JPS60235403A - Thin film resistor - 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 (Technical Field to Which the Invention Pertains) The present invention relates to a thin film resistor using a thin film resistor, and more particularly to a heat generating resistor having substantially one conductive layer serving as an electrode.

(Prior art) In a thermal head that performs thermal recording using a heating resistor, the electrode material of the heating resistor is a highly conductive material such as gold palladium or rhodium with an intermediate layer such as titanium, nichrome, or chromium, or Aluminum or the like is used, but recently it has become common to use base metals such as aluminum to reduce the cost of equipment. However, when aluminum is directly deposited on a tantalum-silicon based thin film resistor material, for example, the heat generation effect of the resistor causes a gap between the electrode material and the resistor material at temperatures above 350°C. A phenomenon occurs in which an alloy is formed and the resistance value of the resistor decreases.

In order to improve such drawbacks, a method of increasing the hardness of aluminum by a film forming method or by adding copper or the like has been proposed in Japanese Patent Publication No. 147002/1983.

According to this, the Vickers hardness necessary to prevent alloy formation is 100 or more, preferably 200 or more. Another characteristic required of the electrode material is that it is capable of wire bonding for electrical connection with a driver IC that drives the heating resistor. However, the conditions for wire bonding generally require a Vickers hardness of 100 or less, which conflicts with the above-mentioned conditions for stabilizing the resistor. In conventional thermal heads, etc., the electrode conductor of the resistor and the signal circuit conductor of the driver IC had to partially intersect on a plane, so a two-layer conductor structure was used in which each layer had a different wiring pattern. It is common to take In two-layer conductor fabrication, the first layer is used as an electrode conductor, 1, a material that does not form a solid solution with the resistor material is selected, and the second layer conductor is selected as a material suitable for wire bonding.
It compensated for the deficiencies mentioned above. However, recent advances in IC and circuit technology have made it possible to create multi-conductor structures that are essentially one layer, and the manufacturing process is becoming simpler.

(Objective of the Invention) The present invention provides a thin film resistor in which the conductor layer has a single-layer structure, which prevents solid solution with the excavated resistance material, which allows wire bonding, and which has a conductor structure with a simple manufacturing process. is intended to provide.

(Structure of the Invention) The gist of the present invention is that in a thin film resistor comprising a heating resistor, an electrode in contact with the heating resistor, and a driver IC for driving the heating resistor, the side where the electrode material contacts the heating resistor has a Vickers hardness of 100. By forming aluminum or aluminum alloy with a Vickers hardness of 100 or less on the aluminum or an aluminum-containing alloy, it is possible to prevent solid solution with the heat-generating resistor material and facilitate wire bonding. Moreover, since the pattern can be formed using the same etching solution for both the upper and lower materials, the manufacturing process can be simplified.

(Embodiment) An embodiment of the present invention will be described below with reference to all the drawings. FIG. 1 is a sectional view schematically showing a heat-sensitive resistor according to the present invention. A glaze layer 2 1 on an alumina substrate (not shown) is a glaze protective layer against etching during formation of a resistor. 3 is a heating resistor, 5 is Vickers hardness 22
0 is an aluminum copper alloy, 6 is aluminum with a Vickers hardness of 60, and 5 and 6 constitute the electrodes of the resistor 3. 4 indicates the heat generating area of the resistor. The driver IC 7 for driving the heating resistor and the electrodes are electrically connected by wire bonding. In Figure 1, bonding is done on the surface of aluminum 6, which has a low hardness, so that highly reliable bonding strength is obtained, and the material that is in contact with the resistor material is a high hardness aluminum-copper alloy. This prevents them from forming a solid solution with each other and deteriorating the resistor. Further, the double membranes 5 and 6 of the electrodes are patterned and heated at the same time with an aluminum etching solution so that they do not become sloppy.

The heat generation stability of the heat generating resistor of this example is shown in FIG. 2 in comparison with a reference example in which the electrodes were formed only from pontable aluminum (Vickers hardness: 80). Figure 2 10
The solid line indicates the change in resistance when a heating resistor whose electrodes are formed only from aluminum with a Vickers hardness of 80 is heated. In this reference example, a decrease in resistance of 10% or more is observed at 400°C. On the other hand, the broken line 11 is an example of the heat generating resistor according to the present invention, and shows that the resistance does not change up to 400° C. and has high thermal reliability. Therefore, according to this embodiment, thermal stability can be improved with bondable electrodes.

In this example, aluminum and aluminum alloy are used as materials with different Vickers hardnesses, but the hardness of aluminum can be adjusted by adjusting the amount of base metals such as copper, and the same film formation The hardness can also be adjusted using this method. Furthermore, as shown in Japanese Patent Publication No. 58-147002, the composition varies depending on the composition of the same aluminum alloy or the film forming force method even when aluminum is used alone. For example, aluminum deposited by vapor deposition generally has lower hardness than aluminum deposited by sputtering, and aluminum deposited by sputtering equipment using a cryopump exhaust system is less hard than aluminum deposited by sputtering. The hardness is lower than that produced by sputtering equipment using

As described above, the hardness can be selected depending on the composition of the film and the film forming conditions, and the means of the present invention is not limited to the above embodiments.

(Effects of the Invention) As explained above, according to the present invention, by using an electrode with a double film structure in which a material with high Vickers hardness is deposited on the heating resistor side and a material with low Vickers hardness is deposited on the heating resistor side, It is possible to obtain a heat generating resistor which can be wire bonded and has excellent thermal stability with reduced solid solution with the resistor material.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing an embodiment of the heat generating resistor of the present invention, and FIG. 2 is a diagram showing the effect of improving the thermal stability of the resistor, which is an effect of the present invention. glaze layer, 2. etching protection layer, 3. heating resistor, 4. heating region, 5. aluminum layer, 6.
Aluminum copper alloy, 7...Driver ICl3...
Wire, 9...Resistor protection layer, 10 bits hardness 8
Change in resistance due to heating when aluminum of 0 is used as an electrode, 11... Change in resistance according to the present invention. Agent Patent attorney Shinatsu Uchihara 7 figure t92/ , jm 4riθ spider 5〃 /7U, valve, λ'tjL (OC) z z figure

Claims (2)

[Claims] (1) In a thin film resistor comprising a heating resistor and an electrode in contact with the heating resistor, the side where the electrode material is in contact with the heating resistor is aluminum or an alloy mainly made of aluminum having a Vickers hardness of 100 or more. 1. A thin film resistor characterized by having a double film structure made of aluminum or an alloy mainly composed of aluminum having a Vickers hardness of 100 or less. (2) The thin film resistor according to claim 1, wherein the electrode material is an aluminum-copper alloy on the heating resistor side and an aluminum layer on the heating resistor side.