Device and method for circuit protection during radiation sterilization

• US 6,594,156 B1
• Filed: 04/24/2000
• Issued: 07/15/2003
• Est. Priority Date: 04/24/2000
• Status: Expired due to Term

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Minimed, Inc. (Medtronic Plc)
• Inventors: Fong, Jason, Prokop, Adrian, Karre, Sheana, Stinson, Sara Akiko, Van Antwerp, William P., Rosenberg, James J.
• Primary Examiner(s): Gandhi, Jayprakash N.
• Application Number:
  US09/556,227
• Time in Patent Office: 1,177 Days
• Field of Search: 361/752, 361/800, 361/814, 361/816, 174/35.R, 174/35.MS, 206/438, 534/25, 250/505--51, 257/659, 257/666
• US Class Current: 361/816
• CPC Class Codes: A61L 2/081 Gamma radiation
• CPC Class Codes: A61L 2/082 X-rays
• CPC Class Codes: A61L 2/087 Particle radiation, e.g. electron-beam, alpha or beta radiation
• CPC Class Codes: A61L 2/26 Accessories or devices or components used for biocidal treatment
• CPC Class Codes: A61L 2202/24 Medical instruments, e.g. endoscopes, catheters, sharps
• CPC Class Codes: H01L 23/556 against alpha rays
• CPC Class Codes: H01L 25/0655 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/1435 Random access memory [RAM]
• CPC Class Codes: H01L 2924/1438 Flash memory
• CPC Class Codes: H01L 2924/145 Read-only memory [ROM]
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49137 Different components
• CPC Class Codes: Y10T 29/49144 by metal fusion

Abstract

A circuit protection device for protection of sensitive components during high energy radiation sterilization that includes a support substrate and a protective housing. The substrate supports the sensitive components. The protective housing is hermetically coupled to the support substrate to seal the sensitive components within the protective housing. Preferably, the protective housing stops high energy used in the high energy sterilization from damaging the sensitive components from a predetermined exposure level of high energy sterilization. The circuit protection device may further include a protective conductor that is coupled to the support substrate on a side which is opposite the protective housing to prevent high energy from entering the opposite side of the support substrate. The circuit protection device can also include an energy absorbing material contained within an area sealed by the protective housing to absorb high energy by products produced by the protective housing stopping the high energy used in the high energy sterilization. Preferably, the support substrate is a circuit board, and the sensitive elements are semiconductors. Also, the high energy sterilization is E-beam sterilization and the high energy are electrons, and the high energy byproducts are x-rays.

Claims

1. A circuit protection device for protection of sensitive components during high energy radiation sterilization, the device comprising;

a support substrate that supports the sensitive components;

a protective housing that is hermetically coupled to the support substrate to seal the sensitive components within the protective housing;

wherein the protective housing stops high energy used in the high energy radiation sterilization from damaging the sensitive components from a predetermined exposure level of high energy sterilization; and

an energy absorbing material contained within an area sealed by the protective housing to absorb high energy byproducts produced by the protective housing stopping the high energy used in the high energy sterilization.

2. The device according to claim 1, further including a protective conductor coupled to the support substrate on a side opposite the protective housing to prevent high energy from entering the side of the support substrate.

3. The device according to claim 2, wherein the support substrate is a circuit board, and wherein the sensitive elements are semiconductors.

4. The device according to claim 2, wherein the high energy sterilization is E-beam sterilization and the high energy are elections.

5. The device according to claim 4, wherein the high energy byproducts are x-rays.

6. The device according to claim 5, wherein the energy absorbing material is an epoxy containing meterial.

7. The device according to claim 3, wherein the predetermined exposure level is above 2.0 Mrad.

8. The device according to claim 3, wherein the predetermined exposure level is less than or equal to 5.0 Mrad.

9. The device according to claim 3, wherein the predetermined exposure level is above 0.5 Mrad.

10. The device according to claim 2, wherein the protective housing and protective conductor are formed from a metal.

11. The device according to claim 10, wherein the metal is selected from the group consisting essentially of titanium and aluminum.

12. The device according to claim 1, wherein the protective housing is formed from a metal.

13. The device according to claim 12, wherein the metal is selected from the group consisting essentially of titanium and aluminum.

14. A circuit element for use in an electronic device, the circuit element comprising:

a semiconductor structure,

wherein the semiconductor structure has been sterilized by a predetermined dosage of radiation,

wherein gain characteristics after radiation sterilization are reduced by less than a predetermined fraction of before radiation sterilization gain characteristics, and

wherein after radiation sterilization, characteristics of a collector current and a base current for a given base voltage change in a generally proportional relationship relative to each other.

15. The circuit element in accordance with claim 14, wherein the radiation sterilization is by gamma radiation.

16. The circuit element in accordance with claim 14, wherein the predetermined fraction of before radiation sterilization gain characteristics is 25%.

17. The circuit element in accordance with claim 14, wherein the predetermined fraction of before radiation sterilization gain characteristics is 20%.

18. The circuit element in accordance with claim 14, wherein the predetermined fraction of before radiation sterilization gain characteristics is 75%.

19. The circuit element in accordance with claim 14, wherein the predetermined dosage of radiation is above 5 kGy.

20. The circuit element in accordance with claim 14, wherein the predetermined dosage of radiation is above 10 kGy.

21. The circuit clement in accordance with claim 14, wherein the predetermined dosage of radiation is above 15 kGy.

22. The circuit element in accordance with claim 14, wherein the predetermined dosage of radiation is above 20 kGy.

23. The circuit element in accordance with claim 14, wherein the predetermined dosage of radiation is above 25 kGy.

24. The circuit element in accordance with claim 14, wherein the predetermined dosage of radiation is above 30 kGy.

25. The circuit element in accordance with claim 14, wherein the circuit element is a transistor.

26. The circuit element in accordance with claim 14, wherein the circuit element is a circuit array.

27. The circuit element in accordance with claim 14, wherein a ratio of collector current to base current, each as a function of the base voltage, has a magnitude greater than one over a predetermined expected operating image.

28. The circuit element in accordance with claim 14, wherein the semiconductor structure is a PNP high voltage structure.