JPS624392A - Thick film hybrid integrated circuit - 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] [Technical field of invention] The present invention relates to membrane hybrid integrated circuits.

[Technical Background of the Invention] In recent years, hybrid integrated circuits have been increasingly used to promote the miniaturization and weight reduction of electronic devices. Among them, especially as a high frequency circuit, a pressure membrane hybrid integrated circuit having the structure shown below is generally used.

In other words, a conductor paste made of copper or the like is printed on an insulating substrate made of ceramics such as aluminum, and then fired in an inert gas to form a copper pattern. After printing and baking Pace 1 to form a thick film circuit, an ultraviolet (UV) curable protective coat made of expository resin or acrylic resin is printed and cured to form electronic components such as ICs and capacitors. A thick film hybrid integrated circuit is used in which the entire thick film circuit board is coated with a resin using a dip method, fluidized dipping method, etc. using a phenolic or Ukiposi resin for moisture-proofing. It is being

However, in conventional pressure film hybrid integrated circuits, in order to prevent surface oxidation of the patterns such as copper that make up the pressure film circuit, the protective coat cannot be baked or cured at high temperatures using the mold material, which is conventionally common. In recent years, a protective coat has been formed using an epoxy resin-based or acrylic resin-based ultraviolet (UV) curing ink that has been used as a solder resist for printed circuit boards.

[Problems with the background art] However, in such a pressure membrane hybrid integrated circuit,
There was a drawback that the moisture resistance of the protective coating layer was not sufficient. For example, when a pressurized and heated test, which is commonly performed to evaluate the moisture resistance of electronic components in a short period of time, occurs, the protective coating layer swells due to moisture absorption and becomes electrically defective in a short period of time. There was a problem. Incidentally, this is thought to be due not only to the insufficient moisture resistance of the protective coating layer, but also to the fact that the coating film of the protective coating material does not stretch sufficiently after UV curing, and the difference in expansion coefficient This is thought to be due to the fact that the protective coating layer easily peels off from the insulating substrate, and this peeling is roughly accelerated by moisture absorption. Furthermore, the above-mentioned conventional device also had the problem that cracks were likely to occur in the resin coating layer due to the difference in expansion coefficients between the alumina substrate and the resin coating material when a temperature cycle test was performed.

[Object of the Invention] The present invention has been made to solve these problems, and an object of the present invention is to provide a highly reliable pressure-film hybrid integrated circuit by preventing electrical failures caused by blistering of the protective coating layer due to moisture absorption. purpose.

[Summary of the Invention] The piezoelectric membrane hybrid integrated circuit of the present invention includes a piezoelectric membrane circuit board formed by forming a piezoelectric membrane circuit on an insulating substrate, a protective coating layer formed thereon, and electronic circuit components mounted at predetermined positions. However, in a pressure membrane hybrid integrated circuit formed by moisture-proofing an insulating substrate containing electronic components with a synthetic resin, moisture resistance and mechanical properties are improved by forming the protective coating layer with a silicone resin. be.

[Embodiments of the Invention] Hereinafter, embodiments of the membrane hybrid integrated circuit of the present invention shown in the drawings will be described. The drawing is a sectional view showing an embodiment of the present invention.

In the figure, the symbol @1 indicates an insulating substrate made of ceramic such as alumina. On this insulating substrate 1, a copper conductor, a glass insulator, and a ruthenium oxide resistor are laminated by a conventional method to form a piezoelectric film circuit 2. It is formed. In addition, this pressure membrane circuit 2
A protective coating layer 3 made of silicone resin is provided on almost the entire surface except for a portion where an electronic circuit component 6 described below is die-bonded. However, the protective coating layer 3 of the lever is printed on the pressure film circuit 2 using a thermosetting or ultraviolet (UV) curable silicone resin ink, and then the coating layer is oxidized so that the underlying conductive layer is oxidized. For example, it is formed by heating at 130° C. for 20 minutes or less, or by irradiating ultraviolet rays to cure it.

In addition, electronic circuit components 4 such as capacitors and ICs are soldered to predetermined positions on the piezoelectric film circuit 2 where the protective coating layer 3 is not formed, and these components also include the back surface of the insulating substrate 1. A sealing layer 5 made entirely of phenolic or epoxy synthetic resin is integrally provided on the outside.

This sealing layer 5 is provided by a dipping method, a fluidized dipping method, or the like.

In the membrane hybrid integrated circuit according to the embodiment constructed as described above, the protective coating layer 3 provided on the membrane circuit 2 exhibits good moisture resistance. In other words, since the silicone resin constituting the protective coating layer 3 has good water repellency, even if there is a defect such as a pinhole in the protective coating layer 3 and moisture infiltrates from there, the pressure membrane circuit 2 No continuous water film is formed on the surface.

In addition, in the embodiment, since the protective coating layer 3 made of silicone resin has rubber-like elasticity, even if there is a difference in expansion coefficient between the protective coating layer 3 and the insulating substrate 1, the protective coating layer 3 absorbs the stress caused by this difference. Absorbs and does not cause peeling. Since it also absorbs the stress caused by the difference in resin composition between the resin coat I~ material and the alumina substrate (insulating substrate), it has the effect of eliminating cracks that tend to occur in the resin coat during temperature cycle tests.

[Effects of the Invention] As is clear from the above description, the membrane hybrid integrated circuit of the present invention has excellent moisture resistance, good electrical properties, and high reliability.

[Brief explanation of drawings]

The drawing is a sectional view showing an embodiment of the membrane hybrid integrated circuit of the present invention. 1... Insulating substrate 2... Thread film circuit 3... Protective coating layer made of silicone resin 4... ...Electronic circuit components 5...Sealing layer attorney Sa Suyama - Procedural amendment (spontaneous) August 78, 1985 1. Indication of case Patent application 1987 -143661 No. 2, Name of the invention Thick film hybrid integrated circuit 3, Relationship with the amended person case Patent applicant 721 Horiyo-cho, Saiwai-ku, Yozaki City, Kanagawa Prefecture (307) Toshiba Corporation 4, Agent Address: 2-1, Kanda Tamachi, Chiyoda-ku, Tokyo 101 Title of the invention and the full text of the specification Correction statement 1 Title of the invention Thick film hybrid integrated circuit 2 Claims (1) A hybrid integrated circuit is formed by forming a protective coating layer on a circuit board on which a circuit is formed, mounting electronic circuit components at predetermined positions, and treating the insulating substrate containing these electronic components with moisture-proofing with synthetic resin. A hybrid integrated circuit characterized in that the protective coating layer is made of a silicone resin. 3. Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to thick film hybrid integrated circuits. [Technical Background of the Invention] In recent years, hybrid integrated circuits have been increasingly used to promote downsizing and weight reduction of electronic devices. Among these, especially as a high frequency circuit, a thick film hybrid integrated circuit having the structure shown below is generally used. That is, a conductive paste made of copper or the like is printed on an insulating substrate made of ceramics such as aluminum, and then fired in an inert gas to form a copper pattern.If necessary, glass-based insulating paste, resistance paste, etc. After printing and baking to form a thick film circuit, an ultraviolet (tJV) curable protective coat made of an expository resin or an acrylic resin is printed and cured.1. This is a structure in which electronic components such as ICs and capacitors are mounted and soldered, and the entire thick film circuit board is coated with a resin using a phenol or Ukiposi resin for moisture-proofing treatment using a dip method, fluidized dipping method, etc. Thick film hybrid integrated circuits are used. However, in conventional thick film hybrid integrated circuits, in order to prevent surface oxidation of patterns such as copper that make up the thick film circuit, the protective coat cannot be baked or cured at high temperatures using the mold material, which is conventionally common. In recent years, a protective coat has been formed using an epoxy resin-based or acrylic resin-based ultraviolet (UV) curing ink that has been used as a solder resist for printed circuit boards. [Problems with the background art] However, in such thick film hybrid integrated circuits,
There was a drawback that the moisture resistance of the protective coating layer was not sufficient. In other words, for example, when a pressurization and heating test, which is commonly performed to evaluate the moisture resistance performance of electronic components in a short period of time, is performed, the protective coating layer swells due to moisture absorption and becomes electrically defective in a short period of time. There was a problem. Incidentally, this is thought to be due not only to the insufficient moisture resistance of the protective coating layer, but also to the fact that the coating film of the protective coating material does not stretch sufficiently after UV curing. This is considered to be because the coating layer easily peels off from the insulating substrate, and this peeling is further accelerated by moisture absorption. In addition, when the above conventional type was subjected to a temperature cycle test,
There was also the problem that cranks were likely to occur in the resin coating layer due to the difference in expansion coefficients between the alumina substrate and the resin coating material. [Object of the Invention] The present invention has been made to solve these problems, and an object of the present invention is to provide a highly reliable thick film hybrid integrated circuit by preventing electrical failures caused by blistering of the protective coating layer due to moisture absorption. purpose. [Summary of the Invention] The thick film hybrid integrated circuit of the present invention includes forming a protective coating layer on a thick film circuit board formed by forming a thick film circuit on an insulating substrate, and mounting electronic circuit components at predetermined positions. However, in thick film hybrid integrated circuits formed by moisture-proofing an insulating substrate containing electronic components with a synthetic resin, moisture resistance and mechanical properties are improved by forming the protective coating layer with a silicone resin. be. [Embodiments of the Invention] Hereinafter, embodiments of the thick film hybrid integrated circuit of the present invention shown in the drawings will be described. The drawing is a sectional view showing an embodiment of the present invention. In the figure, reference numeral 1 indicates an insulating substrate made of ceramic such as alumina, and a thick film circuit 2 is formed by laminating a copper conductor, a glass insulator, and a ruthenium oxide resistor on this insulating substrate 1 by a conventional method. has been done. Also, this thick film circuit 2
A protective coating layer 3 made of silicone resin is provided on almost the entire surface except for a portion where an electronic circuit component 6 described below is die-bonded. However, the protective coating layer 3 of the lever is printed on the thick film circuit 2 using a thermosetting or ultraviolet (LJV) curable silicone resin ink, and then the underlying conductive layer is oxidized. For example, it is formed by heating at 130° C. for 20 minutes or less, or by irradiating ultraviolet rays to cure it. Furthermore, electronic circuit components 4 such as capacitors and ICs are soldered to predetermined positions on the thick film circuit 2 where the protective coating layer 3 is not formed, and these components also include the back surface of the insulating substrate 1. A sealing layer 5 made entirely of phenolic or epoxy synthetic resin is integrally provided on the outside. This sealing layer 5 is provided by a dipping method, a fluidized dipping method, or the like. In the thick film hybrid integrated circuit of the embodiment constructed as described above, the protective coating layer 3 provided on the thick film circuit 2 exhibits good moisture resistance. In other words, since the silicone resin constituting the protective coating layer 3 has good water repellent properties, even if there is a defect such as a pinhole in the protective coating layer 3 and moisture infiltrates from there, it will not reach the surface of the thick film circuit 2. No continuous water film is formed. In addition, in the embodiment, since the protective coating layer 3 made of silicone resin has rubber-like elasticity, even if there is a difference in expansion coefficient between the protective coating layer 3 and the insulating substrate 1, the protective coating layer 3 absorbs the stress caused by this difference. Absorbs and does not cause peeling. It also absorbs the stress caused by the difference in resin composition between the resin coating material and the alumina substrate (insulating substrate), which has the effect of eliminating cracks in the resin coating that tend to occur during temperature cycle tests. [Effects of the Invention] As is clear from the above description, the thick film hybrid integrated circuit of the present invention has excellent moisture resistance, good electrical properties, and high reliability. 4. Brief Description of the Drawings The drawings are cross-sectional views showing one embodiment of the thick film hybrid integrated circuit of the present invention. 1...Insulating substrate 2...Thick film circuit 3...Protective coating layer 4 made of silicone resin ...Electronic circuit component 5...Sealing layer

Claims (1)

[Claims] (1) A protective coating layer is formed on a piezoelectric film circuit board formed by forming a piezoelectric film circuit on an insulating substrate, electronic circuit components are mounted in predetermined positions, and the insulating substrate containing these electronic components is made of synthetic resin. 1. A pressure membrane hybrid integrated circuit subjected to moisture-proofing treatment, wherein the protective coating layer is made of a silicone resin.