Electrochemical etching of semiconductors

A semiconductor and current technology, applied in semiconductor devices, semiconductor/solid-state device manufacturing, circuits, etc., can solve the problems of damaged diode performance loss, increased process time and cost, and complicated preparation process, so as to eliminate complicated steps and improve reliability. sexual effect

Inactive Publication Date: 2012-08-01
ROHM & HAAS ELECTRONICS MATERIALS LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this requires the use of a controlled atmosphere during sintering and splits the plating operation into two steps, which complicates the fabrication process
Also, there is a greater chance of damaging the diode or loss of performance due to shunting
Moreover, process time and cost are increased

Method used

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  • Electrochemical etching of semiconductors
  • Electrochemical etching of semiconductors
  • Electrochemical etching of semiconductors

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] A doped monocrystalline silicon wafer having pyramidal bumps on its front side is provided. The wafer has n+ doped regions on the front side of the wafer forming the emissive layer. The wafer also has a PN junction below the emissive layer. The front side of the wafer is coated with SiN x Composed of anti-reflection layer. The front side of the wafer has a pattern for current paths that passes through the anti-reflection layer, exposing the surface of the silicon wafer. Each current path spans the entire length of the wafer. The current paths are bonded to busbars at one end of the wafer and at the center of the wafer. The backside of the wafer is p+ doped and contains aluminum electrodes.

[0057] The wafer was immersed in a 1 wt% hydrofluoric acid solution to clean the current paths and busbars. Wash for one minute at room temperature. The wafer was rinsed with water. In addition to removing contaminants from the wafer, the hydrofluoric acid solution also remo...

Embodiment 2

[0062] The method described above in Example 1 was repeated except that silver was electroplated on the nickel seed layer instead of copper. Use ENLIGHT TM Silver Plate 620 silver electroplating bath plated silver. The current density is 1.5A / dm 2And the plating is finished for 10 minutes. Artificial light was also applied to the wafer throughout the plating. The light source is a 250 watt halogen lamp. Plating temperatures range from 20°C to 40°C. An 8-10 μm layer of silver is deposited on this nickel.

[0063] The adhesion of the metal layer was tested using the ASTM D3359-97 standard tape test. Adhesion at the interface between the nickel and the silicon wafer was unacceptable in all current paths and busbars.

Embodiment 3

[0065] A single crystal wafer of the same type as in the previous Example 1 was provided. The wafer was placed on a metal plating support with the backside aluminum electrode in direct contact with the metal plating support. The interface between the cell and the support was sealed around the circumference of the wafer to minimize solution penetration between the back of the cell and the plating support. During the anode cycle, current from the rectifier flows through the holder and into the cell through the back contact.

[0066] Afterwards, the current paths and busbars were oxidized using 5 wt% hydrogen peroxide aqueous solution to ensure that the silicon surface was oxidized. Thereafter, the wafers mounted on supports described in the previous paragraphs were immersed in an aqueous composition in the electroplating tank comprising 10 g / L of nickel ions from nickel sulfamate, 45 g / L of sodium bifluoride, and 15 g / L of L sulfamic acid. The holder with the wafer was connec...

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Abstract

Semiconductors are electrochemically etched in solutions containing sources of bifluoride and nickel ions. The electrochemical etching may form pores in the surface of the semiconductor in the nanometer range. The etched semiconductor is then nickel plated.

Description

[0001] Related Application Cross Reference [0002] This application claims priority to US Provisional Application No. 61 / 422,597, filed December 13, 2010, based on US 35 U.S.C. § 119(e), the entire contents of which are hereby incorporated by reference. technical field [0003] The invention relates to a semiconductor electrochemical etching method. More specifically, the present invention relates to a semiconductor electrochemical etching method for improving the adhesion between metal and semiconductor. Background technique [0004] Metallization of semiconductors, such as photovoltaic devices and solar cells, involves forming conductive contacts on the front and back sides of the semiconductor. The metal coating must be able to establish ohmic contact with the semiconductor in order to ensure that charge carriers leave the semiconductor and enter the conductive contact without disturbance. In order to reduce current losses as much as possible, the metallized contact gr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L21/3063
CPCC25D5/12H01L31/1804C25F3/12C25D7/123C25D3/12H01L21/76879H01L31/022425C25D7/12H01L31/0224H01L24/03Y02E10/547C25D5/00H01L2924/12042H01L2924/12036Y02P70/50H01L2924/00H01L21/306C25D11/32
Inventor G·哈姆J·A·里斯G·R·奥拉德伊斯
Owner ROHM & HAAS ELECTRONICS MATERIALS LLC
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