Method and system for electroplating a MEMS device

Abstract

In described examples, a method for electroplating a semiconductor device includes: forming a metal foil; forming an inert anode support; attaching the metal foil to the inert anode support to form an anode; forming a cathode using a semiconductor substrate; immersing the anode and the cathode within an electrolyte solution; forming a circuit with a current source, the anode and the cathode; generating a current through the circuit; and electroplating a metal from the electrolyte solution onto the semiconductor substrate.

Claims

1. A system, comprising: an anode comprising an inert anode support and a metal foil attached to the inert anode support, wherein the inert anode support comprises multiple rings in an eccentric pattern; an electrolyte solution around the anode; and a circuit connected to the anode.

2. The system of claim 1, wherein the inert anode support comprises plastic.

3. The system of claim 1, wherein the inert anode support comprises polyvinyl chloride (PVC).

4. The system of claim 1, wherein the metal foil is inert to the electrolyte solution.

5. The system of claim 4, wherein a thickness of the metal foil is less than 500 microns.

6. The system of claim 5, wherein the thickness of the metal foil is less than 150 microns.

7. The system of claim 4, wherein the metal foil is a platinum foil.

8. The system of claim 4, wherein the metal foil is a zirconium foil.

9. The system of claim 1, wherein the multiple rings comprise a first ring and a second ring, wherein the first ring encircles the second ring.

10. The system of claim 1, wherein the multiple rings comprise: a first plastic ring; a second plastic ring, the second plastic ring surrounding the first plastic ring, a center of the second plastic ring offset from a center of the first plastic ring; and a third plastic ring, the third plastic ring surrounding the first plastic ring and the second plastic ring, a center of the third plastic ring offset from the center of the first plastic ring and the center of the second plastic ring.

11. The system of claim 10, comprising multiple openings in the first plastic ring.

12. The system of claim 1, wherein the metal foil comprises multiple rings.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 (prior art) is an illustration of a semiconductor electroplating apparatus.

(2) FIG. 2 (prior art) is a drawing of an anode.

(3) FIG. 3 is an illustration of a plastic or PVC type anode, according to example embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(4) FIG. 3 shows an anode support 300, according to example embodiments. The anode support 300 is formed in an approximately circular shape. The anode support 300 includes multiple rings 302 in an eccentric pattern and/or a concentric pattern. Openings 304 are disposed within the anode support 300. An opening 306 is centrally located within an innermost one of the multiple rings 302. Attachments 308 provide a means for attaching the anode support 300 onto an anode metal foil.

(5) In an example embodiment, the titanium anode support 200 (FIG. 2) coated with platinum is replaced by the anode support 300, which is formed of an inert material such as polyvinyl chloride (PVC) or plastic. A metal foil (or, alternatively, a wire or a mesh), such as platinum or zirconium, is attached onto the PVC or plastic support 300 to form an anode. The anode (including the inert support 300 and metal foil) is placed within the electrolyte solution 104 during the electroplating process.

(6) In at least one example, the metal foil has a shape and size similar to the inert support 300. The metal foil is attached to the inert support 300 before the electroplating process. The inert support 300 provides a corrosion resistant and chemically inert support for the metal foil. The inert support 300 is not degraded during the electroplating process. In an example embodiment, the metal foil's thickness is less than 500 microns.

(7) Accordingly, in described examples, the anode and a cathode are immersed in an electrolyte solution. The cathode includes a semiconductor substrate. The anode includes at least one of the following attached to an inert support 300 of a similar shape and size: a metal foil; a wire; and a mesh. The metal foil (or, alternatively, the wire or the mesh) may be formed using a metal, such as platinum or zirconium. The support 300 may include a plastic or polyvinyl chloride (PVC) or plastic. The metal foil (or, alternatively, the wire or the mesh) and inert support 300 include numerous openings 304 within both materials to allow liquid flow. The metal foil is not consumed, and the electrolyte solution does not damage the inert support 300.

(8) In the example method, an anode and a cathode are immersed in an electrolyte solution. The cathode includes a semiconductor substrate. The anode includes a metal foil, a mesh or a wire attached to a plastic support of a similar shape and size as the metal anode it replaces. The metal foil, mesh or wire is formed using an inert metal, such as platinum or zirconium. The metal foil and the inert support 300 do not corrode, and neither the metal foil (or, alternatively, the wire or the mesh) nor the inert support 300 are damaged by the electrolyte solution.

(9) The anode (formed by the inert support 300 supporting the metal foil) obtains a consistent and uniform layer of metal on the cathode. The electroplating process does not require ongoing adjustment for corrosion and maintenance using the anode formed of the inert support 300 and a metal foil. By using the inert support 300 with a metal foil, foils of alternate metals (such as titanium, zirconium, and palladium) for electroplating are more readily evaluated. Indium or other ions in the indium sulfite electrolyte solution do not precipitate with the use of metal foil supported by the inert support 300. Also, anode lifetime is increased by orders of magnitude (from weeks to years of use) with an anode formed of the inert support 300 supporting the metal foil. Moreover, changes in placement of the openings 304 in the inert support 300 and metal foil may be easily made, allowing alterations in flow patterns of the electrolyte solution through the anode.

(10) Modifications are possible in the described embodiments, and other embodiments are possible, within the scope of the claims.