KR100237588B1 - Thermal head and manufacturing method of the same - Google Patents

Abstract

In the case of a multi-layered wiring structure, it is possible to reliably prevent the occurrence of connection failure or insulation failure in each layer, and to maintain the reliability by making it easy to manufacture even real edges. It is to provide a method of manufacturing the thermal head and the thermal head without a problem in the terminal connection.

The insulating layer 12, the conductive layer 13, the interlayer insulating layer 15, the heat generating resistor 16, the common electrode 17a, the individual electrode 17b, and the protective layer 18 are stacked on the heat radiating substrate 11. The conductive layer 13 is formed of a fused material of nitride or oxide and metal, and is electrically connected to the common electrode 17a. The interlayer insulating layer 15 is formed of at least the conductive layer 13. Is formed with an oxide film.

Description

Thermal head and its manufacturing method {THERMAL HEAD AND MANUFACTURING METHOD OF THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head used in a thermal printer, and more particularly, to a method of manufacturing a thermal head and a thermal head capable of realizing the thermal head of a thermal head and improving the printing quality in a thermal transfer printer.

The thermal head mounted on the thermal printer arranges a plurality of heat generating elements linearly on a substrate, and selectively heats the heat generating elements by selectively energizing any one of the heat generating elements based on the desired printing information. The recording paper is developed, and in the thermal transfer printer, the ink of the ink ribbon is partially melted, transferred to plain paper, and printed.

Fig. 11 shows a conventional general thermal head. An insulating layer 2 made of glass or the like is formed on a heat dissipating substrate (hereinafter referred to as a substrate) 1 made of an insulating material such as alumina. The upper surface is formed so that it may become circular arc shape. A plurality of heat generating resistors 3 are formed in the vertex portion 2a of the heat insulating layer 2, aligned in a straight line in the paper vertical direction. The heat generating resistor 3 is formed by attaching a material of the heat generating resistor 3 made of Ta-SiO ₂ to the surface of the heat insulating layer 2 by sputtering or the like and then etching by photolithography. The common electrode 4a connected to each of the heat generating resistors 3 is stacked on one side of the upper surface of the heat generating resistors 3, and the other side of each of the heat generating resistors 3 is energized independently of the heat generating resistors 3. The individual electrodes 4b for carrying out are stacked respectively. The common electrode 4a and the individual electrode 4b are made of Al, Cu, or the like, for example, are attached by vapor deposition, sputtering, or the like, and are formed in a desired pattern by etching.

In addition, the heating resistors 3 and the electrodes 4a and 4b are formed on the surfaces of the heating resistors 3, the common electrodes 4a, the individual electrodes 4b, the exposed substrate 1 and the heat insulating layer 2, respectively. A protective layer 5 having a film thickness of approximately 5 to 10 탆 is formed, and the protective layer 5 is formed so as to cover all surfaces other than the terminal portions of the electrodes 4a and 4b.

In such a conventional thermal head, since the width of the common electrode 4a needs to be wider, the resistance value needs to be formed lower. Therefore, as shown in FIG. 11, the heat generating portion 3a of the heat generating resistor 3 is formed of the thermal head. It is provided near the center or the end of the board | substrate 1, and the dimension (henceforth an edge distance L) from the heat generating part 3a of the heat generating resistor 3 to the board | substrate 1 edge part is 1 mm or more. I had.

However, in recent years, there has been a growing demand for real-edge formation of the heat generating resistor 3 of the thermal head at the end of the substrate 1, and thus, the space on the common electrode 4a side of the substrate 1 is greatly reduced. Do it.

Such real-edge formation of the thermal head reduces the loss of pressure contact pressure between the head and the platen, and improves the printing energy efficiency. Also, in the thermal transfer printer using the ink ribbon, the wax-based ink to the resin-based ink are used. It can be used widely, and has the advantage of remarkably improving the printing quality of rough paper.

However, for example, when the real-edge of the thermal head is achieved when the edge distance is 0.2 mm or less, the width of the common electrode 4a is extremely thin because the arrangement space of the common electrode 4a is significantly reduced. As a result, the common electrode 4a becomes a resistor, and the resistance thereof increases to increase the difference in voltage drop between the both ends of the heat generating resistor 3 and the center portion. In addition, when the current electrode of the common electrode 4a is in shortage and energized by each of the heat generating resistors 3, the common electrode 4a may be melted and cut, resulting in a highly practical real edge head. It was difficult.

Although not illustrated as another electrode of the thermal head for real edge formation, for example, the common electrode 4a is the same electrode as the individual electrode 4b as a folding electrode ('c'-shaped electrode) or a comb-shaped electrode. However, in order to derive the common electrode 4a and the individual electrode 4b in the same direction, a processing accuracy of 300 dpi is required to achieve the same resolution as that of 600 dpi. In the case of 800dpi resolution, the same high-definition processing technology as in the case of increasing the number of manufacturing processes is required, resulting in a decrease in yield and reliability, and at the same time, an increase in manufacturing cost. .

In addition, although the common electrode 4a is formed on the rear surface from the end face of the substrate 1 of the thermal head, the electrode 1 is formed after dividing and polishing the substrate 1, resulting in a large number of manufacturing steps and a decrease in manufacturing efficiency. In addition, there is a drawback that the reliability of real-edification within 0.2 mm is extremely low.

In the case where the end face of the substrate 1 is polished to form the heat insulating layer 2, and the heat generating resistor 3 is formed on the upper face thereof, the number of manufacturing steps increases and the number of manufacturing steps is increased. Poor productivity and disadvantage of cost increase.

In view of the above, there is conventionally intended to achieve real edge by making the common electrode 4a a multilayer wiring structure in the heat generating portion. This is carried out by forming a conductive layer 6 made of metal on the insulating layer 2, and forming an interlayer insulating layer 7 made of SiO ₂ or the like thereon by sputtering or the like, and then forming the interlayer insulating layer ( 7) is partially removed by photolithography, and the conductive resistor 7 and the heating resistor 3 are electrically connected by stacking the heating resistor 3 thereon. The heating resistor 3 generates heat at a high temperature. Underneath, the interlayer insulating layer 7 and the conductive layer 6 are formed in a layered manner.

In the thermal head having such a multi-layered wiring structure, a common electrode having extremely narrow width dimensions due to real edges is applied when the desired heat generating resistor 3 is energized through the individual electrodes 4b based on a desired printing signal. In addition to (4a), since the conductive layer 6 is sent to the terminal portion, the partial voltage difference of the heating resistor 3 is generated without increasing the resistance of the common electrode 4a, and the current of the common electrode 4a. It is possible to prevent the occurrence of insufficient capacity and to perform high quality printing.

In the conventional thermal head, however, the interlayer insulating layer 7 is formed on the upper surface of the conductive layer 6, and each layer is formed under the heat generating resistor 3 that generates heat at a high temperature. Since the mutual stress stress is large, the reliability of the adhesion between the layers to the thermal shock is significantly lowered, and the interlayer insulating layer 7 is formed by etching, so that the surface of the interlayer insulating layer 7 and the conductive layer 6 is reduced. There is a possibility that a step may occur, and this step may cause a poor connection between the heat generating resistor 3 and the conductive layer 6, and if the interlayer insulating layer 7 is formed by a vapor deposition method such as sputtering, interlayer insulation may be caused by foreign matter or the like. There is a problem that pinholes are generated in the layer 7 and poor insulation of the interlayer insulating layer 7 occurs.

In order to overcome the above problems, if the thickness of the interlayer insulating layer 7 is made thick, the stress imbalance between the layers is increased, and the reliability of connection failure due to the increase of the etching step amount is remarkable. It has a problem that causes degradation.

In the conventional connection type thermal head as shown in Fig. 12, the thermal head block 8 to be connected has the same layer structure as a conventional thermal head, but the terminals 9 of the common electrode 4a are provided only on either of the left and right sides. The point is the main difference. That is, in the conventional connection type thermal head, two thermal head blocks 8 and 8 having symmetrical shapes are bonded to the connection substrate 1.

The reason why the two thermal head blocks are conventionally connected is that the terminals 9 and 9 of the common electrode 4a shown in FIG. 12 can be formed only in the left and right sides of each of the thermal head blocks 8. . In other words, this is because when three or more thermal head blocks 8 are connected, there is no practical way of connecting the common electrode 4a of the thermal head block 8 at the center portion other than the left and right ends to the terminal 9. Do.

SUMMARY OF THE INVENTION An object of the present invention is to prevent the occurrence of connection failure or insulation failure in each layer in the case of a multi-layered wiring structure, to be easy to manufacture even if it is real edged, to maintain reliability, and to provide a thermal head block. It is an object of the present invention to provide a thermal head and a method for manufacturing the thermal head, which have no problem with the terminal connection of the common electrode even when the number of connections is three or more.

1 is a cross-sectional view of a thermal head in a first embodiment of the present invention;

2 is a plan view of a thermal head according to a first embodiment of the present invention;

3 is a cross-sectional view showing a multi-layered wiring board during manufacture in the first embodiment of the present invention;

4 is a flowchart showing a method for manufacturing a multilayer wiring board of a thermal head according to the first embodiment;

5 (a) is a cross-sectional view showing a substrate of a thermal head immediately before entering a cutting process;

(b) is sectional drawing which showed the state which formed the groove | channel by irradiating a laser beam,

(c) is sectional drawing which showed the state which cut | disconnected from the bottom of a groove to the back surface of a board | substrate by dicing method,

6 (a) is a plan view of the heat generating portion of the thermal head connected in the main scanning direction;

(b) is a cross-sectional view along the line X-X 'of (a),

7 is a cross-sectional view of a thermal head in a second embodiment of the present invention;

8 is a sectional view of a thermal head according to a third embodiment of the present invention;

9 is a flowchart showing a method for manufacturing a multilayer wiring board of a thermal head in the second and third embodiments;

10 is a cross-sectional view of a thermal head showing a fourth embodiment of the present invention;

11 is a cross-sectional view showing the configuration of a conventional general thermal head,

12 is a plan view illustrating the structure of a conventional connection type thermal head.

The thermal head according to claim 1 of the present invention is a thermal head formed by laminating a heat insulating layer, a conductive layer, an interlayer insulating layer, a heating resistor, a common electrode, an individual electrode, and a protective layer on a heat dissipating substrate, wherein the conductive layer is formed of nitride, oxide, and metal. And the interlayer insulating layer is formed with at least an oxide film of the conductive layer. The thermal head of claim 5 is a thermal head of claim 1, wherein the conductive layer is a high melting point metal. And conductive ceramics of boride, nitride, carbide and silicide. By forming the said conductive layer from the above materials, even if it carries out high temperature thermal oxidation process, it can be set as the outstanding adhesiveness with a board | substrate.

The thermal head of claim 2 of the present invention is the thermal head of claim 1, wherein the conductive layer is formed of a nitride of silicon, an oxide of silicon, an nitride of aluminum, or an oxide of aluminum, or a composite and a high melting point metal. The thermal head according to claim 3 or 4 is characterized in that the fusion of nitride and metal is made of aluminum nitride and tantalum, and the fusion of oxide and metal is made of aluminum oxide and tantalum. It is characterized by the above-mentioned, and it can make said effect more remarkable by doing so.

The thermal head according to claim 6 is the thermal head according to any one of claims 1 to 5, wherein the interlayer insulating layer is formed on the first interlayer insulating layer using an oxide film of the conductive layer as the first interlayer insulating layer. It is a multi-layer interlayer insulating layer using the insulating ceramic as the second interlayer insulating layer, and since the first interlayer insulating layer is formed by the surface oxidation of the conductive layer, the second interlayer insulating layer is 1 탆 or less. Even if it is a thin insulating layer, sufficient insulation can be obtained, and since the level difference between the surface of the insulating layer and the surface of the conductive layer can be made small, electrical connection between the heating resistor and the electrode formed on the upper surface and the conductive layer is prevented. It can be reliably performed and the reliability and yield reduction by multilayer wiring can be completely eliminated.

The thermal head according to claim 7 is the thermal head according to claim 6, wherein the second interlayer insulating layer is formed of at least one of nitride of silicon, oxide of silicon, nitride of aluminum and oxide of aluminum. The reliability of insulation can be dramatically increased.

The thermal head according to claim 8 is characterized in that the common electrode has at least three external circuit connection portions formed in the substrate, and according to the thermal head, voltage is applied not only at both ends of the substrate but also at the center of the substrate. It becomes possible to apply, and it becomes possible to apply uniform voltage to each heat generating resistor.

The thermal head of claim 9 is characterized in that the common electrode is formed between the conductive layer and the heating resistor in a single layer, and the individual electrodes are formed so as to be sandwiched between the heating resistors in two layers. By forming a single layer, the mechanical strength of this portion can be increased to realize a structure in which film peeling does not occur with respect to the pressure contact force applied during printing.

According to the method of manufacturing a thermal head according to claim 10 of the present invention, a heat insulating layer is formed to protrude from a position corresponding to a heat generating portion on a heat radiating substrate, and a conductive layer made of a fusion of nitride or oxide and metal on the upper surface of the substrate and the heat insulating layer. Forming a mask layer on the conductive layer, and forming a mask pattern at a position corresponding to a common electrode of the mask layer and an external circuit connection portion of the common electrode. A step of forming an interlayer insulating layer by heat or plasma oxidation in an oxidation atmosphere on a surface of a conductive layer other than the mask layer forming part by the mask pattern, a step of removing the mask of the oxidation resistance, and both ends thereof Forming a predetermined heating resistor so as to be located above the interlayer insulating layer and the conductive layer, respectively; and on the upper surface of the heating resistor. At the same time as the end portion of the insulating layer side to form a separate electrode, it characterized in that it comprises a step of forming a protective layer laminated on a step and those of the uppermost surface to form the common electrode at an end of the conductive layer side.

According to the method of manufacturing the thermal head, in the manufacturing process of the multilayer substrate, since the nitride and the like constituting the conductive layer are hard-etched to the etchant, there is no damage to the conductive layer and the interlayer insulating layer, and thermal oxidation is performed with high accuracy. Since a mask and a resistor pattern can be formed, and an oxidation resistant mask is formed on the surface of the conductive layer to thermally oxidize, an interlayer insulating layer integrated with the conductive layer is formed, so that the step between the exposed portion of the conductive layer and the interlayer insulating layer can be reduced. It can be minimized.

In the method of manufacturing a thermal head according to claim 11, a heat insulating layer is formed to protrude from a position corresponding to a heat generating portion on a heat radiating substrate, and a conductive layer made of a fusion of nitride or an oxide and a metal is laminated on the top surface of the substrate and the heat insulating layer. A mask pattern is formed by photolithography at a position corresponding to a common electrode of the mask layer and a position where the terminal portion of the common electrode is formed; Forming a layer, and forming an interlayer insulating layer by heat or plasma oxidation in an oxidizing atmosphere on surfaces of conductive layers other than the mask layer forming portion by the mask pattern, and both ends of the interlayer insulating layer and the conductive layer, respectively. Forming a predetermined heating resistor so as to be positioned above the upper end of the heating resistor; Forming a common electrode and forming a common electrode at an end portion of the conductive layer side; and forming a protective layer on the uppermost surface thereof.

According to the method of manufacturing the thermal head, the same effects as those of the method of manufacturing the thermal head can be obtained even if the step of removing the oxidation resistant mask is omitted.

In the method of manufacturing a thermal head according to claim 12, a step of forming a heat insulating layer at a position corresponding to a heat generating portion on a heat radiating substrate, and laminating a conductive layer made of a resistor material on the upper surface of the substrate and the heat insulating layer; Stacking an oxidation resistant mask layer on the layer, forming a mask pattern at a position corresponding to a common electrode of the mask layer and the position at which the external circuit connection portion of the common electrode is formed, and a mask layer using the mask pattern Forming a first interlayer insulating layer by thermal or plasma oxidation in an oxidizing atmosphere on a surface of a conductive layer other than the forming portion; laminating an insulating layer made of an insulating ceramic material on the first interlayer insulating layer, and forming a common electrode and The position corresponding to the formation position of the terminal portion of the common electrode is etched by photolithography to expose the conductive layer to form a second interlayer insulating layer. Forming a predetermined heat generating resistor so that both ends thereof are positioned above the second interlayer insulating layer and the conductive layer, respectively, and separately at an end of the second interlayer insulating layer side of the top surface of the heat generating resistor. Forming an electrode and forming a common electrode at the end of the said conductive layer side, and forming a protective layer on these upper surfaces are characterized by the above-mentioned.

Since the first interlayer insulating layer is formed by oxidation of the surface of the conductive layer, the pinhole inside the conductive layer is also sufficiently oxidized to have insulation and can be formed integrally with the conductive layer. The heat resistance becomes remarkably high. Moreover, since the 2nd interlayer insulation layer which is excellent in insulation, adhesiveness, and heat resistance is coat-covered again on the upper surface of a 1st interlayer insulation layer, insulation reliability can be improved.

And the manufacturing method of the thermal head of Claim 13 is a manufacturing method of the thermal head of Claim 10 or 12 WHEREIN: The said oxidation resistant mask layer is formed from silicon dioxide, The manufacturing of the thermal head of Claim 14 The method is characterized in that the oxidation resistant mask layer is formed of molybdenum silicide in the method of manufacturing a thermal head according to claim 11 or 12.

The method of manufacturing a thermal head according to claim 15 is characterized in that the substrate of the thermal head unit is cut by applying laser processing. According to the method of manufacturing the thermal head, the real edge of each thermal head block is realized. And it is possible to precise cutting without chipping or cracking the cutting surface.

The method of manufacturing a thermal head according to claim 16 is characterized in that after cutting the heat radiating substrate, only the heat radiating substrate is polished so that the cross-sections of the heat insulating layer and the heat insulating layer are substantially flush with the cross section of the heat radiating substrate. The slanted portion is polished at an angle so that the laser cut surface of the laminated film is most protruding so that the connection can be made to increase the connection accuracy of the thermal head block.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 10.

1 is a cross-sectional view of a thermal head according to a first embodiment of the present invention, and FIG. 2 similarly shows a plan view. 3 shows a multilayer wiring board during manufacture.

In the thermal head shown in FIG. 1, a heat insulating layer 12 made of glass or the like protrudes in an arc shape on an insulating substrate 11 made of ceramic or the like, and on the upper surface of the substrate 11 and the heat insulating layer 12. A conductive layer 13 made of a low thermal conductive, low thermally expansible metal nitride and a fusion of a metal is formed into a film having a thickness of approximately 3 to 10 탆 by sputter deposition or the like. As the fusion of the nitride of the metal and the metal, the fusion of aluminum nitride and tantalum is most suitable, but instead of the fusion of the nitride of the metal with the metal, it is also possible to use a fusion of an oxide of the metal with the metal, in which case oxidation Fusion of aluminum and tantalum is most suitable. The target material used for the film formation of the conductive layer 13 by the sputtering method is a sintered body of aluminum nitride and tantalum in the former case, and a sintered body of aluminum oxide and tantalum in the latter case. 50 to 70% is suitable for satisfying the below-mentioned function. In this embodiment, a sintered target having a composition of 60% of tantalum and 40% of aluminum nitride was used. In addition, the conductive layer 13 may be substituted for the conductive ceramic of boride, nitride, and silicide of a high melting point metal.

The conductive layer 13 is covered with the oxidation resistant mask layer 14 after the mounting portion of the common electrode 17a of the thermal head and the connection portion with the external circuit are covered with the oxidation resistant mask layer 14, as shown in FIG. By oxidizing, the interlayer insulating layer 15 is formed to a thickness of approximately 1 to 2 mu m. At this time, the conductive pads 13a and 13b are exposed by partially exposing the conductive layer 13 from the interlayer insulating layer 15. The drop in height between the surface of the interlayer insulating layer 15 and the surface of the conductive pad portion 13a of the conductive layer 13 is approximately 1 µm or less, and the edge is formed in a smooth shape.

The mask layer 14 having oxidation resistance used in the formation of the interlayer insulating layer 15 is made of insulating silicon dioxide or conductive molybdenum silicide and the like, and has a thickness of about 0.3 μm by the sputter deposition method. After the film is formed in succession, the common electrode multilayer wiring board is completed by etching away with buffered fluoric acid (BHF) when silicon dioxide is used by photolithography. On the other hand, when molybdenum silicide is used, a mask pattern is formed by dry etching with CF ₄ + O ₂ gas to perform a thermal oxidation treatment step. In this case, since the molybdenum silicide is conductive, the removal of the mask layer 14 is arbitrary. The materials are selected in the conductive layer 13 and the interlayer insulating layer 15 with respect to these corrosives so that aluminum nitride and alumina serve as a etch-resistant material and perform a protective action.

In the present embodiment, the oxidation treatment for the formation of the conductive layer 13 is performed by heat treatment in an air atmosphere at a temperature of 700 ° C. for 3 to 9 hours due to the heat resistance limit of the insulating layer 12 made of glass or the like. Shall be. In addition, the thermal oxidation treatment of the conductive layer 13 may be substituted for the plasma oxidation treatment.

On the upper surface of the conductive pad portion 13a and the interlayer insulating layer 15 of the conductive layer 13, a material of the heat generating resistor 16, for example, Ta-SiO ₂ or the like, is attached by sputtering or the like. A plurality of heat generating resistors 16 are formed by etching with CF ₄ + O ₂ gas by photolithography, and both ends of the conductive pad portion 13a and the interlayer insulating layer 15 of the conductive layer 13 are formed. It is formed to align in a straight line so as to be located above. On the upper surface of the conductive pad portion 13a of the conductive layer 13 of each of the heat generating resistors 16, the common electrode 17a connected to each of the heat generating resistors 16 is approximately 1 to 1 by sputtering such as aluminum or copper. It is laminated with a thickness of 2 μm. The common electrode 17a is connected to the conductive layer 13 at a position beyond the heat generating resistor 16. On the upper surface of the interlayer insulating layer 15, individual electrodes 17b for energizing independently of each of the heat generating resistors 16 are formed and connected in the same manner as the common electrodes 17a. The configuration of both electrodes 17a and 17b is explained by a single layer structure of aluminum or copper, but in addition, the two-layer structure of thinly formed high melting point metal molybdenum, tungsten, or the like forms one side of the heat generating resistor 16 with higher accuracy. Can be configured. This will be described later as a second embodiment.

In addition, in order to protect the surfaces of the heat generating resistor 16, the upper common electrode 17a, the individual electrode 17b, the exposed interlayer insulating layer 15, and the like from oxidation and friction, a cylon or the like is used. A protective layer 18 having a film thickness of approximately 5 to 10 mu m is formed, and the protective layer 18 covers all surfaces other than the external circuit connection portions (not shown) of the electrodes 17a and 17b. have.

Next, a method of manufacturing a multi-layered wiring board of the thermal head in the present embodiment will be described with reference to the flowchart shown in FIG.

First, in FIG. 3, the heat insulation layer 12 which consists of glass etc. which formed the upper surface in circular arc shape is protruded and formed in the upper surface of the flat board | substrate 11 which consists of ceramics, etc. (step ST1).

The conductive layer 13 made of aluminum tantalum nitride summit is formed on the upper surface of the substrate 11 and the insulating layer 12 by sputtering or the like so as to have a film thickness of approximately 3 to 10 mu m (step ST2).

Subsequently, a mask layer 14 made of silicon dioxide or molybdenum silicide having heat resistance and oxidation resistance is laminated on the upper surface of the conductive layer 13 to a film thickness of approximately 0.3 占 퐉 (step ST3).

By photolithography, silicon dioxide is etched by buffered fluoric acid or molybdenum silicide by CT ₄ + O ₂ gas to correspond to the wiring portion and the external circuit connection portion of the common electrode 17a. A mask pattern is formed (step ST4).

The etchant used to form this mask has sufficient selectivity without etching the aluminum nitride and aluminum oxide contained in the conductive layer 13 and the interlayer insulating layer 15, so that the reliability of the multilayer wiring can be made high.

After that, by using the oxygen atmosphere heat treatment furnace forcibly oxidizing the conductive layer 13 exposed at approximately 700 ° C. for several hours, an interlayer insulating layer 15 made of tantalum pentoxide and aluminum having a thickness of about 1 to 2 μm is formed ( Step ST5). Then, the mask layer 14 is etched away to complete the manufacture of the common electrode multilayer wiring board of the present invention (step ST6). At this time, when molybdenum silicide is used for the material of the mask layer 14, since the conductivity can be ensured even after thermal oxidation, the mask layer 14 does not need to be removed, thereby reducing the number of steps.

The real edge as shown in Figs. 1 and 2 is formed by laminating and patterning the heat generating resistor 16, the electrodes 17a and 17b, and the protective layer 18 on the multilayer wiring substrate by the manufacturing process as described above. Prepare the thermal head.

The thermal head includes a plurality of thermal head insulation layers 12, conductive layers 13, interlayer insulating layers 15, and heating resistors on a heat radiating substrate 11 having a plurality of times the area of each thermal head. 16, the thermal head unit 20 formed by forming the common electrode 17a, the individual electrode 17b, and the protective layer 18 is formed, and then the thermal head unit 20 is connected to each thermal head block 21, 21) to prepare.

Hereinafter, a method of cutting the thermal head unit 20 will be described with reference to FIGS. 5 and 6.

In the method of manufacturing the thermal head of this embodiment, laser light is used in the cutting process of the thermal head unit 20 having the plurality of thermal head blocks 21, and the laser light is particularly an excimer laser light. .

The excimer laser emits ultraviolet rays having a wavelength of 308 nm in XeCl gas, 248 nm in KrF gas, and 193 nm in ArF gas, depending on the type of gas used for the laser oscillation. Generally, CO ₂ lasers or YAG lasers are used in laser processing. However, since they are processed by high heat spots, they are not suitable for fine processing because they have disadvantages such as leaving a thermal pile on the workpiece or attaching heat-dissolving fugitives. On the other hand, the excimer laser is an ultraviolet laser, and it is characterized by high thermal quality due to the small thermal action by disassembling and scattering the workpiece at a moment.

In the method of manufacturing the thermal head according to the present embodiment, the characteristics of the excimer laser are applied to form a groove in the cut portion with the excimer laser beam in the cutting step of the thermal head unit 20, and then the bottom of the groove is diced. To cut.

5 is an explanatory diagram showing a cutting process of the thermal head unit 20.

That is, the formation of the protective layer 18 is complete | finished, and the board | substrate 11 of the thermal head just before entering a cutting process is shown to FIG. 5 (A). On the other hand, as shown in Fig. 5B, the dimension a from the end of the common electrode 17a is appropriately adjusted, and then the grooves 22 are formed by irradiating the KrF excimer laser light B. The depth of the groove 22 at this time is assumed to reach the substrate 11. The power of the laser was suitably 10 to 50 W.

Next, as shown in FIG. 5C, the bottom of the groove 22 and the back surface of the substrate 11 are cut by the dicing method in the C direction.

By this method, mechanical stress and thermal stress applied to the film thickness layer portion of the thermal head can be extremely reduced during cutting, so that defects such as chipping and cracking are eliminated. That is, although the dimension (a) from the end of the common electrode 17a to the cut surface is conventionally required, even if the minimum is 20 mu m, it can be reduced to several mu m by the method of the present embodiment. Moreover, the time required for the groove formation by the laser is from 1 minute to several minutes, and can be shortened by 1/5 to 1/10 hours as compared with the case of performing the same work by polishing, thereby achieving cost reduction.

Fig. 6 (A) is a plan view of the heat generating portion when the thermal head cut by the cutting method is connected in the main scanning direction to form a long thermal head, and Fig. 6 (B) shows the X-X 'line. It is sectional drawing when it divides along.

The dot gap G shown in plan view 6 (A) decreases as the heating element density increases and is now about 20 탆. Therefore, also in the connection part 23, the distance between the ends of the heat generating resistor 16 of both the thermal head blocks 21 must be finished to about 20 micrometers. That is, it is necessary to cut the substrate within 10 占 퐉 from the end of the heat generating resistor 16, and considering the cost, the method according to the present invention is effective.

In the present embodiment, only the portion of the substrate 11 is polished so that the laser cut surface 25 of the laminated film and the end face 26 of the substrate 11 are approximately the same as shown in the cross-sectional view of Fig. 6B. In this case, since a single kind of material such as the substrate 11 is polished, it can be processed with high precision in a short time. In addition, it is possible to increase the connection accuracy of the thermal head block 21 which can be connected by polishing the substrate 11 to be inclined so that the laser cut surface of the laminated film is most protruded.

As described above, in the present embodiment, the common electrode 17a is formed on approximately the entire surface of the substrate 11 in the case where it is energized with the desired heating resistor 16 via the individual electrodes 17b based on the desired printing signal. Since the active conductive layer 13 is arranged, an equal voltage can be applied to each of the heat generating resistors 16 from the conductive pad portion 13b serving as the external circuit connection portion, and the nonuniformity of the printing concentration can be eliminated. .

In addition, in a line thermal head in which the aspect ratio of the substrate is significantly large, when a voltage is applied from both ends of the substrate 11, the distance to the center portion of the substrate 11 is long, resulting in an increase in the resistance of the conductive layer 13. Although a voltage drop occurs in the substrate 11, the heat generation temperature of the heat generating resistor 16 is lowered, causing nonuniformity in the printing concentration. In the thermal head of this embodiment, the conductive layer 13 is formed on the entire surface of the substrate 11 of the thermal head. 2, the conductive pad portion 13b serving as an external circuit connection portion of the common electrode 17a can be pulled out anywhere on the upper surface of the substrate 11, so that the common electrode ( It is possible to connect three or more thermal heads without considering the connection of 17a). That is, in the line thermal head as described above, the voltage can be applied not only at both ends of the substrate 11 but also at the center of the substrate 11, so that a uniform voltage is applied to each of the heating resistors 6. The occurrence of nonuniformity can be eliminated.

In the present embodiment, the fused film of the metal nitride and the metal used as the conductive layer 13 has low thermal conductivity and low thermal expansion, excellent adhesion to the substrate, can withstand high temperature annealing, and Compared with this, there is an advantage that the thermal conductivity is particularly low and that the thermal characteristics of the thermal head are not deteriorated.

In addition, since the interlayer insulating layer 15 made of tantalum pentoxide and alumina is formed and used by thermal oxidation of the conductive layer 13, a conductive layer generated when an interlayer insulating layer is formed of a deposition film or a coating film. (13) and the short circuit by the pinhole and dust of the heat generating resistor 16 can be eliminated. In addition, the interlayer insulating layer 15 formed by the thermal oxidation treatment has a high hardness, hardly generates frictional damage in the treatment, and tantalum pentoxide and alumina have a high degree of insulation reliability. In addition, since the conductive layer 13 and the interlayer insulating layer 15 are integrally formed, it is possible to significantly increase the adhesion in addition to the insulating property. In addition, since the whole substrate 11 is annealed at a high temperature through the thermal oxidation process, the mechanical and thermal reliability of the multilayer wiring board can be assured.

When the interlayer insulating layer 15 is formed by thermal oxidation, the surface heights of the conductive connection pad portion 13a and the interlayer insulating layer 15 of the conductive layer 13 can be made approximately the same. Electrical connection between the heat generating resistor 16 and the conductive layer 13 to be formed can be reliably performed.

Therefore, according to the thermal head of this embodiment, even if the space of the wiring portion of the common electrode 17a is extremely small, the conductive layer 13 having the same function as the common electrode 17a is provided on the entire surface of the substrate 11 even if it is real edged. Therefore, it is possible to apply voltage equally to each of the heat generating resistors 16, and it is possible to reliably prevent shortcomings caused by uneven printing concentration and lack of current capacity, thereby achieving proper real edge.

In this way, it becomes possible to attain proper real edge formation, which makes it possible to reduce the size of the substrate 11 and to reduce the manufacturing cost. In addition, it is possible to use a resin-based ink ribbon, which has not been available in the conventional line thermal head, so that the rough paper printing quality can be remarkably improved. In addition, the real-edge thermal head can reduce power loss of the pressure-sensitive resistor 16 of the heat generating resistor 16 with respect to the platen, thereby achieving power saving.

In addition, real edges can be realized by cutting a substrate using laser processing, and high quality printing on rough paper or plain paper is possible. According to the cutting method of the substrate, precise cutting without chipping or cracking on the cutting surface is possible, so that a precise and fine connection type thermal head having a large heating element density can be produced and the time required for cutting is short. It has an effect that can be manufactured at low cost.

7 and 8 show the second and third embodiments of the thermal head of the present invention, and Fig. 9 is a flowchart showing the manufacturing method of the multilayer wiring board of the thermal head of the present embodiment.

In the second embodiment shown in FIG. 7, the insulating layer 12 made of glass or the like is projected in an arc shape on the insulating substrate 11 such as ceramics, and on the substrate 11 and the insulating layer 12. The conductive layer 13 made of a resistor material is formed of a film having a thickness of approximately 3 to 10 mu m. The first interlayer insulating layer 15a is formed on the upper surface of the conductive layer 13 by the heat or plasma oxidation treatment on the upper surface of the thermal head other than the installation portion of the common electrode 17a and the connection portion with the external terminal (not shown). A conductive or insulating mask layer 14 made of molybdenum silicide or silicon dioxide having oxidation resistance is laminated on the conductive layer 13 with a thickness of 2 to 2 µm.

On the upper surface of the first interlayer insulating layer 15a on the conductive layer 13, a second interlayer insulating layer 15b made of silicon or aluminum oxide or nitride is formed into a film having a thickness of approximately 0.1 to 1.0 mu m by the sputtering method. After that, the conductive mask layer 14 is exposed by etching by photolithography, thereby forming multiple interlayer insulating layers 15a and 15b. In this case, when the insulating mask layer 14 is formed, all of the mask layer 14 is removed similarly to the first embodiment.

After addition the heat generating resistor 16 is formed of a Ta-SiO _2, etc. is formed on the formed film by a sputtering method, a plurality of heat generating resistor 16 is formed by etching in photolithography. Each of the heat generating resistors 10 is formed such that both ends thereof are positioned above the conductive mask layer 14 and the second interlayer insulating layer 15b.

On the upper surface of the side end portion of the conductive mask layer 14 of each of the heat generating resistors 16, a common electrode 17a made of a high melting point metal or silicide thereof connected to each of the heat generating resistors 16 is laminated. On the upper surface of the side end portion of the second interlayer insulating layer 15b of (16), an individual electrode 17b made of a high melting point metal or silicide thereof, and aluminum, copper, gold, etc., for conducting power independently of each of the heat generating resistors 16; The individual electrodes 17c each consisting of these are connected. Here, the common electrode 17a side does not need to install a soft good conductor material like the individual electrode 17c by multi-layer wiring, so that it can be made into a hard and thin electrode. The fall of a lifetime can be prevented.

In addition, a protective layer 18 having a thickness of approximately 5 to 10 µm that protects the heat generating resistor 16, the common electrode 17a, and the individual electrodes 17b and 17c covers all surfaces other than the external connection terminal (not shown). It is formed to.

In the third embodiment shown in FIG. 8, the order in which the heat generating resistors 16 and the electrodes 17a and 17b are formed is reversed, and silicides of high melting point metals or high melting point metals are formed in the lower layer of the heat generating resistors 16. FIG. The common electrode 17a and the individual electrode 17b are formed by laminating by sputtering or the like to a thickness of 0.1 to 0.5 mu m and etching by photolithography. The heat generating resistor 16 is formed by similarly stacking and etching the heat generating resistor material on the upper surface. Only the individual electrodes 17c are formed on the upper surface by laminating by conductive material sputtering made of aluminum, copper, gold or the like and etching by photolithography. Thus, the common electrode 17a is made of a high melting point metal or silicide thereof, and is formed thin only under the heat generating resistor 16 without using a soft electrode material, so that the common electrode 17a is applied to the common electrode 17a of the real edge thermal head. The endurance life becomes higher with respect to the factor concentrated load.

Next, a manufacturing method of the real edge thermal head in the second and third embodiments will be described with reference to a flowchart showing the manufacturing process of the multilayer wiring substrate shown in FIG.

First, in FIG. 9, the heat insulation layer 12 which consists of glass etc. in which the upper surface was formed in circular arc shape is protruded on the upper surface of the flat board | substrate 11 which consists of alumina etc. (step ST1).

Next, the high melting point metals Ta, Cr, Mo, W, Ti, Zr, Nb, Hf, V and the insulators SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ are formed on the upper surfaces of the substrate 11 and the insulating layer 12. The conductive layer 13 is formed by sputtering or forming a resistive summ of AlN or a conductive ceramic of boride, nitride, carbide, or silicide of a high melting point metal into a thin film having a thickness of approximately 3 to 10 µm (Step ST 2). .

Next, on the upper surface of the conductive layer 13, a mask layer 14 made of molybdenum silicide or insulating SiO ₂ having heat resistance, oxidation resistance and conductivity is laminated to a film thickness of approximately 0.1 to 0.5 mu m by sputtering or the like ( Step ST 3).

Next, an oxide mask pattern is formed at a position corresponding to the wiring portion of the common electrode 17a and the connection portion of the external terminal (not shown) by the photolithography technique (step ST 4).

Next, the surface of the conductive layer 13 is forcedly oxidized by heat treatment of an oxidation atmosphere (approximately 2 to 6 hours at 700 to 800 ° C.) or plasma oxidation to form the first interlayer insulating layer 15a having a thickness of about 1 to 2 μm. It forms (step ST 5).

Next, a film having a thickness of approximately 0.1 to 1.0 µm is formed on the upper surface of the first interlayer insulating layer 15a by sputtering any one of SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ , and AlN having heat resistance, oxidation resistance, and insulation property. Lamination is carried out in thickness (step ST 6).

Next, the insulating film at a position corresponding to the installation portion of the common electrode 17a and the connection portion with the external terminal (not shown) is removed by etching to expose the conductive portion of the mask layer 14 by photolithography technique. The manufacture of the wiring board is completed (step ST 7).

Thereafter, the heat generating resistor 16 and the electrodes 17a, 17b, and 17c are formed on the multilayer wiring board, and the protective layer 18 is coated thereon to produce a real edge thermal head as shown in FIG. have.

Before forming the heat generating resistor 16 on the multilayer wiring board, each electrode 17a, 17b, 17c is formed of a high melting point metal or silicide of about 0.1 to 0.5 mu m, and then the heat generating resistor 16 and the individual electrode. The real edge thermal head as shown in FIG. 8 can be manufactured by forming (17c) and coating the protective layer 18 thereon.

Next, the operation of the second and third embodiments will be described.

In the present embodiment, in the case where the desired heating resistor 16 is energized via the individual electrodes 17b and 17c based on a desired printing signal, conduction of the same action as that of the common electrode 17a is performed on the entire surface of the substrate 11. Since the layer 13 is provided, a current flows through the other conductive layer 13 of the common electrode 17a, so that an equal voltage can be applied to each of the heat generating resistors 16.

In this case, in this embodiment, the insulating oxide formed by forcibly oxidizing the surface of the conductive layer 13 has the reliability of insulation between the conductive layer 13, the heat generating resistor 16, and the electrodes 17a, 17b, 17c. Since the first interlayer insulating layer 15a made of a thin film is used, the inside of the pinhole of the conductive layer 13 also has insulation and can be formed integrally with the conductive layer 13, thereby increasing the reliability of the insulating property and adhesion. It becomes possible. In addition, a second interlayer insulating layer 15b having excellent insulation and adhesion, which is formed of an oxide or nitride of silicon or aluminum, is laminated on the upper surface of the first interlayer insulating layer 15a to form a plurality of interlayer insulating layers 15a and 15b. Therefore, the multilayer wiring board of this embodiment can make the reliability of insulation and adhesiveness remarkably high. In the present embodiment, the surface of the conductive layer 13 is oxidized to integrally form the first interlayer insulating layer 15a and when the conductive mask layer 14 is used, this can be used without removing the same. Therefore, the height of the surface of the first interlayer insulating layer 15a and the surface of the conductive mask layer 14 which is the exposed portion of the conductive layer 13 can be made approximately the same, and the film of the second interlayer insulating layer 15b Since the heat generating resistor 16 or the common electrode 17a can be formed thereon in a stepped state having a thickness of approximately 0.1 to 1.0 mu m, the electrical connection can be more reliably performed.

In addition, since the conductive layer 13 of the present embodiment uses a resistor material made of a high melting point metal summ and a ceramic, the material is essentially excellent in heat resistance, heat insulation, and adhesiveness, and particularly formed on the entire surface of the substrate 11. The thermal efficiency of the heat generating element is not lowered. In addition, since a soft conductor material does not need to be provided on the common electrode 17a side, it is possible to obtain a thermal head having excellent print life, even if it is real-edgeed close to the limit.

Therefore, according to the real edge thermal head of the present embodiment, even if the space of the wiring portion of the common electrode 17a becomes real edge close to the limit, the conductive layer 13 having the same function as the common electrode 17a on almost the entire surface of the substrate 11. ), And having multiple interlayer insulating layers 15a and 15b, it is possible to apply voltage equally to each of the heat generating resistors 16, which is a disadvantage due to nonuniform factor concentration, lack of current capacity or current leakage. It is possible to reliably prevent the back and the like, and to produce a real edge thermal head close to the limit with good yield.

In this regard, the edge distance of the real edge thermal head of the present embodiment is the distance from the center of the heating element provided at the end of the substrate 11 to the edge of the substrate 11 for removing the ink ribbon. Also in 100 micrometers or less can be easily carried out. As a result, a new improvement effect which has not been conventionally calculated is calculated. In this manner, real edge formation can be achieved close to the limit, so that the substrate 11 can be miniaturized and manufacturing costs can be reduced. In addition, it is possible to use a resin-based ink ribbon which cannot be used by the conventional line thermal head, and the rough paper printing quality can be remarkably improved.

In addition, the thermal head, which has been real-edgeed to the extreme, has significantly reduced the loss of pressure contact pressure of the heating element with respect to the platen, and increases the effect of removing the irregularities of the paper fiber. The transfer efficiency is improved, and the power saving can be achieved.

10 is a cross-sectional view of the thermal head block 21 showing the fourth embodiment of the thermal head of the present invention.

The thermal head block 21 of the present embodiment uses a silicon wafer as the heat dissipation substrate 11, and also forms the heat generating portion 11a in a convex shape, and forms the heat insulating layer 12 thereon. And a common electrode side lower electrode layer 24a and an individual electrode side lower electrode layer 24b formed under the heat generating resistor 16, and the like. Is configured similarly to the first embodiment described above.

The silicon wafer constituting the heat dissipation substrate 11 has good heat dissipation because the heat conductivity is about 5 times higher than that of the alumina ceramic which is frequently used as a material of the heat dissipation substrate 11, and the heat dissipation of the thermal head is improved, so that high-speed driving This becomes possible.

Since silicon wafers are single crystals, anisotropic etching is possible. Thus, by using this feature, the part which contacts the heat generating part 11a can be formed in convex shape. Since anisotropic etching is used, convex dimensional reproducibility is good.

Next, the insulating layer 12 is composed of a fusion of an oxide of silicon and an oxide of a metal, but the oxide of the metal is preferably tantalum oxide and tungsten oxide. In addition, when the sputtering method is used for film formation, dispersion of the film thickness can be suppressed to ± 5%.

As described above, the thermal head block 21 according to the present embodiment has a high dimensional accuracy in three dimensions, and also has a thermal characteristic determined by the thickness of the thermal insulation layer 12. The thermal head block 21 can be combined at the time of connection. Since 21 can be selected easily, the productivity of a connection type thermal head can be improved.

The lower electrode layer 24 is formed of a thin film of molybdenum and is formed by dry etching. Therefore, the dimension of the heat generating resistor in the sub-scanning direction is trimmed, and the nonuniformity of the resistance value of the heat generating resistor can be suppressed. When the lower electrode layer 24 is formed as in the present embodiment, only the individual electrode 17b is formed as the electrode layer, and the common electrode 17a does not have to be provided. In other words, the common electrode side is provided with only the lower electrode layer 24a, and the common electrode side lower electrode layer 24a is sandwiched between the conductive layer 13 and the heat generating resistor 16, and the individual electrode side is the individual electrode 17a. ) And the lower electrode 24b, the heat generating resistor 16 is sandwiched between them. Since the lower electrode layer 24a of the common electrode side is electrically connected to the conductive layer 13, there is no need to provide the common electrode 17a, but rather a flexible film such as aluminum is provided on the common electrode side as the electrode layer. By not doing so, the mechanical strength of this part is increased so that no film peeling occurs with respect to the pressure contact force applied during printing.

As described above, according to the thermal head of the present embodiment, the printing durability of the thermal head can be improved.

In addition, this invention is not limited to the above-mentioned embodiment, It can change as needed.

As described above, according to the present invention, since it is a conductive layer made of a fused material of a nitride and a metal having a low thermal conductivity and thermal expansion or a fused material of an oxide and a metal, adhesion to a substrate is performed even at a high temperature thermal oxidation treatment. It is excellent.

In addition, since a conductive layer having the same function as the common electrode of the thermal head is provided on the entire surface of the substrate, an equal voltage can be applied to each of the heat generating resistors. Since it is possible to reliably prevent disadvantages caused by leaks and the like, it is possible to appropriately cope with real edge formation of the thermal head. In addition, when the interlayer insulating layer is formed of a plurality of layers, the insulation reliability is further increased.

In the manufacturing process of the multilayer substrate, nitrides (for example, aluminum nitride) and oxides (for example, aluminum oxide) constituting the conductive layer are used for etching agents such as buffered fluoric acid and CF ₄ + O ₂ gas. Since it is difficult to etch, the thermal oxidation mask and the resistor pattern can be formed with high accuracy without damaging the conductive layer and the interlayer insulating layer, thereby increasing the manufacturing yield.

In addition, an interlayer insulating layer integrated with the conductive layer is formed on the surface of the conductive layer to form an oxidation resistant mask and thermally oxidize, thereby minimizing the step difference between the exposed portion of the conductive layer and the interlayer insulating layer. The electrical conductivity with the heat generating resistor can be assured. In addition, the mechanical and thermal reliability of the multilayer wiring board can be improved by high temperature annealing during the oxidation process for forming the interlayer insulating layer.

In addition, by using the real edge thermal head using the multilayer wiring board of the present invention, at least three external circuit connection portions of the common electrode can be formed in the substrate, and the defects due to the uneven printing concentration or the insufficient current capacity can be reliably prevented. have. In addition, the line thermal head substrate can be miniaturized, and manufacturing cost can be reduced. In addition, since the edges of the common electrode can be made thin with hard materials even if they are real-edgeed close to the limit, the life of the print can be extended to match the protective layer. In addition, the use of resin-based ink ribbons is possible by real edge formation, and the rough paper printing quality can be remarkably improved by proper ink ribbon. In addition, it is possible to remarkably reduce the loss of pressure contact pressure of the heat generating resistor against the platen, and the effect of removing the irregularities of the paper fibers is remarkably increased, in particular, the rough paper printing quality is remarkably improved and energy power can be improved. .

In addition, real cutting of individual thermal head blocks can be realized by cutting the substrate of the thermal head unit using laser processing, and high quality printing on rough paper or plain paper can be achieved. In addition, according to the cutting method of the substrate, precise cutting without chipping or cracking at the cutting surface is possible, so that a precise and fine connection type thermal head having a large heating element density can be manufactured and the time required for cutting is short. This has the effect of being able to manufacture at low cost.

Claims (16)

In a thermal head formed by laminating a heat insulating layer, a conductive layer, an interlayer insulating layer, a heating resistor, a common electrode, an individual electrode, and a protective layer on a heat radiating substrate, And the conductive layer is formed of a fusion of nitride or oxide with a metal, and is electrically connected to a common electrode, wherein the interlayer insulating layer is formed with at least an oxide film of the conductive layer. The method of claim 1, And the conductive layer is formed of a conductive summ consisting of one kind of a nitride of silicon, an oxide of silicon, an nitride of aluminum, and an oxide of aluminum, or a composite and a high melting point metal. The method of claim 2, The conductive layer is a thermal head, characterized in that the fusion of aluminum nitride and tantalum. The method of claim 2, And the conductive layer is a fusion of aluminum oxide and tantalum. The method of claim 1, And the conductive layer is formed of a conductive ceramic of boride, nitride, carbide, or silicide of a high melting point metal. The method of claim 1, The interlayer insulating layer is a multilayer interlayer insulating layer comprising an oxide film of the conductive layer as a first interlayer insulating layer and an insulating ceramic laminated on the first interlayer insulating layer as a second interlayer insulating layer. . The method of claim 6, And said second interlayer insulating layer comprises at least one of nitride of silicon, oxide of silicon, nitride of aluminum and oxide of aluminum. The method of claim 1, And said common electrode has at least three external circuit connecting portions formed in said substrate. The method of claim 1, Wherein the common electrode is formed by sandwiching the conductive layer and the heat generating resistor in a single layer, and the individual electrode is formed so as to sandwich the heat generating resistor in two layers. Forming a heat insulating layer at a position corresponding to the heat generating portion on the heat dissipation substrate, and laminating a conductive layer made of a fusion of nitride or oxide and metal on the upper surface of the substrate and the heat insulating layer; A step of laminating an insulating and oxidation resistant mask layer on the conductive layer, Forming a mask pattern at a position corresponding to the position at which the common electrode of the mask layer and the external circuit connection portion of the common electrode are formed; Forming an interlayer insulating layer by heat or plasma oxidation in an oxidizing atmosphere on surfaces of conductive layers other than the mask layer forming portion by the mask pattern; Removing the oxidation resistant mask; Forming a predetermined heating resistor so that both ends thereof are positioned above the interlayer insulating layer and the conductive layer, respectively; Forming an individual electrode at the end of the interlayer insulating layer on the upper surface of the heat generating resistor and forming a common electrode at the end of the conductive layer; A method of manufacturing a thermal head, comprising the step of laminating a protective layer on these top surfaces. Forming a heat insulating layer at a position corresponding to the heat generating portion on the heat radiating substrate, and laminating a conductive layer made of a fusion of nitride or oxide and metal on the upper surface of the substrate and the heat insulating layer; Laminating a conductive and oxidation resistant mask on the conductive layer; Forming a mask pattern at a position corresponding to the position at which the common electrode of the mask layer and the external circuit connection portion of the common electrode are formed; Forming an interlayer insulating layer by heat or plasma oxidation in an oxidation atmosphere on surfaces of conductive layers other than the mask layer forming portion by the mask pattern; Forming a predetermined heating resistor so that both ends thereof are positioned above the interlayer insulating layer and the conductive layer, respectively; Forming an individual electrode at the end of the interlayer insulating layer on the upper surface of the heat generating resistor and forming a common electrode at the end of the conductive layer; A method of manufacturing a thermal head, comprising the step of laminating a protective layer on these top surfaces. Forming a heat insulating layer at a position corresponding to the heat generating portion of the heat radiating substrate, and laminating a conductive layer made of a resistor material on the upper surface of the substrate and the heat insulating layer; Laminating an oxidation resistant mask layer on the conductive layer; Forming a mask pattern at a position corresponding to the position at which the common electrode of the mask layer and the external circuit connection portion of the common electrode are formed; Forming a first interlayer insulating layer by heat or plasma oxidation in an oxidizing atmosphere on surfaces of conductive layers other than the mask layer forming portion by the mask pattern; An insulating layer made of an insulating ceramic material is laminated on the first interlayer insulating layer, and the conductive layer is exposed by etching the position corresponding to the common electrode and the position where the terminal portion of the common electrode is formed by photolithography technique to expose the second interlayer insulation. Forming a layer, Forming a predetermined heating resistor so that both ends thereof are positioned above the second interlayer insulating layer and the conductive layer, respectively; Forming an individual electrode at an end of the upper surface of the heat generating resistor on the side of the second interlayer insulating layer and forming a common electrode at the end of the conductive layer; A method of manufacturing a thermal head, comprising the step of forming a protective layer on the uppermost surface thereof. The method of claim 10 or 12, The oxidation-resistant mask layer is a method of manufacturing a thermal head, characterized in that formed of silicon dioxide. The method of claim 11 or 12, The oxidation resistant mask layer is formed of molybdenum silicide. A plurality of thermal head blocks are provided, and the respective thermal substrates of the thermal head unit formed by laminating a heat insulating layer, a conductive layer, an interlayer insulating layer, a heat generating resistor, a common electrode, an individual electrode, and a protective layer on the heat radiating substrate are cut off. As a method of manufacturing a thermal head for manufacturing a head, At least the laminated film is removed by laser light irradiation, and then the exposed heat dissipation substrate is cut. The method of claim 15, And after the cutting of the heat radiating substrate, only the heat radiating substrate is polished so that the cross-sections of the heat insulating layer and the protective layer are substantially the same as the end faces of the heat radiating substrate.