining the array in one of the mold halves;
c) applying the caps simultaneously to one side of a wafer with each cap overlying part or all of a device with a free edge of the perimeter wall contacting the wafer;
wherein d) the coefficient of thermal expansion of the mold half retaining the array is compatible with the coefficient of thermal expansion of the wafer.
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Accused Products
Abstract
A method is disclosed for applying a plurality of caps to a plurality of microfabricated devices at the wafer stage. A wafer is provided-having a plurality of microfabricated devices. The method requires forming a plurality of first hollow molded caps from a layer of thermoplastic material which is placed in a mold. The mold has first and second mold halves which are brought together to form the caps. Each cap has a central portion and a perimeter wall. The caps are formed first as an array of caps in the mold. Separated caps are applied simultaneously to one side of the wafer. The first caps are attached to the wafer, and then the wafer is then eventually separated into individual chips.
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Citations
20 Claims
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1. A method of applying a plurality of caps to a plurality of microfabricated devices at the wafer stage, the method including:
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a) forming a plurality of hollow molded caps, as an array, from a layer of thermoplastic material which is placed in a mold, the mold having first and second mold halves which are brought together to form the caps, each cap having a central portion and a perimeter wall;
b) retaining the array in one of the mold halves;
c) applying the caps simultaneously to one side of a wafer with each cap overlying part or all of a device with a free edge of the perimeter wall contacting the wafer;
whereind) the coefficient of thermal expansion of the mold half retaining the array is compatible with the coefficient of thermal expansion of the wafer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification