JPH0759398B2 - METHOD FOR FORMING ELECTRODE PATTERN OF EDGE-TYPE THERMAL PRINT HEAD AND EXPOSURE APPARATUS USED FOR THE SAME - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for forming an electrode pattern of an end face type thermal print head in which a heating element is arranged on a continuous side end face which is rounded from a main plane part of a head substrate having a constant thickness by a photoetching method and The present invention relates to an exposure apparatus used for this.

[Prior art and its problems]

For example, serial type thermal print heads are
A heating element is formed in a continuous line on the main plane of the ceramic substrate, and a selected portion of the heating element is heated via a comb-shaped electrode pattern that is continuous with the heating element. . In the conventional thermal print head as described above, a driver circuit is often mounted on the main plane of the head substrate. In such a case, as shown in FIG. 7, the recording paper is bent so as to avoid the driver circuit. However, the troublesome handling of recording paper, such as pressing it against the heating element with a platen or a backup member, requires an increase in the size of the thermal print head-using device and the backup member over the entire length of the heating element that extends linearly. Since it is necessary to apply a uniform pressing force to the recording paper supported by the sheet, a bending rigidity of a certain level or more is required, and there is a problem that the thermal print head itself cannot be thinned. In order to solve such a problem, for example, JP-A-60-
As disclosed in Japanese Patent No. 19558, an end surface type thermal print head in which a heating element is arranged on a side end surface portion of a head substrate has been proposed. However, in the thermal print head disclosed in the above publication, a comb-shaped electrode pattern for conducting from the driver circuit on the main plane to the heating element on the end face is formed by a photoetching method which is a conventional simple method. Therefore, a cumbersome and expensive method is adopted in which the head itself is made of semiconductor silicon and the resistor is formed on the end face portion by diffusion. The end face type thermal print head disclosed in the above publication has a flat end face portion, but as shown in the drawings of the present application, the end face portion has a convex arcuate cross section to obtain a more appropriate printing pressure. If you do
Furthermore, it has been difficult to easily and properly form the electrode pattern extending from the main plane to the end surface portion having the convex arcuate cross section by the photoetching method. The present invention has been devised under the circumstances described above, and in a vertical thermal print head, a heating element is formed from the main plane of the head by a simple method by photoetching. It is intended to provide a method for accurately forming an electrode pattern that wraps around a part and an exposure apparatus used at that time.

[Means for solving the problem]

In order to solve the above conventional problems, the present invention takes the following technical means. That is, the electrode pattern forming method for the end surface type thermal print head according to the first invention of the present application includes the following steps. With respect to the head substrate on which the conductor coating is formed from the main plane to the entire end face portion having a convex arcuate cross section, (a) by photoetching using a flat plane mask for a main plane brought into contact with the main plane, the main plane or The unnecessary conductor coating up to the middle part of the end surface portion of the convex arcuate section which is connected to this main plane is deleted. (B) Next, the end surface of the convex arcuate section is intersected with the main plane section at an acute angle. Photolithography is performed by using a flat plate mask for the end face portion which is brought into contact with the end face portion so as to remove the unnecessary conductor coating in the region of the end face portion having the convex arc shape in section from the intermediate portion to the end face side. The exposure apparatus used for forming the electrode pattern of the end surface type thermal head, which is the second invention of the present application, is provided with the following configuration. A mask plate having a mask mounting surface extending in the XY plane direction on its upper surface and having a lighting hole penetrating the mask mounting surface, and a position in the XY plane direction and a Z-axis direction orthogonal to the XY plane below the mask plate, In addition, in an exposure apparatus having a substrate support table supported via a position adjusting mechanism capable of adjusting the rotational position around the Z axis and an ultraviolet light source arranged above the mask plate, the substrate support table is selectively mounted on the substrate support table. Further provided with a first substrate chuck and a second substrate chuck, and a visible light source that irradiates non-ultraviolet light into the lighting hole. The first substrate chuck mainly includes a head substrate having a main plane and an end face portion. The second substrate chuck holds the head substrate so that its main plane is parallel to the XY plane.
It is configured so that it is held so that it intersects the XY plane at an acute angle.

[Action and effect]

In the electrode pattern forming method of the end face type thermal print head according to the present invention, by the first stage photoetching using the flat plate mask for the main plane, the main plane or the intermediate portion of the convex arc-shaped end face section in cross section connected to this main plane is formed. After removing the unnecessary conductor coating, by the second stage photoetching using a flat plate mask for the end surface portion, the unnecessary conductor coating from the intermediate portion to the end surface side region in the convex arc-shaped end surface portion is removed, As a result, an electrode pattern made of a comb-shaped conductor coating that wraps around from the main plane to the end face is formed. Moreover, in the method of the present invention, the flat plate mask for the end face portion is brought into contact with the end face portion of the substrate so as to intersect the main plane at an acute angle during the second-step photoetching. This is, while the portion near the end face portion in the main plane can be visually observed with a microscope or the like from the ultraviolet irradiation direction orthogonal to the mask, the distance from the mask to the surface portion of the convex arc-shaped end face portion in cross section with respect to the main plane of the mask. It means that the length becomes shorter than that in the case of abutting so as to be orthogonal. As a result, it is very easy to align the pattern on the flat mask for the end face with the electrode pattern already formed by the second stage photoetching on the horizontal plane or the intermediate part of the end face with a convex arcuate cross section. In addition, the exposure blur on the end surface portion having the convex arcuate cross section is reduced.
Therefore, the electrode pattern formed on the main plane by the first-stage photoetching can be accurately connected to the electrode pattern formed on the convex arc-shaped end surface section by the second-stage photoetching, and the alignment for that can be performed. The work becomes very easy, and an accurate electrode pattern with less exposure blur can be formed over the main plane or the end face portion having a convex arcuate cross section connected to the main plane. Therefore, according to the method for forming the electrode pattern of the end surface type thermal print head according to the present invention, the end surface can be simply and accurately used by utilizing the method for photoetching that is widely used in the field of manufacturing electronic devices. It is possible to form a comb-shaped electrode pattern that wraps around the main surface of the mold thermal print head to the end surface portion having a convex arc shape in cross section. Next, the exposure apparatus for an end face type thermal print head according to the second invention of the present application is used as follows, and the above method is performed. First, the photoetching in the first stage is performed by using the apparatus of the present invention in which the first substrate chuck is mounted on the support and the flat plate mask for the main plane is mounted on the mask table. That is, after the main plane of the head substrate held on the first substrate chuck is positioned by the position adjusting mechanism,
Contact the flat plate mask for the main plane, expose the main plane to ultraviolet rays through the mask to expose it, and remove the unnecessary conductor film from the main plane to the intermediate part from this to the end face through a predetermined etching process. To do. Next, the second-stage photo-etching for the head substrate that has been subjected to the above-mentioned first-stage photo-etching is performed by mounting the second substrate chuck on the support base and mounting the end face flat plate mask on the mask table. The invention apparatus is used. First, the main plane on the second substrate chuck
The head substrate held so as to intersect the XY plane, that is, the mask surface at an acute angle is positioned with respect to the pattern of the end face flat plate mask. This is performed by operating the position adjusting mechanism while looking through the surface of the mask or the head substrate with a microscope in the ultraviolet irradiation direction. At this time, in the present invention, since the head substrate on the second substrate chuck is held with a predetermined inclination, it is possible to visually recognize the electrode pattern already formed in the portion near the end face portion of the main plane from the ultraviolet irradiation direction. Moreover, since the electrode pattern is illuminated by the visible light source, it can be more easily visually recognized. Further, since the lens aperture of the microscope can be further narrowed to widen the depth of field, it becomes possible to align each other while superimposing the pattern on the mask and the electrode pattern on the head substrate as a clear image. . As described above, according to the exposure apparatus for an end face type thermal print head of the present invention, the first photo etching for the main plane is followed by the second photo process for the end face portion by the simple method accompanying the conventional photo etching. The exposure for etching can be performed accurately.

[Explanation of Examples]

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. First, FIG. 1a shows an example of an end surface type thermal print head 11 manufactured according to the present invention. A strip-shaped head substrate 12 formed of ceramic or the like having a constant thickness has one side surface as a main plane 13, and this main plane
It has an end face portion 14 extending from 13 in a curved shape in a convex arc shape in section.
A driver circuit (not shown) is mounted on the main plane 13 as in the conventional thermal printhead. In this end surface type thermal print head 11, a heating resistor (not shown) is formed on the top of the convex arc-shaped end surface portion 14 continuously and linearly extending in the longitudinal direction of the head substrate. The comb-shaped electrode pattern 15 extending from the driver circuit is electrically connected. That is, as shown in FIG. 1a, from the driver circuit mounting portion on the main plane 13, a comb-shaped driving electrode pattern 15a extending in parallel at equal intervals in the width direction of the head substrate is a top portion of the end surface portion 14. The so-called common comb-shaped electrode pattern 15 that extends to the vicinity
b is formed such that the tips of the electrodes are inserted between the tips of the driving electrodes. The heating resistor (not shown) is formed linearly along the longitudinal direction of the end face portion so as to simultaneously intersect the respective tips of the driving electrodes and the common electrodes formed as shown in FIG. 1a. Of. By the way, conventionally, it has been considered difficult to form an electrode pattern by photoetching on a substrate having a curved surface as described above through a contact exposure method using a flat plate-shaped mask. The invention made this possible. Next, before explaining the method of the present invention, first,
The configuration of an example of the exposure apparatus used for this will be described. FIG. 2 is a vertical sectional view of an exposure device 16 for an end surface type thermal print head according to the present invention, and FIG. 3 is a sectional view taken along line III-III thereof. Reference numeral 17 denotes a mask plate 17 having a mask mounting surface 18 extending on the upper surface in the XY plane direction, and an elongated rectangular lighting hole 19 is provided at the center of the mask mounting surface 18. Then, in the housing hole 20 formed in the inner wall 19a of one long side of the daylighting hole 19 and extending in the horizontal direction, several lamps 21 capable of irradiating light into the daylighting hole 19 are housed and held. To be done. This lamp may be any type of lamp, but if the light contains ultraviolet rays, it is necessary to install an ultraviolet filter 22 on the front surface of the lamp to prevent exposure by the lamp 21. The mask plate 17 is fixedly attached to a fixed body (not shown). Below the mask plate 17, a substrate support table 23 supported via a position adjusting mechanism capable of adjusting a position in the XY plane direction, a position in the Z axis direction orthogonal to the XY plane, and a rotational position around the Z axis is arranged. To be done. Among the position adjusting mechanisms, a mechanism for finely adjusting the position of the substrate support table 23 in the XY plane direction and a mechanism for adjusting the rotational position around the Z axis are known and are not shown. Thus, in the illustrated example, the mechanism for adjusting the position of the substrate support base 23 in the Z-axis direction, that is, the vertical direction, can raise and lower the piston cylinder 25 inserted inside the outer guide cylinder 24 by, for example, air drive. It is composed of a lifting device 26. The substrate support base 23 is configured by attaching a chuck base 23b capable of selectively mounting a first substrate chuck 27 and a second substrate chuck 28, which will be described later, on the upper surface of a disk-shaped base plate 23a. By mounting the convex spherical seat 29 on the lower surface of the base plate 23a and providing the concave spherical seat 30 capable of sliding contact with the convex spherical seat 29 on the inner circumference of the upper end of the piston cylinder 25, the automatic support for the substrate support base 23 can be achieved. It is configured to form a leveling mechanism. Now, as shown in FIG. 4, when the main plane 13 of the head substrate 12 is exposed, the first substrate chuck 27 mounted and used on the chuck base 23b has the chuck surface 27a facing upward and the head substrate It is constructed so that it can be held with its principal plane 13 facing the upper surface. A suction hole 31 for sucking the back surface of the head substrate 12 by vacuum pressure is formed on the chuck surface 27a. Further, the second substrate chuck 28, which is used by being mounted on the chuck base 23b when exposing the end surface portion 14 of the head substrate 12, has a chuck surface as shown in FIG.
28a is inclined, and the main plane 13 of the head substrate 12 held by the 28a is configured to be inclined at an acute angle with respect to the XY plane, that is, the mask mounted on the mask plate 17. Similar to the first substrate chuck 27, a suction hole 31 is formed in the chuck surface 28 so that the back surface of the head substrate 12 can be attracted to the chuck surface 28a by vacuum pressure. In FIGS. 2 and 3, reference numeral 33 indicates a Z-axis rotational axis 34 while supporting the substrate support 23 so as to surround the convex spherical seat 29 by the receiving hole 33a when the piston cylinder 25 descends. A rotatable turntable is shown, and when it is rotated 180 degrees from the state shown in FIGS. 2 and 3, the substrate support 23 can be carried to a position displaced laterally of the mask plate 17, thereby exposing. Front head substrate
Head substrate 12 after setting 12 on the support or after exposure
Is to make it easy to take out. Next, an electrode pattern forming method of the end surface type thermal plate head according to the present invention using the exposure apparatus 16 will be described. First, the first substrate chuck 27 is mounted on the substrate support 23, and the first photoetching is performed through the first exposure process by the apparatus of the present invention in which the main plane flat plate mask 35 is mounted on the mask plate 17. To do. In this first photoetching, among the conductor coatings formed in advance by vapor deposition or the like on the entire main plane 13 or the end surface portion 14 having a convex arcuate cross section, unnecessary conductors up to the main plane 13 or an intermediate portion between this main plane and the end surface portion are formed. The coating, that is, the unnecessary conductor coating in the area indicated by the symbol A in FIG. 1a is deleted to obtain an intermediate product as shown in FIG. 1b. The pattern of the flat plate mask 35 for the main plane for this purpose is, for example, as shown in FIG. In this figure, the shaded portion is a portion that does not transmit ultraviolet rays, and consequently the pattern corresponding to the shaded portion of this pattern on the head substrate 12 is removed by etching as an unnecessary conductor portion. Of course, if the photoresist coated on the conductor film is of the type that the photosensitive portion dissolves,
The pattern of the mask 35 is the reverse of that shown in FIG. It should be noted that the point of adjusting the position of the substrate with respect to the mask pattern by operating the position adjusting mechanism while looking through a microscope (alignment scope) (not shown) located above the mask plate 17 is similar to the conventional exposure method of this type. is there. Next, with respect to the intermediate product of FIG. 1b, the second substrate chuck 28 is mounted on the substrate support 23, and the end face flat plate mask 36 is mounted on the mask plate 17 according to the second device of the present invention. After the exposure process, second photo etching is performed.
In this case, the first substrate chuck 27 on the substrate support base 23 may be replaced with the second substrate chuck 28, or another exposure apparatus in which the second substrate chuck 28 is mounted on the substrate support base 23 in advance is used. May be. In this second photo-etching, unnecessary portions are further removed from the conductor film remaining from the intermediate portion between the main plane 13 and the end face portion 14 to the end face portion 14 having a convex arcuate cross section. Flat plate mask for this purpose
The pattern of 36 is, for example, as shown in FIG. In this figure, the shaded portion is a portion that does not transmit ultraviolet rays, and eventually the pattern corresponding to the shaded portion of this pattern is removed by etching as an unnecessary conductor portion. In addition, the ultraviolet ray non-transmissive portion in the flat plate mask 35 for the main plane of FIG. 5 and the flat plate mask for the end face portion of FIG.
The ultraviolet ray non-transmissive portion in 36 is formed so as to partially overlap when projected onto the head substrate, and as a result, the head substrate that has undergone the first photo etching and the second photo etching is adjacent to each other. That is, the comb-shaped electrode pattern in which electrical continuity between them is obstructed is formed continuously from the main plane 13 to the convex arc-shaped end surface portion 14 in cross section. The second exposure step is performed as follows. The substrate support 23 or the second substrate chuck 28 introduced below the mask plate 17 by the rotation of the turntable 33.
The upper head substrate 12 is lifted by the air pressure of the lifting device 26. That is, the concave spherical seat 30 of the piston cylinder 25 rises while coming into contact with the convex spherical seat 29 of the substrate support table 23. At this time, first, a pair of elastic stopper pistons 37 such as rubber projecting from the support base 23 so as to sandwich the substrate 12 on a straight line orthogonal to the longitudinal line of the head substrate 12 are provided on the lower surface of the mask plate 17. Abut, at this time, the auto-leveling mechanism consisting of the convex spherical seat 29 and the concave spherical seat 30 functions,
The angle of the principal plane 13 of the substrate 12 with respect to the mask 36 is automatically determined. At the same time, when the entire length of the convex arcuate end surface portion 14 of the head substrate 12 abuts on the back surface of the mask 36, the auto-leveling mechanism functions to make the convex arcuate end surface portion 14 of the substrate 12 accurately correspond to the mask 36. Will be parallel to. Next, while looking through the alignment scope, the pattern formed on the substrate 12 by the first photoetching and the pattern of the end face flat mask 36 are aligned by operating the position adjusting mechanism. At this time, the substrate 12 has its main plane 13 as shown in FIG.
Is held so as to intersect the mask 36 at an acute angle, the pattern on the substrate can be seen by the alignment scope, particularly the pattern image of a portion near the end face portion in the main plane important for alignment. Moreover, the main plane side of the substrate 12 located in the lighting hole 19 is a lamp
Since the light is illuminated by the visible light source including the filter 21 to the ultraviolet filter 22, the pattern image on the substrate 12 can be seen more clearly. In addition, since the exposure of the alignment scope can be narrowed to increase the depth of field, it is possible to see the pattern image of the mask 36 and the pattern image on the substrate 12 below the mask 36 without blurring both. Therefore, the above position adjustment can be performed very easily. As a result, it is possible to easily and accurately form an electrode pattern that wraps around the main plane to the convex arc-shaped end surface section in a simple manner by a conventional photoetching technique in this field. Of course, the scope of the present invention is not limited to the above embodiments. In particular, the mechanism for adjusting the position of the substrate support in the XY direction, the Z direction, and the direction around the Z axis can be achieved by combining various known mechanisms.

[Brief description of drawings]

FIG. 1a is a perspective view of a head substrate of an end surface type thermal print head on which an electrode pattern is formed by using the method of the present invention, and FIG. 1b is a perspective view of the head substrate at the time of finishing the first photoetching, FIG. 2 is a longitudinal sectional view of an essential part of the device of the present invention, FIG. 3 is a sectional view taken along the line III-III of FIG. 2, and FIG. 4 is a longitudinal sectional view of an essential part of the device of the present invention equipped with a first substrate chuck. FIG. 5 is a pattern diagram of an example of a flat plate mask for the main plane,
FIG. 6 is a pattern diagram of an example of a flat plate mask for the end face portion,
The figure is an illustration of a conventional example. 11 ... Thermal print head, 12 ... Head substrate, 13
...... Main plane, 14 …… End surface, 16 …… Exposure device, 17 …… Mask plate, 18 …… Mask mounting surface, 21 …… Lamp (ultraviolet light source), 23 …… Substrate support, 27 …… First substrate chuck, 28 …… Second substrate chuck, 35 …… Main surface flat plate mask, 36 …… End surface flat mask.

Claims (2)

[Claims] 1. A principal plane is obtained by photoetching a head substrate on which a conductor coating is formed from the principal plane to the entire end face portion having a convex arcuate cross section, using a principal plane flat plate mask brought into contact with the principal plane. Or a step of removing the unnecessary conductor coating up to the middle portion of the convex arcuate end surface portion connected to the main plane, and abutting the convex arcuate end surface portion in cross section at an acute angle to the main plane. And a step of removing unnecessary conductors in a region on the end face side of the intermediate portion of the convex arc-shaped end face portion by photo-etching using a flat plate mask for the end face portion. Pattern forming method for mold type thermal print head. 2. A mask plate having a mask mounting surface extending in the XY plane direction on an upper surface, and a mask mounting surface having a lighting hole penetrating through the mask plate, and below the mask plate, a Z plate orthogonal to the XY plane direction and the XY plane. An exposure apparatus having a substrate support supported via a position adjusting mechanism capable of adjusting a position in an axial direction and a rotational position around the Z axis, and an ultraviolet light source arranged above a mask plate, wherein the substrate support is provided. Further comprising a first substrate chuck and a second substrate chuck that are selectively mounted on the first substrate chuck, and a visible light source that irradiates non-ultraviolet light into the lighting hole. The first substrate chuck has a main plane and an end face portion. Holding the head substrate so that the main plane is parallel to the XY plane, and the second substrate chuck holds the head substrate in the main plane.
An exposure device for an end surface type thermal print head, which is configured to be held so as to intersect an XY plane at an acute angle.