JPH0464867B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method of manufacturing a thin film type thermal head.

(Description of Prior Art) In a conventional method for manufacturing a thin thermal head, a pattern of a heat generating resistor is formed on a glaze layer on an alumina substrate, and a metal pattern of a power supply body is formed above the pattern.

According to this conventional manufacturing method, almost the same conductor patterns, such as the heating resistor pattern and the power supply pattern, must be created twice.
For this reason, when the pattern becomes finer, two types of finer masks must be prepared, and the process of matching the masks becomes extremely difficult.

(Objective of the invention) The object of the invention is to use one fine mask and one rough mask, and to easily match the masks.
Moreover, it is an object of the present invention to provide a method of manufacturing a thermal head that allows the formation of fine heating resistor and power supply body patterns easily.

(Structure of the Invention) In order to achieve this object, the method for manufacturing a thermal head of the present invention includes a step of providing an insulating layer on a heat insulating layer formed on a substrate, and a step of forming an insulating layer on a heat insulating layer formed on a substrate. so that it remains in the area of the heating resistor pattern and the power supply pattern.
A patterning process and etching of this heat insulating layer using the obtained insulating layer pattern as a mask,
A step of forming a plurality of convex portions having this insulating layer pattern on the top, a step of sequentially depositing materials for a heat generating resistor and a power feeder on this insulating layer pattern, and a step of sequentially depositing materials for a heat generating resistor and a power feeder on this insulating layer pattern, and a step of forming a heat generating resistor on this insulating layer pattern. The present invention is characterized in that it includes the step of removing the material for the power supply body above the part where the heat generating part pattern of the body is to be formed.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1A to 1D are manufacturing process diagrams for explaining the method of manufacturing the thermal head of the present invention, and FIG. 2 is a plan view showing the pattern of the heating part of the heating resistor and the pattern of the power supply body formed in this process. It is.

First, as shown in FIG. 1A, an alumina substrate is prepared as the substrate 1. A glaze layer 2 having a thickness of, for example, 40 μm is provided on the surface 1a of the alumina substrate 1 as an underlayer. In this case, this glaze layer 2 acts as a heat retaining layer. An insulating layer 3 is formed on the upper side of the glaze layer 2 of the substrate 1 .
This insulating layer 3 is formed by sputtering Si ₃ N ₄ and has a thickness of, for example, 5000 Å.

Next, the Si ₃ N ₄ layer 3, which is this insulating layer, is patterned. This patterning is carried out using ordinary photolithography techniques and plasma etching using CF ₄ gas, using a single fine mask to form the Si ₃ N ₄ layer 3 of the heating resistor to be formed later. A pattern 3a of the Si ₃ N ₄ layer, which is an insulating layer pattern as shown in FIG. 1B, is obtained by forming the same pattern as the pattern and the pattern of the power supply body. When viewed from above, the pattern in this case is the overall pattern of the heating element and the power supply element, as shown in FIG. 2, which will be described later.

Next, after removing the organic resist for the mask used in the process shown in FIG.
Using pattern 3a of the Si ₃ N ₄ layer as a mask, glaze layer 2 is etched over a portion of its thickness to obtain a structure as shown in FIG. 1C. This etching is performed using a 5% HF aqueous solution, and the etching depth is, for example, 1.5 μm. In this case, the Si ₃ N ₄ of pattern 3a is
This Si ₃
The pattern 3a of the _N4 layer remains substantially intact, and the glaze layer 2 below it is laterally etched (side etching), as shown in FIG. Convex portion 2a
Pattern 3 of Si ₃ N ₄ in the shape of a flat umbrella.
a is formed, and its peripheral edge protrudes parallel to the surface 1a of the substrate 1 from the convex upper part 2a.

A heating resistor material 4 is applied to the entire surface of the thus obtained member having the structure shown in FIG. 1C on the remaining glaze layer 2 side. The material 4 for the heating resistor is, for example, Ta ₂ N,
This is formed by sputtering to a thickness of 2500 Å over the entire surface of the substrate.

Subsequently, metal 5, which is a material for a power supply body, is deposited on the upper side of this material 4 for a heating resistor. This power supply metal 5 is made of Al, for example, and has a thickness of, for example, 1.5μ.
It is formed by vacuum deposition to a thickness of m.

The thin film laminate 6 obtained by sequentially depositing the heating resistor and power supply materials 4 and 5 is as follows:
As shown in FIG. 1D, due to the step between the convex portion 2a of the glaze layer 2 and the etched portion 2b around it, the upper side of the convex portion 2a is lowered. They are individually and well formed by cutting out the steps. Because of this step break, the pattern of the heating resistor and the pattern of the power feeder are formed at the same time as the deposition of the laminate 6, and this pattern is made of the above-mentioned Si ₃ N ₄ layer insulation. It is determined by the pattern of layer 3, ie by the fine mask forming this pattern of insulating layer 3.

Next, the metal material for the power feeder above the portion that should be the heating part pattern of the heating resistor of the laminate 6 obtained in this way is removed by selective etching using photolithography technology. Second
It is possible to form a heat generating part pattern part 7 and a power supply pattern part 8 of a heat generating resistor as shown in the plan view of the figure. FIG. 3 shows a partial perspective view of the thermal head formed through the steps up to this point.

The mask used in this photolithography process may ultimately be a single rough mask that has a width corresponding to each heat generating pattern and can be etched to expose all heat generating pattern parts. . Finally, an antioxidant film (for example,
2 μm thick SiO ₂ ), wear-resistant layer (e.g. 3 μm thick Ta _{2 )}
The thermal head is completed by sequentially forming O ₅ ) by a sputtering method.

In the above-described embodiment, the insulating film 3 is made of Si ₃ N ₄
has been described, but instead of using this, for example, Al ₂ O ₃ may be used, or SiO ₂ may be deposited on the glaze layer 2 by CVD method,
It is possible to use a material on which SiO ₂ is formed by sputtering, and even in that case,
It can achieve the same action and effect as Si ₃ N ₄ . Further, the dimensions of this insulating layer and other conditions can be arbitrarily set according to the design.

Furthermore, a substrate made of a material other than an alumina substrate may be used as the substrate.

Furthermore, conditions such as materials, dimensions, and methods of adhering the heat generating resistor and power supply body can be arbitrarily selected according to settings.

(Effects of the Invention) As is clear from the above description, according to the method of manufacturing a thermal head according to the present invention, a single fine mask is used to form an insulating layer, and the pattern of the heating portion of the heating resistor is then changed. Since only one rough mask is used for forming the pattern, each pattern of the heat generating part and the power supply body can be formed by a simple mask alignment process.

In addition, a fine pattern of the insulating layer provided on the base layer is formed in advance in correspondence with the pattern of the heating resistor and the power supply, and height differences are created in the base layer using this insulating layer pattern as a mask. A laminate of materials for the heat generating resistor and the power feeder is applied to the portion, and fine patterns of the heat generating resistor and the power feeder can be effectively formed by cutting the steps due to the steps.

Furthermore, since the heating resistor itself is not etched, a fine pattern can be formed even if the heating resistor itself is made of a material that is difficult to etch. Furthermore, since the low-temperature layer (base layer) is formed in a convex shape, heat dissipation to the substrate side is reduced and heat retention is improved, and the heat generating part pattern is formed on this convex part. The contact pressure with the paper during printing increases, and from this point of view it becomes possible to reduce the power consumption of the thermal head.

[Brief explanation of drawings]

1A to 1D are manufacturing process diagrams for explaining the method of manufacturing a thermal head of the present invention, and FIG. 2 shows patterns of a heating resistor and a power supply body obtained by the method of manufacturing a thermal head of the present invention. The plan view and FIG. 3 are partial perspective views showing the formation state of each pattern of the heat generating part of the thermal head and the power supply body formed by the manufacturing method of the present invention. 1...Substrate, 1a...Surface (of the substrate), 2...
Base layer, 3...Insulating layer, 3a...Insulating layer pattern, 4...Heating resistor, 5...Power feeder, 6...Thin film laminate, 7...Heating part pattern of resistor, 8...
...Power feeder pattern section.

Claims (1)

[Claims] 1. A step of providing an insulating layer on a heat insulating layer provided on a substrate, and leaving the insulating layer at the portions of the heating resistor pattern and the power supply pattern that will be formed thereafter. , a step of patterning, a step of etching the heat insulating layer using the obtained insulating layer pattern as a mask, and forming a plurality of convex portions having the insulating layer pattern on the top; and a step of etching the heat insulating layer at least on the insulating layer pattern. A step of sequentially depositing a resistor and a material for the power feeder, and removing the material for the power feeder above a portion of the insulating layer pattern where a heat generating part pattern of the heat generating resistor is to be formed. A method for manufacturing a thermal head, comprising the steps of: