Method of making lithographic contact elements
View Patent ↗A method of forming an interconnection, including a spring contact element, by lithographic techniques. In one embodiment, the method includes applying a masking material over a first portion of a substrate, the masking material having an opening which will define a first portion of a spring structure, depositing a structure material (e.g., conductive material) in the opening, and overfilling the opening with the structure material, removing a portion of the structure material, and removing a first portion of the masking material. In this embodiment, at least a portion of the first portion of the spring structure is freed of masking material. In one aspect of the invention, the method includes planarizing the masking material layer and structure material to remove a portion of the structure material. In another aspect, the spring structure formed includes one of a post portion, a beam portion, and a tip structure portion.
1. A process of making an electrical contact structure, the process comprising:
forming a first part of the contact structure on a terminal of an electronic component by depositing structural material in at least one opening in a first masking material on the electronic component;
forming a second part of the contact structure by depositing structural material in at least one opening in a second masking material on a sacrificial substrate;
attaching the second part of the contact structure to the first part of the contact structure; and
releasing the second part of the contact structure from the sacrificial substrate.
2. The process of claim 1 , wherein:
the first part of the contact structure comprises a post; and
the second part of the contact structure comprises a beam and a contact tip.
3. The process of claim 2 , wherein the forming the second part of the contact structure comprises:
depositing a first portion of the structural material into a first opening in a first layer of the second masking material to form the contact tip; and
depositing a second portion of the structural material into a second opening in a second layer of the second masking material to form the beam structure,
wherein the second layer of the second masking material is disposed on the first layer of the second masking material, and the second opening exposes a first end of the contact tip.
4. The process of claim 3 , wherein the first opening in the first layer of the second masking material exposes a pit in the sacrificial substrate, the pit defining a shape of a second end of the contact tip.
5. The process of claim 3 , wherein:
the depositing the first portion comprises electroplating the first portion of the structural material into the first opening; and
the depositing the second portion comprises electroplating the second portion of the structural material into the second opening.
6. The process of claim 3 , wherein:
the depositing the first portion comprises overfilling the first opening with the first portion of the structural material;
the process further comprises planarizing the first portion of the structural material deposited into the first opening;
the depositing the second portion comprises overfilling the second opening with the second portion of the structural material; and
the process further comprises planarizing the second portion of the structural material deposited into the second opening.
7. The process of claim 2 , wherein the contact tip is disposed on a first side of the beam, and the attaching comprises attaching the beam at a second side thereof to the post, the second side being opposite the first side.
8. The process of claim 7 , wherein the contact tip is disposed at a first end of the beam, and the attaching further comprises attaching the beam at a second end thereof to the post, the second end being opposite the first end.
9. The process of claim 8 , wherein the beam is curved along a length of the beam from the first end to the second end.
10. The process of claim 8 , wherein the beam is tapered along a length of the beam from the first end to the second end.
11. The process of claim 1 , wherein:
the first part of the contact structure comprises a post and a beam; and
the second part of the contact structure comprises a contact tip.
12. The process of claim 11 , wherein the forming the first part of the contact structure comprises:
depositing a first portion of the structural material into a first opening in a first layer of the first masking material to form the post, the first opening exposing the terminal of the electronic component; and
depositing a second portion of the structural material into a second opening in a second layer of the first masking material to form the beam structure,
wherein the second layer of the first masking material is disposed on the first layer of the first masking material, and the second opening exposes a second end of the post that is opposite a first end attached to the terminal.
13. The process of claim 12 , wherein:
the depositing the first portion comprises electroplating the first portion of the structural material into the first opening; and
the depositing the second portion comprises electroplating the second portion of the structural material into the second opening.
14. The process of claim 12 , wherein:
the depositing the first portion comprises overfilling the first opening with the first portion of the structural material;
the process further comprises planarizing the first portion of the structural material deposited into the first opening;
the depositing the second portion comprises overfilling the second opening with the second portion of the structural material; and
the process further comprises planarizing the second portion of the structural material deposited into the second opening.
15. The process of claim 11 , wherein the at least one opening in the second masking material exposes a pit in the sacrificial substrate, the pit defining a shape of a first end of the contact tip, and the attaching comprises attaching the contact tip at a second end thereof to the beam, the second end being opposite the first end.
16. The process of claim 11 , wherein the post is disposed on a first side of the beam, and the attaching comprises attaching the contact tip to a second side of the beam, the second side being opposite the first side.
17. The process of claim 16 , wherein the post is disposed at a first end of the beam, and the attaching further comprises attaching the contact tip to a second end of the beam, the second end being opposite the first end.
18. The process of claim 17 , wherein the beam is curved along a length of the beam from the first end to the second end.
19. The process of claim 17 , wherein the beam is tapered along a length of the beam from the first end to the second end.
20. The process of claim 1 further comprising, prior to the attaching:
removing the first masking material; and
removing the second masking material.