JPH0443050A - Manufacturing method of thermal print head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial applicability! ! ? ] The present invention relates to a method of manufacturing a thermal print head that performs thermal printing.

[Problems to be Solved by the Invention] However, in the above-mentioned thermal print head, the thin film heating resistor layer is formed by depositing a substance such as tantalum nitride or ruthenium oxide by sputtering or vapor deposition.
Sometimes the substrate is heated to about 150 to 200°C. Therefore, since a substrate with a high coefficient of thermal expansion causes thermal deformation, a heat-resistant substrate such as a ceramic substrate must be used, which increases the cost of the substrate.

An object of the present invention is to provide a method for manufacturing a thermal print head that does not require an expensive heat-resistant substrate and can form a thin-film heating resistor layer with a uniform thickness even on an inexpensive resin substrate. be.

[! Means for Solving III] In order to achieve the above-mentioned object, the present invention involves forming a thin film heating resistor layer using a thin film forming apparatus such as sputtering or vapor deposition while cooling the other side of the resin substrate. be.

[Function] According to the present invention, a thin film heating resistance layer is formed using a thin film forming apparatus such as spar 2 or vapor deposition while cooling the other side of the resin substrate, so an expensive substrate with heat resistance is used. Even if an inexpensive resin substrate such as polyimide or polyester is used, thermal deformation such as fI does not occur, and a thin film heat generating resistor layer can be formed with a uniform thickness.

[Example] Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 6.

1 to 5 show the manufacturing process of a thermal print head. First, as shown in FIG. 1, a film substrate 1 is prepared. This film substrate 1 is made of synthetic resin such as polyimide or polyester. On this film substrate l, a selection electrode 2 and a common electrode 3 are formed so as to be spaced apart and facing each other. In this case, as shown in FIG. 5, a large number of one selection electrodes 2 and common electrodes 3 are arranged facing each other over the entire width of the film substrate l. Further, each electrode 11.12 is made of Cu or A.
1. Or it consists of a single layer or multilayer metal scrap whose surface is plated with Ni, ^U, etc., and the film thickness is 10 gm.
By forming it relatively thickly, the width can be increased to 30~
Even when the current is as small as about 70 uLm, it is possible to conduct a large current. Note that the selection electrodes 2tL are each formed in a thin strip shape, and these are equally spaced, for example, 16 dots)/
mm, they are arranged in parallel at intervals of about 82.5 pm. The common electrode 3 is formed into a comb shape. That is, one end 5 on the selection electrode 2 side is formed in the same shape as the selection electrode 2 and is arranged at a predetermined distance from each end 4 of the selection electrode 2, and the other end 6 is arranged in the same manner as the one end 5 described above. It is formed into a wide band shape along the direction, and one end portion 5 of each is connected. Then, a polyimide adhesive 8 is applied to each electrode 2, between the opposing ends wA4.5 of the selection electrode 2 and the common electrode 3.
3. Apply it in a band shape along the arrangement direction of 3.

Next, as shown in FIG. 2, a fiber 7 having a thickness of about 50 pm is bonded to the film substrate l using an adhesive 8. Then, the fiber 7 is provided so that its upper part protrudes above the upper surface of each electrode 2.3. At this time, since the fiber 7 has a circular cross section, when the fiber 7 presses the adhesive 8, the excess adhesive 8 rises along the outer peripheral surface of the fiber 7. As a result, the outer periphery of the fiber 7 and each electrode 2.
3 and the end 4.5 of the adhesive 8 is provided with a gentle slope. Note that the fiber l is a linear material made of glass, quartz, resin, etc., and even if it is transparent,
The adhesive 8 does not need to be transparent, and it is preferable that the adhesive 8 is made of polyimide, which has good reliability against heat stress, but is not limited thereto.

After that, #adhesive 8 was dried and TaN was applied on the fiber 7.
, a thin film heating resistance layer 9 made of tantalum nitride such as Ta2N.
is formed to a film thickness of about 1000λ. In this case, there are two methods: one using a metal mask and the other using photolithography.

The former method, as shown in FIG. 3, is a method in which a metal mask 10 is placed on a film substrate l and tantalum nitride is deposited thereon. In this case, strip-shaped openings 11 are previously formed in the metal mask 10 at locations corresponding to the thin film heat generating resistor layer 9. Therefore, when this metal mask lO is placed on the film substrate l, only the region where the thin film heat generating resistor layer 9 is formed will be exposed. In this state, when tantalum nitride is deposited by sputtering and the metal mask 1O is removed, tantalum nitride is formed in a band shape along the arrangement direction of the electrodes 2.3 only at the locations corresponding to the openings 11 of the metal mask 1o. be coated. As a result, as shown in FIG. 5, a thin film heat generating resistor layer 9 is formed over the fiber 7 and its both ends are connected to the end portion 4.5 of the electrode 2.3. In particular, the heat generating portion of the thin film heat generating resistor layer 9 is projected upwardly by the fiber 7 at a uniform height compared to other portions.

Note that when tantalum nitride is deposited, since the adhesive 8 is provided between the fiber 7 and each electrode 2.3 with a gentle slope, disconnection will occur even if the thin film heating resistance layer 9 is thin. It is well formed without any problems.

In addition, in the latter method, tantalum nitride is deposited on the entire surface of the film substrate l by sputtering, a resist is applied to the surface, a pattern is formed on this resist by photolithography technology, and the nitride is nitrided using this resist as a mask. This method involves etching the tantalum film and removing unnecessary parts. Also with this method, the thin film heating resistance layer 9 can be formed in the same manner as described above.

What is important here is that in either method, when depositing tantalum nitride by sputtering, the film substrate 1 is cooled with the cooling device 12.

This cooling device 12 has a structure in which a flow path 15 through which a cooling liquid 14 such as cold water flows is formed in a stainless steel mounting table 13 on which the film substrate 1 is placed. This cooling device 1
In an experiment using 2, the film substrate 1 was heated to around 150 to 200°C without cooling, but when cooling was performed, the temperature was around 50 to 60°C, and there was no thermal deformation in the film substrate 1. It was possible to uniformly and flatly JtlII the tantalum nitride without causing any occurrence of .

Finally, as shown in FIG. 4, a protective layer 16 is provided on the entire surface to protect the thin film heating resistor layer 9 and the electrodes 2.3. This protective layer 16 may have a single-layer structure, but a moisture-resistant protective film 17 such as 5i02 and a wear-resistant protective film 111g such as Ta205 etc.
2M! When forming the protective layer 16 with this two-layer structure, which has a desirable structure, first, thermal oxidation 1 of SiO2 is applied to the entire surface.
'jlya CV D (Cbe+5ical Vapor
A moisture-resistant protective film 17 is formed by CVD deposition method, and then Ta205 is deposited on its surface by CVD.
The wear-resistant protective film 18 can be formed by growing the wear-resistant protective film 18 by a method of growth.In this case as well, since each protection film 817, 18 is formed while being cooled by the cooling device 112, thermal stress can be suppressed and each protection film 18 can be formed by The films 17 and 18 can be formed in a stable manner.

In such a thermal print head, a thin film heating resistor layer 9 is used.
Since the protective film 16 at the location corresponding to the heat generating part is formed to sufficiently protrude from the protective film 16 in the entire surrounding area,
The heat-generating portion of the thin-film heat-generating resistor layer 9 has better contact with the recording paper, etc., making it possible to print with good quality and clarity.

Note that the present invention is not limited to the above-mentioned embodiments6. For example, the thin film heating resistance layer 9 need not be made of tantalum nitride, but may also be made of ruthenium oxide (RL102) or polysilicon doped with ions. Often, the shape thereof does not have to be strip-like, and may be arranged at equal intervals between the one selection electrode 2 and the common electrode 30 facing each other. Moreover, the thin film heating resistance layer 9 does not need to be formed directly on the fiber 7. For example '; i07 ``ey
Absolutely no polyimide thin film! i) The selection electrode 2 and the common electrode 3 may be formed after providing a calendar, or the selection electrode 2 and the common electrode 3 may be formed after the fiber 7 is bonded to the film substrate 1.

In this case, as shown in FIG. 6, the ends 4.5 of the selection electrode 2 and the common electrode 3 are alternately arranged on the fiber 7, and the thin film heat generating resistor layer 9 is placed on the electrodes 2.3. The heat generating portion in this case is the thin film heat generating resistor layer 9 between the selection electrode 2 and the common electrode 3.

Furthermore, the fiber 7 from which the thin film heating resistance layer 9 protrudes is
If the film substrate l is provided with a groove and mounted, it can be stably provided, and it is not necessarily necessary to use the fiber 7, but a protruding insulating layer made by growing an insulating material such as 5i02 or SiN in a protruding shape may also be used. , various modifications can be made in details.

Figure Is6 is a plan view of the main part in the state shown in the figure, and is a plan view of the main part showing a modified example of the thermal print head.

[Effects of the Invention] As described above in detail, according to the present invention, sputtering is performed while cooling the other side of the resin substrate.

Since the thin film heating resistance layer is formed using a thin film forming device such as vapor deposition, there is no need to use an expensive heat-resistant substrate, and even if an inexpensive resin substrate such as polyimide or polyester is used, no thermal deformation will occur. Therefore, it is possible to form a thin heat generating resistor layer with a uniform thickness.

l...Film substrate, 2...Selection electrode, 3...Common electrode, 9...Thin film heating resistance layer, 12...Cooling Device.

Casio Computer Co., Ltd. ! vinegar·

[Brief explanation of the drawing]

1 to 6 show examples of the present invention. FIG. 1 is a cross-sectional view of the state in which electrodes and adhesive are provided on the film substrate, FIG. 2 is a cross-sectional view of the state in which fibers are bonded, and FIG. Figure 3 is a cross-sectional view of a thin film heating resistor layer formed while cooling.
Figure 4 is a cross-sectional view of the state in which a protective layer is formed while cooling.
Figure 5 is 3rd figure, 4th figure

Claims (1)

[Claims] A method for manufacturing a thermal print head having a selective electrode, a common electrode, and a thin film heat generating resistive layer connected to both electrodes on a resin substrate, the method comprising: cooling the other side of the resin substrate; A method for manufacturing a thermal print head, characterized in that the thin film heat generating resistive layer is formed using a thin film forming apparatus such as sputtering or vapor deposition.