JPH0649376B2 - Method of manufacturing thermal head - Google Patents

Description

The present invention relates to a thermal head used in a thermal printer, and more particularly to a method for manufacturing a thin film type thermal head.

[Conventional technology]

The thermal head mounted on the thermal printer, for example, a plurality of heating resistor elements are linearly arranged on the same substrate, and the heating resistor elements are energized and heated according to the information, and color recording is performed on the thermosensitive recording paper. Alternatively, it is used for transfer recording on plain paper via an ink ribbon.

3 and 4 show examples of general structures of thermal heads manufactured by a conventional manufacturing method. In FIGS. 3 and 4, a glaze layer 2 made of glass that functions as a heat storage layer is formed on an insulating substrate 1 such as a ceramic substrate.
In FIG. 3, the insulating substrate 1 is formed on almost the entire surface in a plane shape, and in FIG. 4, the heating resistor forming region is formed so that its upper surface has an arcuate cross section. A heating resistor layer 3 made of T _a2 N or the like is deposited on the glaze layer 2 by vapor deposition, sputtering or the like, and then etched to form a plurality of linearly arranged layers. A power supply layer 4 for supplying power to the heating resistor layer 3 is further formed on the heating resistor layer 3. The power supply layer 4 is made of, for example, aluminum, copper, gold, or the like, and is formed into a pattern of a desired shape by etching after being deposited by vapor deposition, sputtering or the like, and is formed on each side of each heating resistor layer 3. One is led out as a common electrode and the other is led out as an individual lead electrode. Then, between the power supply layers 4 and 4 forming a pair as the common electrode and the individual lead electrodes, the individual heat generating resistor layers 3 each having a heat generating region corresponding to one dot are formed in the power supply layer 4 forming a pair. , 4 is heated by applying a voltage between them. In addition,
4a is a dividing part of the power feeding layer formed by etching.

The protective layer 7 is formed on the heating resistor layer 3 and the power feeding layer 4 described above. The protective layer 7, the anti-oxidation layer 5 made of S _i O ₂ for protecting the heating resistor layer 3 from deterioration due to oxidation, is laminated on the oxidation-resistant layer 5, the heat-sensitive recording paper (not shown) The heat resistance layer 3 and the power feeding layer 4 are protected from wear due to contact with the wear resistant layer 6 made of T _a2 O ₅ or the like, and this protective layer 7 covers all of the head surface except the terminal portion. It is designed to cover. The oxidation resistant layer 5 and the wear resistant layer 6 of the protective layer 7 are sequentially formed by means such as sputtering, and thereafter,
In the final step, the insulating substrate 1 is divided to obtain a desired thermal head chip.

The structure of the thermal head is shown in FIG. 4 since the heating resistor layer 3 is disposed on the conventional plane shown in FIG. 3 due to the recent improvement in the printing quality of the thermal head printer. Such a partial glaze layer 2 having an arcuate cross section is provided, and the heating resistor layer 3 is arranged on the top surface of the partial glaze layer 2 to improve contact with the thermal recording medium and obtain high print quality with relatively low power. There is.

[Problems to be solved by the invention]

However, in the configurations shown in FIGS. 3 and 4 described above, the power supply layer 4 is divided with the heating resistor layer 3 sandwiched therebetween, and therefore the dividing portion 4a causes the concave portion 7a to be formed on the upper surface of the protective layer 7. Since a void is generated in the thermal recording medium during printing, heat cannot be efficiently conducted, and the print density tends to be thin. If an attempt is made to increase the applied energy to increase the printing density in order to eliminate this point, the thermal head is deteriorated due to the increase of thermal strain, and the life is shortened. Further, since the dividing portion 4a is present, a concentrated load acts on the edge portion of the power feeding layer 4 during printing, and cracks or peeling easily occur in the protective layer 7. In this case, the resistance value due to oxidation of the heating resistor layer 3 or the like is generated. There is also a possibility that printing may become substantially impossible due to the fluctuation of.

The present invention overcomes the above-mentioned problems in the prior art, has good contact with a thermal recording medium, is capable of efficient heat conduction, and is free from the risk of mechanical damage due to sliding. It is intended to provide a manufacturing method.

[Means for solving problems]

The method for manufacturing a thermal head of the present invention comprises: stacking a heating resistor layer and a power feeding layer on an insulating substrate by sputtering; forming a resist layer on this power feeding layer by spin coating; heating to evaporate the solvent. A pattern is baked on the resist layer and developed to form a mask pattern of the resist layer, and the thickness of the power feeding layer is etched to about 1/2 to cause side etching on the power feeding layer; The layer is heated and fluidized so that the end of the resist layer is bent on the side-etched slope of the power feeding layer, and the power feeding layer is etched again to divide the power feeding layer to form the heating resistor layer. It has a feature.

[Work]

According to the method of manufacturing a thermal head of the present invention, since the resist layer is not heated before the first etching of the power feeding layer, the first etching is performed in a state where the adhesion between the resist layer and the power feeding layer is weak. As a result, a large amount of side etching of the power feeding layer occurs, and thereafter, the resist layer is heated to bend the end portion of the resist layer onto the side-etched slope of the power feeding layer to divide the power feeding layer accurately. It is possible to enhance the adhesion between the resist layer and the power feeding body layer, and then perform the etching of the power feeding body layer again to divide the power feeding body layer to form the heating resistor layer with high accuracy. Moreover, since the resist layer is curved and joined to the slope formed by the side etching of the power feeding layer, the protective layer formed on the resist layer is also curved, so that the mechanical contact by sliding with the thermal recording medium may occur. Damage can also be reduced.

〔Example〕

 The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 shows an intermediate stage of the steps in the method for manufacturing a thermal head according to the present invention. To reach the state of this figure, first, an upper surface of an insulating substrate 1 such as a ceramic substrate is formed into a substantially arc shape. The glaze layer 2 is partially formed, and T _a2 N is formed on the glaze layer 2 and the exposed insulating substrate 1.
A heating resistor layer 3 made of a material such as and a power feeding layer 4 made of a material such as Al are stacked by sputtering,
Further, a resist layer 8 is formed on the power feeding layer 4 by spin coating.

Then, the resist layer 8 is heated at a temperature of about 80 ° C. to evaporate the solvent, and then a mask pattern is formed by the resist layer 8 by the photolithography technique.
After a pattern is printed on the resist layer 8 using a photomask, development processing is performed. In this way, when the mask pattern of the resist layer 8 is formed on the power feeding layer 4,
The resist layer 8 formed by the conventional method is removed by 15
By omitting the step of heating at a temperature of 0 to 160 ° C., the adhesiveness between the resist layer 8 and the power feeding layer 4 is kept weak, and about half the thickness of the power feeding layer 4 is etched. . Then, since the adhesiveness between the resist layer 8 and the power feeding layer 4 is weak, both side surfaces 4 etched in the power feeding layer 4 are etched.
Side etching largely occurs on b and 4b, and slopes 4c and 4c are formed so as to spread upward.

This is the state shown in FIG.

Next, in order to form the divided portion 4a of the power feeding layer 4 shown in FIG. 2 and expose the heating resistor layer 3 in the vicinity of the top of the glaze layer 2, first, the resist layer 8 is heated to a temperature higher than a normal heating temperature. The resist layer 8 is fluidized by heating at a temperature of, for example, 160 ° C. to 180 ° C., and both ends 8a, 8a of the resist layer 8 indicated by development lines are bent on the slopes 4c, 4c of the power feeding layer 4. After that, when the remaining thickness of the power feeding layer 4 is etched, the state shown in FIG. 2 is obtained. Then, the exposed heating resistor layer 3, power feeding layer 4, and resist layer 8 are covered with a protective layer (not shown) made of an oxidation resistant layer and a wear resistant layer by sputtering to form a thermal head.

According to the above-described method of manufacturing the thermal head, both end portions 8 of the resist layer 8 are formed on both slopes 4c, 4c formed on the power supply layer 4 by the side etching in the first etching.
Since the a and 8a are bent and joined, the accuracy of the cutting of the power feeding layer 4 is improved as compared with the conventional one when the cutting portion 4a of the power feeding layer 4 is formed by etching thereafter, and the heating resistor layer 3 is formed. It is possible to manufacture a thermal head having a stable resistance value with a small dot area variation. Further, since the end portion of the resist layer 8 is curved, no edge is formed in the protective layer that covers the upper part of the thermal head, and the resist layer 8 has a curved shape, which has good contact with the thermal recording medium and ensures efficient heat conduction. It is also possible to reduce mechanical damage due to friction.

〔The invention's effect〕

As described above, in the method of manufacturing a thermal head according to the present invention, etching of the power feeding layer is divided into two times, large side etching is generated in the first etching, and a slope is formed. Since the second etching is performed after the resist layer is bent and joined to the above, the accuracy of the division of the power feeding layer can be improved during the second etching, and the resistance value of the heating resistor layer can be reduced. It is possible to manufacture a thermal head that can be stabilized, has good contact with the heat-sensitive recording medium, can perform efficient heat conduction, and has less mechanical damage due to friction.

[Brief description of drawings]

1 and 2 are longitudinal sectional views of the manufacturing process of the thermal head showing the embodiment of the method of manufacturing the thermal head according to the present invention, and FIGS. 3 and 4 are thermal products manufactured by the conventional method. It is a longitudinal cross-sectional view showing a head. 1 ... Insulating substrate, 2 ... Glaze layer, 3 ... Heating resistor layer, 4 ... Feeder layer, 5 ... Oxidation resistant layer, 6 ... Wear resistant layer, 7 ... Protective layer, 8 ... ... resist layer.

Claims (3)

[Claims] 1. A heating resistor layer and a power feeding layer are laminated on an insulating substrate by sputtering, a resist layer is formed on the power feeding layer by spin coating, and the solvent is evaporated by heating to form a resist layer on the resist layer. The pattern is baked and developed to form a mask pattern of the resist layer, and about 1/2 of the thickness of the power feeding layer is etched to cause side etching in the power feeding layer to heat and fluidize the resist layer. The thermal head is characterized in that the end portion of the resist layer is bent to the side-etched slope of the power feeding layer, and the power feeding layer is etched again to divide the power feeding layer to form the heating resistor layer. Manufacturing method. 2. Heating to evaporate the solvent is approximately 80.
The method for manufacturing a thermal head according to claim 1, wherein the temperature is set to ° C. 3. The method for manufacturing a thermal head according to claim 1, wherein the temperature for heating and fluidizing the resist layer is 160 ° C. to 180 ° C.