JPH0418371A - Thermal head and manufacture thereof - Google Patents

Abstract

PURPOSE:To suppress the accumulation quantity of heat low by providing porous oxide and a drive circuit to a semiconductor substrate and arranging the heating element of a heating part to the upper part of porous oxide and connecting the heating part to the drive circuit. CONSTITUTION:An SiO2 film 26 is formed to the entire upper surface of a silicon substrate 22 containing porous silicon oxide 28 and a drive circuit 29 and a passivation film 35 is subsequently formed to the entire upper surface of the SiO2 film 26. Next, Ta2N is formed on porous silicon oxide 28 as a heating resistor layer 36. Next, an opening is formed to the passivation film 35 on the IC conductor layer 34 connected to each N-type collector 31 and Al is formed to the upper surfaces of the passivation film 35 and the heating resistor layer 36 as a thermal head conductor layer 37. Thereafter, the thermal head conductor layer 37 and the heating resistor layer 36 are removed and each drive circuit 29 is connected to one terminal of a heating element 39 and the other terminal of the heating element 39 is connected to a common electrode conductor layer 40.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermal head for printing in a thermal transfer printer using an ink ribbon or the like, a thermal printer using thermal paper, etc., and a method for manufacturing the same.

[Prior Art] In general, the printer used as a type of output device for various information processing apparatuses is required to have high density, high 1i1, and high speed output.

Therefore, conventionally, from the glue head 1 having the configuration shown in FIG.
and 3, they are gradually becoming larger.

To explain further, in the thermal head 1 shown in FIG. 12, heat generating parts 5 made of, for example, 48 dot heat generating elements are arranged in a row along one edge of an alumina substrate 4, and each heat generating part 5 is A conductor pattern 6 connected to the common electrode and the individual electrodes is provided on the alumina substrate 4, and each conductor end of the flexible printed circuit (hereinafter referred to as FPC) 7 is attached to the end of the conductor pattern 6 on the alumina substrate 4. It is formed by soldering the parts. The other end of the FPC 7 is connected to a drive circuit (not shown).

Thermal heads 2 and 3 shown in FIGS. 13 and 14 are respectively enlarged versions of the thermal head 1, and instead of the conductor pattern 6 and FPC 7 on the alumina substrate 4 shown in FIG. A drive circuit 9 made of an IC chip or the like is disposed on the wafer, and a wiring pattern 10 is disposed to connect the drive circuit 9 and each heat generating element of the heat generating section 5. The upper common electrode and individual electrodes are soldered together. On the other hand, in the thermal head 2 shown in FIG. 13, the number of heating elements in the heating section 5 is 64 dots, and the wiring pattern 10 on the tape carrier 8 is bent 90 degrees from the drive circuit 9 side to the heating section 5 side. The size of the neck just before is F! iA is said to be approximately 6.4 shoes.

The other thermal head 3 shown in FIG. 14 has a heat generating section 5 with 160 dots of heating elements, and has a tape main ceria 8.
The neck dimension B of the wiring pattern 10 above is approximately 16 mm.

For example, in a thermal transfer printer, as shown in FIG. 15, the thermal head 2 or thermal head 3 formed as described above is mounted on a carriage (not shown) of the printer, and a ribbon is applied to the printer. 11 into the head insertion recess 12 and thermal head 2 or thermal head 3.
The ink ribbon 13 in the ribbon cassette 11 is inserted into the carriage, and the ink ribbon 13 in the ribbon cassette 11 is moved between the paper and the platen (
(both not shown), the drive circuit 9 energizes a predetermined heating element of the heat generating section 5 to generate heat, and the ink on the ink ribbon 13 is transferred to the paper to perform printing. ing.

[Problem to be solved by the invention]

However, nowadays it has been proposed to standardize the ribbon cassettes 11 that are available in many different types, and in that case, the width of the head insertion recess 12 is narrowly limited. 8 B
．． It needs to be 5aw or less.

In the thermal head 3 in Fig. 14, wiring pattern 1
Approximately 160 conductive parts are provided at a pitch of 0.1 mm on the 16 am wide neck of the 0.0 mm, but arranging these conductive parts at even smaller pitches requires advanced technology and the manufacturing cost is extremely high. It is expensive, and the narrow width of the conductive portion increases the electrical resistance, which is a major electrical problem.

Therefore, conventionally, as shown in the thermal head 14 in FIGS. 16 and 17, a drive circuit 9 made of an IC chip or the like is directly mounted on a ceramic substrate 17, and an output terminal of this drive circuit 9 and a heat generating part 5 are mounted directly on the ceramic substrate 17. The common electrode and individual electrodes of the drive circuit 9 were connected by a wiring pattern 10, and a terminal group 15 such as a signal terminal, a power supply terminal, and a ground terminal for controlling the operation of the drive circuit 9 was connected to an external device by an FPC 16.

However, the thermal head 1 in FIGS. 16 and 17
In No. 4, since the drive circuit 9 mounted on the ceramic substrate 17 protrudes more toward the paper side than the heat generating part 5, there is a risk that it will come into contact with the paper when feeding the paper in the printer, thus preventing paper feeding. There was a risk. Moreover, it is very complicated to arrange the chip of the drive aJ circuit 9 on the ceramic substrate 17, and the manufacturing cost is also high.

Furthermore, in the conventional thermal head shown in FIGS. 16 and 17, a glass glaze is provided on the ceramic substrate 17 as a heat insulating part of the heat generating part, and a heat generating element is disposed on this glass glaze waste. It is formed by In order to perform high-speed printing using such a thermal head 14, it is necessary to improve the thermal responsiveness of the thermal head 1/I. Conventionally, the temperature of each heating element when the same power is applied increases as the glaze layer becomes thicker. As a result, the thermal response was poor. Furthermore, since the ceramic substrate 17 has a low thermal conductivity, the ceramic substrate 17 accumulates heat, and a temperature gradient occurs within the substrate, causing the temperature of the ceramic substrate 17 to change depending on the printing history. There was a problem in that the print density was changed and the print quality deteriorated. In addition, when forming a glaze layer, the melting point of the glass is high, and glaze layer formation requires a temperature of 1200°C.
There was also the disadvantage that the ceramic substrate 17 itself had to be heated to ~1300[deg.] C. and extremely expensive.

The present invention has been made in view of these points, and by forming a heat generating part and a drive circuit for driving the heat generating part on a semiconductor substrate using the materials of the semiconductor substrate, the dots of the heat generating element can be reduced. Even if the number of terminals is large, the number of terminals consisting of signal lines for connecting the drive circuit and the control device can be kept small, there are few soldering points, it is easy to mount, and the manufacturing cost is low. Moreover, it is an object of the present invention to provide a thermal head and a method for manufacturing the same that can achieve high printing density, high definition, and high speed printing.

Means for Solving Problem C] In order to achieve the above object, the thermal head of the present invention includes a semiconductor substrate and a semiconductor substrate on the V conductor substrate. It is characterized by having a heat generating part formed therein and a drive circuit that controls supply of a drive current to the heat generating part.

Further, as claimed in claim 2, the method for manufacturing a thermal head of the present invention provides a driving method in which a porous oxide serving as a thermal insulation part of a heat generating part is applied to a semiconductor substrate and a drive current is controlled to be applied to the heat generating part. The invention is characterized in that a heating element of the heating section is disposed above the bolus outside, and the heating element and the driving circuit are connected.

[For production]

The thermal head of the present invention is manufactured by the method of the present invention.

That is, a porous oxide serving as a thermal insulation part of a heat generating part of a semiconductor substrate and a driving current are applied to the heat generating part.
The heating element of the heat generating section is disposed above the porous oxide, and the heat generating section and the drive circuit are connected and covered.

The thermal head of the present invention manufactured in this way is
Due to the high thermal conductivity of the semiconductor substrate, the amount of heat storage can be kept to a small level.Furthermore, the porous oxide that serves as the thermal insulation part of the heat generating part has low thermal conductivity, so the responsiveness of heating and cooling is high. Become something. Therefore, according to the thermal head of the present invention, printing can be performed at high speed and with high quality. Furthermore, by forming the heat generating part and the drive circuit that drives the heat generating part on the semiconductor substrate using the material of the semiconductor substrate, the drive circuit and the control device can be easily maintained even if the number of dots of the heat generating element increases. The number of terminal groups consisting of signal lines for connection can be kept small, there are few soldering points, and mounting is easy and manufacturing costs are low.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 11.

1 and 2 show an embodiment of the thermal head 21 of the present invention, and in FIG. 1, each component is shown by solid lines regardless of the vertical relationship in order to explain the arrangement of each component.

3 to 10 show the thermal head 21 of the present invention.
k shows the steps of an example of the JTh method.

Next, the structure of the thermal head 21 of the present invention will be explained together with its manufacturing method.

1: First, a silicon substrate 22 as a type of semiconductor substrate shown in FIG. 3 is prepared. As this silicon substrate 22, for example, a P-type substrate having a resistivity of 5 to 10 Ω·1 is used.

Next, as shown in FIG.
- by sputtering a tantalum film 23 of 0.1
It is formed with a film thickness of ~0.5 μm. Then, this tantalum film 23 is etched by photolithography to expose only the area [24] where the thermal insulation portion is to be formed, thereby exposing the surface of the silicon substrate 22.

Next, thermal oxidation is performed in the atmosphere at a temperature of 500° C. to 1000° C. to form tantalum oxide l (T a 20 s ) 25 on the tank 1123 as shown in FIG. The thickness of this tantalum oxide film 25 depends on the oxidation temperature. Further, at this time, the surface of the silicon in the region 24 where the thermal insulation portion is to be formed is also oxidized to form the 5102 film 26.

Next, a 20 wt % aqueous solution of hydrofluoric acid is placed in an electrolytic cell with the platinum plate as the cathode, and the silicon substrate 22 is used as the anode to face the platinum plate, and anodization is carried out for 20 minutes at a current density of 50 TrLA/cIi. Let's do it.

At this time, since tantalum oxide 125 is a defective Li film and is not corroded by hydrofluoric acid, tantalum oxide film 125 formed on silicon substrate 22 as shown in FIG.
5 plays the role of a mask, and only the portion of the silicon substrate 22 where the tantalum oxide 125 is not formed, that is, the region 24 where the thermal insulation portion is to be formed, is coated with a thickness of 40 μm and a porosity of 80.
% porous silicon 1127 is formed. The thickness of this porous silicon layer 27 can be freely adjusted depending on the FfI layer to be anodized.

Although it is possible that tantalum oxide 1J25 is dielectrically broken down during the above-mentioned FiA electrode anodization, since the area of the thermal insulation part formation area W1.24 is small, it is difficult to anodize the silicon substrate surface in this @ area. The current density required for (50
The voltage required to obtain mA・'cti culm degree) is 0.
Because it is as small as 4■, no dielectric breakdown occurs.

Next, after cleaning for one minute, as shown in FIG. 7, the tantalum film 23 and tantalum oxide FA 25 formed on the silicon substrate 22 are removed with concentrated hydrochloric acid.

Next, after washing for 4 minutes, as shown in FIG. 8, thermal oxidation is performed at 850 DEG C. to 1000 DEG C. to oxidize the porous silicone skin 27.

Further, Burano 7 may be used for this oxidation.

As the porous silicon layer 27 is oxidized, the volume of the porous silicon layer 27 increases, and convex portions of the porous silicon oxide 28 as a type of porous oxide protrude from the surface of the silicon substrate 22 are formed. The protruding height of the convex portion of this porous silicon oxide 28 is 2 to 3 μm. The porous silicon oxide 28 thus formed becomes a thermal insulation part.

Further, on the surface of the silicon substrate 22 which was exposed at this time, a SiO2 film 26 is simultaneously formed with a thickness of 62 to 0.5 μm.

Next, as shown in FIG.
form 9. This drive circuit 29 is an N+ type embedded [130
, an N-type collector 31, a P-type base 32, and an N-type emitter 33. Each component of this drive circuit 29 is made of SiO2VIA made of photoresist.
Patterning to 26, opening by etching, N type or PIj by thermal diffusion:! diffusion, SiO2 film 26
It is formed by a normal manufacturing method using an appropriate combination of six lengths within the film.

Next, as shown in FIG.
5 inch 211026 is formed on the entire upper surface of the silicon substrate 22 including the drive circuit 29, and then S i 02
g! After that, a passivation film 35 is formed on the entire upper surface including the IC conductor layer 34.

Next, on the upper surface of the passivation film 35 and above the porous silicon oxide 28 which becomes a heat insulating part, a heating resistor position 36 which becomes a heat generating part is made of Ta2N, Dina-Cr-N,
, TaSi02 etc. by sputtering,
It is formed to a diameter of 19 with a diameter of 0.05 to 0.3 μm.

Next, holes are formed in the passivation film 35 on the upper part of the IC conductor layer 34 that is in contact with each N-type collector 31, and a thermal head conductor layer 37 is formed on the upper surface of the passivation film 35 and the heating resistor H36. J, Ni-
Cr/Au'8 is formed by vapor deposition to a thickness of 1 to 2 μm. Thereafter, the upper surface of the heating resistor layer 36 is exposed by photolithography, and as shown in FIG. 2, the heating resistor layer 36 is exposed. i36 and thermal head conductor layer 3
The thermal head conductor layer 37 and the heating resistor layer 36 are etched and removed so as to divide 7 into a plurality of parts in the column direction, and each drive circuit 29 connects one end of the heating element 39 via the individual electrode conductor layer 38. connected to each heating element 39
The other end is connected to the common electrode conductor layer 40.

Note that in this embodiment, the drive circuit 2 is provided on the silicon substrate 22.
9, a signal processing section 41 for controlling energization to each drive circuit 29 is formed at the same time.

Next, as shown in FIG. 2, as protection 1i42, 5IO
2/Ta205, Sialon, etc. are formed by sputtering to a thickness of 5 to 7 μm, and a terminal group 43 is formed on the uppermost surface to complete the thermal head.

In addition, in the method for manufacturing a thermal head of the present invention, materials that can be used as a mask during anodization of the silicon substrate 22 are not limited to the tantalum oxide film 25, and in addition to various passive films, fluorine Cr2O3 or Sialon can also be used as an insulator that is not attacked by hydrochloric acid.

CrCr203l as a mask! When a sialon film or a sialon film is used, pattern formation and removal of this film is performed by dry etching or the like. Additionally, MO is a material for masks that is not affected by hydrofluoric acid.

W and the like can also be used, and can be used by increasing the film thickness. Furthermore, during the heat diffusion process during the manufacture of the drive circuit 29 or when forming the basicon curtain, the porous silicon oxide 28 may be oxidized or the upper surface of the porous silicon oxide 28 may be flattened, if necessary.

In the thermal head 21 of this embodiment manufactured in this way, since the thermal conductivity of the silicon substrate 22 which is a semiconductor substrate is 8, it is possible to suppress the amount of heat storage to a small value, and furthermore, it is possible to keep the amount of heat storage small. The porous silicon oxide 28 as the F side of the porous 71 in the R section is thin and has low thermal conductivity, so it has high responsiveness to heating and cooling. Therefore,
According to the thermal head 21 of this embodiment, high-speed, high-quality printing can be performed with low power consumption. Furthermore, by forming the heat generating section and the drive circuit 29 for driving the heat generating section on the silicon substrate 22 which is a semiconductor substrate using the silicon substrate 22, the drive circuit 29 can be used even if the number of dots of the heat generating elements increases. The terminal group 43 consisting of signal lines for connecting the circuit and the control device can be kept small, the number of soldering points is small, the mounting is easy, and the manufacturing cost is low.

Further, in the method of manufacturing the thermal head shown in FIGS. 3 to 10, a porous silicon oxide layer is formed on the silicon substrate 22.
8 and the drive circuit 29 (), but the drive circuit 29
Of course, the drive circuit 29 and the porous silicon oxide 28 may be provided in this order by forming the wiring material using a high melting point metal such as W.

FIG. 11 shows another embodiment of the thermal head of the present invention.

In this embodiment, the thermal head 21 shown in FIGS.
The extraction position of the terminal group 43 is arranged at the edge of the silicon substrate 22 opposite to the edge on which the heating element 39 is disposed, and the plurality of thermal heads 21a, 21a, .
The heating elements 39 are arranged and installed in a line to form a line head 44. In this case, by using heating elements 39 of each thermal head 21a that have a small difference in resistance value, it is possible to obtain a line head 44 that has a small difference in resistance value and can print one line with uniform density.

Note that the present invention is not limited to the above-mentioned embodiments, and can be modified as necessary.

(Effects of the Invention) Since the method for manufacturing a thermal head and groove of the present invention is configured and operates as explained in d below, a heat generating part and a drive circuit for driving the heat generating part are respectively provided on a semiconductor substrate. By using the semiconductor substrate for formation, even if the number of dots in the heating element increases, the number of terminals consisting of signal lines for connecting the drive circuit and the control device can be kept small, and soldering is unnecessary. There are few places and it is easy to implement.
The manufacturing cost is also low, and moreover, there are effects such as high density, high definition, and high speed printing.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the thermal head of the present invention. Figure 1: J41 is a plan view showing each component with solid lines regardless of the vertical relationship of each component, and Figure 2 is a plan view of the thermal head of the present invention. ■ of the diagram
3 to 10 are the same sectional views as FIG. 2 showing the steps in the manufacturing method of the thermal head of the present invention, and FIG. 11 is a line head-shaped cross-sectional view. A schematic plan view showing another embodiment of the thermal head of the present invention, FIGS. 12 to 14 are schematic plan views showing conventional thermal heads, and FIG. 15 is a perspective view showing the relationship between the thermal head and the ribbon cassette. 16 is a plan view showing a conventional thermal head, and FIG. 17 is a bottom view of only the thermal head portion. 21... Thermal head, 22... Silicon substrate,
28... Porous silicon oxide, 29... Drive circuit,
36...Heating resistor layer, 39...Heating element. 11th concave 14th

Claims (1)

[Scope of Claims] 1) It is characterized by having a semiconductor substrate, a heat generating part formed using the semiconductor substrate on the semiconductor substrate, and a drive circuit that controls the supply of a drive current to the heat generating part. thermal head. 2) A semiconductor substrate is provided with a porous oxide serving as a heat insulating part of a heat generating part and a drive circuit that controls the supply of a drive current to the heat generating part, and then a heat generating element of the heat generating part is arranged above the porous oxide. A method for manufacturing a thermal head, comprising the step of connecting the heating element and the drive circuit.