Integrated package design and method for a radiation sensing device

• US 7,084,010 B1
• Filed: 10/17/2003
• Issued: 08/01/2006
• Est. Priority Date: 10/17/2003
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Bailey, Michael, Kennedy, Adam M., Meissner, Edward, Dodds, Robert K., VanLue, David
• Primary Examiner(s): Pham, Hoai
• Assistant Examiner(s): Trinh, (Vikki) Hoa B.
• Application Number:
  US10/688,708
• Time in Patent Office: 1,019 Days
• Field of Search: 438/115, 438/121, 438/125, 438/64, 250/349, 250/332, 250/353, 250/352, 250/343, 250/345, 250/346, 250/339.14
• US Class Current: 438/115
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/045 Sealings; Vacuum enclosures; Encapsulated packages; Wafer bonding structures; Getter arrangements getter arrangements per se H01L23/26 and H01L21/3221
• CPC Class Codes: G01J 5/046 Materials; Selection of thermal materials
• CPC Class Codes: G01J 5/0875 Windows; Arrangements for fastening thereof
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 27/14618 Containers
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01327 Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 31/0203 Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80

Abstract

A radiation detector (10) has a base (30), a frame (48), a window (46), and solder layers (50, 52) formed from a solder pre-form (58, 60) to define a vacuum chamber (56). Feedthroughs (18, 40, 44) penetrate the base (30) for electrical connection to internal components. A method for sealing the detector (10) aligns a lower detector assembly (62), the frame (48) the window (46), and the solder pre-forms (58, 60) in a non-sealed relation within a processing chamber (80, 94). High temperature and low pressure is imposed, and the getter (42) is activated by resistive heating imposed by current leads (88). The window (46), frame (48), and lower detector assembly (62) are then pressed together and sealed by the liquefied solder pre-forms (58, 60). The method eliminates the need for a seal port, combines several steps within the processing chamber (80, 94), and eliminates certain prior art cleaning steps.

Claims

1. A method of making a radiation detector comprising:

assembling a lower detector assembly;

enclosing the lower detector assembly, a window, and a first solder entity within a processing chamber such that the window is spaced from the lower detector assembly;

reducing pressure within the processing chamber;

increasing temperature within the processing chamber;

maintaining a spaced relation between the window and the lower detector assembly until the first solder entity reaches a melting point;

moving at least one of the window and the lower detector assembly into contact with one another for forming a hermetically sealed compartment using the interposed first solder entity; and

equalizing pressure between the processing chamber and external of the processing chamber while maintaining the reduced pressure within the hermetically sealed compartment.

2. The method of claim 1 wherein assembling a lower detector assembly comprises:

disposing a plurality of TE elements, a ceramic stage, a radiation sensor, and a getter all in fixed relation to the base, and

electrically connecting the sensor, the getter, and at least two TE elements to associated conductive pathways that pass through feedthroughs, each feedthrough being defined by the base.

3. The method of claim 1 further comprising reducing the temperature within the processing chamber after moving at least one of the window and the lower detector assembly into contact with one another.

4. The method of claim 3 wherein reducing the temperature within the processing chamber is characterized by an average rate of temperature reduction that is greater than 20°

C. per minute.

5. The method of claim 1 wherein increasing temperature within the processing chamber includes raising the temperature according to a first and a second heat-up ramp.

6. The method of claim 5 wherein the second heat-up ramp raises temperature within the processing chamber no more than 20°

C. per minute.

7. The method of claim 5 wherein the maximum temperature of the first heat-up ramp is below a melting temperature of the first solder entity, and the maximum temperature of the second heat-up ramp is at least above the melting temperature of the first solder entity.

8. The method of claim 1 wherein enclosing the lower detector assembly, a window, and a first solder entity within a processing chamber includes also enclosing a frame and a second solder entity within the processing chamber, and further wherein the frame is spaced from one of the lower detector assembly or the base.

9. The method of claim 8 wherein the first and second solder entities each comprise a solder pre-form.

10. The method of claim 8 wherein the first and second solder pre-forms are temporarily fixed to the frame by a press.

11. The method of claim 1 wherein maintaining a spaced relation between the window and the lower detector assembly includes activating the getter by resistive heating prior to reaching a melting point of the first solder entity.

12. The method of claim 1 as applied to at least two detectors, both detectors being simultaneously subjected to varying pressures and temperatures within a single processing chamber.