JPH07329331A - Thermal head and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a thermal head in which high minuteness and high printing quality in the case of printing at a high speed can be held for a long period, its yield is improved and which has excellent productivity, and a method for manufacturing the same. CONSTITUTION:A board 10 is formed of single crystalline silicon. The board 10 is formed of a flat plate part 10A and a mesa part 10B formed integrally on the part 10A, adjacently disposed via substantially V-shaped or U-shaped groove 10c, and made of a mesa 10a for a heat generator having a heat generating element 12a and a mesa 10b for an edge having an ink ribbon peeling edge 13. The board 10 is formed on its surface with a heat insulation layer 11 having a substantially uniform thickness made of Si and low oxide content of transition metal, and with a common electrode 15 on the surface of the layer 11 on the groove 10c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head mounted on a thermal transfer printer and a method for manufacturing the same, and more particularly to a thermal head having good printing performance and suitable for high speed printing, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally, a thermal head mounted on a thermal transfer printer has a plurality of heating elements, for example, heating elements, arranged in one or more rows on a substrate, and each heating element is formed according to desired print information. Is selectively heated by energizing to record on various recording media such as color recording on a thermal recording paper or transfer recording onto a paper via an ink ribbon.

A conventional thermal head is shown in FIG.
Will be described.

FIG. 6 is an enlarged vertical sectional view showing a main part of a conventional thermal head.

As shown in FIG. 6, a conventional thermal head 1 has a substantially arc-shaped cross section made of glass or the like that functions as a heat retaining layer (heat storage layer) on an insulating substrate 2 made of ceramics such as alumina. The glaze layer 3 is formed. Then, a trapezoidal mesa 3b having a substantially trapezoidal cross section is formed by isotropic etching in a region where a heat generating portion 4 will be formed, which will be described later, at approximately the top 3a of the glaze layer 3. Ta ₂ is formed on the upper surface of the trapezoidal mesa 3b.
Heating element 4a made of a desired heating resistor made of N or the like
However, after being deposited by an appropriate method such as vapor deposition or sputtering, the heat generating portions 4 are formed by being aligned according to the number of dots corresponding to a desired resolution by etching or the like. Further, a desired common electrode 5 connected to each heating element 4a is formed on one side (right side) of the heating section 4. Further, on the other side (left side) of the heat generating portion 4, desired individual electrodes 6 for independently energizing each heat generating element 4a are formed. Both electrodes 5 and 6 are made of, for example, aluminum,
After using copper or gold as a material and depositing it by a desired method such as vapor deposition or sputtering, a pattern having a desired shape is formed by etching or the like.

The upper right side of the substrate 2 is an ink ribbon peeling edge portion 7 for peeling an ink ribbon (both not shown) from the recording medium.

A desired protective layer 8 having a film thickness of about 5 to 10 μm is formed on the surfaces of the heating element 4a, the common electrode 5 and the individual electrode 6 in order to protect them from oxidation or abrasion. There is. The protective layer 8 covers all surfaces of the electrodes 5 and 6 except the terminal portions, and is made of sialon or the like having good oxidation resistance and wear resistance, and laminated by a desired method such as sputtering. Has been formed.

Incidentally, a conventional thermal head 1 of this type
Is a production method in which a plurality of thermal heads 1 are simultaneously formed on one large substrate (not shown), and the large thermal substrates 1 are simultaneously obtained by dividing the large substrate at desired positions. It is often used for such reasons.

In such a thermal transfer printer (not shown) using the conventional thermal head 1, the desired recording medium (both not shown) in which the thermal head 1 is conveyed to the platen via the ink ribbon is used. , For example, in the state of being pressed against the paper, the individual electrodes 6 connected to the heating elements 4a selected based on the desired print signal are energized, and the desired heating elements 4a are heated to generate heat. The ink (both not shown) of the ink ribbon at the portion facing the heating element 4a is melted and transferred to the paper, and desired printing of characters and figures is performed on the paper.

When a thermal recording paper is used as the recording medium, the thermal head 1 is in direct contact with the desired thermal recording paper (both not shown) conveyed to the platen without the ink ribbon. , The individual electrodes 6 connected to the heating elements 4a selected on the basis of the desired print signal are energized to heat the desired heating elements 4a, whereby the heat-sensitive recording of the portion facing the heating elements 4a Printing is performed by partially coloring the paper.

In such a conventional thermal head 1, the glaze layer 3 has a low thermal conductivity (2.5 × 1).
0 ⁻³ cal / cm · sec · ° C.) and the thermal conductivity of the substrate 2 made of alumina or the like (40 × 10 ⁻³ cal / cm · sec)
.Degree. C.), a heat storage effect of Joule heat generated in the heating element 4a is utilized to obtain a balance of power efficiency and printing characteristics. In other words, the heat storage effect of the glaze layer 3 lengthens the cooling time constant of the heating element 4a, and causes print quality deterioration such as tailing, bleeding, and smearing of printing in high-speed printing. Is determined by the design concept in consideration of both power efficiency and printing characteristics, and is generally 30 to 6
The thickness is about 0 μm, and the end portion of the substrate 2 (see FIG.
A trapezoidal mesa 3b is provided on the upstream side (right side in the running direction of the thermal head 1 indicated by an arrow at the right side), and the heat generating portion 4 is disposed on the trapezoidal mesa 3b. There is.

In recent years, the thermal head 1
The printing speed has been increased, the resolution has been improved, and the printing quality has been improved. The thermal transfer printer (not shown) has a printing resolution of 400 dpi and a printing speed of 100 cps.
Has been put to practical use. In such a high-speed and high-definition thermal transfer printer, the driving cycle of the heating element 4a is 3
Energization control is performed with an extremely short pulse width of 00 μs or less. Further, future thermal transfer printers are required to further increase the printing speed, increase the definition, and improve the printing quality.

In such a high-definition and high-speed printing thermal transfer printer, the thermal head 1 accumulates a lot of heat, and the thickness of the glaze layer 3 is about 30 μm in order to prevent the deterioration of the printing quality due to the thermal head 1. In addition, the thermal history correction LSI is used to correct the energization time to the heat generating element 4a to finely control the temperature rise due to the heat storage of the thermal head 1.

[0014]

However, in the above-mentioned conventional thermal head 1, it is necessary to use an expensive thermal history correction LSI, which increases the economical burden and consequently the apparatus becomes expensive. Has
Generally, the one excluding the advanced thermal control performance is used,
There is a problem that the temperature rise due to the heat storage of the thermal head 1 cannot be controlled sufficiently.

Further, the heat storage in the conventional thermal head 1 was caused only by the low thermal conductivity glaze layer 3, but as a result of the inventors' earnest research over the years, as described above. It was found that the low thermal conductivity of the substrate 2 is the main cause in the case of high-speed printing in which the heating element 4a has a short energization period.

Further, in the conventional thermal head 1, the energization control is performed with an extremely short pulse width of the driving period of the heating element 4a of 300 μs or less, and in order to obtain high quality printing quality, the thermal head 1 has It is necessary to increase the peak temperature of the heating element 4a and apply a predetermined high-temperature printing energy to the ink ribbon or the thermal paper (both not shown) in a short time. When the temperature is set to ˜35 ° C., it is necessary to maximize the applied energy in order to obtain the required peak temperature of the heating element 4a at a low temperature of 5 ° C. Depending on the print pattern, the peak temperature of the heating element 4a is The temperature becomes higher than about 700 ° C. which is the heat resistant temperature of the glaze layer 3 and the heating element 4a, the glaze layer 3 is thermally deformed or melted, and
There is a problem in that the resistance value of the heating element 4a changes and high-speed printing cannot be performed in a low temperature environment.

Furthermore, in the conventional thermal head 1, the heating element 4a made of a cermet-based material such as Ta-SiO ₂ has a characteristic that its sheet resistance value is halved by high temperature heat treatment. Therefore, heat treatment at a temperature higher than the actual use temperature (high temperature vacuum annealing treatment)
However, since the heat resistant temperature of the glaze layer 3 is low as described above, there is a problem that the heat treatment cannot be performed at a temperature higher than the actual use temperature.

Further, in the conventional thermal head 1, when manufacturing the thermal head 1 as described above, a plurality of thermal heads 1 are simultaneously formed on one large substrate, and the substrate is desired. A manufacturing method is used in which a plurality of desired thermal heads 1 can be obtained at the same time by dividing at a position, and since this large substrate is divided by grinding, the thermal head 1 with a real edge is particularly used. In the above, since the grinding process is performed including the glaze layer 3, the edge portion of the divided portion formed by the grinding process becomes sharp, and
There is a problem that chipping occurs in the glaze layer 3 to lower the yield and print quality. For this reason, the edge portion of the substrate 2 is not subjected to the grinding process for dividing the substrate 1 but is subjected to a polishing process for smoothing (rounding) the sharp edge portion in a separate step after the dividing process. There is a problem that accuracy, yield, and productivity are reduced.

Furthermore, in the conventional thermal head 1, the trapezoidal mesa 3b having a substantially trapezoidal cross section formed on the glaze layer 3 is formed by increasing the inclination angle α of the slope with a height of about 5 to 10 μm. Although the printing efficiency and the printing quality on the rough paper can be improved, when the trapezoidal mesa 3b is formed on the glaze layer 3 using isotropic etching, a curved surface cannot be formed at the corner 3c of the trapezoidal mesa 3b. A trapezoidal mesa 3b having a step (a sharp corner is formed)
When the inclination angle α of the slope is increased to, for example, approximately 15 degrees or more, a problem that a mask formation defect frequently occurs in the photolithography process of forming the heating element 4a and each of the electrodes 5 and 6 and the yield is significantly reduced. There was a point. In addition, the trapezoidal mesa 3b formed in the glaze layer 3 is formed by isotropic etching of a material made of glass. In the isotropic etching of glass, the slope of the trapezoidal mesa 3b is inclined. There is a problem in that the controllability of the angle α is poor and the yield is reduced, and unevenness of contact between the heating element 4a and the recording medium is generated, and the print quality is degraded.

Further, in the conventional thermal head 1, if an attempt is made to further realize a real edge, the pressure contact force between the thermal head 1 and the platen (not shown) becomes
The heat generating element 4a concentrates on the heat generating portion 4 and the common electrode 5 adjacent to the heat generating portion 4, and the protective layer 8 on the common electrode 5 is prematurely cracked or peeled off, resulting in long-term print quality and print life. However, there is a problem in that it cannot be held for a long time. Further, since the common electrode 5 is arranged between the heating element 4a and the ink ribbon peeling edge portion 7,
When a further realization of the edge is attempted, the heat generating portion 4 comes closer to the edge of the substrate 2, which narrows the width of the common electrode 5 and causes a voltage drop (common drop). There is a problem in that the printing life is shortened as well as the deterioration occurs.

Furthermore, in the conventional thermal head 1, the thermal conductivity of the glass glaze layer 3 is small at room temperature (2.5 × 10 ⁻³ cal / cm · sec).
.Degree. C.) and 600.degree. C., it has a characteristic of being about twice as large as that at room temperature, and there is a problem that the thermal efficiency of printing is insufficient when used in the thermal head 1. Further, the glaze layer 3 is formed by subjecting the glass paste to a thick film printing and firing method, and in such a forming method,
There is a problem in that waviness occurs in the length direction and the height direction, unevenness of contact between the heating element 4a and the recording medium occurs during printing, and print quality deteriorates.

Furthermore, in the conventional thermal head 1, the substrate 2 made of alumina is formed by firing alumina particles in the form of green sheets. However, there is a problem in that when the fine pattern is formed, defects such as pattern short-circuiting and opening frequently occur due to the influence of surface irregularities, and the yield decreases. Also,
Since the substrate 2 made of alumina is formed by firing a green sheet, there is a problem in that the substrate 2 is largely warped by firing and the yield and the manufacturing quality are deteriorated.

The present invention has been made in view of these points, and it is possible to maintain high definition in high-speed printing and high printing quality for a long period of time, improve the yield, and improve the productivity. An object is to provide a head and a manufacturing method thereof.

[0024]

In order to achieve the above-mentioned object, the thermal head of the present invention according to claim 1 has a heat insulating layer formed on the surface of a substrate, and a plurality of heating elements are formed on the surface of this heat insulating layer. And a separate electrode and a common electrode connected to each heating element are formed, and at least the surface of the heat retaining layer, the heating element, the individual electrode and the common electrode is covered with a protective layer, and the substrate is a single crystal. Heat generated from silicon, the substrate being formed integrally with the flat plate portion and adjacent to each other via a substantially V-shaped or U-shaped groove portion on the flat plate portion Part mesa and a mesa part composed of an edge mesa provided with an ink ribbon peeling edge part, and a low oxide of Si and a transition metal on the surface of the substrate. Forming a heat insulating layer of uniform thickness, and is characterized by forming the common electrode on the surface of the insulation layer above the groove.

A thermal head according to a second aspect of the present invention is characterized in that, in the first aspect, the substrate is made of single crystal silicon having a surface crystal orientation of (100).

Further, a thermal head according to a third aspect of the present invention is characterized in that, in the first or second aspect, the heat generating portion mesa and the edge mesa are offset to one side of the substrate. There is.

A thermal head according to a fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, the inclination angle of the slope of the edge mesa is approximately 55 degrees. I am trying.

A thermal head according to a fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, the height of the heat generating portion mesa is 5 to 15 μm. There is.

A thermal head according to a sixth aspect of the present invention is the thermal head according to any one of the first to fifth aspects, wherein the heat retaining layer is formed in a columnar shape, and
It is characterized in that its thickness is 15 to 35 μm.

A thermal head according to a seventh aspect of the present invention is the thermal head according to any one of the first to sixth aspects, wherein the heat insulating layer is made of a black low oxide containing Si and Ta as main components. It is characterized by becoming.

The method of manufacturing a thermal head of the present invention according to claim 8 is any one of claims 1 to 7.
The method of manufacturing a thermal head as described in 1 above, wherein a heat insulating layer is formed on the surface of the substrate, and on the surface of the heat insulating layer, a heat generating portion including a plurality of heat generating elements and an individual electrode and a common electrode connected to each heat generating element. And a mask for forming a mask layer on the surface of a substrate made of single crystal silicon in a method of manufacturing a thermal head in which Forming step, a mask pattern forming step of forming a mask pattern for forming a heating portion mesa on the mask layer, and a heating portion mesa forming step of forming a heating portion mesa on the substrate on which the mask pattern is formed And a residual mask removing step of removing a residual mask layer by etching the substrate on which the heat generating portion mesa is formed, The mesa intermediate finishing step for the heat generating part to reduce the inclination angle of the surface, the final finishing step for the mesa for the heating part to set the inclination angle of the slope of the mesa for the heating section to a predetermined value and round the corners, and the final finishing are performed. A re-mask forming step of forming a mask layer again on the surface of the substrate having the heat generating portion mesa formed therein, and forming a groove and an edge mesa on the surface of the substrate having the heat generating portion mesa on which the mask layer has been formed again. A re-mask pattern forming step of re-forming a mask pattern for forming a groove pattern and an edge mesa forming step of forming a groove portion and an edge mesa in a substrate having a heat generating portion mesa on which the mask pattern is formed again; A heat retaining layer forming step of forming the heat retaining layer on the substrate on which the mesa, the groove and the edge mesa are formed, and the warp of the substrate caused by the heat retaining layer forming step. Strain removing step for removing, heating element stabilization treatment step for stabilizing the resistance value of the heating element formed on the surface of the heat retaining layer, and common electrode forming step for forming a common electrode on the surface of the heat retaining layer on the groove portion. And are performed in this order.

The method of manufacturing a thermal head according to a ninth aspect of the present invention is characterized in that, in the eighth aspect, the heating portion mesa forming step and the groove / edge mesa forming step are anisotropic etching. There is.

According to a tenth aspect of the present invention, in the method of manufacturing a thermal head according to the eighth aspect or the ninth aspect, the mesa intermediate finishing step for the heating portion is a full anisotropic etching and a full isotropic etching. It is characterized by being.

According to the eleventh aspect of the present invention, in the method of manufacturing a thermal head according to the eighth aspect, the heat retaining layer forming step is O ₂ reactive sputtering. It has a feature.

A thermal head manufacturing method according to a twelfth aspect of the present invention is the thermal head manufacturing method according to any one of the eighth to eleventh aspects, wherein the strain removing step is 800 to 900 ° C.
It is characterized by the heat treatment of.

Further, a method of manufacturing a thermal head according to a thirteenth aspect of the present invention is the method of manufacturing a thermal head according to any one of the eighth to twelfth aspects, wherein the heating element stabilization treatment step is 800.
It is characterized in that the heat treatment is up to 900 ° C.

According to a fourteenth aspect of the present invention, in the thermal head of the present invention, a heat retaining layer is formed on the surface of the substrate, and a plurality of heat generating elements and individual electrodes connected to each heat generating element are formed on the surface of the heat retaining layer. In a thermal head having a common electrode and at least the surfaces of the heat retaining layer, the heating element, the individual electrode and the common electrode covered with a protective layer, the substrate is formed of single crystal silicon, and the substrate is a flat plate. Section, and a heat generating section mesa and an ink ribbon peeling edge section which are integrally formed on the flat plate section and are adjacent to each other through a common electrode groove section having a flat bottom surface. And a heat-insulating layer having a substantially uniform thickness made of Si and a low oxide of a transition metal on the surface of the substrate. And it is characterized by forming the common electrode on the surface of the insulation layer above the groove.

A thermal head according to a fifteenth aspect of the present invention is characterized in that, in the fourteenth aspect, the substrate is made of single crystal silicon having a surface crystal orientation of (100).

A thermal head according to a sixteenth aspect of the present invention is characterized in that, in the fourteenth aspect or the fifteenth aspect, the heat generating portion mesa and the edge mesa are offset to one side of the substrate. There is.

A thermal head according to a seventeenth aspect of the present invention is the thermal head according to any one of the fourteenth to sixteenth aspects, wherein the slope angle of the edge mesa is approximately 55 degrees. I am trying.

Further, the thermal head of the present invention according to claim 18 is characterized in that, in any one of claims 14 to 17, the height of the mesa for the heat generating portion is 5 to 15 μm. There is.

A thermal head according to a nineteenth aspect of the present invention is the thermal head according to any one of the fourteenth to eighteenth aspects, wherein the heat retaining layer is formed in a columnar shape and has a thickness. The feature is that it is 15 to 35 μm.

A thermal head according to a twentieth aspect of the present invention is characterized in that, in the nineteenth aspect, the heat retaining layer is made of a low oxide containing Si and a transition metal as a main component.

A method of manufacturing a thermal head according to a twenty-first aspect of the present invention is the method of manufacturing a thermal head according to any one of the fourteenth to twentieth aspects, wherein the heat insulating layer is provided on the surface of the substrate. A heat-generating part composed of a plurality of heat-generating elements and individual electrodes and common electrodes connected to the heat-generating elements are formed on the surface of the heat-retaining layer, and at least the heat-retaining layer, the heat-generating elements, the individual electrodes and the common electrode are formed. In a method of manufacturing a thermal head having a surface covered with a protective layer, a first mask forming step of forming a mask layer on the surface of a substrate made of single crystal silicon, and a mesa for a heating portion is formed on the mask layer. First to form a mask pattern for
Mask pattern forming step, a heating portion mesa forming step of forming a heating portion mesa by etching the substrate on which the first mask pattern is formed, and a substrate on which the heating portion mesa is formed. A first residual mask removing step of removing the remaining mask layer, a heating portion mesa intermediate finishing step of reducing the inclination angle of the slope of the heating portion mesa, and an inclination angle of the slope of the heating portion mesa are set to predetermined values. A final finishing process for the heat generating part that rounds the corners with the value,
A second mask forming step of forming a mask layer again on the surface of the substrate having the final-finished mesa for the heating portion, and accommodating a common electrode on the surface of the substrate on which the second mask layer is formed. A second mask pattern forming step of forming a mask pattern for forming a common electrode groove having a flat surface at the bottom, and a flat surface having a flat bottom surface by etching the substrate on which the second mask pattern is formed. Forming a common electrode groove portion, forming a common electrode groove portion, forming a common electrode groove portion, a second residual mask removing step of removing a mask layer remaining on the substrate in which the common electrode groove portion is formed, the heat generating portion mesa and A third mask forming step of forming a mask layer again on the surface of the substrate on which the common electrode groove is formed,
A third mask pattern forming step of forming a mask pattern for forming an edge mesa on the surface of the substrate on which the third mask layer is formed; and etching the substrate on which the third mask pattern is formed. An edge mesa forming step of forming an edge mesa by performing the third step, a third residual mask removing step of removing a mask layer remaining on the substrate on which the edge mesa is formed, the heating section mesa and the common electrode Forming a heat insulating layer on the substrate on which the groove and the edge mesa are formed, a strain removing step of removing warp of the substrate caused by the heat insulating layer forming step, and forming on the surface of the heat insulating layer The heat generating element stabilization treatment step for stabilizing the resistance value of the heat generating element and the common electrode forming step for forming a common electrode on the surface of the heat insulating layer on the common electrode groove are performed. It is characterized in that it is carried out in the order.

According to a twenty-second aspect of the present invention, in the method of manufacturing a thermal head according to the twenty-first aspect, the heating section mesa forming step is anisotropic etching, and the heating section mesa intermediate finishing step is performed. The entire surface is anisotropically etched, and the final finishing step of the mesa for the heating portion is isotropic rounding etching.

The thermal head manufacturing method according to the twenty- _{third aspect} of the present invention is the thermal head manufacturing method according to the twenty-first aspect or the twenty-second aspect, wherein the heat retaining layer forming step is an O ₂ reaction using an alloy target of Si and a transition metal. It is characterized in that it is a characteristic sputter.

A thermal head manufacturing method according to a twenty-fourth aspect of the present invention is the thermal head manufacturing method according to any one of the twenty-first to twenty-third aspects, wherein the distortion removing step is 800 to 900.
It is characterized in that it is a heat treatment at ℃.

A thermal head manufacturing method according to a twenty-fifth aspect of the present invention is the method of manufacturing a thermal head according to any one of the twenty-first to twenty-fourth aspects, wherein the heating element stabilization treatment step is 80.
It is characterized by being a heat treatment of 0 to 900 ° C.

A method of manufacturing a thermal head according to a twenty-sixth aspect of the present invention is the method of manufacturing a thermal head according to any one of the fourteenth to twentieth aspects, wherein the heat insulating layer is provided on the surface of the substrate. A heat-generating part composed of a plurality of heat-generating elements and individual electrodes and common electrodes connected to the heat-generating elements are formed on the surface of the heat-retaining layer, and at least the heat-retaining layer, the heat-generating elements, the individual electrodes and the common electrode are formed. In a method of manufacturing a thermal head having a surface covered with a protective layer, a first mask forming step of forming a mask layer on the surface of a substrate made of single crystal silicon, and a mesa for a heating portion is formed on the mask layer. First to form a mask pattern for
Mask pattern forming step, a heating portion mesa forming step of forming a heating portion mesa by etching the substrate on which the first mask pattern is formed, and a substrate on which the heating portion mesa is formed. A first residual mask removing step of removing the remaining mask, a heat generating portion mesa intermediate finishing step of reducing the inclination angle of the slope of the heat generating portion mesa, and a predetermined inclination angle of the slope of the heat generating portion mesa. And at the same time the mesa final finishing process for the heating part that rounds the corners,
Forming a mask layer made of thermally oxidized SiO _{2 on} the surface of the substrate having the final-finished mesa for the heating portion
And a second mask pattern for forming a mask pattern for forming a common electrode groove having a flat bottom surface for accommodating the common electrode on the surface of the substrate on which the second mask layer is formed. A forming step, a common electrode groove forming step of forming a common electrode groove having a flat bottom surface by etching the substrate on which the second mask pattern is formed, and the heating portion mesa and common electrode A third mask forming step of forming again a mask layer made of thermally oxidized SiO _{2 on} the surface of the substrate on which the groove for use is formed, and forming an edge mesa on the surface of the substrate on which the third mask layer is formed. And a third mask pattern forming step of forming a mask pattern for forming the edge mesa by etching the substrate on which the third mask pattern is formed. A mesa forming step for forming a heat insulating layer, a heat insulating layer forming step for forming the heat insulating layer on the substrate on which the heat generating portion mesa, the common electrode groove portion and the edge mesa are formed, and a warp of the substrate caused by the heat insulating layer forming step. To remove the strain, a heating element stabilization treatment step to stabilize the resistance value of the heating element formed on the surface of the heat insulating layer, and a common electrode is formed on the surface of the heat insulating layer on the common electrode groove. The common electrode forming process is performed in this order.

According to a twenty-seventh aspect of the present invention, in the method of manufacturing a thermal head according to the twenty-sixth aspect, the heating portion mesa forming step is anisotropic etching, and the heating portion mesa intermediate finishing step is performed. The entire surface is anisotropically etched, and the final finishing step of the mesa for the heating portion is isotropic rounding etching.

Further, the manufacturing method of the thermal head of the present invention according to claim 28 is the method according to claim 26 or 27, wherein the heat insulating layer forming step is an O ₂ reaction using an alloy target of Si and a transition metal. It is characterized in that it is a characteristic sputter.

A thermal head manufacturing method according to a twenty-ninth aspect of the present invention is the method of manufacturing a thermal head according to any one of the twenty-sixth to twenty-eighth aspects, wherein the distortion removing step is 800 to 900.
It is characterized in that it is a heat treatment at ℃.

A thermal head manufacturing method according to a thirtieth aspect of the present invention is the method according to any one of the twenty-sixth to twenty-ninth aspects, wherein the heating element stabilization treatment step is 80.
It is characterized by being a heat treatment of 0 to 900 ° C.

[0054]

According to the thermal head of the present invention as set forth in claim 1, by using the substrate made of single crystal silicon, the heating portion mesa and the ink ribbon peeling edge portion on which the heating element is formed are formed. It is possible to directly and easily form the edge mesa and the substantially V-shaped or U-shaped groove portion in which are formed, and it is possible to improve processing accuracy and thermal characteristics. By forming the common electrode on the groove, the width of the common electrode can be widened and the voltage drop can be reduced. Furthermore, by using a low oxide of Si and a transition metal for the heat retaining layer, it is possible to reduce the thermal conductivity and improve the heat resistance.

According to the thermal head of the second aspect of the present invention, by using the substrate made of single crystal silicon having a surface crystal orientation of (100), the mesa for the heating portion and the ink ribbon peeling edge portion are formed. The formed edge mesa and the substantially V-shaped or U-shaped groove portion can be directly and accurately formed easily.

According to the thermal head of the third aspect of the present invention, the heating portion mesas and the edge mesas are offset to one side of the substrate without narrowing the width of the common electrode, thereby forming a real edge. Can be easily achieved.

According to the thermal head of the present invention described in claim 4, by setting the angle of the slope of the edge mesa to about 55 degrees, the peeling edge of the ink ribbon having an angle suitable for peeling the ink ribbon can be obtained. Can be easily formed.

According to the thermal head of the fifth aspect of the present invention, the printing efficiency and the printing quality on the rough paper can be improved by setting the height of the heat generating portion mesa to 5 to 15 μm.

According to the thermal head of the sixth aspect of the present invention, the heat resistance can be improved by using the heat insulating layer formed in the columnar shape having a thickness of 15 to 35 μm.

According to the thermal head of the seventh aspect of the present invention, by using the heat insulating layer made of black low oxide containing Si and Ta as main components, the thermal conductivity is small and the heat resistance is excellent. The heat insulating layer can be easily formed.

According to the method of manufacturing a thermal head of the present invention described in claim 8, the thermal head described in claims 1 to 7 can be manufactured accurately, efficiently and easily.

According to the method of manufacturing a thermal head of the present invention as defined in claim 9, by anisotropic etching, an edge mesa having a slope angle of about 55 degrees can be easily and accurately and easily manufactured on the substrate. can do.

According to the method of manufacturing a thermal head of the present invention as set forth in claim 10, the height is 5 to 15 μm and the inclination angle of the slope is 15 to 20 degrees by anisotropic etching and isotropic etching on the entire surface. The mesa for the heat generating portion can be manufactured easily with high accuracy and efficiency.

According to the method of manufacturing a thermal head of the present invention as set forth in claim 11, the heat insulating layer formed into a columnar material by O ₂ reactive sputtering having a small thermal conductivity and excellent heat resistance can be easily formed. Can be formed.

According to the method of manufacturing a thermal head of the present invention as set forth in claim 12, the warp of the substrate can be easily removed by performing the heat treatment at 800 to 900 ° C.

According to the method of manufacturing a thermal head of the present invention as set forth in claim 13, heat treatment at 800 to 900 ° C. can surely stabilize the resistance value of the heat generating element in a use state. .

According to the thermal head of the 14th aspect of the present invention, by using the substrate made of single crystal silicon, the heating portion mesa and the ink ribbon peeling edge portion on which the heating element is formed are formed. It is possible to directly and easily form a common electrode groove with a flat bottom surface between the edge mesa and the mesa for heat generating portion and the edge mesa where the machining accuracy and thermal characteristics are improved. Can be made. By forming the common electrode on the common electrode groove portion, the width of the common electrode can be widened, and the voltage drop can be reduced. Furthermore, by using a low oxide of Si and a transition metal for the heat retaining layer, it is possible to reduce the thermal conductivity and improve the heat resistance.

According to the thermal head of the 15th aspect of the present invention, by using the substrate made of single crystal silicon having a surface crystal orientation of (100), the mesa for the heat generating portion and the ink ribbon peeling edge portion are formed. It is possible to directly and accurately and easily form the edge mesa and the common electrode groove having a flat bottom surface between the heat generating portion mesa and the edge mesa.

According to the thermal head of the sixteenth aspect of the present invention, the heat generating portion mesa and the edge mesa are offset to one side of the substrate without narrowing the width of the common electrode, so that a real edge is formed. Can be easily achieved.

According to the thermal head of the seventeenth aspect of the present invention, by setting the angle of the slope of the edge mesa to about 55 degrees, the peeling edge of the ink ribbon having an angle suitable for peeling the ink ribbon can be obtained. Can be easily formed.

According to the thermal head of the eighteenth aspect of the present invention, the printing efficiency and the printing quality on the rough paper can be improved by setting the height of the heat generating portion mesa to 5 to 15 μm.

According to the thermal head of the present invention as set forth in claim 19, the heat resistance can be improved by using the heat insulating layer formed in the columnar material having a thickness of 15 to 35 μm.

According to the thermal head of the present invention as set forth in claim 20, by using the heat retaining layer made of a low oxide containing Si and a transition metal as a main component, the thermal conductivity is small and the heat resistance is excellent. The heat retaining layer can be easily formed.

According to the method of manufacturing a thermal head of the present invention described in claim 21, the thermal head described in any one of claims 14 to 20 can be manufactured accurately, efficiently and easily. .

According to the method of manufacturing a thermal head of the present invention as set forth in claim 22, anisotropic etching, total anisotropic etching and isotropic rounding etching are performed.
The mesa for the heat generating portion of the thermal head according to any one of claims 14 to 20, which has a height of 5 to 15 µm and an inclination angle of the slope of 15 to 20 degrees, is easily and accurately manufactured on a substrate. be able to.

According to the method of manufacturing a thermal head of the present invention as set forth in claim 23, the thermal conductivity formed in the columnar material is small by O ₂ reactive sputtering using an alloy target of Si and a transition metal. It is possible to easily form the heat retaining layer of the thermal head according to any one of claims 14 to 20, which has excellent heat resistance.

According to the method of manufacturing a thermal head of the present invention described in claim 24, the thermal head of any one of claims 14 to 20 is subjected to heat treatment at 800 to 900 ° C. The warp of the substrate can be easily removed.

According to the method of manufacturing a thermal head of the present invention as set forth in claim 25, the thermal head of any one of claims 14 to 20 is obtained by performing heat treatment at 800 to 900 ° C. It is possible to reliably stabilize the resistance value of the heating element in the use state.

According to the manufacturing method of the thermal head of the present invention described in claim 26, the thermal head described in any one of claims 14 to 20 can be manufactured accurately, more efficiently and easily. it can.

According to the method of manufacturing a thermal head of the present invention as set forth in claim 27, anisotropic etching, total anisotropic etching and isotropic rounding etching are performed.
The mesa for the heat generating portion of the thermal head according to any one of claims 14 to 20, which has a height of 5 to 15 µm and an inclination angle of the slope of 15 to 20 degrees, is easily and accurately manufactured on a substrate with high accuracy. can do.

According to the method of manufacturing a thermal head of the present invention as set forth in claim 28, the thermal conductivity formed in the columnar material is small by O ₂ reactive sputtering using an alloy target of Si and a transition metal. It is possible to easily form the heat retaining layer of the thermal head according to any one of claims 14 to 20, which has excellent heat resistance.

According to the method of manufacturing a thermal head of the present invention described in claim 29, the thermal head of any one of claims 14 to 20 is formed by performing heat treatment at 800 to 900 ° C. The warp of the substrate can be easily removed.

According to the method of manufacturing a thermal head of the present invention described in claim 30, heat treatment at 800 to 900 ° C. is performed, so that the thermal head according to any one of claims 14 to 20 is formed. It is possible to reliably stabilize the resistance value of the heating element in the use state.

[0084]

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

FIG. 1 shows a first thermal head according to the present invention.
FIG. 4 is an enlarged vertical sectional view showing the main parts of the embodiment.

As shown in FIG. 1, the thermal head 9 of this embodiment has a substrate 10 made of single crystal silicon. The substrate 10 includes a flat plate portion 10A and the flat plate portion 10A.
A heat generating portion mesa 10a, which is integrally formed on each A, and which is provided with a heat generating element 12a which becomes a heat generating portion 12 via a heat retaining layer 11 described later, and an edge mesa 10b which is provided with an ink ribbon peeling edge portion 13 are provided. Abbreviation V
And a mesa portion 10B arranged adjacent to each other via a groove portion 10c formed in a U shape or a U shape. Then, on the surface of the substrate 2, a heat retaining layer 11 made of Si and a black low oxide of a transition metal and having a substantially uniform thickness is formed. Further, on the surface of the heat retaining layer 11 located above the heat generating portion mesa 10a, a heat generating element 12a made of a heat generating resistor forming the heat generating portion 12 is provided, and one side (left side) thereof is A desired individual electrode 14 for independently energizing each heating element 12a is formed. In addition, the heating unit 1
A desired common electrode 15 connected to each heating element 12a is formed on the surface of the heat retaining layer 11 above the groove portion 10c located on the other side (right side) of 2.

A protective layer 16 is formed on the surfaces of the heating element 12a, the common electrode 15 and the individual electrode 14 to protect them from oxidation or abrasion.

Further, the corner portion of the protective layer 16 located above the right end portion of the top of the edge mesa 10b is the ink ribbon peeling edge portion 13 for peeling the ink ribbon (both not shown) from the recording medium. .

The thermal head 9 of this embodiment will be further described.

The substrate 10 is made of single crystal silicon, especially
It is formed of single crystal silicon having a plane orientation (100). The height H is about 5 to 15 μm and the inclination angle β of the slope is on the upper surface of the one end of the substrate 10, that is, the upstream side (right side) of the thermal head 9 in the traveling direction indicated by the arrow in FIG.
Is formed at about 15 to 20 degrees, and a mesa 10a for a heat generating portion having a substantially trapezoidal cross section is formed.
On the right side of a, a groove portion 1 formed in a substantially V-shape or U-shape
An edge mesa 10b having a substantially trapezoidal cross section with an inclination angle γ of the slope of about 55 degrees is formed through 0c. The height of the heat generating portion mesa 10a and the inclination angle β of the slope
Is less than this range, sufficient pressure cannot be obtained against rough paper and the printing quality tends to deteriorate, and if it is more than this range, the fine pattern of the electrode pattern of the heating element 12a and the electrodes 14 and 15 is formed. Tend to occur, and the yield tends to decrease. Also, the edge mesa 10
If the inclination angle γ of the slope of b is smaller than this inclination angle γ, the ink cuttability tends to be unstable, and if it is larger than this angle, the ink tends to drop from the ink ribbon. The upper surfaces of the heat generating portion mesa 10a and the edge mesa 10b are substantially flat top surfaces having a desired width, and the height position of the top surface of the heat generating portion mesa 10a is
It is located above and above the height of the top surface of the edge mesa 10b.

On the surface of the substrate 10, in this embodiment, a heat insulating layer 11 containing a black low oxide of Si and Ta as a main component is formed. And this heat insulation layer 11
Is formed to have a substantially uniform thickness of about 15 to 35 μm, which is suitable for heat retention during high-speed printing, and has a columnar shape. In addition, as a main component of the heat insulation layer 11,
Si and a transition metal, for example, a low oxide such as Ta, W, Cr, or Mo may be used, and is not particularly limited to the configuration of this embodiment.

Ta ₂ N or Ta-SiO ₂ is formed on the surface of the heat retaining layer 11 located above the heat generating portion mesa 10a.
After a desired heating element 12a composed of, for example, is deposited by an appropriate known method such as vapor deposition or sputtering, it is aligned according to the desired number of dots so as to correspond to the resolution by known etching or the like. The heating portion 12 is thus formed. A desired individual electrode 14 connected to each heating element 12a and independently energized is formed on one side (downstream side in the traveling direction: left side) of the heating section 12, and the other side of the heating section 12 ( A common electrode 15 connected to each heating element 12a is formed in the groove 10c on the upstream side in the traveling direction: right side). The individual electrode 14 and the common electrode 15 are made of, for example, Al, Cu, Au, or the like, and are applied to the surface of the heat retaining layer 11 by a known method such as vapor deposition or sputtering, and then are formed into a desired shape by a known etching or the like. Formed in a pattern.

On the surfaces of the heating element 12a, the common electrode 15 and the individual electrode 14, 5 to protect them are provided.
The desired protective layer 16 having a thickness of about 10 μm is formed on the common electrode 1.
5 and the individual electrodes 14 are formed so as to cover all the surfaces outside the terminal portions. This protective layer 16 is
In order to protect the heating element 12a from deterioration due to oxidation and to protect the heating element 12a and the electrodes 14 and 15 from abrasion due to contact with an ink ribbon (not shown), a sialon having good oxidation resistance and abrasion resistance, Si-
It is formed by a known method such as sputtering using ON or the like as a material.

Further, the corner portion of the protective layer 16 above the right end portion of the edge mesa 10b (above the right end portion of the right top surface) serves as the ink ribbon peeling edge portion 13, and
The ink ribbon peeling distance L from the center CL of the heat generating portion 12 to the ink ribbon peeling edge portion 13 is formed as short as possible in order to achieve a further real edge. The ink ribbon peeling distance L may be determined based on the design concept, the result of thermal analysis simulation, and the like.

Next, a method of manufacturing the thermal head 9 of this embodiment will be described.

FIG. 2 is a process drawing showing the main part of one embodiment of the method of manufacturing the thermal head of the first embodiment according to the present invention.

A method of manufacturing the thermal head 9 of this embodiment will be described with reference to the process chart shown in FIG.

First, in the mask forming step, on the surface of the substrate 10 made of mirror-finished single crystal silicon, a SiO ₂ film having a thickness of about 0.5 μm is formed by thermal oxidation, or SiO ₂ or Ta is formed by sputtering or the like. ₂
A film of O ₅ , Si ₃ N ₄ or the like is formed to form a desired mask layer.

Next, in the mask pattern forming step, a photoresist is applied to the surface of the mask layer by a spinner or the like to form a desired resist pattern by a photolithography technique. If the mask layer is SiO ₂ , then a buffered layer is formed. Etching with hydrofluoric acid (BHF), mask layer is T
In the case of a ₂ O ₅ and Si ₃ N ₄ , RIE (Reacti
ve ion etching) or CDE (Che
A desired mask pattern is formed by etching with a mechanical dry etching.

Next, in the heat generating portion mesa forming step,
By anisotropically etching the substrate 10 on which the mask pattern is formed using an alkaline solution such as a KOH aqueous solution, the substrate 10 made of single crystal silicon having a plane orientation (100) has a height of about 5 to 15 μm. The mesa 10a for the heat generating portion having the slope angle of about 55 degrees is formed. By anisotropically etching single crystal silicon having a plane orientation (100), the inclination angle is necessarily about 55 degrees.

Next, in the residual mask removing step, the mask layer is removed by etching the substrate 10 on which the heat-generating-portion mesa 10a having an inclination angle of about 55 degrees is formed.

Next, in the heat generating portion mesa intermediate finishing step, the heat generating portion mesa 10a having a slope angle of about 55 degrees.
The entire surface of the substrate 10 on which is formed is anisotropically etched using an alkaline solution such as a KOH aqueous solution to reduce the inclination angle of the slope from 55 degrees to about 25 degrees.

Next, in the mesa final finishing step for the heat generating portion, a hydrofluoric nitric acid etchant (HF: HNO ₃ : CH ₃
COOH = 1: 8: 3) is used to perform isotropic etching on the entire surface so that the inclination angle of the slope of the heat generating portion mesa 10a is about 15 to 20 degrees and the heat generating portion mesa 1 is formed.
The corner formed by the top of 0a and the slope is formed into a curved surface.

Next, in the re-mask forming step, a mask layer having a thickness of about 0.5 to 1 μm is formed again on the surface of the substrate 10 having the heat generating portion mesa 10a in the same manner as in the mask forming step.

Next, in the re-mask pattern forming step, a desired mask pattern is formed again on the surface of the substrate 10 having the heat generating portion mesa 10a in the same manner as the mask pattern forming step.

Next, in the groove / edge mesa molding step, the substrate 10 on which the mask pattern is formed again is KO
Depth of 20-60 μm using alkaline solution such as H aqueous solution
By anisotropically etching the degree, an edge mesa 10b having a slope angle of approximately 55 degrees is formed so as to be adjacent to the heat generating portion mesa 10a, and the heat generating portion mesa 10a and the edge mesa 10b are formed. An approximately V-shaped or U-shaped groove portion 10c is formed by using the characteristic of anisotropic etching. Then, the mask layer formed again is removed from the substrate 10 in the same manner as the residual mask removing step.

Next, in the heat insulating layer forming step, the surface of the substrate 10 formed in a predetermined shape has a low thermal conductivity, a low thermal expansion coefficient, and a high heat resistance made of a black low oxide containing Si and Ta as main components. The heat insulating layer 11 is formed by vapor-depositing the above material into a columnar material with a thickness of 15 to 35 μm by a method such as O ₂ reactive sputtering.

Next, in the strain removing step, the heat insulating layer 1
1. The substrate 10 having 1 is heat treated, in this example,
800-900 using vacuum or atmosphere annealing furnace
A high temperature annealing process at about ℃ is performed. As a result, the substrate 10
The warp is removed (corrected) and the heat insulating layer 11 is stabilized. If the heat treatment temperature is lower than this range, the straightening will be insufficient, and if it is higher than this temperature range, the straightening will be excessive.

[0109] Then, the surface of the heat insulating layer 11, conventional in the same manner, depositing a heating element 12a formed of Ta-SiO ₂ or the like, and deposited by sputtering or the like, after forming into a desired pattern by etching, In the heating element stabilization treatment step of the present invention, heat treatment, in this embodiment, a high temperature annealing treatment of about 800 to 900 ° C. is performed using a vacuum annealing furnace. As a result, the resistance value of the heating element 12a is stabilized while preventing the deterioration of the heating element 12a due to oxidation. If the heat treatment temperature is lower than this range, the thermal resistance of the thermal head will be insufficient, and if it is higher than this range, the quality will be excessive.

Then, as in the conventional case, a material of Al, Cu, Au or the like is deposited on the heating element 12a to a thickness of about 2 μm by vapor deposition or sputtering, and then a desired pattern is formed by etching. Thus, the common electrode 15 and the individual electrode 14 are formed. At this time, the common electrode 15 is formed by the common electrode forming step of the present invention so as to be dropped onto the heat retaining layer 11 located above in the substantially V-shaped or U-shaped groove portion 10c.
The height position of the highest part of 5 is made lower than the height position of the highest part of the heat generating part 12.

Thereafter, as in the conventional case, the protective layer 16 is formed by laminating materials such as sialon with a thickness of about 5 to 10 μm, and the thermal head 9 of this embodiment is formed.
Is completed.

Next, the operation of this embodiment having the above-mentioned structure will be described.

The heat generating portion mesa 10a of the thermal head 9 of this embodiment is a substrate 10 made of smooth single crystal silicon which is mirror-finished by anisotropic etching.
Since the glaze layer (heat insulating layer) 3 is directly and easily formed on the upper surface, the processing accuracy can be dramatically improved, unlike the conventional method in which the glaze layer (heat insulating layer) 3 is subjected to isotropic etching. Then, since the mesa 10a for the heat generating portion is isotropically etched, a sufficiently large curved surface can be formed at the corner portion of the mesa 10a for the heat generating portion (the corner portion can be made smooth). Even when the inclination angle β of the slope is set to be larger than that of the related art, it is possible to reliably prevent a decrease in yield in the photolithography process and reliably improve manufacturing efficiency. Further, the heat generating portion mesa 10a of the present embodiment.
Since the dimensional variation is small and waviness does not occur, the thermal head 9 having the heat generating portion mesa 10a can eliminate the unevenness of contact with the recording medium, so that the deterioration of the print quality due to the unevenness of contact is reliably prevented. can do.

The edge mesa 10b on which the ink ribbon peeling edge portion 13 is formed has no chipping because the substrate 10 made of single crystal silicon having a surface crystal orientation of (100) is anisotropically etched. Since the inclination angle γ (approximately 55 degrees) of the inclined surface suitable for peeling the ink ribbon is inevitably formed, the ink ribbon peeling edge portion 13 with high precision, which cannot be achieved by the conventional grinding or polishing processing. As a result, the running state of the ink ribbon is stabilized, and it is possible to reliably reduce variations in printing quality.Unlike conventional methods, there is no need to perform polishing in a separate process, so yield, It is possible to reliably improve productivity and print quality.

Further, the V-shaped or U-shaped groove 10c on which the common electrode 15 is formed can be easily formed by anisotropically etching the substrate 10 made of single crystal silicon. There is no side edge due to isotropic etching of the conventional glaze layer 3, and the processing accuracy can be dramatically improved. Also, this V
Since the common electrode 15 having a low height can be easily formed by dropping it above the U-shaped or U-shaped groove portion 10c, the contact force of the platen applied to the protective layer 16 on the common electrode 15 is reduced. In addition, it is possible to reliably prevent cracking and peeling of the protective layer 16 and maintain good print quality for a long period of time. Further, since the height position of the common electrode 15 is lowered, the abutting force of the platen is concentrated on the heat generating portion 12, and the print quality can be improved. In addition, the common electrode 15 is formed into the V-shaped or U-shaped groove 1
The width of the common electrode 15 can be increased by forming the common electrode 15 so as to be dropped above 0c, and unlike the conventional case, the width of the common electrode 15 is shortened to cause a voltage drop due to an increase in resistance value. As a result, it is possible to surely prevent the inconvenience that the printing quality is deteriorated such as uneven printing density and the printing life is shortened.

Further, since the step between the heat generating portion 12 and the ink ribbon peeling edge portion 13 can be made small, the ink of the ink ribbon which is heated in the heat generating portion 12 and is in a melted state is used as a recording medium (both shown in FIG. (Not shown), the fixing property can be surely improved, and the distance L from the center CL of the heat generating portion 12 to the ink ribbon peeling edge portion 13 can be shortened. Further realization of the edge can be ensured, and good printing can be performed on rough paper by using a resin-based thin film ribbon having high thermal response.

Further, since single crystal silicon is used as the material of the substrate 10, the thermal conductivity of the substrate 10 (340 × 1
0 ^-3 cal / cm · sec · ° C.) is high, and is approximately the same as the thermal conductivity (about 40 × 10 ⁻³ cal / cm · sec · ° C.) of the conventional substrate 2 made of ceramics such as alumina. Even in the case of high-speed printing in which the cycle is eight times and the heating element 12a has a short energization cycle, it is possible to eliminate the influence of heat accumulation by the substrate 10 and reliably prevent the print quality from deteriorating.

The substrate 10 made of single crystal silicon
Since the surface of which is mirror-finished can be used, the unevenness of the surface of the substrate 10 is extremely small, and each electrode 1
It is possible to sufficiently follow the fine patterning of Nos. 4 and 15, and it is possible to reliably improve the manufacturing quality, the yield, and the like.

The heat insulating layer 11 is made of a material having a low thermal conductivity containing black low oxides of Si and Ta as main components, and the manufacturing method thereof is an alloy containing Si and Ta as main components. The target was formed into a black film by O ₂ reactive sputtering at a gas pressure of about 1.0 Pa under conditions where the film forming rate with respect to the O ₂ gas flow rate was almost the maximum.
A columnar material having a thickness of about 35 μm can be easily obtained. The heat insulating layer 11 made of black and columnar has a thermal conductivity (2 × 10 ⁻³ cal / cm ·
(sec · ° C.) is smaller than that of the conventional glaze layer 3, and good heat storage properties (heat insulation properties) can be obtained. The heat insulating layer 11 is formed in a columnar shape, and the columnar shape is densified by performing an appropriate annealing treatment.
The strain generated when the heat insulating layer 11 is formed is removed, and the substrate 1
Since the warp of 0 can be reliably removed, the processing accuracy when the heating element 12a, the common electrode 15, and the individual electrode 14 are formed can be reliably improved. Furthermore, the coefficient of thermal expansion of the heat insulating layer 11 (approximately 3 × 10 ⁻⁶ / ° C.) is
The coefficient of thermal expansion of the substrate 10 made of single crystal silicon (2.6
(× 10 ⁻⁶ / ° C.), and the formed heat retaining layer 11 has good adhesion to the substrate 10 made of single crystal silicon. In addition, the heat insulation layer 11 has improved heat resistance,
It is possible to reliably prevent the heat insulating layer 11 from peeling, cracking, or melting and deforming due to high-temperature heat treatment at about 00 ° C. Furthermore, even if the peak temperature in printing of the heating element 12a exceeds 700 ° C., thermal deformation of the heat retaining layer 11 does not occur, and deterioration of high-speed printing quality in a low temperature environment can be prevented. Moreover, since the heat resistance of the heat insulating layer 11 is as high as approximately 1000 ° C., it is 800 to 90 degrees after forming the heating element 12a.
A heating element stabilization process can be performed by a high temperature vacuum annealing process at about 0 ° C., whereby a heat history higher than the heat generation peak temperature at the time of printing is given to the heating element 12a, and the resistance value of the heating element 12a due to a thermal change at the time of printing. It is possible to surely prevent the change.

Therefore, the thermal head 9 of this embodiment is
Can maintain high printing quality for a long time even in high-speed printing.

FIG. 3 shows a second thermal head according to the present invention.
FIG. 4 is an enlarged vertical sectional view showing the main parts of the embodiment. Incidentally, regarding the configuration which is the same as or equivalent to that of the first embodiment described above,
The same reference numerals are given in the drawings, and the description thereof will be omitted.

As shown in FIG. 3, the common electrode 15a of the thermal head 9a of the present embodiment is replaced by the groove 10c formed in the substantially V-shape or U-shape of the first embodiment described above.
The bottom portion 10e is formed by using the common electrode groove portion 10d having a flat surface. That is, a common electrode groove 10d having a flat bottom surface 10e is formed between the heat generating portion mesa 10a and the edge mesa 10b. Other configurations are similar to those of the above-described first embodiment.

Next, one example of a method of manufacturing the thermal head 9a of this example will be described.

FIG. 4 is a process chart showing the main part of an embodiment of a method of manufacturing a thermal head according to the second embodiment of the present invention.

A method of manufacturing the thermal head 9a of this embodiment will be described with reference to the process chart shown in FIG.

First, in the first mask forming step, SiO ₂ , Ta ₂ O ₅ , Si _{3 having} a thickness of about 0.5 μm is formed on the surface of the substrate 10 made of single crystal silicon having a mirror finish by sputtering or the like. A desired mask layer is formed by forming a film of N ₄ or the like.

Next, in the first mask pattern forming step, a photoresist is applied to the surface of the mask layer by a spinner or the like, and a desired resist pattern is formed by photolithography. Then, when the mask layer is SiO ₂ . Is etched with buffered hydrofluoric acid (BHF), and RIE or CD when the mask layer is Ta ₂ O ₅ or Si ₃ N _4.
Etching with E forms a mask pattern for forming the heat generating portion mesa 10a.

Next, in the mesa forming step for the heat generating portion,
By anisotropically etching the substrate 10 on which the mask pattern is formed using an alkaline solution such as a KOH aqueous solution, the substrate 10 made of single crystal silicon having a plane orientation (100) has a height of about 5 to 15 μm. The mesa 10a for the heat generating portion having the slope angle of about 55 degrees is formed. By anisotropically etching single crystal silicon having a plane orientation (100), the inclination angle is necessarily about 55 degrees.

Next, in the first residual mask removing step, the residual mask layer is removed by etching or the like on the substrate 10 on which the heating-unit mesa 10a having the slope angle of about 55 degrees is formed.

Next, in the heat generating portion mesa intermediate finishing step, the heat generating portion mesa 10a having a slope angle of about 55 degrees.
The entire surface of the substrate 10 on which is formed is anisotropically etched using an alkaline solution such as a KOH aqueous solution to reduce the inclination angle of the slope from 55 degrees to about 25 degrees.

Next, in the mesa final finishing step for the heat generating portion, a hydrofluoric / nitric acid etchant (HF: HNO ₃ : CH ₃
COOH = 1: 8: 3) is used to perform isotropic rounding etching to make the inclination angle of the slope of the heat generating portion mesa 10a about 15 to 20 degrees and to generate heat generating portion mesa 1a.
The corner formed by the top of 0a and the slope is formed into a curved surface.

Next, in the second mask forming step,
A thickness of 0.5 to 1 μm is formed on the surface of the substrate 10 having the heating portion mesa 10a in the same manner as in the first mask forming step.
A mask layer of a certain degree is formed again.

Next, in the second mask pattern forming step, on the surface of the substrate 10 having the heat generating portion mesa 10a, in the same manner as in the first mask pattern forming step,
A mask pattern for forming the common electrode groove portion 10d is formed.

Next, in the common electrode groove forming step, the substrate 10 on which the second mask pattern is formed is subjected to K
Depth of 2 to 10 μm using alkaline solution such as OH solution
By anisotropically etching the degree, a common electrode groove 10d having a flat bottom surface 10e is formed so as to be adjacent to the heat generating portion mesa 10a.

Then, in the second residual mask removing step, the residual mask layer is etched on the substrate 10 in which the common electrode groove portion 10d is formed in the same manner as the first residual mask removing step. To remove.

Next, in the third mask forming step,
On the surface of the substrate 10 having the heating portion mesa 10a and the common electrode groove portion 10d, a thickness of 0.5 to 1 μm is formed in the same manner as the first mask forming step and the second mask forming step.
A mask layer of about m is formed again.

Next, in the third mask pattern forming step, the heat generating portion mesa 10a and the common electrode groove portion 10 are formed.
A mask pattern for forming the edge mesa 10b is formed on the surface of the substrate 10 having d in the same manner as the first mask pattern forming step and the second mask pattern forming step.

Next, in the edge mesa molding step,
The substrate 10 on which the third mask pattern is formed is treated with KOH.
An edge mesa 10b is formed adjacent to the common electrode groove 10d by anisotropically etching to a depth of about 20 to 60 μm using an alkaline solution such as an aqueous solution.

Next, in the third residual mask removing step, in the same manner as the first residual mask removing step and the second residual mask removing step, the mask remaining on the substrate 10 on which the edge mesa 10b is formed. The layer is removed, such as by etching.

Next, in the heat insulating layer forming step, on the surface of the substrate 10 formed in a predetermined shape, a low thermal conductivity and a low thermal expansion coefficient, which consist of a low oxide containing Si and a transition metal such as Ta as main components, The heat-retaining layer 11 is formed by depositing a highly heat-resistant material into a columnar material with a thickness of 15 to 35 μm by a method such as O ₂ reactive sputtering. The heat insulating layer 11 is preferably made of a black low oxide. In addition to Ta, a low oxide such as W, Cr, or Mo can be used as the transition metal.

Next, in the strain removing step, the heat insulating layer 1
1. The substrate 10 having 1 is heat treated, in this example,
800-900 using vacuum or atmosphere annealing furnace
A high temperature annealing process at about ℃ is performed. As a result, the substrate 10
The warp is removed (corrected) and the heat insulating layer 11 is stabilized. If the heat treatment temperature is lower than this range, the straightening will be insufficient, and if it is higher than this temperature range, the straightening will be excessive.

Then, a heating element 12a made of Ta ₂ N or Ta-SiO ₂ is deposited on the surface of the heat insulating layer 11 by vapor deposition, sputtering or the like and formed into a desired pattern by etching in the same manner as in the prior art. Then, in the heating element stabilization treatment step of the present invention, heat treatment, in this embodiment, a high temperature annealing treatment of about 800 to 900 ° C. is performed using a vacuum annealing furnace. Thereby, the heating element 12a
It is possible to stabilize the resistance value of the heating element 12a while preventing the deterioration of the heating element 12a due to oxidation. If the heat treatment temperature is lower than this range, the thermal resistance of the thermal head will be insufficient, and if it is higher than this range, the quality will be excessive.

Then, as in the prior art, a material of Al, Cu, Au or the like is deposited on the heating element 12a to a thickness of about 2 μm by vapor deposition or sputtering, and then a desired pattern is formed by etching. Thus, the common electrode 15a and the individual electrode 14 are formed. At this time,
The common electrode 15a is formed by the common electrode forming process of the present invention.
The bottom portion 10e is formed so as to be dropped onto the heat insulating layer 11 located above in the common electrode groove portion 10d having a flat surface, and the height position of the highest portion of the common electrode 15a is the highest portion of the heat generating portion 12. Lower than the height position.

Thereafter, as in the conventional case, the protective layer 16 is formed by laminating a material such as sialon in a thickness of about 5 to 10 μm, and the thermal head 9 of this embodiment is formed.
The production of a is completed.

With this structure, the same effect as that of the thermal head 9 of the first embodiment described above can be obtained, and the common electrode 15a is formed in the substantially V shape or the U shape of the first embodiment. Unlike the groove portion 10c formed by the above, since the bottom portion 10e having no acute angle is formed on the heat retaining layer 11 located above the groove portion 10d for the common electrode forming a flat surface, the thickness is uniform and uniform. The common electrode 15a is reliably formed, and the more reliable common electrode 15a can be obtained.

Next, another embodiment of the method of manufacturing the thermal head 9a of this embodiment will be described.

FIG. 5 is a process diagram showing the main part of another embodiment of the method of manufacturing a thermal head according to the second embodiment of the present invention.

In this embodiment, the mask layer in the second mask forming step and the third mask forming step of the method of manufacturing the thermal head 9a of the second embodiment described above is formed of thermally oxidized SiO ₂ , and the second mask forming step is performed. The residual mask removing step and the third residual mask removing step are omitted.
The other structure is the thermal head 9 of the second embodiment described above.
It is the same as the manufacturing method of a.

With such a structure, the number of manufacturing steps can be reduced as compared with the method of manufacturing the thermal head 9a of the second embodiment described above, so that the production efficiency can be surely improved and The economic burden can be surely reduced.

The present invention is not limited to the above embodiment, but can be modified as necessary. Further, it can be applied to both serial and line heads.

[0151]

As described above, according to the present invention, high definition in high speed printing and high printing quality can be maintained for a long period of time, and yield and productivity can be improved. It has an excellent effect.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a main part of a first embodiment of a thermal head according to the present invention.

FIG. 2 is a process chart showing an embodiment of a method of manufacturing a thermal head according to the first embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing a main part of a second embodiment of a thermal head according to the present invention.

FIG. 4 is a process chart showing one embodiment of a method of manufacturing a thermal head according to a second embodiment of the present invention.

FIG. 5 is a process chart showing another embodiment of the method of manufacturing the thermal head according to the second embodiment of the present invention.

FIG. 6 is a vertical sectional view showing a main part of a conventional thermal head.

[Explanation of symbols]

 9, 9a Thermal head 10 Substrate 10A Flat plate portion 10B Mesa portion 10a Heat generating portion mesa 10b Edge mesa 10c Groove portion 10d Common electrode groove portion 10e (Common electrode groove portion) 11 Heat insulating layer 12 Heat generating element 12a Heating element 13 Ink ribbon Peeling edge part 14 Individual electrodes 15 and 15a Common electrode 16 Protective layer H (Heating part mesa) height L Ink ribbon peeling distance β (Slope of heating part mesa) Inclination angle γ (Slope of edge mesa) Tilt angle

Claims (30)

[Claims] 1. A heat insulating layer is formed on a surface of a substrate, and a plurality of heat generating elements and individual electrodes and a common electrode connected to each heat generating element are formed on the surface of the heat insulating layer, and at least the heat insulating layer and the heat generating layer are formed. In a thermal head in which surfaces of elements, individual electrodes and common electrodes are covered with a protective layer, the substrate is formed of single crystal silicon, and the substrate is formed integrally with a flat plate portion on the flat plate portion. And a mesa portion composed of a mesa for a heat generating portion and a mesa portion for an edge provided with an ink ribbon peeling edge portion which are arranged adjacent to each other through a groove portion having a substantially V shape or a U shape. A heat insulating layer made of Si and a low oxide of a transition metal and having a substantially uniform thickness is formed on the surface of the substrate, and a common electrode is formed on the surface of the heat insulating layer on the groove. The thermal head. 2. The crystal orientation of the surface of the substrate is (10
The thermal head according to claim 1, wherein the thermal head is made of single crystal silicon of 0). 3. The heat generating portion mesa and the edge mesa are biased to one side of the substrate.
Alternatively, the thermal head according to claim 2. 4. The thermal head according to claim 1, wherein the slope angle of the slope of the edge mesa is approximately 55 degrees. 5. The height of the heat generating portion mesa is 5 to 15 μm.
The thermal head according to any one of claims 1 to 4, wherein 6. The thermal head according to claim 1, wherein the heat insulating layer is formed in a columnar shape and has a thickness of 15 to 35 μm. . 7. The heat insulating layer is made of a black low oxide containing Si and Ta as main components.
The thermal head described in. 8. A heat insulating layer is formed on a surface of a substrate, and a heat generating portion including a plurality of heat generating elements and an individual electrode and a common electrode connected to each heat generating element are formed on the surface of the heat insulating layer, and at least the heat insulating layer is formed. A mask forming step of forming a mask layer on a surface of a substrate made of single crystal silicon, in a method of manufacturing a thermal head in which a surface of a heat insulating layer, a heating element, individual electrodes and a common electrode is covered with a protective layer, A mask pattern forming step of forming a mask pattern for forming a heating portion mesa on the substrate, a heating portion mesa forming step of forming a heating portion mesa on the substrate on which the mask pattern is formed, and a heating portion mesa A residual mask removing step of removing the remaining mask layer by etching the substrate on which the heat generation portion is formed, and reducing the inclination angle of the slope of the mesa for the heating portion. The heating part mesa intermediate finishing step, the heating part mesa final finishing step of setting the inclination angle of the slope of the heating part mesa to a predetermined value and rounding the corners, and the heating part mesa subjected to the final finishing A re-mask forming step of forming a mask layer again on the surface of the substrate having the mask layer, and a mask pattern for forming a groove and an edge mesa on the surface of the substrate having the heat generating portion mesa on which the mask layer has been formed again. Re-mask pattern forming step, a groove / edge mesa forming step of forming a groove portion and an edge mesa on a substrate having a heating portion mesa on which the mask pattern is formed again, the heating portion mesa and groove portion, and an edge mesa. A heat insulating layer forming step of forming the heat insulating layer on the substrate on which the heat insulating layer is formed, and a strain removing step of removing warp of the substrate caused by the heat insulating layer forming step. The heating element stabilization treatment step of stabilizing the resistance value of the heating element formed on the surface of the heat insulating layer, and the common electrode forming step of forming a common electrode on the surface of the heat insulating layer on the groove are performed in this order. Claim 1 thru | or Claim 7 characterized by the above-mentioned.
The method of manufacturing a thermal head according to any one of 1. 9. The method of manufacturing a thermal head according to claim 8, wherein the heat generating portion mesa forming step and the groove / edge mesa forming step are anisotropic etching. 10. The thermal head manufacturing method according to claim 8 or 9, wherein the mesa intermediate finishing step for the heating portion is a full anisotropic etching and a full isotropic etching. Head manufacturing method. 11. The method of manufacturing a thermal head according to claim 8, wherein the heat retaining layer forming step is O ₂ reactive sputtering. . 12. The method of manufacturing a thermal head according to claim 8, wherein the strain removing step is a heat treatment at 800 to 900 ° C. . 13. The method of manufacturing a thermal head according to claim 8, wherein the heating element stabilization treatment step is a heat treatment at 800 to 900 ° C. Manufacturing method. 14. A heat insulating layer is formed on a surface of a substrate, and a plurality of heat generating elements and individual electrodes and a common electrode connected to each heat generating element are formed on the surface of the heat insulating layer. In a thermal head in which surfaces of elements, individual electrodes and common electrodes are covered with a protective layer, the substrate is formed of single crystal silicon, and the substrate is formed integrally with a flat plate portion on the flat plate portion. And a mesa portion composed of an edge mesa provided with the heating element provided adjacent to each other via a common electrode groove having a flat surface and provided with the heating element, and an edge mesa provided with an ink ribbon peeling edge portion. Then, a heat insulating layer made of a low oxide of Si and a transition metal having a substantially uniform thickness is formed on the surface of the substrate, and a common electrode is formed on the surface of the heat insulating layer on the groove. A thermal head characterized by being made. 15. The crystal orientation of the surface of the substrate is (10
15. The thermal head according to claim 14, wherein the thermal head is made of 0) single crystal silicon. 16. The thermal head according to claim 14, wherein the heat generating portion mesa and the edge mesa are offset to one side of the substrate. 17. The tilt angle of the slope of the edge mesa is about 55 degrees.
The thermal head according to any one of 6 above. 18. The height of the mesa for the heat generating portion is 5 to 15 μm.
The thermal head according to any one of claims 14 to 17, wherein m is m. 19. The thermal head according to claim 14, wherein the heat insulating layer is formed in a columnar shape and has a thickness of 15 to 35 μm. . 20. The heat insulating layer is made of a low oxide containing Si and a transition metal as main components.
9. The thermal head according to item 9. 21. A heat insulating layer is formed on a surface of a substrate, and a heat generating portion including a plurality of heat generating elements and an individual electrode and a common electrode connected to each heat generating element are formed on the surface of the heat insulating layer.
In a method of manufacturing a thermal head in which at least the surfaces of the heat retaining layer, the heating element, the individual electrode and the common electrode are covered with a protective layer, a first mask forming step of forming a mask layer on the surface of a substrate made of single crystal silicon A first mask pattern forming step of forming a mask pattern for forming a heating portion mesa on the mask layer; and a heating portion mesa by etching the substrate on which the first mask pattern is formed. And a first residual mask removing step of removing a mask layer remaining on the substrate on which the mesa for heat generating portion is formed, and a small inclination angle of the slope of the mesa for heat generating section. Heat-generating part mesa intermediate finishing step and a heat-generating part mesa final finishing step of rounding the corners while setting the inclination angle of the slope of the heat-generating part mesa to a predetermined value A second mask forming step of forming a mask layer again on the surface of the substrate having the final-finished mesa for the heating portion, and accommodating a common electrode on the surface of the substrate on which the second mask layer is formed. A second mask pattern forming step of forming a mask pattern for forming a common electrode groove having a flat bottom surface, and the bottom portion is flattened by etching the substrate on which the second mask pattern is formed. A common electrode groove forming step of forming a common electrode groove forming a surface; a second residual mask removing step of removing a mask layer remaining on the substrate in which the common electrode groove is formed; And a third mask forming step of forming a mask layer again on the surface of the substrate on which the common electrode groove is formed, and forming an edge mesa on the surface of the substrate on which the third mask layer is formed. A third mask pattern forming step of forming a mask pattern for forming, an edge mesa forming step of forming an edge mesa by etching the substrate on which the third mask pattern is formed, A third residual mask removing step of removing a mask layer remaining on the substrate on which the mesa is formed, and forming the heat retaining layer on the substrate on which the heat generating portion mesa and the common electrode groove portion and the edge mesa are formed. Insulating layer forming step, strain removing step for removing warp of the substrate caused by the insulating layer forming step, heating element stabilization treatment step for stabilizing the resistance value of the heating element formed on the surface of the insulating layer, The common electrode forming step of forming a common electrode on the surface of the heat insulating layer on the common electrode groove is performed in this order. 2. A method of manufacturing a thermal head according to item 1. 22. The method of manufacturing a thermal head according to claim 21, wherein the heating portion mesa forming step is anisotropic etching, and the heating portion mesa intermediate finishing step is full surface anisotropic etching, A method of manufacturing a thermal head, characterized in that the final finishing step of the mesa for the heating portion is isotropic rounding etching. 23. The method of manufacturing a thermal head according to claim 21, wherein the heat retaining layer forming step is O ₂ reactive sputtering using an alloy target of Si and a transition metal. Method for manufacturing a thermal head. 24. Any one of claims 21 to 23.
The method for manufacturing a thermal head according to the item 1, wherein the distortion removing step is a heat treatment at 800 to 900 ° C. 25. The method according to any one of claims 21 to 24.
The method of manufacturing a thermal head as described in the item 1, wherein the heating element stabilization treatment step is a heat treatment at 800 to 900 ° C. 26. A heat insulating layer is formed on a surface of a substrate, and a heat generating portion composed of a plurality of heat generating elements and an individual electrode and a common electrode connected to each heat generating element are formed on the surface of the heat insulating layer.
In a method of manufacturing a thermal head in which at least the surfaces of the heat retaining layer, the heating element, the individual electrode and the common electrode are covered with a protective layer, a first mask forming step of forming a mask layer on the surface of a substrate made of single crystal silicon A first mask pattern forming step of forming a mask pattern for forming a heating portion mesa on the mask layer; and a heating portion mesa by etching the substrate on which the first mask pattern is formed. And a first residual mask removing step of removing a mask remaining on the substrate on which the heat generating mesa is formed, and a slant angle of a slope of the heat generating mesa is reduced. A mesa intermediate finishing step for the heat generating part, and a final finishing step for the mesa for the heat generating part in which the inclination angle of the slope of the mesa for the heat generating part is set to a predetermined value and the corners are rounded Second forming a mask layer of a thermally oxidized SiO ₂ on the surface of the substrate having the final finish heating unit mesa subjected
And a second mask pattern for forming a mask pattern for forming a common electrode groove having a flat bottom surface for accommodating the common electrode on the surface of the substrate on which the second mask layer is formed. A forming step, a common electrode groove forming step of forming a common electrode groove having a flat bottom surface by etching the substrate on which the second mask pattern is formed, and the heat generating portion mesa and the common electrode A third mask forming step of forming a mask layer made of thermally oxidized SiO ₂ again on the surface of the substrate on which the groove for use is formed, and forming an edge mesa on the surface of the substrate on which the third mask layer is formed. And a third mask pattern forming step of forming a mask pattern for forming the edge mesa by etching the substrate on which the third mask pattern is formed. An edge mesa forming step, a heat retaining layer forming step of forming the heat retaining layer on the substrate on which the heat generating portion mesa and the common electrode groove portion and the edge mesa are formed, and a warp of the substrate caused by the heat retaining layer forming step. A strain removing step for removing the heat-generating element, a heat-generating element stabilization treatment step for stabilizing the resistance value of the heat-generating element formed on the surface of the heat retaining layer, and forming a common electrode on the surface of the heat retaining layer on the common electrode groove. 21. The method of manufacturing a thermal head according to claim 14, wherein the common electrode forming step and the common electrode forming step are performed in this order. 27. The method of manufacturing a thermal head according to claim 26, wherein the heat generating portion mesa forming step is anisotropic etching, and the heat generating portion mesa intermediate finishing step is total anisotropic etching. A method of manufacturing a thermal head, characterized in that the final finishing step of the mesa for the heating portion is isotropic rounding etching. 28. The method of manufacturing a thermal head according to claim 26, wherein the heat retaining layer forming step is O ₂ reactive sputtering using an alloy target of Si and a transition metal. Method for manufacturing a thermal head. 29. The apparatus according to any one of claims 26 to 28.
The method for manufacturing a thermal head according to the item 1, wherein the distortion removing step is a heat treatment at 800 to 900 ° C. 30. Any one of claims 26 to 29.
The method of manufacturing a thermal head as described in the item 1, wherein the heating element stabilization treatment step is a heat treatment at 800 to 900 ° C.