Aqueous solution for surface treatment of tin films and method for preventing discoloration of a tin film surface

An aqueous solution and metal technology, which is applied in the coating process of metal materials, semiconductor/solid-state device components, printed circuit manufacturing, etc., can solve the problems of unrevealed compounds with excellent properties, unsuitability, and inability to eliminate wood grain patterns on tin-plated surfaces

Active Publication Date: 2011-10-12
ROHM & HAAS ELECTRONICS MATERIALS LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Also, according to the patent, the application of sodium phosphate does not eliminate the woodgrain pattern on tinplated surfaces, and this com...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-4 and comparative example 0-38

[0047] Cathodic electrolytic degreasing of the copper lead frame in an alkaline electrolytic degreasing agent (Cleaner 160P, Meltex Inc.) solution at a bath temperature of 60°C for 1 minute at a voltage of 4 volts; rinse the product with water; It is immersed in a persulfate chemical abrasive (Actronal 55) for 30 minutes for chemical abrasion; the product is rinsed with water, washed with acid in a 10% sulfuric acid solution, and then washed with water; In the plating tank, nickel plating was carried out for 2 minutes at a current density of 3 amps / cubic decimeter to form a 1 micron thick nickel film; the product was rinsed with water; using a conventional methanesulfonic acid tin plating bath (SOLDERON TM TMBT-280 tin plating) to form a tin coating film with a thickness of 3 microns; the product was rinsed with water, immersed in an aqueous solution at 25°C with the composition and pH value shown in Table 1 for 30 seconds, rinsed with water, and then dried. Sodium polyphosph...

Embodiment 27 and 28

[0064] Working examples 27 and 28 (solder wettability test)

[0065] The lead frames subjected to the surface treatment of the tin film were prepared under the same conditions as in the operation examples 1 and 5, except that the treatment temperature of the aqueous solution used for the surface treatment in the operation examples 1 and 5 was 60°C. Under the conditions of 105°C and 100% relative humidity, the moisture resistance test (PCT (105°C, 100% relative humidity, 4 or 8 hours)) was carried out on the prepared lead frame for 4 hours and 8 hours, using SAT-5000 Solder Checker (RHESCA Co., Ltd.) evaluated the solder wettability by measuring the zero-crossing time of the coating film after the moisture resistance test by the meniscograph method. The measurement conditions are as follows.

[0066] Zero Crossing Time Measurement Conditions

[0067] Solder bath: Sn / Pb=63 / 37

[0068] Bath temperature: 235°C

[0069] Immersion depth: 1mm

[0070] Immersion speed: 10 mm / s

...

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PUM

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Abstract

To provide a solder-plating film which has good solder wettability and with which discoloration and twisting of the tin film after heat treatment are prevented. A method and a solution for surface treating a tin film are disclosed. The aqueous solution contains specific compounds and is brought into contact with a tin-plating film before reflow treatment of the tin film.

Description

technical field [0001] The present invention relates to a solution for surface treatment of metals, specifically tin coatings; and also to a method for surface treatment of tin coatings. More specifically, the present invention relates to a method of applying a solution for surface treatment to the surface of the tin plating film before performing reflow treatment when the tin film is formed using a tin plating method; the present invention It also relates to the treatment solutions used in the method. Background technique [0002] Tin and tin alloy thin films have excellent adhesion properties, low cost, electrical properties, and solderability; therefore, they are widely used in chips, crystal oscillators, lead frames, printed circuits, and other electronic components that require electrical contact It is also widely used as a resist in the steps of semiconductor and printed substrate manufacturing. [0003] Over time, hair-like metallic deposits known as whiskers can fo...

Claims

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Application Information

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IPC IPC(8): C23C22/05
CPCC25D5/48H01L23/49582H01L2224/16H01L2224/81801H01L2924/01012H01L2924/01078H01L2924/19041H01L2924/19043H05K3/3473H05K2203/0392H05K2203/043H01L2924/01019C23C22/58C25D5/505
Inventor 折桥正典
Owner ROHM & HAAS ELECTRONICS MATERIALS LLC
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