JP2012166409A - Method for manufacturing thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of manufacturing a thermal head which has a high exoergic efficiency and a stable quality.SOLUTION: The method for manufacturing the thermal head includes a recess formation step S1 for forming a recess on the surface of a support substrate, a joining step S2 for joining an upper plate substrate to the surface of the support substrate in which the recess is formed, in a stacked state, a thin plate processing step S3 for thinning the upper plate substrate joined to the support substrate, a thickness measuring step S4 for measuring the thickness of the sheeted upper plate substrate, a re-thinning step R5 for re-thinning the area of the upper plate substrate whose thickness is a prescribed value or more, and a heating resistor formation step S6 for forming a heating resistor in the area corresponding to the recess in the surface of the sheeted upper plate substrate.

Description

  The present invention relates to a method for manufacturing a thermal head.

  2. Description of the Related Art Conventionally, a method for manufacturing a thermal head that is used in a thermal printer and performs printing on a thermal recording medium such as paper by selectively driving a plurality of heating elements based on print data (for example, Patent Documents). 1).

  In the method of manufacturing a thermal head disclosed in Patent Document 1, a recess is formed on the surface of an upper substrate, and a support substrate is bonded to the upper substrate so as to close the recess, whereby the upper substrate A cavity is formed between the substrate and the support substrate, and a heating resistor is formed in a region corresponding to the recess on the back surface of the upper substrate.

  According to the thermal head manufactured in this way, the amount of heat escaping from the heating resistor to the support substrate side through the upper substrate is reduced by making the cavity function as a heat insulating layer with low thermal conductivity, and printing is performed. The heat generation efficiency can be improved by increasing the amount of heat used for the heating.

JP 2010-94939 A

  In the thermal head disclosed in Patent Document 1, variations in the dimensions of the recesses and the thickness of the upper substrate greatly affect the heat generation efficiency of the thermal head. Therefore, it is required to reduce variations in these dimensions. The In particular, it has been found that the variation in the thickness dimension of the upper substrate has the greatest influence on the heat generation efficiency, and it is very important to control this.

  However, according to the manufacturing method of the thermal head disclosed in Patent Document 1, the thickness of the upper substrate varies within the same substrate, or the thickness of the upper substrate varies from substrate to substrate. I will. For this reason, there is a problem that heat efficiency varies from thermal head to thermal head, making it difficult to manufacture a thermal head with stable quality.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a method capable of manufacturing a thermal head having high heat generation efficiency and stable quality.

In order to achieve the above object, the present invention employs the following means.
The present invention includes a step of forming a recess on a surface of a support substrate, a step of bonding an upper substrate to the surface of the support substrate on which the recess is formed, and a step of bonding to the support substrate. A thinning step for thinning the upper substrate, a thickness measuring step for measuring a thickness of the thinned upper substrate, and a region where the thickness of the upper substrate is equal to or greater than a predetermined value is thinned again. A thermal head manufacturing method including a re-thinning step and a heating resistor forming step of forming a heating resistor in a region corresponding to the recess on the surface of the thinned upper substrate is employed.

  According to the present invention, the concave portion is formed on the surface of the support substrate in the concave portion forming step, and the upper substrate is bonded to the surface of the support substrate on which the concave portion is formed in the bonding step. As a result, a cavity is formed between the support substrate and the upper substrate. This hollow portion functions as a hollow heat insulating layer that blocks heat generated from the heating resistor, and can improve the heat generation efficiency of the thermal head. In the thinning step, the upper substrate bonded to the support substrate is thinned, and in the heating resistor forming step, the heating resistor is formed in a region corresponding to the concave portion on the surface of the thinned upper substrate. The

  In this case, prior to the heating resistor forming step, the thickness of the upper substrate thinned in the thickness measurement step is measured, and in the re-thinning step, there is a region where the thickness of the upper substrate is a predetermined value or more. Thinned again. Thereby, the variation in the thickness dimension of the upper substrate that greatly affects the heat generation efficiency can be reduced, and a constant heat generation efficiency can be maintained. As described above, according to the present invention, a thermal head having high heat generation efficiency and stable quality can be manufactured.

In the above invention, the re-thinning step may thin the upper substrate in units of regions where one thermal head is formed.
By doing in this way, it can prevent that the thickness dimension of an upper-plate board | substrate changes rapidly in one thermal head. This also makes it possible to make the heat generation efficiency of each thermal head in a large substrate uniform, and to make the heat generation efficiency from a plurality of heat generating parts uniform in one thermal head. Variation in density can be suppressed.

  In the above invention, the re-thinning step includes a resist mask forming step of forming a resist mask in a region where the thickness measured by the thickness measuring step is a predetermined value or less, and the resist mask is formed And an etching process step of performing an etching process on the upper substrate.

  By doing so, a resist mask is formed in a region having a thickness equal to or smaller than a predetermined value in the resist mask forming step, and an etching process is performed on the upper substrate on which the resist mask is formed in the etching processing step. Done. Thereby, the variation in the thickness dimension of the upper substrate can be easily reduced, and the heat generation efficiency can be stabilized.

  In the above invention, the resist mask forming step may be performed by exposing a region where the thickness of the upper substrate is larger than the predetermined value after applying a positive resist to the upper substrate. A resist mask may be formed for the following regions.

  In the above invention, in the resist mask forming step, a negative resist is applied to the upper substrate, and then an area where the thickness of the upper substrate is equal to or less than the predetermined value is exposed. A resist mask may be formed for the region.

  According to the present invention, there is an effect that a thermal head having high heat generation efficiency and stable quality can be manufactured.

1 is a schematic configuration diagram of a thermal printer according to an embodiment of the present invention. It is the top view which looked at the thermal head of FIG. 1 from the protective film side. It is AA arrow sectional drawing of the thermal head of FIG. FIG. 3 is a plan view of a multilayer substrate in the manufacturing process of the thermal head of FIG. 2. It is sectional drawing which expanded the laminated substrate of FIG. 4 partially. FIG. 3 is a plan view of a laminated substrate on which a resist mask is formed in the manufacturing process of the thermal head of FIG. 2. It is sectional drawing which expanded the laminated substrate of FIG. 6 partially. 3 is a flowchart showing a method for manufacturing the thermal head of FIG. 2. It is a flowchart which shows the detailed process in the thickness measurement process of FIG. 8, and a re-thinning process. It is a flowchart which shows the modification of FIG.

Hereinafter, a thermal head 1 according to an embodiment of the present invention will be described with reference to the drawings.
The thermal head 1 according to the present embodiment is used in, for example, a thermal printer 10 as shown in FIG. 1, and prints thermal paper 12 or the like by selectively driving a plurality of heating elements based on print data. Printing on an object.

  The thermal printer 10 includes a main body frame 11, a horizontally arranged platen roller 13, a thermal head 1 arranged to face the outer peripheral surface of the platen roller 13, and a heat radiating plate 15 supporting the thermal head 1 (FIG. 3). A paper feed mechanism 17 that feeds the thermal paper 12 between the platen roller 13 and the thermal head 1, and a pressure mechanism 19 that presses the thermal head 1 against the thermal paper 12 with a predetermined pressing force. .

The thermal head 1 is pressed against the platen roller 13 via the thermal paper 12 by the operation of the pressure mechanism 19. As a result, the load of the platen roller 13 is applied to the thermal head 1 via the thermal paper 12.
The heat radiating plate 15 is a plate-like member made of, for example, a metal such as aluminum, resin, ceramics, glass, or the like, and is intended for fixing the thermal head 1 and radiating heat.

  As shown in FIG. 2, the thermal head 1 has a plurality of heating resistors 7 and a pair of electrodes 8 (a common electrode 8 </ b> A and an individual electrode 8 </ b> B described later) arranged in the longitudinal direction of the support substrate 3. An arrow Y indicates the feeding direction of the thermal paper 12 by the paper feeding mechanism 17. A rectangular recess 2 extending in the longitudinal direction of the support substrate 3 is formed on the surface of the support substrate 3.

A cross-sectional view taken along line AA in FIG. 2 is shown in FIG.
As shown in FIG. 3, the thermal head 1 includes a flat support substrate 3 fixed to the heat radiating plate 15, a flat upper plate substrate 5 bonded to the surface of the support substrate 3, and an upper plate substrate 5. A heating resistor 7 provided above, a pair of electrodes 8 connected to the heating resistor 7, and a protective film 9 that covers the heating resistor 7 and the pair of electrodes 8 and protects them from wear and corrosion. Yes.

  The support substrate 3 is an insulating substrate such as a glass substrate or a silicon substrate having a thickness of about 300 μm to 1 mm, for example. A rectangular recess 2 extending in the longitudinal direction of the support substrate 3 is formed on the surface of the support substrate 3, that is, on the boundary surface with the upper substrate 5. For example, the recess 2 has a depth of 1 μm to 100 μm and a width of about 50 μm to 300 μm.

  The upper substrate 5 is made of, for example, a glass material having a thickness of about 10 μm to 100 μm, and functions as a heat storage layer that stores heat generated from the heating resistor 7. The upper substrate 5 is bonded to the surface of the support substrate 3 so as to close the recess 2. By covering the recess 2 with the upper substrate 5, a cavity 4 is formed between the upper substrate 5 and the support substrate 3.

  The hollow portion 4 has a communication structure that faces all the heating resistors 7, and serves as a hollow heat insulating layer that suppresses heat generated from the heating resistors 7 from being transmitted from the upper substrate 5 to the support substrate 3. Function. By making the hollow portion 4 function as a hollow heat insulating layer, the amount of heat transmitted to the support substrate 3 via the upper substrate 5 below the heating resistor 7 is transmitted to the upper side of the heating resistor 7 and used for printing or the like. The amount of heat generated can be increased, and the thermal efficiency of the thermal head 1 can be improved.

  The heating resistors 7 are provided on the upper end surface of the upper substrate 5 so as to straddle the recesses 2 in the width direction, and a plurality of the heating resistors 7 are arranged at predetermined intervals in the longitudinal direction of the recesses 2. That is, each heating resistor 7 is provided so as to face the cavity 4 via the upper substrate 5, and is disposed on the cavity 4.

  The pair of electrodes 8 are for heating the heating resistors 7. The common electrode 8 A connected to one end in a direction orthogonal to the arrangement direction of the heating resistors 7 and the other end of each heating resistor 7. And an individual electrode 8B connected to the. The common electrode 8A is integrally connected to all the heating resistors 7, and the individual electrodes 8B are connected to the individual heating resistors 7, respectively.

  When a voltage is selectively applied to the individual electrode 8B, a current flows through the heating resistor 7 to which the selected individual electrode 8B and the common electrode 8A opposite to the selected individual electrode 8B are connected, and the heating resistor 7 generates heat. It has become. In this state, the thermal paper 12 is colored and printed by pressing the thermal paper 12 against the surface portion (printing portion) of the protective film 9 covering the heat generating portion of the heat generating resistor 7 by the operation of the pressurizing mechanism 19. It is like that.

  Note that a portion of each heat generating resistor 7 that actually generates heat (hereinafter, the heat generating portion is referred to as “heat generating portion 7A”) is a portion where the pair of electrodes 8 do not overlap the heat generating resistor 7, that is, the heat generating resistor. 7 is a region between the connection surface of the common electrode 8 </ b> A and the connection surface of the individual electrode 8 </ b> B, and is a portion located almost directly above the cavity 4.

A method for manufacturing the thermal head 1 configured as described above will be described below with reference to FIGS.
In the present embodiment, a method for manufacturing a plurality of thermal heads 1 from a large support substrate 3 and an upper substrate 5 as shown in FIGS. 4 and 5 will be described.

  As shown in FIG. 8, the manufacturing method of the thermal head 1 according to the present embodiment includes a recess forming step S1 for forming the recess 2 on the surface of the support substrate 3, and the surface of the support substrate 3 on which the recess 2 is formed. Measuring the thickness of the thinned upper substrate 5, the bonding step S2 for bonding the back surface of the plate substrate 5 in a laminated state, the thinning step S3 for thinning the upper substrate 5 bonded to the support substrate 3 The thickness measurement step S4 to be performed, the re-thinning step S5 for thinning again the region where the thickness of the upper substrate 5 is equal to or greater than the predetermined value, and the region corresponding to the recess 2 on the surface of the thinned upper substrate 5 A heating resistor forming step S6 for forming the heating resistor 7; an electrode forming step S7 for forming a pair of electrodes 8 at both ends of the heating resistor 7; and an upper substrate including the heating resistor 7 and the pair of electrodes 8 A protective film forming step S8 for forming a protective film 9 on the surface of A plurality of thermal heads 1 formed and a cutting step S9 carving individually. Hereafter, each said process is demonstrated concretely.

  In the recess forming step S1, as the support substrate 3, for example, an insulating glass substrate having a thickness of about 300 μm to 1 mm is used. First, the large support substrate 3 is distributed, and the area is divided for each thermal head 1. For example, in FIG. 4, a rectangular area divided into four in one direction (vertical direction on the paper surface) and 14 in the other direction (horizontal direction on the paper surface) is an area of each thermal head 1. In the recess forming step S1, a rectangular recess 2 extending in the longitudinal direction is formed for each region of each thermal head 1 on one surface of the support substrate 3.

  The width and depth of the recess 2 are more effective as the dimensions are larger in terms of thermal efficiency, but it is necessary to keep them within a predetermined range in order to suppress variations in quality among products. Moreover, when the width dimension of the recessed part 2 is too large, the intensity | strength of the upper board | substrate 5 will become weak. Further, increasing the depth dimension of the recess 2 is not preferable because it leads to an increase in manufacturing cost.

  The recess 2 can be formed, for example, by subjecting one surface of the support substrate 3 to sandblasting, dry etching, wet etching, laser processing, drilling, or the like. When processing by sandblasting is performed, a photoresist material is coated on one surface of the support substrate 3. Then, the photoresist material is exposed using a photomask having a predetermined pattern, and a portion other than the region where the recess 2 is formed is solidified.

  Thereafter, the surface of the support substrate 3 is washed to remove the uncured photoresist material. Then, an etching mask (not shown) in which an etching window is formed in a region where the recess 2 is formed is obtained. In this state, the surface of the support substrate 3 is sandblasted to form the recess 2 having a predetermined depth.

  When processing by etching such as dry etching or wet etching is performed, an etching mask in which an etching window is formed in a region where the concave portion 2 is formed on one surface of the support substrate 3 is formed in the same manner as the processing by the sandblast described above. Form. In this state, the surface of the support substrate 3 is etched to form the recess 2 having a predetermined depth.

  For the etching process, for example, dry etching such as reactive ion etching (RIE) or plasma etching can be used in addition to wet etching using a hydrofluoric acid-based etching solution or the like. In the case where the supporting substrate is single crystal silicon, wet etching is performed with an etching solution such as a tetramethylammonium hydroxide solution, a KOH solution, or a mixed solution of hydrofluoric acid and nitric acid.

  Next, in the bonding step S <b> 2, a glass substrate made of the same material as the support substrate 3 is used as the upper plate substrate 5. A glass substrate having a thickness of 100 μm or less is difficult to manufacture and handle, and is expensive. Therefore, instead of joining the thin upper substrate 5 to the support substrate 3 from the beginning, the upper substrate 5 having a thickness that is easy to manufacture and handle is joined to the support substrate 3, and then the upper plate is subjected to the thinning step S3. The substrate 5 is processed to a desired thickness.

  In the bonding step S2, first, the etching mask is completely removed from the surface of the support substrate 3 and cleaning is performed. And the upper board | substrate 5 is bonded together on the surface of the support substrate 3 so that all the recessed parts 2 may be obstruct | occluded. At this time, the support substrate 3 and the upper substrate 5 are preferably directly bonded by heat treatment or anodic bonding having an extremely thin adhesive layer. Bonding with a thick adhesive layer is less desirable for thermal efficiency.

  A plurality of cavities 4 are formed between the support substrate 3 and the upper substrate 5 by covering the surface of the support substrate 3 with the upper substrate 5 and closing the openings of the recesses 2. In this state, the bonded support substrate 3 and upper substrate 5 are subjected to heat treatment, and these are bonded by thermal fusion. Hereinafter, a substrate obtained by bonding the support substrate 3 and the upper substrate 5 is referred to as a laminated substrate 6.

  Next, in the thinning step S3, the upper substrate 5 of the multilayer substrate 6 is thinned based on preset processing conditions. The upper substrate 5 is thinned by etching or polishing. Various etchings can be used for etching the upper substrate 5 as in the recess forming step S1. For polishing the upper substrate 5, for example, CMP (chemical mechanical polishing) used for high-precision polishing of a semiconductor wafer or the like can be used.

  Here, the thickness of the upper substrate 5 serving as the heat storage layer greatly affects the thermal efficiency of the thermal head. The upper substrate 5 is desirably thin in terms of thermal efficiency, but cannot be very thin in terms of strength. Therefore, the thickness of the upper substrate 5 is desirably about 10 μm to 50 μm. Further, in order to suppress variations in product quality, it is desirable that variations in the thickness of the upper substrate 5 within the substrate or between the substrates be within a standard of about ± 10 μm.

  However, it is not easy to process uniformly and put it in the above variation range. In general, when polishing is performed, the amount of polishing tends to be large because pressure is easily applied to the peripheral portion of the substrate. Even when etching is performed, the etching amount tends to increase because the peripheral portion is more likely to circulate the etching solution. In the case of etching, a large amount of processing can be performed at one time, which is advantageous in terms of productivity, but it is expected that the amount of variation between substrates in one processing will also increase.

  Therefore, in the method for manufacturing the thermal head 1 according to the present embodiment, the thickness of the upper substrate 5 is measured in the thickness measurement step S4, and the upper substrate 5 is thinned again as necessary in the re-thinning step S5. Process. Detailed processing at this time will be described below with reference to the flowchart shown in FIG.

  As shown in FIG. 9, in the thickness measurement step S4, for example, the thickness of the upper substrate 5 is measured using a measurement microscope, a contact type surface roughness meter, a non-contact type laser displacement meter, or the like. (Step S11). At this time, the thickness of the upper substrate 5 is preferably measured in units of thermal heads, but may be measured only for a plurality of preset measurement points (for example, the peripheral portion and the central portion). In addition, it is desirable to measure the thickness of the upper substrate 5 at a plurality of locations (for example, 3 locations) in one thermal head and calculate the average of the measured thicknesses.

  Next, the thickness of the upper substrate 5 for each thermal head is captured as data (step S12). This data is recorded as electronic data for later feedback to the re-thinning step S5.

In the re-thinning step S5, first, a positive photoresist is applied to the entire surface of the upper substrate 5 (step S13).
Next, the thickness data of the upper substrate 5 recorded in step S12 is collated (step S14), and exposure / development is performed on an area where the measured thickness is larger than a predetermined value (for example, 20 μm ± 5 μm). This is performed (step S15: resist mask forming step).

  As a result, as shown in FIGS. 6 and 7, a resist mask 30 (shaded portion in FIG. 6) is formed in a region where the measured thickness is not more than a predetermined value (for example, 20 μm ± 5 μm). The resist mask 30 is formed for each thermal head. 6 and 7, reference numeral 31 indicates a non-resist mask region that is not covered with the resist mask 30.

  For the exposure in units of thermal heads, selective patterning as described above can be performed by using, for example, a stepper exposure machine. In addition, as a method of exposing only the target portion, for example, a liquid crystal shutter equivalent to the substrate size is prepared instead of the photomask, collated with the thickness data of the upper substrate 5, and light is irradiated to the portion to be exposed. It is good also as switching so that it may permeate | transmit.

  In the case of the method of selectively performing exposure and etching as described above, it is necessary to have a one-to-one correspondence between the thickness data and the substrate to be processed. For this purpose, it is very effective that an apparatus that prints a barcode or the like on a substrate, and that automatically exposes or etches reads the barcode on each substrate to perform an on-demand process.

Next, an etching process is performed on the upper substrate 5 on which the resist mask 30 is formed (step S16: etching process). Here, the same processing as in the above-described thinning step S3 is performed. As a result, the region not covered by the resist mask 30, that is, the non-resist mask region 31, is etched, and the non-resist mask region 31 is thinned.
Next, the resist mask 30 is peeled off (step S17), and the thickness of the upper substrate 5 is measured again (step S18).

  In step S18, when the thickness of the upper substrate 5 is out of specification, that is, larger than 20 μm ± 5 μm, the processing from step S12 to step S17 is repeated. On the other hand, when the thickness of the upper substrate 5 is within the specification, that is, 20 μm ± 5 μm or less, the thickness measurement step S4 and the re-thinning step S5 are finished, and the process proceeds to the heating resistor forming step S6.

  In the case where the thickness of the upper substrate 5 is measured at a plurality of locations (for example, three locations) in one thermal head, the minimum value of data at the plurality of locations does not deviate from the range of 20 μm ± 5 μm. In addition, the processing from step S12 to step S17 is performed.

  Next, in the heating resistor forming step S6, a plurality of heating resistors 7 are formed in regions corresponding to the respective recesses 2 on the surface of the thin upper substrate 5 as described above. The heating resistors 7 are arranged at a predetermined interval in the longitudinal direction of each cavity 4 and are formed so as to straddle the cavity 4 in the width direction.

  A thin film forming method such as sputtering, CVD (Chemical Vapor Deposition), or vapor deposition can be used to form the heating resistor 7. A thin film of Ta-based or silicide-based heating resistor material is formed on the upper substrate 5, and this thin film is formed using a lift-off method, an etching method, or the like, so that the heating resistor 7 having a desired shape is formed. Can be formed.

  Next, in the electrode forming step S7, an electrode material is formed on the upper substrate 5 by sputtering, vapor deposition or the like, similar to the heating resistor forming step S6. Then, this film is formed by using a lift-off method or an etching method, or the electrode material is screen-printed and then baked to form a pair of electrodes 8. As the electrode material, for example, Al, Al—Si, Au, Ag, Cu, Pt, or the like can be used.

  The order in which the heating resistor 7 and the pair of electrodes 8 are formed is arbitrary. In the resist material patterning for lift-off or etching in the heating resistor 7 and the pair of electrodes 8, the photoresist material is patterned using a photomask.

Next, in a protective film forming step S8, a protective film material is formed on the upper substrate 5 on which the heating resistor 7 and the pair of electrodes 8 are formed, thereby forming the protective film 9. As the protective film material, for example, SiO ₂ , Ta ₂ O ₅ , SiAlON, Si ₃ N ₄ , diamond-like carbon, or the like is used. Further, as a film forming method, sputtering, ion plating, CVD method or the like is used. By forming the protective film 9, the heating resistor 7 and the pair of electrodes 8 can be protected from wear and corrosion.

  Next, in the cutting step S <b> 9, the large laminated substrate 6 is cut for each area of the thermal head 1. In the present embodiment, 56 thermal heads 1 are formed from one large laminated substrate 6.

  As described above, according to the method for manufacturing the thermal head 1 according to the present embodiment, the recess 2 is formed on the surface of the support substrate 3 in the recess forming step S1, and the recess 2 is formed in the bonding step S2. 3, the back surface of the upper substrate 5 is bonded in a laminated state. As a result, the cavity 4 is formed between the support substrate 3 and the upper substrate 5. The hollow portion 4 functions as a hollow heat insulating layer that blocks heat generated from the heating resistor 7 and can improve the heat generation efficiency of the thermal head. Then, in the thinning step S3, the upper substrate 5 bonded to the support substrate 3 is thinned, and in the heating resistor forming step S6, the region corresponding to the recess 2 on the surface of the thinned upper substrate 5 is formed. A heating resistor 7 is formed.

  In this case, prior to the heating resistor forming step S6, the thickness of the upper substrate 5 thinned in the thickness measuring step S4 is measured, and in the re-thinning step S5, the thickness of the upper substrate 5 is predetermined. The region above the value is thinned again. Thereby, the variation in the thickness dimension of the upper substrate 5 that greatly affects the heat generation efficiency can be reduced, and a constant heat generation efficiency can be maintained. That is, according to the method for manufacturing the thermal head 1 according to the present embodiment, a thermal head with high heat generation efficiency and stable quality can be manufactured.

  In the re-thinning step S5, the thickness of the upper substrate 5 is rapidly changed in one thermal head by thinning the upper substrate 5 in units of areas where one thermal head is formed. Can be prevented. As a result, within one thermal head, the heat generation efficiency from the plurality of heat generating resistors 7 can be made uniform, and variations in print density can be suppressed.

  In addition, the process of steps S12 to S17 is repeated according to the thickness of the upper substrate 5 measured in step S18, instead of performing the thinning process of the upper substrate 5 only once. The substrate 5 can be thinned with high accuracy.

  As a modification of the method for manufacturing the thermal head 1 according to the present embodiment, as shown in FIG. 10, the thickness data of the upper substrate 5 recorded in step S12 is collated (step S14) and measured. A light-shielding mask that blocks exposure to an area having a thickness equal to or less than a predetermined value (for example, 20 μm ± 5 μm) may be formed (step S21). Specifically, the light-shielding film is cut out with a laser cutter in a region where the thickness measured in step S11 is larger than a predetermined value (for example, 20 μm ± 5 μm), and this is used as a light-shielding mask.

  In the present embodiment, in the re-thinning step S5, a positive photoresist is applied to the entire surface of the upper substrate 5 (step S13), and exposure is performed on an area where the measured thickness is larger than a predetermined value. The development is performed (step S15). Instead, a negative type photoresist is applied to the entire surface of the upper substrate 5, and the measured thickness is exposed to an area of a predetermined value or less. It is good also as developing.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the above embodiment, the upper substrate 5 is thinned in units of the large laminated substrate 6, but the upper substrate 5 may be thinned for each thermal head 1. . By doing in this way, the higher quality thermal head 1 can be manufactured. Alternatively, the thermal head 1 may be individually manufactured using the support substrate 3 and the upper plate substrate 5 that are cut in advance for each thermal head 1.

  Moreover, in the said embodiment, although the recessed part 2 was formed in the support substrate 3 in recessed part formation process S1, you may form the recessed part 2 in at least any one of the support substrate 3 and the upper board | substrate 5. FIG. For example, a recess may be formed on one surface of the upper substrate 5, or a recess may be formed on both the support substrate 3 and the upper substrate 5.

DESCRIPTION OF SYMBOLS 1 Thermal head 2 Concave part 3 Support substrate 4 Cavity part 5 Upper board 6 Laminated board 7 Heating resistor 8 Electrode 9 Protective film 10 Thermal printer S1 Concave formation process S2 Joining process S3 Thinning process S4 Thickness measurement process S5 Rethinning Process S6 Heating resistor forming process S7 Electrode forming process S8 Protective film forming process S9 Cutting process

Claims (5)

A recess forming step for forming a recess on the surface of the support substrate;
A bonding step of bonding the upper substrate to the surface of the support substrate on which the concave portion is formed;
A thinning step of thinning the upper substrate bonded to the support substrate;
A thickness measuring step for measuring the thickness of the thinned upper substrate;
A re-thinning step of thinning again the region where the thickness of the upper substrate is a predetermined value or more;
A heating resistor forming step of forming a heating resistor in a region corresponding to the recess on the surface of the thinned upper substrate.   The method of manufacturing a thermal head according to claim 1, wherein the re-thinning step thins the upper substrate in units of regions where one thermal head is formed. The re-thinning step includes
A resist mask forming step of forming a resist mask for a region whose thickness measured by the thickness measuring step is a predetermined value or less;
The manufacturing method of the thermal head of Claim 1 or Claim 2 including the etching process process which etches the said upper board | substrate board | substrate with which the said resist mask was formed.   In the resist mask forming step, a positive resist is applied to the upper substrate, and then an area where the thickness of the upper substrate is larger than the predetermined value is exposed to an area below the predetermined value. The method of manufacturing a thermal head according to claim 3, wherein a resist mask is formed.   In the resist mask forming step, a negative resist is applied to the upper substrate, and an area where the thickness of the upper substrate is not more than the predetermined value is exposed, so that the region having the predetermined value or less is exposed. The method of manufacturing a thermal head according to claim 3, wherein a resist mask is formed.

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