Integrated circuit packages including damming and change protection cover for harsh environments
View Patent ↗An electronic assembly for use in a downhole tool includes a damming boot deployed about at least one integrated circuit component on a circuit board. The boot is disposed to house the integrated circuit leads and solder joints in a substantially sealed cavity between the circuit board, the integrated circuit body, and an inner surface of the damming boot. The boot is also disposed to support the integrated circuit body and thereby improve the shock and vibration resistance of various electronic assemblies used in downhole tools. The invention also tends to improve the reworkability of downhole electronic assemblies.
1. An electronic assembly for use in a downhole tool, the assembly comprising:
a circuit board;
a plurality of integrated circuit packages deployed on the circuit board, each integrated circuit package including a plurality of electrically conductive leads protruding from a solid body, the integrated circuit packages in electrical communication with the circuit board via the plurality of leads; and
at least one damming boot deployed about at least one of the integrated circuit packages, the damming boot including a solid housing sized and shaped such that (i) an inner surface thereof sealingly engages an outer, peripheral surface of the solid body, (ii) a lower face of the damming boot sealingly engaging the circuit board, and (iii) an inner surface of an enlarged lower opening is spaced apart from an outer surface of the leads.
2. The electronic assembly of claim 1 , further comprising an electrical connector disposed to provide electrical communication between the integrated circuit packages and other devices in the downhole tool.
3. The electronic assembly of claim 1 , wherein the circuit board, the plurality of integrated circuit packages, and the at least one damming boot are encapsulated in an encapsulating material.
4. The electronic assembly of claim 1 , wherein the damming boot is disposed to house the leads of the at least one integrated circuit package in a substantially sealed cavity between the circuit board, the solid body, and an inner surface of the damming boot.
5. The electronic assembly of claim 1 , wherein the lower face of the damming boot is sealed to the circuit board via an adhesive.
6. The electronic assembly of claim 1 , wherein the damming boot comprises an open top.
7. The electronic assembly of claim 1 , wherein the damming boot is disposed to provide structural support for the at least one integrated circuit package.
8. The electronic assembly of claim 1 , wherein the damming boot is fabricated from an electrically insulating material.
9. The electronic assembly of claim 1 , wherein the damming boot is fabricated from a material having a coefficient of thermal expansion less than about 16×10 −6 .
10. A method for fabricating an electronic assembly for a downhole tool, the method comprising:
(a) providing a circuit board having a plurality of integrated circuit packages deployed thereon; and
(b) deploying a damming boot about at least one of the integrated circuit packages, the damming boot including a solid housing sized and shaped to be deployed about the at least one integrated circuit package such that (i) an inner surface of the housing sealing engages an outer, peripheral surface of a body portion of the at least one integrated circuit package, (ii) a lower face of the housing sealingly engages the circuit board, and (iii) an inner surface of an enlarged lower opening of the housing is spaced apart from an outer surface of a plurality of electrically conductive leads.
11. The method of claim 10 , further comprising:
(c) applying an adhesive between a lower face of the housing and the circuit board.
12. The method of claim 10 , further comprising:
(c) encapsulating the damming boot, the at least one integrated circuit package, and at least a portion of the circuit board in an encapsulating material.
13. The method of claim 10 , further comprising:
(c) applying an adhesive between the inner surface of the damming boot and the body portion of the at least one integrated circuit package.
14. The method of claim 10 , further comprising:
(c) applying an adhesive between a lower face of the housing and the circuit board; and
(d) encapsulating the damming boot, the at least one integrated circuit package, and at least a portion of the circuit board in an encapsulating material.
15. A downhole tool comprising:
a downhole tool body configured for coupling with a drill string;
a controller deployed in the tool body, the controller including at least one circuit board, the circuit board including at least one integrated circuit package, the integrated circuit package including a plurality of electrically conductive leads protruding from a solid body and in electrical communication with the circuit board;
at least one damming boot deployed about at least one of the integrated circuit packages, the damming boot including a solid housing sized and shaped such that (i) an inner surface thereof sealingly engages an outer, peripheral surface of the solid body, (ii) a lower face of the damming boot sealingly engaging the circuit board, and (iii) an inner surface of an enlarged lower opening is spaced apart from an outer surface of the leads.