JPS6313322B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to hybrid integrated circuits, resistor networks,
The present invention relates to a method for forming thick film resistors in the field of high-density packaging technology such as chip components. Conventional configurations and their problems In recent years, electronic devices such as VTRs have rapidly become smaller. Correspondingly, from the viewpoint of high-density packaging, electronic components (such as resistor networks and R-C networks) and hybrid integrated circuits using ceramic substrates containing alumina as a main component have been put into practical use. Until now, these devices have been used only in fields where high reliability is required, such as in measuring instruments, due to manufacturing costs. In order to apply it to consumer electronic devices, it is required to reduce manufacturing costs by taking advantage of high reliability, small size, and high density. This general manufacturing method uses gold, silver, silver-palladium, or gold, silver, silver-palladium, or
Copper or the like is mixed with an organic binder and an organic solvent to form a paste, and a pre-designed electrode pattern is printed using a screen printer. After drying, the printed pattern is fired in an electric furnace.
Baked onto a ceramic substrate. By repeating the screen printing, drying, and firing processes described above, an electric circuit is constructed by sequentially forming thick films of different materials such as resistors and dielectrics, and layering designed circuits. In this thick film technology, there are many technical problems when mass-producing the printing process. That is, printing work involves a lot of know-how that is difficult to quantify, requires skill, and has too many control items for mass production, which is particularly problematic when forming resistors. The resistive paste used for screen printing contains an inorganic component as a resistive material, an organic binder as an adhesive component, and an organic solvent as a solvent, and this solvent plays the most important role in printability and reproducibility of printing thickness. do. This solvent evaporates over time during printing, making it difficult to maintain initial performance. It is important to obtain desired characteristic values and reduce variations when forming a resistor. For this reason, preliminary experiments involving many steps to check the resistance value must be performed, which takes too much time. There were flaws. Also, when forming a resistor, 10Ω,
There are standard resistance pastes such as 100Ω, 1KΩ...1MΩ, but on the other hand, the resistance values of designs vary, so you will need to repeat screen printing and drying using several types of resistance paste from the above resistance pastes. . Even if there is only one resistor, if the resistance range is different, the same process will be repeated.
It was necessary to carefully manage plate-making patterns (screen mesh extension and emulsion wear), printing alignment accuracy, printing pressure during printing, printing speed, printing gap, etc. moreover,
If there is a pattern change due to a design change, it is necessary to perform plate making for all screens, and due to these problems, a mass production method that can be manufactured at low cost has been desired. Purpose of the Invention The present invention solves the above-mentioned conventional drawbacks, and provides a method for forming a thick film resistor that realizes the possibility of automation, improves the reproducibility of resistance values, and can quickly adapt to any circuit pattern. The purpose is to provide Structure of the Invention In order to achieve the above object, the method for forming a thick film resistor of the present invention includes providing a thermoplastic resin film as a first layer on a base film having mold releasability, and forming a second layer on the first layer. A green sheet consisting of the first layer and the second layer is created on the base film by applying a thick film resistance material to a constant thickness using an organic binder, and the green sheet is coated with a predetermined thickness without cutting the base film. A slit is made in the shape of , a piece of the green sheet with the slit is taken out from the base film, heat is applied to the substrate surface, the first layer side is aligned with the electrode terminal, and the first layer side is adhered to the substrate surface. The structure is such that this substrate is fired. This eliminates the need for skill in resistor printing operations as in the past, and also eliminates the need to manage plate-making patterns, making it possible to improve the reproducibility of resistance values and improve mass productivity. DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 show resistance films, 1 is a base film, 2 is a thermoplastic resin film, and 3 is a resistance layer. This resistive film is formed as follows. First, a thermoplastic resin film 2 is formed by applying a thermoplastic resin as a first layer to a constant thickness on a base film 1 having mold releasability using a doctor blade method, a reverse roll method, or a dip method. do. After that, a resistor material (silver-palladium type, ruthenium oxide type,
After stirring a mixture of tungsten carbide (based on tungsten carbide, indium oxide, thallium oxide) and glass frit in a mixer using an organic binder and an organic solvent, the thermoplastic resin film is formed using a doctor blade method or a reverse roll method. A resistive layer 3 is formed on the resistive layer 2 to a predetermined thickness. After drying, the sheet 4 formed on the two layers 2 and 3 (hereinafter referred to as green sheet) is slit 5 in the vertical and horizontal directions without cutting the base film 1 into an arbitrary shape as shown in FIG. Put in. In this way, a resistive film having a large number of resistive sheets 6 in the required resistance range can be formed. The slit 5 may be inserted immediately before use or immediately after drying. In addition, since the two-layered sheet is changed from slurry to green sheet 4, it has high uniformity within the lot, and when stored, it is rolled up together with base film 1 and stored away from dust. be able to. Such a green sheet 4 is created and saved in advance for the required resistance range. Next, the resistor sheet 6 is placed on the ceramic substrate.
We will explain how to install it. The ceramic substrate on which the conductive pattern is formed is heated to a temperature at which the thermoplastic resin film 2, which is the first layer, softens, and a piece of resistor green sheet 4 with slits 5 of predetermined dimensions is placed over the base film 1. The sheets 6 are pulled apart by the vacuum suction of the mounting device. The resistance sheet 6 sucked into the mounting device is lowered to a predetermined position on the ceramic substrate by the mounting device, aligned with the resistance terminals, and mounted. As a result, the thermoplastic resin film 2 of the resistance sheet 6 is softened by the heat from the substrate, becomes adhesive, and is adhered onto the substrate. At this time, the vacuum suction of the mounting device is released and the mounting of the resistance sheet 6 is completed. In this way, they are sequentially mounted, and finally the board is baked under predetermined baking conditions. As described above, the resistance sheet 6 having the desired resistance range is continuously formed, and this automation can be performed using the same configuration as the chip mount machine. That is, an X-Y table equipped with a heating device, a conveyance device for the ceramic substrate, a mount head equipped with a vacuum suction device, and a resistive film with a taped resistive green sheet 4 are used for NC control or computer control. By combining controls, automation becomes possible just by preparing a program. This is advantageous for hybrid integrated circuits where models are frequently changed, and there is no need to manage and store many plate-making patterns. In addition, printing that previously required skill can be easily reproduced by anyone by following the steps in this method. Next, another embodiment that further embodies the above embodiment will be described. Note that FIG. 1 to FIG. 3 are used as the drawings in the same manner as in the embodiment described above. A release-treated polyester film with a thickness of 135 μm is used as the base film 1, and a heated and melted polyamide resin (softening point: 120°C ± 5°C) is applied as the first layer onto this polyester film 1 using the pipe doctor method. It is applied to form a resin film 2 with a thickness of 20 μm, and then cooled and hardened. Next, the sheet resistance
The resistance material (including glass as a frit) in the table showing the characteristics of 1KΩ□ and polyvinyl butyral (PVB) as an organic binder in the weight percentage shown in the table,
Also dibuchel phthalate (DBP) as a plasticizer
was added at 2.5% by weight, alcohol was added as an organic solvent, and mixed in a ball mill for 20 hours.
After degassing, a second layer is formed on the polyamide resin film 2 by a doctor blade method, and the resistance layer 3 has a dry film thickness of 40 μm±3 μm.
form. In this way, a green sheet 4 of a predetermined thickness is created on the polyester film 1. Using a cutter, cut a slit 5 into the green sheet 4, which has been confirmed to have the specified thickness, to a size of 2.5 mm x 1.5 mm, taking care not to cut the polyester film 1.
Put in. On the other hand, an alumina substrate on which an electrode pattern (2 mm x 1 mm) of a resistive terminal (2 mm x 1 mm) was printed and fired using a silver-palladium conductor was heated to 120 to 150 degrees Celsius, and a green sheet 4 with slits 5 formed thereon was heated to 120 to 150 degrees Celsius.
A single resistor sheet 6 of 2.5 mm x 1.5 mm is sucked up from above the polyester film 1 using vacuum tweezers and attached to a predetermined terminal electrode position of the substrate with the first layer resin film 2 facing down. Thereafter, when the resin film 2, that is, the polyamide resin has softened, the vacuum of the vacuum tweezers is returned to normal pressure to complete the attachment. The maximum temperature of the alumina substrate transferred in this way is
The resistance value when baked at 850℃ for 10 minutes will be the value shown in the table. As is clear from the results of this example, it is possible to provide an effective method for forming a thick film.

[Table] Effects of the Invention As described above, according to the present invention, the resistance is formed in advance in the form of a green sheet whose thickness can be controlled to a predetermined thickness, and if necessary, slits are made into any desired shape. By cutting it out and mounting it on a ceramic substrate, it becomes possible to form a thick film resistor. In addition, this makes it possible to solve problems that conventionally required skill and were problematic in resistive printing, such as changes in paste over time, management of plate-making patterns, and time loss associated with changing models. Easy to automate. Furthermore, it is possible to quickly respond to any circuit pattern.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the configuration of an embodiment of the present invention, FIG. 2 is a sectional view taken along the line X-X in FIG. 1, and FIG. FIG. 1... Base film (polyester film), 2... Thermoplastic resin film, 3... Resistance layer, 4
...Green sheet, 5...Slit, 6...Resistance sheet.

Claims (1)

[Claims] 1. A thermoplastic resin film is provided as a first layer on a base film having mold releasability, and a second layer is provided on this first layer.
A thick film resistive material is applied as a layer to a constant thickness using an organic binder to form the first layer on the base film.
A green sheet consisting of a layer and a second layer is created, a slit is made in the green sheet in a predetermined shape without cutting the base film, a piece of the green sheet with the slit is taken out from the base film, and the substrate surface is A method of forming a thick film resistor, in which the first layer side is bonded to the substrate surface by applying heat to the electrode terminal, and then the substrate is fired. 2. The method for forming a thick film resistor according to claim 1, wherein the thick film resistor material is silver-palladium based, ruthenium oxide based, tungsten carbide based, indium oxide, or thallium oxide.