JPH11162718A - Manufacture o resistor substrate for electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a resistor substrate for an electronic part which, with less sliding noise, leads to smaller size, thin type, mass production, and lower cost. SOLUTION: (a) A resistor 14 is printed/baked in a specified form on one main surface of a smooth conductive metal thin plate 13 to produce a resistance sheet 16, (b) a prepreg 17 is placed on the upper surface of the resistance sheet 16 on the side of the resistor 14 and a thin-plate like substrate 18 is placed over it, which is pressed, from both above and below, with hot plates 15 of a pressing machine for thermal press-bonding for cure, (c) related to a sheet wherein a cured resin layer 17' with the prepreg 17 thermally press-bonded for curing includes the resistor 14 in tight-contact manner, (d) a photo-resist is coated on the conductive metal thin-plate 13 side and a terminal part 21 and a conductive part 22 are UV-cured with a positive mask for removing a non-cured photoresist, and a remaining photo-resist is used as a mask to selectively etching a conductive metal, so that the conductive metal is removed except for the terminal part 21 and the conductive part 22 of specified form, resulting in the surface of the resistor 14 being mirror-surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a resistor substrate of an electronic component in which a resistor is formed on a substrate, and more particularly to a method of manufacturing a resistor substrate of an electronic component such as a variable resistor or a rotary encoder. .

[0002]

2. Description of the Related Art A conventional resistor substrate of an electronic component having a resistor as a typical component, such as a variable resistor or a rotary encoder, will be described with reference to a slide-type variable resistor 10 shown in FIG. The resistor substrate 11 includes a resistor 4, conductive portions 3, 3 ′, and a low-resistance body 5 formed on the upper surface of the insulating resin substrate 2 and a conductive portion 3 ′ that is conductive with both ends of the conductive portion 3 and the resistor. The terminals 7a, 7b and 7c are conductively connected by caulking to the ends of the.

The conventional method of manufacturing the resistor substrate 11 is as follows.
On the upper surface of an insulating resin substrate made of a plastic resin such as phenol resin, the patterns of the conductive portions 3 and 3 'are printed in a predetermined pattern by silver screen printing and the resistor 4 is printed by a silk screen printing or the like. Baking, and then fixing the frame lead to the end of the substrate 2 by caulking (the portion denoted by reference numeral 8), cutting the surplus portion of the frame lead, and attaching the terminals 7a, 7b, 7c. It is a target.

Reference numeral 1 denotes a slider, reference numeral 6 denotes a slider, and reference numeral 9 denotes a resin case. The resistor substrate 11 is disposed inside the resin case 9, and the slider 1 is positioned just above the resistor substrate 11 in the longitudinal direction. , The slider 6 attached to the bottom surface of the slider 1 slides while contacting and conducting with both the resistor 4 and the conductive portion 3, and the resistance value between the terminals 7c and 7b or the terminals 7c and 7a. Becomes variable.

There are various types of structures of the slide type variable resistor, but the structure of the resistor substrate 11 is basically the same. The structure of the rotary variable resistor or the rotary encoder is the same as that of the slide variable resistor 10 except for the shape of the resistor substrate.

[0006]

In the resistor substrate 11 having the above-described structure, the surface of the resistor is slid as much as possible because the surface of the resistor slides while the slider 6 is in contact with the surface of the resistor. It is important to smooth the contact with the moving element 6 to reduce the sliding noise.

Further, there is a strong demand for miniaturization and thinning of all electronic components including fixed resistors, as well as variable resistors, and the widths W1 and W2 of the resistor 4 and the conductor 3 themselves and the distance d between them. Although it is desirable to make it narrower, it is necessary to maintain dimensional accuracy in order to obtain desired characteristics.

However, in the conventional method for manufacturing a resistor substrate, the interval d is approximately 0.5 mm, which is a processing limit, and it has been difficult to reduce the size. In addition, to reduce the sliding noise, the surface of the resistor 4 printed and baked on the insulating resin substrate 2 is a rough surface with some unevenness, and drastic improvement is required.

On the other hand, cost reduction of variable resistors and the like has been remarkably reduced, and a manufacturing method suitable for mass production has been sought. However, the problem of the dimensional accuracy and the work of crimping terminals have been a bottleneck in productivity. Was.

The present invention has been made in view of the above circumstances. First, the surface of the resistor is made a mirror surface without unevenness to dramatically reduce sliding noise, and second, the processing accuracy of the resistor is improved. The new resistance of electronic components that realizes miniaturization and cost reduction by adopting completely new terminals that improve the characteristics and improve the characteristics and downsize, and thirdly eliminate the need for terminal mounting work such as terminal crimping A method for manufacturing a body substrate is provided.

[0011]

The present invention provides: (1) a first step of printing and baking a resistor in a predetermined shape on one main surface of a smooth conductive metal sheet to form a resistor sheet; A second step in which a prepreg impregnated with uncured resin is placed on the upper surface of the resistor sheet on the resistor side, a thin plate-shaped substrate is placed on top of the prepreg, and a thermocompression curing is performed; The above object is achieved by providing a method for manufacturing a resistor substrate of an electronic component, comprising: a third step of removing a terminal portion and a conductive portion having a predetermined shape by etching. .

(2) In the method of manufacturing a resistor substrate for an electronic component according to the above (1), the prepreg in the middle of the step of thermocompression bonding of the resistance sheet, the prepreg and the substrate in the second step is semi-cured. In the state, a step of selectively etching the conductive metal thin plate in the third step to remove the terminal portion and the conductive portion is performed, and this is further heated and press-hardened to form a resistor and a terminal portion of the conductive metal. The above object is achieved by providing a method of manufacturing a resistor substrate for electronic components, which comprises a step of flattening the surface of the resistor substrate by eliminating the step.

(3) In the method of manufacturing a resistor substrate for an electronic component according to the above (1) or (2), a resin varnish is applied directly to the upper surface of the resistor sheet on the resistor side instead of the prepreg, and the uncured resin varnish is applied. The above object is achieved by providing a method for manufacturing a resistor substrate of an electronic component, which comprises a second step of placing a thin plate-like substrate on the resin varnish in a state, superimposing the substrate, and curing by thermocompression bonding. Solve.

(4) A first step of printing and baking a resistor in a predetermined shape on one main surface of a smooth conductive metal sheet to form a resistor sheet; A second step of inserting the resin into the mold and injecting the compatible resin only into the resistor side to integrally mold, and a second step of selectively etching while leaving the terminal portion and the conductive portion from the conductive metal thin plate side of the integrally molded resistor substrate. The above object is achieved by providing a method of manufacturing a resistor substrate for an electronic component, comprising the steps of:

(5) Further, when the conductive metal sheet is selectively etched in the third step, the resist forming portion, the terminal portion, and the photo resist on the conductive portion of the conductive metal sheet in the photoresist applied as masking are used. The conductive metal thin plate is etched away to remove the conductive metal in other portions while leaving the resist, and then the surplus portion of the resistor that protrudes beyond a predetermined design dimension of the resistor during printing is formed on the conductive metal remaining on the resistor. The photoresist is used as a mask to remove by sandblasting, then the photoresist on the conductive metal on the resistor is removed, and then only the conductive metal on the resistor is selectively etched again to remove the conductive metal on the resistor. By providing the method of manufacturing a resistor substrate for an electronic component according to the above (1) or (2) or (3) or (4), the method further comprises a removing step. To solve the problems.

Here, the above-mentioned prepreg means that a resin substrate varnish adjusted by a dip roll is impregnated into a base material for a laminated board such as glass cloth or paper, the varnish adhesion amount is adjusted by a squeeze roll, and This refers to an uncured sheet that has been dried and B-staged.

Further, the resistor sheet according to the present invention means a resistor (including a low resistor) printed and baked in a predetermined shape on one main surface of a conductive metal thin plate. It means a final substrate on which a resistor in an assembly stage is formed as an electronic component.

The term "sandblasting" refers to an apparatus or method for scraping an object by spraying hard fine particles (sand) such as carborundum at a high speed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a resistor substrate of an electronic component comprising a resistor according to the present invention will be described with reference to the drawings.

[0021] Note that a variable resistor or a rotary encoder is a typical electronic component having a resistor as a constituent element.
The method for manufacturing a resistor substrate according to the present invention can be applied to various electronic components having a resistor as a component with the same structure as described above except that the shape of the substrate and the pattern of the resistor are different. A description will be given based on an example of a slide type variable resistor as a typical example.

FIG. 1 is a flow chart for explaining a manufacturing process of a resistor substrate of a slide type variable resistor according to claim 1 of the present invention, and FIG. 2 is a slide type variable resistor according to claim 2 of the present invention. It is a process flow figure showing a manufacturing process of a resistor substrate of a resistor. FIG. 3 is a cross-sectional view illustrating a method of manufacturing a resistor substrate of a slide-type variable resistor according to claim 4 of the present invention, and FIG. 4 illustrates a method of manufacturing a resistor substrate according to claim 5 of the present invention. FIG. 4 is a process flow chart for performing the following.

In FIG. 1, as a basic step of the method for manufacturing a resistor substrate of the present invention, a resistor 14 (low resistor 15) is provided on one main surface of a smooth conductive metal sheet 13 as shown in FIG. Is printed and printed in a predetermined shape (for example, a strip shape in the case of a slide type variable resistor) to form the resistance sheet 16, and as shown in (b),
A prepreg 17 impregnated with an uncured resin is placed on the upper surface of the resistor sheet 16 on the resistor 14 side, a thin plate-like substrate 18 is placed thereon and superimposed, and a hot plate 19 of a press is pressed from above and below. A second step of thermocompression curing, and a sheet in which a cured resin layer 17 ′ formed by thermocompression curing of the prepreg 17 tightly encloses the resistor 14 (including the low resistance body 15) as shown in FIG. As shown in (d), a photoresist is applied to the conductive metal sheet 13 side, and the terminal portion 21 and the conductive portion 22 are UV-coated with a positive mask.
Curing, removing the uncured photoresist, and selectively etching the conductive metal using the remaining photoresist as a mask, thereby removing the conductive metal while leaving the terminal portion 21 and the conductive portion 22 in a predetermined shape. And a step (corresponding to claim 1).

After all, conventionally, an insulating resin substrate was provided on the base, and a resistor and a conductive metal were formed thereon in a predetermined pattern. On the contrary, in the present invention, a resistor was formed on a conductive metal thin plate. The substrate is fixed thereon, and the vertical relationship in FIG. 1 is reversed.

The resistor substrate 30 manufactured through the above steps
As shown in (e), which is a cross-sectional view taken along the line AA in (d), a cured resin layer 17 ′ which is a prepreg 17 is formed on a substrate 18, and the resistor 14 is connected to the cured resin layer 17. 'And the surface is exposed. The conductive portions 22 and the terminal portions 21 are formed on the cured resin layer 17 '.

Here, the exposed surface of the resistor 14 was originally an adhesive surface of the resistor 14 with the conductive metal sheet 13 applied and printed on the surface of the smooth conductive metal sheet 13. The surface of the resistor has a very smooth mirror surface with no irregularities.

Thus, it is clear that the sliding noise generated when the slider is slid is remarkably eliminated and good resistance characteristics can be obtained.

As can be seen from the sectional view of FIG. 1E, the substrate 18, the resistor 14, the conductive portion 22, and the terminal portion 21 are formed.
Are insulated because there is a cured resin layer 17 'between them.
Therefore, the substrate 18 need not be limited to an insulating resin substrate, but may be a ceramic substrate or a metal conductor substrate. In the case of a metal conductor substrate, the heat dissipation as a resistor substrate becomes good, and if a resin flexible sheet is used, it becomes a wiring sheet as it is.

In order to make the surface of the resistor 14 a mirror surface while adopting the conventional manufacturing method, a method of performing transfer printing will be adopted. However, depending on the resin of the resistor ink, the resistance of the mirror surface may be reduced. May not be able to peel off from the body. In this regard, the manufacturing method of the present invention has an advantage that a resistor substrate having good wear resistance can be obtained because a resin for the resistor ink is not selected and a release agent is not used.

(B) Since the terminals are integrally formed, there is no contact failure due to loosening. (B) No frame lead is used for the terminals, and no crimping is performed, so that an ultra-thin body can be achieved.
The terminal part can be made into any shape by etching, and the terminal part itself can be used for wiring. (D) Since the shape of the conductive part can be freely designed, it can be applied to various electronic parts such as switches and rotary encoders. E) A large number of resistors are formed in a row on a wide conductive metal sheet in a matrix, and each step (almost all steps) such as etching is performed at a time, so that mass production is possible, and productivity is high and cost is low. Needless to say, it has effects such as:

Next, as a second manufacturing method according to the present invention, as shown in the manufacturing process flow chart of FIG. 2, a step (b) of thermocompression bonding of the above-described resistance sheet 16, prepreg 17, and substrate 18 is performed. ), When the prepreg 17 is in a semi-cured state (a state in which the prepreg 17 is bonded to the resistance sheet 16 and the substrate 18 but is not yet sufficiently cured).
As shown in (c), after performing the step of selectively etching the conductive metal thin plate 13 to remove the other conductive metal while leaving the terminal portion 21 and the conductive portion 22, this is further heated and compressed and cured. As shown in (e), a step of flattening the surface of the resistor substrate 30 by eliminating a step between the resistor 14 and the terminal portion 21 and the conductive portion 22 of the conductive metal is performed.

In the end, not only the resistor 14 but also the conductive portion 22 and the terminal portion 21 have the same height as the cured resin layer 17 ′ so that the prepreg 17 is in a semi-cured state in a later thermocompression bonding step. Embed in.

In this manufacturing method, as can be seen from the cross section (e) of FIG.
Since it is not embedded in 7 ', a step is avoided at the boundary between the resistor 14 and the terminal portion 21, and the resistor substrate 30 is completely flush. Thus, the use of the resistor substrate makes it possible to reduce the thickness of the substrate, and to eliminate problems such as the slider being caught.

Next, as a third manufacturing method according to the present invention, in place of the prepreg 17 in the above-mentioned second step, a resin varnish is directly applied to the upper surface of the resistance sheet on the resistor side, and the uncured state is obtained. The same can be achieved by placing a thin plate-shaped substrate on a resin varnish, superimposing it, and performing thermocompression curing. This manufacturing method is suitable for thinning by a technique of applying a resin varnish to a uniform thickness (such as a technique of rotating a silicon substrate at a high speed in a LSI manufacturing and dripping a photoresist liquid uniformly) without using a prepreg 17. Therefore, it contributes to cost reduction.

Next, as a fourth manufacturing method according to the present invention, a resistor 1 is placed on one main surface of a smooth conductive metal sheet 13.
4 is printed and baked in a predetermined shape to form a resistance sheet 16; and FIG.
As shown in FIG. 3B, a second step of inserting into the injection molds 25 and 26 and injecting the compatible resin only from the injection port 27 only to the resistor 14 side through the injection port 27 and integrally forming the mold is shown in FIG. And selectively etching the terminal body 21 and the conductive portion 22 from the conductive metal thin plate side of the integrally formed resistor substrate 40 so as to be etched.

Since the molding resin portion 28 is formed in an arbitrary shape by a metal mold, insert resin molding is performed on the resistor 14 so as to leave a space for the slider to slide, and the molding resin portion 28 itself as a substrate is formed. Can be a case of a slide type variable resistor.

Thus, if it is spread, it is possible to omit a considerable number of steps of an assembly process of a manufacturing process of an electronic component including a resistor as a constituent element, thereby realizing mass production and cost reduction.

Next, as a fifth manufacturing method according to the present invention, in the step of selectively etching the conductive metal sheet 13 in the above-described first to fourth manufacturing methods, the photoresist applied as masking is used. As shown in FIG. 4 (b), using a mask 41 as shown in FIG. 4 (a), as shown in FIG. 4 (b), a resistor forming portion, a terminal portion and a photoresist on the conductive portion (reference numerals 44 and 45, respectively). , 46) are cured by UV and the conductive metal sheet is etched to remove the conductive metal in other portions, and then, when the resistor sheet 16 is printed, the resistance that exceeds the predetermined design dimension of the resistor is printed. The surplus part 42 of the body is removed by sandblasting using the photoresist 44 on the conductive metal remaining on the resistor as a mask (as shown in (c), the area F surrounded by a dashed line is blown). The photoresist 44 on the conductive metal on the resistor 14 is removed, then only the conductive metal back on the resistor 14 is selectively etched, characterized in that it comprises a step of removing.

However, it is usually difficult to print a narrow fine pitch of the resistor 14 of 0.4 mm or less by silk screen printing because of short-circuiting or the like.
Although a resistor with high accuracy cannot be obtained, the application of the fifth manufacturing method improves the dimensional accuracy of the resistor 14 itself and reduces the distance d between the resistor 14 and the conductive portion 22 by 0.1 mm.
Can be as narrow as possible. Thus, improvement of resistance characteristics,
The size of the variable resistor can be further reduced.

In the prototype of the present inventor, as a small slide type variable resistor, a thin plate (foil) of phosphor bronze or copper having a thickness of 0.1 mm was used for the conductive metal thin plate 13 and a carbon resistor ink was used for the resistor 14. Was formed to a thickness of 10 μm with good results.

The conductive portion 22 may be made of low resistance 15 ink, or the low resistance 15 may be made of conductive metal.

It should be noted that the method for manufacturing a resistor substrate of an electronic component according to the present invention can be applied not only to the above-described variable resistor but also to a fixed resistor. It may be preferable to add a step of wrapping the resistor 14 portion with a protective resin except for the portion of the terminal to be soldered in order to increase the size.

[0042]

The method for manufacturing a resistor substrate of an electronic component according to the present invention has the above-described structure, and thus exhibits the following excellent effects.

(1) The surface of the resistor becomes a mirror surface, and the sliding noise is significantly reduced.

(2) Since the terminals are formed integrally with the resistor substrate, there is no poor contact due to looseness.

(3) Since the terminal portion is formed by etching, it can be formed in any shape.

(4) Since the shape of the conductive portion can be freely designed, the present invention can be applied to an electronic component including a resistor such as a switch or a rotary encoder.

(5) The substrate is free of resin, metal, ceramic, etc. If a metal is used for the substrate, a resistor with good heat dissipation can be formed, and if a resin flexible sheet is used, it becomes a wiring sheet as it is.

(6) A highly efficient, economical and accurate resistor can be obtained.

(7) It is suitable for ultra-thin, ultra-small, and low cost.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining a manufacturing process of a resistor substrate of a slide type variable resistor according to claim 1 of the present invention.

FIG. 2 is a process flow chart showing a manufacturing process of a resistor substrate of a slide type variable resistor according to claim 2 of the present invention.

FIG. 3 is a sectional view for explaining a method of manufacturing a resistor substrate of a slide type variable resistor according to claim 4 of the present invention.

FIG. 4 is a process flow chart for explaining a method of manufacturing a resistor substrate according to claim 5 of the present invention.

FIG. 5 is an exploded perspective view for explaining the structure of a conventional slide-type variable resistor.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 slider 2 insulating resin substrate 3, 3 ′ conductive portion 4, 14 resistor 5, 15 low resistor 6 slider 7 a, 7 b, 7 c terminal 8 caulking portion 9 resin case 10 slide-type variable resistor 11 resistor substrate 13 Conductive metal thin plate 16 Resistive sheet 17 Prepreg 17 'Cured resin layer 18 Substrate 19 Hot plate of press machine 21 Terminal part 22 Conductive part 30, 40 Resistor substrate 25, 26 Mold 27 Injection 28 Mold resin part 41 Mask 44 Conductive metal Photoresist at the portion where the thin-plate resistor is formed 45 Photoresist at the terminal portion of the thin conductive metal plate 46 Photoresist on the conductive portion of the thin conductive metal plate W1 Width of resistor W2 Width d of conductive portion

Claims (5)

[Claims] 1. A first step of printing and baking a resistor in a predetermined shape on one main surface of a smooth conductive metal sheet to form a resistor sheet, and an uncured upper surface of the resistor sheet on the resistor side. A second step of placing a prepreg impregnated with a resin, placing a thin plate-like substrate on top of the prepreg, overlapping and thermocompression-curing, and selectively etching the conductive metal thin plate to form a terminal portion having a predetermined shape. And a third step of removing the conductive portion while leaving the conductive portion. 2. The method according to claim 1, wherein the prepreg is in a semi-cured state during the thermocompression bonding of the resistance sheet, the prepreg, and the substrate in the second step. In the third step, the conductive metal sheet is selectively etched to remove the terminal portion and the conductive portion, leaving the terminal portion and the conductive portion, and further heat-press-hardened to eliminate the step between the resistor and the terminal portion of the conductive metal. A step of flattening the surface of the resistor substrate by heating. 3. The method of manufacturing a resistor substrate for an electronic component according to claim 1, wherein a resin varnish is applied directly to the upper surface of the resistor sheet on the resistor side in place of the prepreg, and the resin in an uncured state is formed. A method of manufacturing a resistor substrate for an electronic component, comprising a second step of placing a thin plate-shaped substrate on a varnish, superimposing the substrate, and curing by thermocompression bonding. 4. A first step of printing and baking a resistor in a predetermined shape on one main surface of a smooth conductive metal sheet to form a resistor sheet, and inserting the resistor sheet into an injection mold. A second step of injecting the compatible resin only into the resistor side and integrally molding, and a third step of selectively etching while leaving the terminal portion and the conductive portion from the conductive metal thin plate side of the integrally molded resistor substrate. And a method for manufacturing a resistor substrate for an electronic component. 5. The method according to claim 1, wherein the resist is selectively etched on the conductive metal sheet in the third step. The conductive metal thin plate is etched to remove other portions of the conductive metal, and then, at the time of printing, a surplus portion of the resistor that protrudes beyond a predetermined design dimension of the resistor is used to remove the photoresist on the conductive metal remaining on the resistor. Removing by sandblasting as a mask, then removing the photoresist on the conductive metal on the resistor, and then selectively etching only the conductive metal on the resistor again to remove the conductive metal on the resistor The method for manufacturing a resistor substrate for an electronic component according to claim 1, wherein the method further comprises: