Mounted x-ray window

• US 10,641,907 B2
• Filed: 02/21/2017
• Issued: 05/05/2020
• Est. Priority Date: 04/14/2016
• Status: Active Grant

• Current Assignee: Moxtek (Polatechno Co.,Ltd.)
• Original Assignee: Moxtek (Polatechno Co.,Ltd.)
• Inventors: Black, Kevin, Abbott, Jonathan
• Primary Examiner(s): Fox, Dani
• Application Number:
  US15/437,660
• Publication Number:
  US 20180323033A1
• Time in Patent Office: 1,169 Days
• CPC Class Codes: G01T 1/00 Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation G01T3/00, G01T5/00 take precedence
• CPC Class Codes: H01J 2235/18 Windows, e.g. for X-ray transmission
• CPC Class Codes: H01J 5/18 Windows permeable to X-rays, gamma-rays, or particles

Abstract

A mounted x-ray window can be strong and transmissive to x-rays, can have a hermetic seal, and can withstand high temperatures. The mounted x-ray window can include a film located on an inner-side of a flange of a housing and can be attached to the flange by a ring of elastic adhesive. The film can comprise silicon nitride. A method of mounting an x-ray window can include placing a ring of elastic adhesive on an inner-side of a flange of a housing, placing a film on the ring of elastic adhesive, and baking the housing, the ring of elastic adhesive, and the film.

Claims

1. A method of mounting an x-ray window, the method comprising the following steps in the following order:

a) providing a housing with an aperture, a flange encircling the aperture, the flange having an inner-side that faces an interior of the housing;

b) locating a ring of elastic adhesive on the inner-side of the flange;

c) locating a film over the ring of elastic adhesive on the inner-side of the flange, extending across and covering the aperture, with the ring of elastic adhesive sandwiched between the film and the inner-side of the flange;

d) baking the housing, the ring of elastic adhesive, and the film at a temperature of at least 300°

C.; and

e) hermetically-sealing the housing and the x-ray window with an internal pressure less than 5 pascals.

2. The method of claim 1, wherein the ring of elastic adhesive includes polyimide.

3. The method of claim 1, further comprising:

a) etching a center region of a silicon wafer, forming an annular-support with an opening and the film extending across the opening, the film having a material composition comprising silicon nitride and the annular-support having a material composition comprising silicon; and

b) the annular-support located on an opposite side of the film from the ring of elastic adhesive.

4. The method of claim 1, wherein:

a) the housing has two openings, the aperture and a distal-opening, opposite of each other and located at opposite ends of the housing; and

b) the flange is farther from the distal-opening than any other portion of the housing.

5. A mounted x-ray window, comprising:

a) a housing including;

i) an aperture;

ii) a flange encircling the aperture, the flange having an inner-side that faces an interior of the housing, the interior of the housing having a pressure less than 5 pascals;

b) a film;

i) extending across the aperture and mounted on the inner-side of the flange;

ii) having a material composition comprising silicon nitride;

c) a ring of elastic adhesive;

i) sandwiched between the film and the inner-side of the flange;

ii) forming a hermetic-seal to the housing;

d) an annular-support;

i) having an opening;

ii) attached to a perimeter of the film with the film extending across the opening;

iii) located on an opposite side of the film from the ring of elastic adhesive;

iv) having a material composition comprising silicon; and

v) including a sloped-face at the opening with a smaller inner diameter adjacent to the film sloping to a larger inner diameter farther from the film.

6. The mounted x-ray window of claim 5, wherein the opening of the annular-support aligns with the aperture of the housing.

7. The mounted x-ray window of claim 5, wherein:

a) the housing has two openings, the aperture and a distal-opening, opposite of each other and located at opposite ends of the housing; and

b) the flange is farther from the distal-opening than any other portion of the housing.

8. The mounted x-ray window of claim 5, wherein the ring of elastic adhesive immediately adjoins the housing and the film.

9. A mounted x-ray window comprising:

a) a housing including;

i) an aperture;

ii) a flange encircling the aperture, the flange having an inner-side that faces an interior of the housing, the interior of the housing having a pressure less than 5 pascals;

b) a film located on the inner-side of the flange and extending across the aperture; and

c) a ring of elastic adhesive, a sheet of elastic adhesive, or both;

i) sandwiched between the film and the inner-side of the flange; and

ii) forming a hermetic-seal to the housing.

10. The mounted x-ray window of claim 9, further comprising the ring of elastic adhesive encircling the aperture of the housing.

11. The mounted x-ray window of claim 10, wherein the film has a material composition comprising silicon nitride.

12. The mounted x-ray window of claim 10, wherein the film includes a silicon nitride thin film sandwiched between two aluminum thin films.

13. The mounted x-ray window of claim 10, wherein the ring of elastic adhesive is capable of withstanding a temperature of at least 300°

C. without failure of the hermetic-seal.

14. The mounted x-ray window of claim 10, wherein the ring of elastic adhesive has a modulus of elasticity of less than 5 GPa.

15. The mounted x-ray window of claim 10, wherein:

a) the housing is hermetically-sealed with an internal pressure of less than 5 pascals; and

b) the housing has a leak-rate of less than 1×

10<sup>−

14</sup> bar*L/s.

16. The mounted x-ray window of claim 10, wherein:

a) the housing has two openings, the aperture and a distal-opening, opposite of each other and located at opposite ends of the housing; and

b) the distal-opening is larger than a diameter of the flange, measured inside of the housing.

17. The mounted x-ray window of claim 10, further comprising an annular-support, wherein:

a) the annular-support is attached to a perimeter of the film;

b) the annular-support has an opening;

c) the film extends across the opening of the annular-support;

d) the annular-support is located on an opposite side of the film from the ring of elastic adhesive;

e) a difference between a coefficient of thermal expansion of the housing and a coefficient of thermal expansion the annular-support is at least 7 μ

m/(m*K); and

f) a difference between a coefficient of thermal expansion of the film and a coefficient of thermal expansion the annular-support is less than 0.7 μ

m/(m*K).

18. The mounted x-ray window of claim 17, wherein the annular-support includes a sloped-face at the opening and the annular-support has a smaller inner diameter adjacent to the film sloping to a larger inner diameter farther from the film.

19. The mounted x-ray window of claim 17, wherein the annular-support has a material composition comprising silicon and the housing is metallic.

20. The mounted x-ray window of claim 10, wherein the film has a thickness of <

10 μ

m and >

400 nm.