JPS62111766A - Thermal head - Google Patents

Abstract

PURPOSE:To increase the thermal efficiency and remove the fear of mechanical failure due to sliding by making the contact property to heat sensitive recording media better, by a method wherein the etching proof layer and the etching layer having the projection part of mesa type the end face of which is gently sloping are formed on the insulation substrate having the partial glazed layer. CONSTITUTION:The good etching proof metal high oxide, high nitride, or high carbide layer 2a is arranged on the insulating substrate having a partial glazed layer and the metal low oxide, low nitride, or low carbide layer 2b having easily etching property is laminated thereon, which is etched with boiling nitric acid or the like. At that time, by utilizing the side etching by the easily etching layer 2b and the bad adhesion of resist, the mesa type projection part the end face of which is gently sloping is formed on the glazed layer 2. Further, after forming the projected part, it is additionally treated by thermal oxidation. The easily etching layer 2b is given its insulating property and the inside stress of each layer is loosened. By this projection forming, the thermal efficiency is improved and the durability is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head used in a thermal printer, particularly a thin film type thermal head.

[Prior art and problems]

To install a thermal printer in a thermal printer, for example, a plurality of heating resistor elements are arranged linearly on the same substrate, and the heating resistor elements are heated with electricity according to the information.
It is used for color recording on thermosensitive recording paper or for transfer recording on plain paper via an ink ribbon.

FIGS. 2 and 3 show an example of the general structure of a conventional thermal head of this type. In the figure, 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. 2, a glaze layer 2 made of glass is formed on almost the entire surface of the insulating substrate 1; (in the area where the heating resistor is to be formed, each section is formed in an arc shape), and on this glaze layer 2, a Taz layer is formed.
A plurality of heating resistor layers 3 made of N or the like are deposited by vapor deposition, sputtering, etc., and then etched to form a plurality of linearly arranged layers. A power supply layer 4 for supplying power to the heat generating resistor layer 3 is further formed on the heat generating resistor layer 3 . This power supply layer 4 is made of, for example, aluminum, copper, gold, etc., and is deposited by vapor deposition, sputtering, etc., and then formed into a desired shape pattern by etching. One is drawn out as a common electrode, and the other is drawn out as an individual lead electrode. Between the pair of power supply layers 4.4 as the common electrode and individual lead electrodes, each individual heat generating resistor 3 having a heat generating area equivalent to one dot is connected to the power supply layer 4, Heat is generated by applying a voltage between the two. In addition, 4a
is a divided portion of the power supply layer 4 formed by etching.

A protective layer 7 is formed on the heating resistor layer 3 and the power supply layer 4. This protective layer 7 protects the heating resistor layer 3 from deterioration due to oxidation and the oxidation-resistant layer 5 made of Si02 or the like, and protects the heating resistor layer 3 from wear due to contact with heat-sensitive recording paper (not shown), etc. It consists of a wear-resistant layer 6 made of Ta205 or the like that protects the body layer 4, and the protective layer 7 covers the entire head surface other than the terminal portion. This protective layer 7 is formed by sequentially forming an oxidation-resistant layer 5 and a wear-resistant layer 6 by means such as sputtering, and then, in the final step, the insulating substrate 1 is divided to obtain desired thermal Rad chips. It has become.

In recent years, the printing quality of thermal printers has been improved, and the structure of the thermal head has changed from one in which a heating resistor layer 3 is arranged on a plane as shown in Fig. 2 to a partial glaze layer 2 as shown in Fig. 3. A heat-generating resistor layer 3 is disposed on the top surface to improve contact with the heat-sensitive recording medium and to obtain high print quality with relatively low power.

However, the second. In the configuration shown in FIG. 3, since the power supply layer 4 is divided across the heating resistor layer 3, the divided portion 4a does not create a recess 7a in the protective layer 7.
Because voids are created on the heat-sensitive recording medium during printing,
Heat cannot be conducted efficiently and print density tends to be weak. If an attempt was made to increase the print density by increasing the applied energy in order to solve this problem, a problem occurred in that the life of the thermal head would be shortened due to the increase in thermal strain.

In addition, due to the presence of the divided portion 4a, a concentrated load acts on the edge portion of the power supply layer 4 during printing, and the protective layer 7 is likely to crack or peel.In this case, the resistance value due to oxidation of the heat generating resistor layer 3, etc. However, due to fluctuations in the printing temperature, printing becomes virtually impossible.

Conventionally, as a means to improve the above-mentioned drawbacks, it has been proposed to form the glaze layer under the heating element part into a convex shape by etching, thereby making the heating dot part convex. FIG. 4 shows its basic form.

However, when etching a glaze layer mainly composed of SiO□ into a convex shape, the resist pattern is disturbed due to halation, the etching rate varies with etching solutions such as boiling nitric acid, corners are not smooth, etc., and the manufacturing time and quality are reduced. This is an improvement over the drawback of large variations.

[Purpose of the invention]

Therefore, it is an object of the present invention to overcome the above-mentioned conventional drawbacks, to provide good contact with a heat-sensitive recording medium, to perform efficient heat conduction, and to avoid mechanical damage caused by sliding. No thermals.

It is to provide the code.

Another object of the present invention is to make it possible to obtain such a thermal conductor by a method that is relatively easy to manufacture.

[Structure of the invention]

In order to achieve the above objects, the thermal head of the present invention has the following features:
A high oxide, high nitride, or high carbide layer of a metal with good etching resistance is arranged on an insulating substrate including a glaze layer, and a low oxide or low carbide layer of the metal, which is easily etched, is disposed on the insulating substrate. A stack of nitride or low carbide layers is etched using boiling nitric acid, etc., and side etching due to poor adhesion between the easily etched layer and the resist is used to form a mesa-shaped protrusion with a gentle end surface. is formed on the glaze layer. Further, after the protrusion is formed, thermal oxidation treatment is applied to impart insulation to the conductive metal low oxide, nitride, or carbide layer, and the internal stress of each layer is relaxed. It is something to do.

〔Example〕

The present invention will be explained below using an example shown in the drawings.

FIG. 1 is a sectional view of the thermal head of the present invention. In the thermal head of the present invention, a partial glaze layer 2 having a substantially semicircular arc cross section is formed on an insulating substrate 1, and a high oxide layer Ta2052a of metal Ta having good etching resistance is formed on top of the partial glaze layer 2 on an insulating substrate 1. Formed by 1-0.5 it m sputtering.

Furthermore, in the same process, gold f4 is continuously formed with an easily etched layer.
A low Ta oxide layer TaOx 2b is formed to a thickness of 2 to 3 μm. Then, a partial glaze layer 2 is created using 7Otrin technology.
The low oxide layer 2b is photo-etched so that the substantially top surface thereof is convex, and the low oxide layer 2b is etched using an air firing furnace.
Calcinate at 00 to 600°C for about 1 hour and slowly cool. On top of this, a heating resistor layer 3 made of Ta2N and a power supply layer 4 made of a metal oxide are laminated, and the heating resistor layer 3 is approximately attached to the convex portion formed on the partial glaze layer 2 by IJ non-technique. The power supply layer 4 is divided so as to be located at the same position. Furthermore, a first protective layer 5 made of oxidation-resistant SiO□ or the like is formed by sputtering, and a wear-resistant Ta205 layer is formed thereon.
A second protective layer 6 made of the following is formed.

In this way, so that the approximately top surface of the glaze layer is convex,
Using the same material that forms etching resistance 2a, a low oxide layer is efficiently formed by continuous reactive sputtering, and then a negative resist is used by photolithography to form the same as in the normal process. By performing this treatment, the low oxide layer can be processed into a convex shape. At this time, since the negative resist has poor durability against boiling nitric acid and its adhesion deteriorates as the immersion time increases, side etching automatically occurs during etching. In the present invention, on the contrary, this side etching characteristic is utilized to impart sufficient roundness to the etched stepped corner, thereby preventing disconnection of the extremely thin heating resistor layer 3, and at the same time, when mechanically sliding contact is made, it is possible to Prevents loads from being applied to corners. This side etching amount is
This can be controlled by removing the resist midway through immersion in the tinda solution and post-baking the resist again.

Next, after forming the low oxide layer 2b in a convex shape, it is fired in an oxidizing atmosphere using an air firing furnace to form a low oxide layer 2b.
The low nitride, low carbide, etc. electrically conductive layer is made into a high oxide layer to impart insulation properties, and the resistance value of the heating resistor layer 3 is stabilized, and by heat treatment,
It has a great effect of alleviating the internal stress of each layer generated during sputtering film formation.

Generally, the sputtering temperature is 300°C due to equipment limitations, and sputtered films always generate large internal stress. To thermal, the heating temperature of the 3rd part of the 7th heating resistor layer is 5
00 to 6000 G, the Suhanota film can be sufficiently annealed at 500 to 600° C. to relieve internal stress, thereby making it difficult to cause mechanical damage.

〔Effect of the invention〕

As described above, the thermal head of the present invention uses the etching-resistant layer and the easy-etching layer formed on the glaze layer to create a convex shape using the futolithography technique, and the corners of the convex portion are turned to the side. The amount of etching is adjusted to make it smooth, and heat treatment is added to impart insulation through oxidation and to relieve the internal stress of the protruding portion, and then a heat generating portion is formed. By doing this, the concavities that conventionally occurred due to division of the power supply layer are completely eliminated, and on the contrary, the convexity can be made, so that the thermal efficiency is significantly improved. In addition, the protrusions have little internal stress and the corners have a smooth curvature, which improves durability against mechanical loads, resulting in a long thermal life.

[Brief explanation of drawings]

FIG. 1 is a structural cross-sectional view showing one embodiment of the thermal head of the present invention, FIGS. 2 and 3 are structural cross-sectional views of a conventional thermal head, and FIG. 4 is a structural cross-sectional view of a conventional thermal head. It is a structural sectional view of what is formed into a shape. 1 Insulating substrate 2...Glaze layer 2a Etching resistant layer 2b Etching easily layer 3 Heat generating resistor layer
4. Power supply layer 5. Oxidation-resistant layer 6, wear-resistant layer 7...protective layer\, J-/ Fig. 1 Fig. 2 q

Claims (2)

[Claims] (1) A glaze layer is formed on an insulating substrate, a plurality of heat generating resistor layers are linearly arranged on the glaze layer, and a power supply layer that supplies power to the heat generating resistor layer, and its power supply. In the thermal head comprising a body layer and a protective layer formed on the heat generating resistor layer, a high oxide, nitride or carbide of a metal with good etching resistance is formed on the insulating substrate having the partial glaze layer. A low oxide, nitride, or carbide layer of the above-mentioned metal having easy etching properties was laminated on top of the layer, and a mesa-shaped protrusion with a gentle end surface was formed on the glaze layer. A thermal head characterized by: (2) The thermal head according to claim (1), characterized in that a thermal oxidation treatment is applied after the protrusion is formed to provide insulation and relieve internal stress in each layer.