Encapsulation of circuit components to reduce thermal cycling stress
OwnerMichael Jininventor
Life of this patent
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Abstract
A method of encapsulating materials to protect circuit components from the stress of thermal cycling includes applying a first substance to cover Wire bonds on a first layer, applying a second substance to wire bonds on a second layer, and curing the first and second substances by application of heat or radiation to bond the first and second substances together. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
Claims57
A method of reducing thermal cycling stress on a circuit assembly, the method comprising:
- applying a first substance to a first layer of the circuit assembly to encapsulate at least one wire bond attached to a first bond pad on the first layer;
- applying a second substance to a second layer of the circuit assembly to encapsulate at least one wire bond attached to a second bond pad on the second layer;
- and
- applying a third substance to encapsulate at least one wire bond connection positioned between the first layer and the second layer,
- wherein the first substance, the second substance, and the third substance have substantially similar thermal coefficients of expansion.
A circuit assembly comprising:
- a first layer having at least one circuit component encapsulated with a first substance;
- a second layer having at least one circuit component encapsulated with a second substance;
- and
- a bridging material substantially encapsulating at least one connective component positioned within a gap between the encapsulated first layer and the encapsulated second layer,
- wherein the first substance, the second substance, and the bridging material have substantially similar thermal coefficients of expansion.
A method of reducing thermal cycling stress in a circuit assembly, comprising:
- dispensing a first encapsulant on a flex layer of a circuit assembly;
- dispensing a second encapsulant on a silicon layer of the circuit assembly;
- curing the second encapsulant onto a plurality of wire bonds on the silicon layer;
- curing the first encapsulant onto the plurality of wire bonds on the first layer to a hard finish;
- and
- applying a third encapsulant to a wire loop connecting the plurality of wire bonds on the flex layer with the plurality of wire bonds on the silicon layer, the wire loop positioned in an area between the silicon layer and the flex layer,
- wherein the first encapsulant is selected for having a substantially similar coefficient of thermal expansion as the first layer, and the second encapsulant is selected for having a substantially similar coefficient of thermal expansion as the second layer.
A method of manufacturing a circuit assembly, comprising:
- dispensing a first substance to encapsulate a plurality of circuit components on a flex layer positioned on a substrate;
- curing the first substance onto the plurality of components on the flex layer so that the plurality of components are entirely encapsulated;
- and
- encapsulating, with a second substance, a connective component used to connect circuit components positioned on the flex layer with circuit components on a silicon layer on the substrate, wherein thermal coefficients of expansion of the first substance and the second substance are matched with the flex layer and with silicon, respectively, so that mechanical stress on the circuit assembly from thermal cycling is reduced.
The method of claim 56, wherein the flex layer is a cable positioned on the substrate.
Dependencies are inferred from the claim text.