阅读说明：本技术 一种锡层抗高温变色组合物 (High-temperature-resistant color-changing composition for tin layer ) 是由 王坤燕 张玉建 唐培松 郭玉华 沈强 王永亚 潘国祥 曹枫 杨圣晨 于 2021-01-20 设计创作，主要内容包括：本发明公开了一种锡层抗高温变色组合物。该组合物使用γ-甲基丙烯酰氧基丙基三甲氧基硅烷为单体的聚合物。特别适用于引线框架电镀锡工艺,能有效避免锡镀层高温变色现象。(The invention discloses a high-temperature discoloration resistant composition for a tin layer. The composition uses a polymer in which gamma-methacryloxypropyltrimethoxysilane is a monomer. Is particularly suitable for the electrotinning process of the lead frame and can effectively avoid the high-temperature discoloration phenomenon of a tin coating.)

1. The tin layer high temperature discoloration resisting composition features that the composition has gamma-methyl acryloxy propyl trimethoxy silane as monomer polymer.

2. The composition according to claim 1, wherein the composition is particularly suitable for use in a lead frame tin electroplating process, and is effective in preventing discoloration of tin plating at high temperatures.

Technical Field

The invention relates to a tin layer high-temperature discoloration resistant composition, in particular to a polymer taking gamma-methacryloxypropyltrimethoxysilane as a monomer, which is introduced into the composition and is used as a key component. The method is preferably used for the lead frame electrotinning process, and can effectively avoid the high-temperature discoloration phenomenon of the tin coating. The invention belongs to the field of traditional packaging processing of semiconductors.

Background

In the lead frame electrotinning process in the traditional packaging process, in order to make the pin have solderability, an electrotinning process is needed. However, in the post-baking or soldering process after tin electroplating, since the high temperature environment easily causes oxidative discoloration of the tin layer, thereby causing a decrease in solderability, it is important to perform a high temperature discoloration resistant treatment on the tin layer.

Aiming at the problems, the invention provides the high-temperature discoloration resistant tin layer composition, and the composition introduces a polymer taking gamma-methacryloxypropyltrimethoxysilane as a monomer as a key component, thereby effectively avoiding the high-temperature discoloration phenomenon of the tin layer.

Disclosure of Invention

The invention aims to provide a tin layer high-temperature discoloration resistant composition, in particular to a polymer taking gamma-methacryloxypropyltrimethoxysilane as a monomer as a key component. The tin layer high-temperature discoloration resistant composition can meet the technical requirements of electrotinning process, and effectively avoids the high-temperature discoloration phenomenon of a tin coating.

The purpose of the invention is realized by the following technical scheme:

the invention provides a polymer taking gamma-methacryloxypropyltrimethoxysilane as a monomer, which has a molecular structure shown in a formula (1).

The polymer is used as a key component of the high-temperature discoloration resistant composition for the tin layer, is particularly suitable for a tin electroplating process of a semiconductor lead frame, and effectively avoids the high-temperature discoloration phenomenon of a tin coating.

The invention relates to a polymer taking gamma-methacryloxypropyltrimethoxysilane as a monomer, which is realized by a chemical reaction process.

The polymer taking gamma-methacryloxypropyltrimethoxysilane as a monomer is realized by taking absolute ethyl alcohol as a solvent and carrying out chemical polymerization reaction on the gamma-methacryloxypropyltrimethoxysilane serving as an initial raw material in the presence of azodiisobutyronitrile AIBN serving as a catalyst. Gamma-methacryloxypropyltrimethoxysilane is a compound of the formula (2).

The specific method comprises the following steps:

dissolving gamma-methacryloxypropyltrimethoxysilane and azodiisobutyronitrile AIBN serving as a catalyst in required amount in absolute ethanol, heating to 60-80 ℃ under stirring, preserving heat for 8-24 hours, naturally cooling to room temperature, and distilling off an ethanol solvent.

The invention also provides a tin layer high-temperature discoloration resistant composition, which comprises a polymer and a solvent, wherein the polymer takes gamma-methacryloxypropyltrimethoxysilane as a monomer.

The gamma-methacryloxypropyltrimethoxysilane is a polymer of monomers, and the addition amount is selected from 1 to 50 percent by weight, preferably 5 to 10 percent by weight.

The solvent is selected from absolute ethyl alcohol, isopropanol and n-propanol, and preferably isopropanol. The amount added is selected from 50-99% by weight, preferably 90-95% by weight.

The high-temperature discoloration resistant tin layer composition containing the polymer in the formula (1) can effectively avoid the high-temperature discoloration phenomenon of a tin coating, and is particularly suitable for a lead frame tin electroplating process.

Detailed Description

The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

Example 1

This example provides a polymer using gamma-methacryloxypropyltrimethoxysilane as a monomer, which has the structural formula shown in table 1, and the synthetic route is as follows:

table 1: example 1 provides the Polymer Structure

Preparation method of polymer P1

Under the protection of nitrogen, gamma-methacryloxypropyltrimethoxysilane (24.81g, 100mmol), azobisisobutyronitrile AIBN (82.1mg, 0.5mmol) and absolute ethyl alcohol (100mL) are added into a two-neck flask, and the temperature is raised to 70 ℃ (can be any value between 60 and 80 ℃) for reaction for 12 hours (can be any value between 8 and 24 hours). The reaction solution was naturally cooled to room temperature. The anhydrous ethanol was distilled off under reduced pressure to give polymer P1.¹H NMR(400MHz，CDCl₃)δ(ppm)：4.06(t，2H)，3.55(s，9H)，2.13(br，1H)，1.60-1.53(br，4H)，0.58(t，2H).

Example 2

The tin layer high temperature discoloration resistant composition is prepared as follows:

the polymer P1 of example 1 was added in an amount of 8% using isopropyl alcohol as a solvent, and stirred at room temperature until completely dissolved.

Example 3

The tin layer high-temperature discoloration resistant composition related to the embodiment 2 is used for soaking a lead frame tin coating at room temperature for 10 seconds, and a reflow soldering application examination test is carried out after three-stage countercurrent water washing, wherein the process is as follows:

a. preheating, raising the temperature from room temperature to 150 ℃, controlling the temperature raising rate to be about 2 ℃/s, and controlling the time of the temperature zone to be 60-150 s.

b. The temperature is equalized from 150 ℃ to 217 ℃, the temperature is stably and slowly increased, and the temperature rising rate is less than 1 ℃/s.

c. Refluxing, and controlling the temperature at 217 ℃ for 60-90 s.

d. Cooling, the temperature reduction rate can not exceed 4 ℃/s at most, and observing the application effect by naked eyes after cooling to room temperature.

After the lead frame tin coating treated by the tin coating high-temperature discoloration resistant composition is subjected to reflow soldering test, any discoloration phenomenon does not occur.

In conclusion, the gamma-methacryloxypropyltrimethoxysilane provided by the invention is a polymer of a monomer, is used as a key component of a tin layer high-temperature discoloration resistant composition, is applied to a lead frame tinning process, effectively avoids the high-temperature discoloration effect of a tinning layer, and shows a good application effect.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.