Infrared light sensor and its sensing element and manufacturing method thereof

Abstract

A sensing element for an infrared light sensor and a method for manufacturing the same. The sensing element of the infrared light sensor includes: a substrate, a support structure, and an infrared light sensing structure. The support structure is disposed on the substrate. The infrared light sensing structure includes: a lower infrared light absorbing stack layer, a first metal shielding layer, and an upper infrared light absorbing stack layer. The lower infrared light absorbing stack layer is located on the support structure and forms a cavity between it and the substrate. A portion of the first metal shielding layer is disposed on the lower infrared light absorbing stack layer, and another portion of the first metal shielding layer is located on the same layer as the lower infrared light absorbing stack layer, and the other portion of the first metal shielding layer directly contacts the support structure. The upper infrared light absorbing stack layer is disposed on the first metal shielding layer. The infrared light sensing structure has a through-hole that communicates with the cavity.

Claims

1. A sensing element of an infrared light sensor, comprising: a substrate; a support structure disposed on the substrate; and an infrared light sensing structure comprising: a lower infrared light absorbing stack layer located on the support structure and forming a cavity between the support structure and the substrate; a first metal shielding layer, a portion of which is disposed on the lower infrared light absorbing stack layer, and another portion of which is located on the same layer as the lower infrared light absorbing stack layer and directly contacts the support structure; an upper infrared light absorbing stack layer disposed on the first metal shielding layer; an infrared light sensing layer located between the lower infrared light absorbing stack layer and the upper infrared light absorbing stack layer, for sensing infrared light based on changes in the resistance value of the infrared light sensing layer; and a second metal shielding layer disposed on the upper infrared light absorbing stack layer, wherein... The projection of the second metal shielding layer onto the substrate completely overlaps with the infrared light sensing layer; wherein the infrared light sensing structure has at least one through-hole and communicates with the cavity.

2. The sensing element of the infrared light sensor as claimed in claim 1, wherein the second metal shielding layer is in direct contact with the upper surface of the upper infrared light absorbing stack layer.

3. The sensing element of the infrared light sensor as claimed in claim 1, wherein the projection of the second metal shielding layer onto the substrate does not overlap with the support structure.

4. The sensing element of the infrared light sensor as claimed in claim 1, wherein the lower infrared light absorption stack layer comprises: a first lower infrared light absorption layer disposed on the support structure; and a second lower infrared light absorption layer disposed on the first lower infrared light absorption layer, wherein the first lower infrared light absorption layer and the second lower infrared light absorption layer are made of different materials.

5. The sensing element of the infrared light sensor as claimed in claim 1, wherein the upper infrared light absorption stack layer comprises one of the upper infrared light absorption layers stacked on top of each other.

6. The sensing element of the infrared light sensor as claimed in claim 1, wherein the upper infrared light absorption stack layer includes a first upper infrared light absorption layer and a second upper infrared light absorption layer stacked on top of each other, wherein the first upper infrared light absorption layer and the second upper infrared light absorption layer are made of different materials.

7. The sensing element of the infrared light sensor as claimed in claim 1, wherein the first metal shielding layer and the second metal shielding layer comprise at least one of titanium and aluminum.

8. The sensing element of the infrared light sensor as claimed in claim 1, wherein the at least one opening penetrates the lower infrared light absorbing stack layer, the first metal shielding layer, and the upper infrared light absorbing stack layer.

9. The sensing element of the infrared light sensor as claimed in claim 1 further includes a conductive layer disposed between the support structure and the substrate.

10. The sensing element of the infrared light sensor as claimed in claim 9 further includes a reflective layer disposed between the infrared light sensing structure and the substrate.

11. The sensing element of the infrared light sensor as claimed in claim 10, wherein the conductive layer and the reflective layer are electrically isolated from each other.

12. The sensing element of the infrared light sensor as claimed in claim 9, wherein the support structure is made of a conductive material and electrically connects the lower infrared light absorption stack layer and the conductive layer.

13. The sensing element of the infrared light sensor as claimed in claim 1, wherein the at least one opening is a double opening, and the second metal shielding layer extends continuously from one end to the other end of the upper surface of the upper infrared light absorbing stack, wherein the one end and the other end of the upper surface are respectively adjacent to the double opening.

14. A method for manufacturing a sensing element of an infrared light sensor, comprising: forming a sacrificial layer on a substrate; embedding a support structure in the sacrificial layer such that the upper surface of the sacrificial layer and the upper surface of the support structure are coplanar; forming a lower infrared light absorbing stack layer on the sacrificial layer and the support structure; forming a first metal shielding layer on the lower infrared light absorbing stack layer; forming an infrared light sensing layer and an upper infrared light absorbing stack layer on the first metal shielding layer; forming at least one opening penetrating the lower infrared light absorbing stack layer, the first metal shielding layer, and the upper infrared light absorbing stack layer; forming a second metal shielding layer on the upper infrared light absorbing stack layer; and heating and vaporizing the sacrificial layer and releasing it through the at least one opening, wherein... The projection of the second metal shielding layer onto the substrate completely overlaps with the infrared light sensing layer.

15. A method of manufacturing a sensing element of an infrared light sensor as claimed in claim 14, wherein forming the second metal shielding layer on the upper infrared light absorbing stack layer comprises: directly contacting the second metal shielding layer with the upper surface of the upper infrared light absorbing stack layer.

16. A method of manufacturing a sensing element of an infrared light sensor as claimed in claim 14, wherein forming the second metal shielding layer on the upper infrared light absorbing stack layer comprises: depositing a metal layer on the upper infrared light absorbing stack layer; and removing a portion of the metal layer located above the support structure to form the second metal shielding layer.

17. A method for manufacturing a sensing element of an infrared light sensor as claimed in claim 14, wherein forming the lower infrared light absorption stack layer on the sacrificial layer and the support structure comprises: depositing a first lower infrared light absorption layer on the sacrificial layer and the support structure; and depositing a second lower infrared light absorption layer on the first lower infrared light absorption layer, wherein the materials of the first lower infrared light absorption layer and the second lower infrared light absorption layer are different.

18. A method for manufacturing a sensing element of an infrared light sensor as claimed in claim 14, wherein the first metal shielding layer and the second metal shielding layer comprise at least one of titanium and aluminum.

19. A method for manufacturing a sensing element of an infrared light sensor as claimed in claim 14, further comprising: forming a metal layer on the substrate before forming the sacrificial layer; and removing a portion of the metal layer to form a conductive layer and a reflective layer, wherein the conductive layer is located between the support structure and the substrate, and the reflective layer is located between the lower infrared light absorption stack layer and the substrate.

20. A method of manufacturing a sensing element of an infrared light sensor as claimed in claim 14, wherein forming the first metal shielding layer on the lower infrared light absorbing stack layer comprises: forming a portion of the first metal shielding layer on the lower infrared light absorbing stack layer, and forming another portion of the first metal shielding layer on the support structure.

21. A method of manufacturing a sensing element of an infrared light sensor as claimed in claim 14, wherein the at least one opening is a double opening, and forming the second metal shielding layer on the upper infrared light absorbing stack layer comprises: forming the second metal shielding layer on the upper infrared light absorbing stack layer, extending continuously from one end to the other end along the upper surface of the upper infrared light absorbing stack layer, wherein the one end and the other end of the upper surface are respectively adjacent to the double opening.

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