KR100271558B1 - Resin Leakage Inhibition and Surface Corrosion Prevention Composition of Copper-based Leadframes - Google Patents

Abstract

The present invention relates to a resin leakage inhibiting and surface corrosion preventing composition of a copper-based lead frame, which is any one selected from higher alkyl phosphate ester salts and higher alkylaryl polyethoxy phosphate ester salts as a weight ratio to a certain weight of deionized water. 0.01 to 0.5 parts by weight of a resin leakage inhibitor; 0.005 to 0.1 parts by weight of any one kind of corrosion inhibitors selected from benzotriazole, benzimidazole and benzotriazole carboxylic acid; 0.085 to 0.3 part by weight of a pH adjuster selected from phosphoric acid and sulfuric acid; It contains 0.002 ~ 0.7 parts by weight of sodium hydroxide as a solvent to maintain the pH at 2 ~ 5pH to prevent surface corrosion of the copper lead frame and at the same time, low molecular resin flowing out along the adhesive interface between the semiconductor chip and the die pad on which silver plating layer is formed. There is a feature that can suppress the decrease in the wire bonding reliability due to leakage.

Description

Resin Leakage Inhibition and Surface Corrosion Prevention Composition of Copper-based Leadframes

The present invention relates to a resin leakage inhibiting and surface corrosion preventing composition of the copper-based lead frame.

Particularly, in the present invention, when a silver epoxy adhesive is doped onto a die pad of a copper lead frame and a semiconductor chip is bonded and cured, a low molecular resin component flows out along an adhesive interface to prevent contamination of the lead frame. It relates to a composition that is formulated to prevent corrosion of the surface of the system leadframe.

Typically, the semiconductor chip is bonded by a die epoxy upper surface to the die pad upper surface on which the silver plating layer of the lead frame is formed by a die bonding process. As described above, the lead frame in which the die bonding process is completed, the low molecular portion of the resin flows out during the curing process of the silver epoxy along the adhesive interface between the lower surface of the semiconductor chip and the upper surface of the die pad, and correspond to the bonding pads of the semiconductor chip. By contaminating the front end portion of the silver plating layer of the inner leads electrically connected by the bonding wire, there was a disadvantage in that the reliability of the wire bonding process to be carried out in the future. Therefore, this lead frame has a cumbersome process that requires a separate chemical cleaning process to ensure the reliability of the wire bonding process.

In addition, since the copper or copper alloy (hereinafter referred to as “copper-based”) leadframe is easily corroded during storage, it is used by coating a corrosion inhibitor on the surface prior to the above-described process and subsequent processes. However, most copper corrosion inhibitors, including benzotriazole, benzimidazole, or benzotriazole carboxylic acid, act as a dysfunction to increase the surface energy of the silver-plated surface of the leadframe, rather increasing the resin leakage. There is a need for a technology that can simultaneously solve two problems: suppression of resin leakage and prevention of surface corrosion of a copper-based lead frame.

Accordingly, the present invention has been made in consideration of the above problems, and an object thereof is to prevent corrosion of the surface of a copper-based lead frame, and at the same time, to prevent an adhesion surface during curing of a silver epoxy adhesive that bonds a die pad and a semiconductor chip. The present invention provides a composition for inhibiting resin leakage and preventing surface corrosion of a copper-based lead frame capable of suppressing leakage of low molecular resin flowing out.

The object of the present invention is a benzotriazole or benzimidazole compound which is a) a water-soluble phosphate ester salt for suppressing resin leakage as a main component and b) a corrosion inhibitor on the surface of a copper-based lead frame, and c) a pH regulator as an auxiliary component. It is achieved by providing a composition composed of phosphoric acid or sulfuric acid and d) sodium hydroxide as an auxiliary component according to a certain ratio.

Here, the resin leakage inhibitor used in the present invention is, for example, a higher alkyl phosphate ester salt, an alkylarylalkoxy phosphate ester salt or a higher alkylaryl polyethoxy phosphate ester salt, the content of which is 0.01 to based on a washing solution (deionized water). 0.5 parts by weight. The content of benzotriazole, benzimidazole or benzotriazole carboxylic acid is 0.001 to 0.05 parts by weight, and the weight ratio is 10: 1 to 100: 1 based on the resin export inhibitor (resin inhibitor: corrosion inhibitor). Should be maintained. In addition, phosphoric acid or sulfuric acid is used as a pH adjuster, and the content is 0.085-0.3 weight part, More preferably, it is 0.16 weight part. In particular, the pH of the pH adjuster should be maintained at 2-5pH. Here, sodium hydroxide is a high alkyl phosphate ester salt and benzotriazole carboxylic acid is added as a solubility because of very low water solubility in water,

The higher alkylarylalkoxy phosphate ester salt used in the present invention is a low molecular resin component along the adhesion interface between the semiconductor chip and the die pad, since a phosphoric acid group having a polarity is combined with a silver plating layer, for example, by adsorbing to lower the surface energy to realize a nonpolar surface. It serves to suppress this flow. In addition, benzotriazole, benzimidazole or benzotriazole carboxylic acid or the like added in an appropriate ratio may be selectively combined with the surface of the copper-based lead frame to simultaneously inhibit the corrosion of the metal.

In addition, sodium hydroxide was added as the solubilizer of the higher alkyl phosphate ester salt and benzotriazole carboxylic acid having a very low water solubility in water, and the weight ratio of the higher alkyl phosphate ester salt and the benzotriazole carboxylic acid was different. It should remain 1: 1 and 2: 1.

In particular, if the composition ratio (resin leakage inhibitor: corrosion inhibitor) is 10: 1 or more, the corrosion prevention effect is good, but the inhibitory effect of resin leakage is lowered. Not good

Hereinafter, preferred embodiments of the present invention will be described.

Experimental Method

(1) Sample treatment (here, "sample" is a copper-based lead frame, in particular a silver plating layer formed on the upper surface of the die pad)

A resin leakage inhibitor and a corrosion inhibitor are used as basic compositions, and a pH control agent and a dissolving agent are optionally prepared by filling a beaker with about 500 ml of a predetermined solution as shown in Tables 1 to 4. Here, the solution refers to a composition containing a predetermined weight part of a resin leakage inhibitor, a corrosion inhibitor, a pH adjusting agent and a dissolving agent as a weight ratio to a predetermined weight of deionized water.

Then, the sample is immersed in the solution at room temperature, stirred for 5 to 10 seconds, the sample is separated, washed with water and dried with deionized water for 8 to 15 seconds, preferably 10 seconds.

(2) Resin Leak Test

After sample treatment, the silver epoxy was dropped on the silver plating layer and left for 25 to 35 seconds, preferably 30 seconds, and then 50 to 70 minutes in an oven capable of maintaining at 170 to 180 ° C, preferably at 175 ° C. Heat for 60 minutes and measure the size of resin leakage before and after sample treatment.

(3) Corrosion prevention test

After filling the beaker with about 500 ml of deionized water, the sample is immersed in a state of 90 to 110 ° C., preferably at 100 ° C., boiled for 8 to 13 minutes, preferably 10 minutes, and dried. The degree of surface discoloration of the dried sample is measured and compared to check the antirust effect.

Herein, the resin leakage inhibitors A, A 'and A ″ of Tables 1 to 4 are the higher alkyl phosphate ester salts, the higher alkyl aryl alkoxy phosphate ester salts and the higher alkyl aryl polyethoxy phosphate ester salts, respectively. B ′, B ″ are benzotriazole, benzimidazole and benzotriazole carboxylic acid, respectively, pH adjuster C is phosphoric acid or sulfuric acid, and finally solvent D is sodium hydroxide.

Comparative example A A ″ B B ′ B ″ C D Antirust test result Resin Leak Size (mm) Before processing After treatment Before processing After treatment One 0.5 0.1 0.16 0.5 Very bad Very good 0.260 0.103 2 0.05 0.16 0.5 Very bad Very good 0.260 Less than 0.005 3 0.01 0.16 0.5 Very bad Very good 0.260 Less than 0.005 4 0.01 0.3 0.5 Very bad Very good 0.260 Less than 0.005 5 0.005 0.16 0.5 Very bad good 0.260 Less than 0.005 6 0.005 0.085 0.5 Very bad good 0.260 Less than 0.005 7 0.1 0.1 0.16 0.1 Very bad Very good 0.260 0.125 8 0.05 0.16 0.1 Very bad Very good 0.260 0.044 9 0.01 0.16 0.1 Very bad Very good 0.260 Less than 0.005 10 0.005 0.16 0.1 Very bad good 0.260 Less than 0.005 11 0.05 0.1 0.16 0.05 Very bad Very good 0.260 0.189 12 0.05 0.16 0.05 Very bad Very good 0.260 0.090 13 0.01 0.16 0.05 Very bad Very good 0.260 0.035 14 0.005 0.16 0.05 Very bad good 0.260 Less than 0.005 15 0.01 0.1 0.16 0.01 Very bad Very good 0.260 0.260 16 0.05 0.16 0.01 Very bad Very good 0.260 0.897 17 0.01 0.16 0.01 Very bad Very good 0.260 0.035 18 0.005 0.16 0.01 Very bad good 0.260 0.025 19 0.5 0.05 0.3 0.5 Very bad Very good 0.260 Less than 0.005 20 0.1 0.01 0.16 0.1 Very bad good 0.260 Less than 0.005 21 0.05 0.05 0.085 0.05 Very bad good 0.260 Less than 0.005 22 0.5 0.1 0.16 0.7 Very bad Very good 0.260 Less than 0.027 23 0.05 0.16 0.6 Very bad Very good 0.260 Less than 0.005 24 0.1 0.01 0.16 0.12 Very bad Very good 0.260 Less than 0.005 25 0.005 0.3 0.11 Very bad good 0.260 Less than 0.005 26 0.01 0.01 0.16 0.03 Very bad Very good 0.260 0.011 27 0.001 0.085 0.012 Very bad good 0.260 Less than 0.005

Comparative example A A ″ B B ′ B ″ C D Antirust test result Resin Leak Size (mm) Before processing After treatment Before processing After treatment 28 0.5 0.1 0.16 0.2 Very bad Very good 0.260 0.952 29 0.05 0.16 0.1 Very bad good 0.260 Less than 0.005 30 0.1 0.1 0.16 0.2 Very bad Very good 0.260 0.130 31 0.01 0.3 0.02 Very bad Very good 0.260 Less than 0.005 32 0.01 0.01 0.16 0.02 Very bad Very good 0.260 0.027 33 0.001 0.085 0.002 Very bad good 0.260 Less than 0.005

Anti-rust test and resin leakage on samples using a solution composed of resin leakage inhibitor (A, A ″), corrosion inhibitor (B, B ′, B ″), pH adjuster (C) and solubilizer (D) The results of the test are shown in Table 1, while the rust preventive effect is good for all the comparative examples, while the resin leakage of the composition at the composition ratios such as Comparative Examples 1,7,11,12,15,16,28,30 It can be seen that the size does not satisfy the desired size (0.076 mm or less; the size of the resin leakage does not impair the reliability of the wire bonding and does not require chemical washing).

Here, sodium hydroxide is added as the solubilizer of the higher alkyl phosphate ester salt and benzotriazole carboxylic acid is very low in water solubility in water, the weight ratio of the higher alkyl phosphate ester salt and benzotriazole carboxylic acid, respectively It should remain 1: 1 and 2: 1. In addition, the pH of the solution used for this comparative example is about 2-5 pH.

Comparative example A ′ B B ′ Antirust test result Resin Leak Size (mm) Before processing After treatment Before processing After treatment 34 0.5 0.5 Very bad Very good 0.260 Less than 0.005 35 0.1 0.01 Very bad Very good 0.260 Less than 0.005 36 0.05 0.05 Very bad good 0.260 Less than 0.005 37 0.5 0.1 Very bad Very good 0.260 0.044 38 0.05 Very bad good 0.260 Less than 0.005 39 0.01 Very bad good 0.260 Less than 0.005 40 0.005 Very bad good 0.260 Less than 0.005 41 0.1 0.1 Very bad Very good 0.260 0.103 42 0.05 Very bad good 0.260 Less than 0.005 43 0.01 Very bad good 0.260 Less than 0.005 44 0.005 Very bad good 0.260 Less than 0.005 45 0.05 0.1 Very bad Very good 0.260 0.112 46 0.05 Very bad good 0.260 0.090 47 0.01 Very bad good 0.260 Less than 0.005 48 0.005 Very bad good 0.260 Less than 0.005 49 0.01 0.1 Very bad Very good 0.260 0.155 50 0.05 Very bad good 0.260 0.897 51 0.01 Very bad good 0.260 0.035 52 0.005 Very bad good 0.260 Less than 0.005

The results of the anti-rust test and the resin leak test on the sample using a solution composed of a resin leakage inhibitor (A ′) and a corrosion inhibitor (B, B ′) at a constant component ratio are shown in Table 2. While it is good for all the comparative examples, it can be seen that the size of the resin leakage does not satisfy the desired size in the composition ratio, such as Comparative Examples 41,45,46, 49,50. In particular, in Comparative Examples 34 to 52, since the higher alkylarylalkoxy phosphate ester salt (A ') is acidic, the pH control agent is not required, but the pH should be maintained at 2 to 5 pH.

Comparative example A ′ B ″ D Antirust test result Resin Leak Size (mm) Before processing After treatment Before processing After treatment 53 0.5 0.1 0.2 Very bad Very good 0.260 0.015 54 0.05 0.1 Very bad Very good 0.260 Less than 0.005 55 0.1 0.01 0.02 Very bad Very good 0.260 Less than 0.005 56 0.005 0.01 Very bad good 0.260 Less than 0.005 57 0.01 0.01 0.02 Very bad Very good 0.260 0.022 58 0.001 0.002 Very bad good 0.260 Less than 0.005

The results of the anti-rust test and the resin leakage test on the sample using a solution having a resin leakage inhibitor (A ′), a corrosion inhibitor (B ″), and a solvent (D) in a certain component ratio are shown in Table 3. , Antirust effect and resin leakage inhibiting effect were found to be good in all the comparative examples. Here, sodium hydroxide is added to the benzotriazole carboxylic acid as their solubility so low solubility in water, the weight ratio to benzotriazole carboxylic acid should be maintained at 2: 1. In addition, the pH of the solution used for this comparative example is about 2-5 pH.

Comparative example A ″ B B ′ C Antirust test result Resin Leak Size (mm) Before processing After treatment Before processing After treatment 59 0.5 0.1 0.16 Very bad Very good 0.260 0.065 60 0.05 0.16 Very bad Very good 0.260 Less than 0.005 61 0.1 0.01 0.16 Very bad Very good 0.260 Less than 0.005 62 0.005 0.3 Very bad good 0.260 Less than 0.005 63 0.01 0.01 0.16 Very bad Very good 0.260 0.889 64 0.001 0.085 Very bad good 0.260 Less than 0.005 65 0.5 0.1 0.16 Very bad Very good 0.260 0.037 66 0.05 0.16 Very bad Very good 0.260 Less than 0.005 67 0.1 0.01 0.16 Very bad Very good 0.260 Less than 0.005 68 0.005 0.3 Very bad good 0.260 Less than 0.005 69 0.01 0.01 0.16 Very bad Very good 0.260 0.035 70 0.001 0.085 Very bad good 0.260 Less than 0.005

The results of the anti-rust test and the resin leakage test on the sample using a solution composed of a resin leakage inhibitor (A ″), a corrosion inhibitor (B, B ′), and a pH regulator (C) at a predetermined ratio are shown in Table 4. As can be seen, while the rust preventive effect is good for all the comparative examples, it can be seen that the size of the resin leakage does not satisfy the desired size at the same composition ratio as Comparative Example 63. Here, pH of the solution used for this comparative example is about 2-5 pH.

Comparing the comparative examples shown in Tables 1 to 4, the amount of benzotriazole, benzimidazole or benzotriazole carboxylic acid used as a corrosion inhibitor showed a good anti-corrosive effect in a given weight range. It was found that the anti-rusting effect and the resin leakage suppressing effect were excellent at the weight ratio of the leak inhibitor and the corrosion inhibitor at 100: 1 to 10: 1. In particular, when the weight ratio of the resin leakage inhibitor and the corrosion inhibitor is 10: 1 or more, it was found that the resin leakage appeared in the desired range (0.076 mm) or more. In addition, when the weight ratio of the resin leakage inhibitor and the corrosion inhibitor within a given weight part range of 100: 1 or more, it was difficult to prepare a solution, and the washing time after the treatment was long, and in particular, the corrosion prevention effect was not sufficient.

As described above, the composition of the present invention prevents surface corrosion of the copper-based lead frame and at the same time reduces the wire bonding reliability caused by the low molecular resin leakage flowing along the adhesive interface between the semiconductor chip and the die pad on which the silver plating layer is formed. There is an effect that can be suppressed. In addition, the composition of the present invention has the effect of improving the pre-productivity and manufacturing cost of the lead by suppressing the resin leakage by not performing the resin leakage removal process proceeded by the chemical method.

Claims (4)

A low-molecular resin portion flows along the adhesive interface during the curing process to prevent corrosion of the copper-based lead frame and at the same time, a silver epoxy adhesive that bonds one surface of the die pad and the die pad on which the silver plating layer of the copper-based lead frame is formed. A lead frame cleaning solution for suppressing contamination of a frame, 0.01 to 0.5 parts by weight of any one of the resin leakage inhibitors selected from higher alkyl phosphate ester salts and higher alkylaryl polyethoxy phosphate ester salts as a weight ratio to deionized water; 0.005 to 0.1 parts by weight of any one kind of corrosion inhibitors selected from benzotriazole, benzimidazole and benzotriazole carboxylic acid; 0.085 to 0.3 part by weight of a pH adjuster selected from phosphoric acid and sulfuric acid; A composition for inhibiting resin leakage and preventing surface corrosion of a copper-based lead frame, which contains 0.002 to 0.7 parts by weight of sodium hydroxide as a solvent to maintain a pH of 2 to 5 pH. A low-molecular resin portion flows along the adhesive interface during the curing process to prevent corrosion of the copper-based lead frame and at the same time, a silver epoxy adhesive that bonds one surface of the die pad and the die pad on which the silver plating layer of the copper-based lead frame is formed. A lead frame cleaning solution for suppressing contamination of a frame, 0.01 to 0.5 parts by weight of a higher alkylarylalkoxy phosphate ester salt which is a resin leakage inhibitor as a weight ratio to a certain weight of deionized water; A composition for inhibiting resin leakage and surface corrosion of a copper-based lead frame, which contains 0.005 to 0.5 parts by weight of a corrosion inhibitor, which is any one selected from benzotriazole and benzimidazole, to maintain a pH of 2 to 5 pH. A low-molecular resin portion flows along the adhesive interface during the curing process to prevent corrosion of the copper-based lead frame and at the same time, a silver epoxy adhesive that bonds one surface of the die pad and the die pad on which the silver plating layer of the copper-based lead frame is formed. A lead frame cleaning solution for suppressing contamination of a frame, 0.01 to 0.5 parts by weight of a higher alkylarylalkoxy phosphate ester salt which is a resin leakage inhibitor as a weight ratio to a certain weight of deionized water; 0.001 to 0.1 parts by weight of benzotriazole carboxylic acid which is a corrosion inhibitor; A composition for inhibiting resin leakage and preventing surface corrosion of a copper-based lead frame, which contains 0.002 to 0.1 parts by weight of sodium hydroxide as a solvent to maintain a pH of 2 to 5 pH. A low-molecular resin portion flows along the adhesive interface during the curing process to prevent corrosion of the copper-based lead frame and at the same time, a silver epoxy adhesive that bonds one surface of the die pad and the die pad on which the silver plating layer of the copper-based lead frame is formed. A lead frame cleaning solution for suppressing contamination of a frame, 0.01 to 0.5 parts by weight of a higher alkylaryl polyethoxy phosphate ester salt which is a resin leakage inhibitor as a weight ratio to a predetermined weight of deionized water; 0.001 to 0.1 parts by weight of any one of corrosion inhibitors selected from benzotriazole and benzimidazole; A composition for inhibiting resin leakage and surface corrosion of a copper-based lead frame, which contains 0.085 to 0.3 parts by weight of a pH regulator, which is any one selected from phosphoric acid and sulfuric acid, to maintain a pH of 2 to 5 pH.