JPH0536865U - Thin film substrate - Google Patents

Abstract

(57) [Summary] [Objective] To obtain a base material structure in which a photosensitive resin thin film formed on the surface of an insulating base material used for a thin film substrate has a uniform thickness. [Structure] A taper 8 is provided on the entire outer peripheral portion of the surface of a substrate 1, and a resin thin film 2 having a uniform film thickness can be obtained by spin coating a resin solution on this surface. 2 is used as a base, and a conductor thin film pattern is formed thereon.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a thin film substrate, and more particularly to a thin film substrate used for mounting electronic components.

[0002]

[Prior art]

 4 and 5 are schematic cross-sectional views of a main part showing a series of conventional manufacturing steps of a thin film substrate. 4 shows steps A to E in the order of steps, and FIG. 5 shows steps F to I following FIG. The cross-sectional view shown in step I shows the reference configuration of the conventional thin film substrate.

In FIGS. 4 and 5, a photosensitive resin thin film 2 is formed on a plate-shaped insulating substrate 1 (step A) made of silicon, ceramics or the like by a spin coating method described later, and B), and a mask 7 formed by forming a negative or positive pattern of a conductor pattern of several μ to several tens of μ on a glass plate by a thin metal film such as Cr is adhered or mask-pattern projected onto it (step C), and ultraviolet rays are applied. Alternatively, the negative or positive latent image 2a of the mask 7 is formed in the photosensitive resin thin film 2 by irradiating with an electron beam or the like (step C).

Next, by utilizing the difference in solubility of the photosensitive resin thin film 2 and the negative or positive latent image 2a formed therein in the developing solution of the photosensitive resin, a fine resin pattern of several μm to several tens of μm is used. 2b was developed (step D). Further, a metal conductor thin film 3 of several 100 A (angstrom) such as Cu was formed on the entire surface by sputtering or vapor deposition to form a metal electrode, and then a plating resist thin film 4 was formed on this plated electrode (step E). In the same manner as described above, the mask 7a is closely contacted or mask pattern projected on the plating resist thin film 4, and ultraviolet rays or electron beams are irradiated to form a negative or positive latent image 4a of the mask 7a in the plating resist thin film 4. By utilizing the difference in solubility between the plating resist thin film 4 and the negative or positive latent image 4a of the plating resist developing solution, a fine plating resist pattern 4b of several μ to several tens μ is formed (step G).

Then, after forming a thick metal plating layer 5 such as Cu by electroplating on a region of the conductor thin film 3 which is not covered by the plating resist pattern 4b, the plating resist pattern 4b is formed by a solvent of the plating resist. After removing (process H), the metal conductor thin film 3 and the thick metal plating layer 5 are collectively etched, and the difference in thickness between the metal conductor thin film 3 and the thick metal plating layer 5 is used. Only the exposed portion of the metal conductor thin film 3 was removed, and a conductor pattern 6 of several μ to several tens μ formed by only the metal conductor thin film 3 and the thick metal plating layer 5 was formed (step I).

The steps A to I as described above complete the formation of the standard configuration of the thin film substrate having the conductor pattern 6 on the base material 1. However, a practical thin film substrate is returned from step I to step B. By repeating this step a predetermined number of times, the formation of a thin film substrate composed of a multilayer thin film for mounting an electronic device is completed.

Here, the above-mentioned spin coating method will be described with reference to the schematic explanatory view of the coating state of the photosensitive resin by the spin coating method of FIG. That is, as a method for forming a uniform resin thin film such as a photosensitive resin and a resist in the manufacturing process as described above, as shown in FIG. By rotating the substrate 1 at a predetermined number of revolutions, spreading the dropped resin solution 2d by the viscosity of the resin solution 2d and the centrifugal force due to the rotation, and spreading the excess resin solution by the centrifugal force to even out the photosensitive resin. The spin coating method for obtaining the functional resin thin film 2 is used.

In the above spin coating method, the resin melt 2d dropped on the base material 1 is spread over the entire surface of the base material by the centrifugal force, and the excess resin solution 2d is shaken off by the centrifugal force to form a uniform resin thin film 2 However, due to the relationship between the centrifugal force and the viscosity of the resin solution, the film thickness of the resin thin film 2 on the outer peripheral portion B of the base material 1 becomes thick as shown in FIG. In order to draw a fine pattern on the resin thin film 2, a photomask 7 is brought into close contact with the resin thin film 2 in advance, and an ultraviolet ray or an electron beam is irradiated to form a negative or positive latent image 2a of the photomask pattern on the resin thin film. Since the film thickness of the resin 2 at the central portion A of the base material 1 is different from that at the outer peripheral portion B of the base material 1, a gap 11 is generated between the photomask 7 and the resin thin film 2 at the central portion A of the base material 1 and ultraviolet rays are generated. Alternatively, when the electron beam is irradiated, the ultraviolet rays or the electron beam wraps around, and the resolution of the latent image 2a formed on the resin thin film 2 decreases. In the conventional technique, after the resin solution 2d dropped on the base material 1 is spread on the base material 1 by the centrifugal force, the rotation speed of the base material 1 is temporarily increased and the outer peripheral portion B of the base material 1 is moved by the centrifugal force. A uniform resin thin film 2 was obtained by shaking off the remaining resin.

[0009]

[Problems to be solved by the device]

 The conventional thin film substrate having the above-described basic structure has the following problems to be solved, as is clear from the detailed description of the manufacturing method in the preceding section.

(B) When the number of revolutions of the base material 1 is temporarily increased and the resin remaining on the outer peripheral portion B of the base material 1 is shaken off to obtain a uniform resin thin film 2, the centrifugal force alone is used. The resin remaining on the outer periphery of the base material 1 is not completely shaken off, and the gap 11 between the photomask 7 and the resin thin film 2 in the central portion A of the base material 1 is not completely eliminated, and ultraviolet rays or electron beams are not emitted. When irradiated, ultraviolet rays or electron beams wrap around, and the resolution of the latent image 2a formed on the resin thin film 2 decreases.

(B) When the rotation speed of the base material 1 is temporarily increased to shake off the resin remaining on the outer peripheral portion B of the base material 1 to obtain a uniform resin thin film 2, the center of the base material 1 When the film thickness of the resin thin film 2 in the part A is shaken off by the centrifugal force and the resin thin film 2 and the conductor pattern 6 are laminated, the resin thin film 2 becomes too thin and the electrical conductivity between the conductor patterns 6 to be laminated is reduced. Insulation is reduced.

The present invention has the above-mentioned problems, that is, (a) the resolution of the pattern is lowered due to insufficient adhesion between the mask and the resin thin film in the central portion A of the base material, and (b) the peripheral portion B of the base material remains. This is done in order to solve the problem that the electrical insulation is deteriorated due to the decrease in the film thickness of the resin thin film 2 in the central portion A of the base material 1 when the rotational speed of the resin thin film is temporarily increased and shaken off. It is an object of the present invention to provide a thin film substrate in which the above-mentioned deterioration in resolution and insulating property is prevented by simple processing of a base material.

[0013]

[Means for Solving the Problems]

 The thin film substrate according to the present invention has a processed shape on the substrate surface of a thin film substrate for mounting electronic parts, which is formed by forming a pattern of a conductive thin film on the surface of a plate-shaped insulating substrate. In the first invention, a taper is provided on the entire outer peripheral portion on the surface side of the base material, in the second invention, a step is provided instead of the above taper, and in the third invention, the above taper is replaced. It has a groove in it.

[0014]

[Action]

 In the present invention, in the first, second, and third inventions, since the taper, the step, and the groove are provided in advance on the entire outer peripheral portion of the thin film substrate, the spin coat method is used. When the resin thin film is formed on the surface of the base material, the resin (solution) that has been spin-diffused from the center to the outer periphery will naturally collect in the taper part, step part, and groove part, and the entire main part of the base material surface A resin thin film having a uniform film thickness can be obtained. Therefore, the adhesion to the mask surface in the subsequent process is improved, and the pattern resolution is not lowered.

[0015]

【Example】

 FIG. 1 is a schematic sectional view illustrating a first embodiment base material according to the present invention, FIG. 2 is a sectional view illustrating a second embodiment base material, and FIG. 3 is a third embodiment base material. FIG.

FIGS. 1 to 3 each show a state in which the resin thin film 2 and the mask 7 are adhered to each other when the photosensitive resin thin film 2 is formed on the base material 1 by the above-mentioned spin coating method. It

First, FIG. 1 shows a case where a taper 8 whose plate thickness becomes thinner toward the outer peripheral portion is provided on the entire outer peripheral portion on the front surface side of the substrate 1. Further, FIG. 2 shows a case where the step 9 is provided on the entire outer peripheral portion of the substrate 1. Further, FIG. 3 shows a case where the groove 10 is provided in a place extremely close to the entire outer peripheral portion of the substrate 1.

As described above, by providing the taper 8, the step 9 or the groove 10 on the outer peripheral portion B of the base material of the thin film substrate according to the present invention, the resin solution 2d (see FIG. 6) is diffused by the spin coating method. In this case, the resin solution on the outer peripheral portion B smoothly collects in the taper portion, the step portion, and the groove portion, respectively, so that the resin thin film 2 having a uniform film thickness is formed. In this way, the resin remaining on the outer peripheral portion B of the base material 1 is eliminated, and the photomask 7 and the resin thin film 2 in the central portion A of the base material 1 are completely adhered to each other. The resolution of the negative or positive latent image 2a of the mask 7 is improved. Further, since the operation of temporarily increasing the rotation speed of the base material 1 and shaking off the resin remaining on the outer peripheral portion B of the base material 1 can be omitted, the film thickness of the resin thin film 2 in the central portion A of the base material 1 is secured. It is possible to secure the electrical insulation between the conductor patterns 6 when the resin thin film 2 and the conductor patterns 6 are laminated. Therefore, it is possible to obtain an excellent thin film substrate without the problems of the resolution of the pattern formed on the substrate 1 according to the present invention and the deterioration of the insulation between the conductor patterns.

[0019]

[Effect of the device]

 As described above, according to the present invention, it is possible to provide a thin film substrate having a uniform thickness in which a taper, a step, or a groove is formed on the entire outer peripheral surface of a base material, and a conductor thin film pattern is formed on the taper. Thus, it is possible to obtain a high-resolution thin film substrate having a high resolution in which the resolution of a negative or positive latent image of a mask is not deteriorated and having no insulation failure between the formed multilayer conductor patterns.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view illustrating a first embodiment substrate according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a second embodiment substrate according to the present invention.

FIG. 3 is a schematic cross-sectional view showing a third embodiment substrate according to the present invention.

4A to 4C are cross-sectional views of steps A to E showing steps of manufacturing a conventional thin film substrate.

5 is a cross-sectional view of steps F to I following FIG.

FIG. 6 is an explanatory view of forming a resin thin film by a spin coating method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 base material 2 resin thin film 2a positive latent image 2b resin pattern 3 metal conductor thin film 4 plating resist thin film 4a positive latent image 4b plating resist pattern 5 thick metal plating layer 6 conductor pattern 7 mask 8 taper 9 step 10 groove 11 gap

Claims (3)

[Scope of utility model registration request] 1. A thin film substrate for mounting an electronic component, comprising a conductive thin film pattern on the surface of a plate-shaped insulating base material, wherein a taper is provided on the entire outer peripheral portion on the front surface side of the base material. A thin film substrate characterized by the above. 2. The thin film substrate according to claim 1, wherein a step is provided instead of the taper. 3. The thin film substrate according to claim 1, wherein a groove is provided instead of the taper.