Electronic devices with cavity-type, permeable material filled packages, and methods of their manufacture
View Patent ↗Embodiments include devices and methods of their manufacture. A device embodiment includes a package housing, at least one electronic circuit (e.g., a sensor circuit), a first material, and a second material. The package housing includes a cavity that is partially defined by a cavity bottom surface, and the cavity bottom surface includes a mounting area and a non-mounting area. The at least one electronic circuit is attached to the cavity bottom surface over the mounting area. The first material has a relatively high, first modulus of elasticity, and covers the non-mounting area. The second material has a relatively low, second modulus of elasticity, and is disposed over the first material within the cavity.
1. A device comprising:
a package housing with a cavity, wherein the cavity is partially defined by a cavity bottom surface, a bonding shelf above the cavity bottom surface, and a lower cavity sidewall extending between the cavity bottom surface and the bonding shelf, wherein the cavity bottom surface includes a mounting area and a non-mounting area;
at least one electronic circuit attached to the cavity bottom surface over the mounting area;
a plurality of conductive structures, each having first and second portions that are electrically coupled, wherein each first portion is accessible within the cavity over the bonding shelf, and each second portion is exposed to an exterior of the package housing;
a plurality of connectors coupled between the at least one electronic circuit and the first portions of the plurality of conductive structures;
a first material having a relatively high, first modulus of elasticity in direct contact with and covering the non-mounting area, the mounting area, and at least a portion of the lower cavity sidewall, and also in direct contact with the at least one electronic circuit, wherein the first material is a die attach material that attaches the at least one electronic circuit to the mounting area and extends to the lower cavity sidewall; and
a second material having a relatively low, second modulus of elasticity disposed over the first material within the cavity.
2. The device of claim 1 , wherein the first modulus of elasticity is sufficiently high so that the first material functions as a restrictor of bubble formation at an interface between the first material and the non-mounting area of the cavity bottom surface.
3. The device of claim 1 , wherein the first material is a single layer of material having a planar top surface, and wherein the at least one electronic circuit is coupled to the planar top surface of the single layer.
4. The device of claim 1 , wherein the first material is a polymer adhesive, and the second material is an elastomer gel.
5. The device of claim 1 , wherein the at least one electronic circuit includes a first electronic circuit configured to produce sensor signals indicating a sensed characteristic of an external environment, and the first electronic circuit is selected from a pressure sensor, an accelerometer, and a transducer.
6. The device of claim 5 , wherein the at least one electronic circuit further includes a second electronic circuit attached to the cavity bottom surface and electrically coupled to the first electronic circuit, wherein the second electronic circuit is configured to provide control signals to the first electronic circuit, receive the sensor signals from the first electronic circuit, and send signals representative of the sensor signals to external circuitry.
7. A device comprising:
a package housing with a cavity, wherein the cavity is partially defined by a cavity bottom surface, a bonding shelf above the cavity bottom surface, and a lower cavity sidewall extending between the cavity bottom surface and the bonding shelf, wherein the cavity bottom surface includes a mounting area and a non-mounting area;
at least one electronic circuit directly attached to the cavity bottom surface over the mounting area with a die attach material;
a plurality of conductive structures, each having first and second portions that are electrically coupled, wherein each first portion is accessible within the cavity over the bonding shelf, and each second portion is exposed to an exterior of the package housing;
a plurality of connectors coupled between the at least one electronic circuit and the first portions of the plurality of conductive structures;
a first material having a relatively high, first modulus of elasticity covering the non-mounting area, wherein the first material is different from the die attach material, and the first material extends from the mounting area to the lower cavity sidewall;
a second material having a relatively low, second modulus of elasticity disposed over the first material within the cavity; and
a lid coupled to the package housing over the cavity, wherein an air gap is present within the cavity between the lid and the second material, and the lid includes an opening between top and bottom surfaces of the lid.
8. The device of claim 7 , wherein the cavity is further defined by:
a bonding area above the cavity bottom surface and below a top of the cavity, wherein the first portions of the plurality of conductive structures are accessible within the cavity at the bonding area; and
wherein the cavity sidewall extends between the cavity bottom surface and the bonding area, wherein the first material covers at least a portion of the cavity sidewall.
9. A method for manufacturing an electronic device, the method comprising the steps of:
providing a package housing with a cavity, wherein the cavity is partially defined by a cavity bottom surface, a bonding shelf above the cavity bottom surface, and a lower cavity sidewall extending between the cavity bottom surface and the bonding shelf, wherein the cavity bottom surface includes a mounting area and a non-mounting area;
coupling a plurality of conductive structures to the bonding shelf, each having first and second portions that are electrically coupled, wherein each first portion is accessible within the cavity over the bonding shelf, and each second portion is exposed to an exterior of the package housing;
applying a first material directly on both the mounting area and the non-mounting area of the cavity bottom surface, wherein the first material extends to the lower cavity sidewall, the first material has a first modulus of elasticity, and the first material is a die attach material;
placing at least one electronic circuit directly on the first material to attach the at least one electronic circuit to the package housing over the mounting area;
coupling a plurality of connectors between the at least one electronic circuit and the first portions of the plurality of conductive structures; and
disposing a second material over the first material, wherein the second material has a second modulus of elasticity that is lower than the first modulus of elasticity.
10. The method of claim 9 , further comprising:
coupling a lid to the package housing over the cavity, wherein an air gap is present within the cavity between the lid and the second material, and the lid includes an opening between top and bottom surfaces of the lid.