JPS62147701A - Carbon system resistance paste - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention B) Industrial Field of Application The present invention relates to a printed resistor circuit board used in high-performance ICs, and more particularly to a printed resistor circuit board for mounting shim parts by solder reflow. It is something.

(b) Conventional technology In recent years, there has been a demand for hybrid ICs with high packaging density, especially in order to make them lighter, thinner, shorter, and smaller.For this purpose, resistors are manufactured by screen-printing a resistor paste on a substrate and then baking it instead of using a chip-mounting method. A method in which the material is formed by Ceramink substrates are usually used, and electrodes, resistors, etc. are printed on this substrate using a glaze paste, and then baked.
It is equipped with electronic parts. However, this ceramic hybrid IC uses an expensive glaze paste and requires a high temperature of 800°C or more to bake it, which not only increases manufacturing costs, but also
Double-sided mounting is essential to achieve higher packaging density, but ceramic substrates have the disadvantage that the large number of holes for through-holes is difficult to process, and the board with holes decreases in strength and is easily damaged. have. Therefore, recently, there has been a demand in this field for hybrid ICs using organic substrates such as paper phenol or glass epoxy resin substrates in place of ceramic substrates. In this method, an electrode circuit is formed by etching a copper-clad resin laminate or by a full additive method on an insulating substrate, and a carbon-based resistance paste is printed between the electrodes, and then fired to form a resistor. It is something that makes you On the other hand, electronic components such as chip capacitors and transistors are mounted between other electrodes to create a hybrid I.
C. Therefore, the carbon-based resistance paste used in this case must not only have excellent electrical properties but also printability and be able to withstand the high temperatures of solder reflow. Many studies have been conducted to date to improve the physical properties of carbon-based resistance pastes. For example, a resistor using a phenolic resin mixed with a cycloaliphatic epoxy resin as a binder, or a resistor paste consisting of an acrylic acid ester solution of a bisphenol A-formaldehyde condensate and conductive particles is cured by electron beam radiation. Resistors have excellent heat resistance and moisture resistance, and it is known that resistors using epoxy-modified polyimide resin as a binder have excellent heat resistance. Furthermore, it is said that a resistor using a two-component binder consisting of a resol type phenolic resin and an amine resin has a small change in resistance value after a pressure tester test. However, even if the resistor paste obtained by the conventional technology is used for printed resistor circuit boards for hybrid ICs, the resistance value changes significantly after solder reflow, and not only does it have insufficient heat resistance and moisture resistance, but also the resistor paste is used during screen printing. Since there are problems with printability, such as bleeding and fading, it has not yet reached the point where it is fully satisfactory for practical use in the field of high-performance ICs and high-performance ICs, where high performance and high reliability are increasingly required.

No. 0 Object of the Invention' The object of the present invention is to improve heat resistance, moisture resistance, etc., which are the shortcomings of conventional carbon-based resistors, and to improve the advantages of screen printing when manufacturing printed resistor circuit boards using organic substrates. An object of the present invention is to provide a carbon-based resistance paste having excellent printability.

B) Structure of the Invention In view of the above object, the present inventors used a three-component initial condensation polymerization mixture consisting of 50 to 75% epoxy resin, 15 to 30% melamine resin, and 10 to 20% cresol resin as a binder. Then, by mixing conductive particles such as carbon black or graphite with organic or inorganic fillers such as polytetrafluoroethylene or boron oxide, and mixing and dispersing them with a high boiling point organic solvent using a roll mill etc. The inventors have discovered that a carbon-based resistance paste with extremely excellent printability can be obtained without impairing electrical characteristics, and have arrived at the present invention.

The three-component resin solution according to the present invention has viscoelasticity that is extremely suitable for the production of carbon-based resistance paste, so there is no bleeding or fading during screen printing, and the leveling is good, compared to the conventional one. Printability is extremely superior compared to . Also, after printing this carbon-based resistance paste on an insulating substrate,
By firing, a cured product with a very complex three-dimensional structure is produced through a t≠circle reaction process such as a cocondensation polymerization reaction and a crosslinking reaction (e).Explanation of Examples Next, the present invention will be explained with reference to Examples. .

(Example 1) Composition ratio (weight ratio) of carbon-based resistance paste according to the present invention
An example is shown below.

■ Epoxy resin = 55 parts (Epicote 1007, Shell Chemical) ■ Butyl etherified melamine resin = 30 parts (Niepan 208E-60, Mitsui Toatsu Chemical) ■ Cresol resin -
15 parts (PL-21109, Gunei Chemical) ■ Catalyst: 4 parts ■ ~ ■ are mixed to form a binder, and in this, 17.9 parts of carbon black and 60.7 parts of organic/inorganic photonic agent are mixed. A carbon-based resistance paste was produced by mixing and dispersing the mixture with butyl calpitol in a roll mill or the like. The obtained resistor paste had a sheet resistance value of 10 Ω/hole, and was printed on a copper-clad glass Epokin resin laminate on which arbitrary circuit electrodes were formed by etching.
The leveling was good, and there was no bleeding or fading in the print, and the printability was extremely excellent. Next, a resistor was formed by firing, and an insulation resist was coated leaving the component mounting area, thereby obtaining a printed resistor circuit board for a hybrid IC. When we performed solder reflow to mount ICs and chip components on this printed resistor circuit board, the resistance value change was as small as ~1.5%. Also, the temperature range from -30 to +85℃ with +25℃ as the standard The temperature coefficient of resistance in the range is −
At 250ppm/'c, resistance change after heat resistance test at 85°C for 1000 hours is -4.5%, 10°C19
The change in resistance value after a 1000 hour humidity test at 0 to 95% LH was +3%, and both values were small and showed excellent electrical properties.

(Example 2) Using the same manufacturing method as in Example 1, the composition ratio (M amount ratio) is set as follows.

■ Epoxy resin = 60 parts ■ Butyl etherified melamine resin: 30 parts ■ Cresol resin: 20 parts ■ Catalyst: 4 parts ■ ~ ■ are mixed to make a binder, and in this, carbon black: 19.6 parts and graphite: 5 .4 parts and 53.7 parts of an inorganic photonic agent were mixed therein and kneaded and dispersed together with butylcarpitol in a roll mill to produce a carbon-based resistance paste. The area resistance value of the obtained resistance paste is IKΩ
When a printed resistor circuit board was manufactured using this in exactly the same manner as in Example 1, there was no bleeding or fading during printing, and the printability was excellent. The change in resistance value of the obtained printed resistor circuit board after solder reflow was as small as 11 inches.

Also, the temperature coefficient of resistance at -30 to +85°C is -2
00ppm 7℃, resistance value change after heat resistance test of 85℃, 1oo-o hour is -3.5%, 40''C, '90
The change in resistance value after the 1,000 hour humidity test was 12%, both of which were small and showed excellent electrical properties.

(Comparative Example) As a comparative example, an example of the composition ratio (weight ratio) when two components of an epoxy resin and a melamine resin are used as a binder is shown below.

■ Epoxy resin 0 parts ■ Butyl etherified melamine resin: 3 parts ■ Catalyst:
4 parts ■ to ■ are mixed to form a binder, and in the same manner as in Example 1, 17.9 parts of carbon 5 plaque and 60.7 parts of organic/inorganic photonic agent are mixed, and mixed with butyl calpitol. A carbon-based resistance paste was produced by mixing and dispersing in a roll mill. The area resistance value of the obtained resistor paste is 8Ω
When I printed and fired this to produce a printed resistance circuit board in exactly the same manner as in Example 1, bleeding occurred during printing and a precise resistance pattern could not be obtained. . Example 1 for the obtained printed resistor circuit board
When a similar test was conducted, the resistance value change after solder reflow was -1.6%, and the temperature coefficient of resistance at -30 to +85°C was -300 ppm.The resistance value after a heat resistance test at 7°C and 85°C for 1000 hours. Change is -・1.8%, 40"C
The resistance value change after the 1,000 hour humidity test at 190 to 95% rL, I-1, was +3.2%, both of which were larger than in Example 1.

(F) Effects of the Invention As can be seen from the above examples, the carbon-based resistance paste of the present invention can be manufactured by using a three-component initial condensation polymer consisting of an epoxy resin, a melamine resin, and a cresol resin as a binder. This is a film that has significantly improved the lack of printing suitability such as flowability, stiffness, and leveling when printing the heat-resistant resistance paste of , and by printing on an insulating substrate, it is a film that does not cause bleeding or fading. Precise resistance patterns with small thickness unevenness can be formed. Therefore, the resistance value of the printed resistance circuit board obtained using the carbon-based resistance paste according to the present invention is very stable, and the change in resistance value after solder reflow during the hybrid IC manufacturing process is extremely small, and it is heat resistant. High-precision products with excellent electrical properties such as heat resistance and moisture resistance can be easily produced. In addition, the present invention has great industrial effects, such as the ability to manufacture carbon-based resistance networks with excellent electrical characteristics at low cost.

Claims (2)

[Claims] (1) Bisphenol A type epoxy resin with an average molecular weight of 900 to 2900 and butyl etherification, whose main components are conductive particles such as carbon black and graphite, and organic or inorganic fillers such as polytetrafluoroethylene and boron nitride. A carbon-based resistance paste characterized in that a three-component initial condensation polymer consisting of a melamine resin and a metacresol resin or a mixed cresol resin of metacresol and para-cresol is used as a binder. (2) The weight mixing ratio of the three-component binder is epoxy resin 50
75%, melamine resin 15-30%, and cresol resin 10-20%.