JPS6080111A - Method and device for manufacturing thin film magnetic head - Google Patents

Abstract

PURPOSE:To prevent the resticking of removed particles by backing a thin metallic film to be etched with a substrate of a different quality to obtain a double structure, and feeding back a characteristic signal of the substrate in accordance with the progress of the etching to control the etching. CONSTITUTION:A substrate 1 consisting of glass, etc., a thin metallic film 2 of Cu, Al, etc. as a conductor, and a photoresist film 3 formed by photoengraving a desired etching pattern are provided. And a thin film 9 of thin Ti or Cr is formed between the substrate 1 and the thin metallic film 2 as a backing layer for the thin metallic film 2. The laminate thus pretreated is placed in an etching device and etched. In this case, characteristic signals of the substrate are fed back in accordance with the progress of etching to continue the etching.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head manufactured through a thin film process (hereinafter abbreviated as a thin film head), and particularly relates to pattern formation by dry etching.

BACKGROUND OF THE INVENTION There are many possible forms of thin film heads and many manufacturing methods, but there are two methods for forming the necessary fine patterns. One of these methods is so-called wet etching (also called wet etching), in which a photoresist pattern having a desired shape is immersed in a chemical solution to form the final pattern. An example of this is shown in FIG. 1 is a substrate made of glass, sapphire, silicon 1 or a magnetic material, 2 is a metal film for a conductor such as Cm, AI, or a magnetic film for a core such as permanent pi or sendust, and 3 is a photograph of the desired etched shape. This is a photoresist film formed by etching technology.

When this is immersed in a suitable chemical solution, the portions not covered with the photoresist are dissolved and a fine metal pattern as shown by diagonal lines is obtained as shown in FIG. 1. In this case, since the dissolution by the chemical solution proceeds isotropically, the etched pattern shape has the disadvantage that it becomes wider than the photoresist pattern, and a phenomenon called undercant occurs (part 20 in FIG. 1). Another method to overcome these drawbacks is a method called dry etching (the name corresponds to the fact that the former is wet etching), and thin film heads have become multi-channel and the precision of fine patterns has increased. This method is considered to be the most effective when FIG. 2 shows a pattern creation method using this dry etching. Various methods can be considered for the method called dry etching, depending on the configuration of the equipment, but in order to explain the present invention, an inert gas such as Ar (argon) is ionized, accelerated, and impinged on the workpiece, causing it to collide with the workpiece. Let's take an example of how to perform etching. However, it is unnecessary to explain that other dry etching methods are also possible. In FIG. 2, the same means are used until the photoresist pattern is formed by photolithography, so the same numbers are used. Argon ions are incident here in the direction shown by 5 and collide with the portions not covered with photoresist to form a pattern by so-called sputtering. In this case, while wet etching progresses isotropically due to a chemical reaction, dry etching progresses anisotropically, making it difficult to undercut and easily forming fine patterns, which is advantageous for making multi-channel thin film heads. It is. However, this ion etching has the disadvantage that the processing time is long. For example, film thickness 2μ
When performing wet etching of mnohermalloy (Fe-Ni alloy), it can be processed in about 5 (minutes), whereas in ion silling, for example, 30 to 40 (minutes) is required even if the ion energy is 1K (eV).

Generally, the higher the ion energy, the higher the etching rate and the shorter the processing time.

This is shown in FIG. However, it is not possible to increase the acceleration energy of ions without limit. Although pattern formation has been explained in FIG. 2, the photoresist shown by 3 in FIG. 2 must be finally removed. This is because if the acceleration energy of the ions is large at this time, the photoresist, which is an organic material that plays the role of a mask, will undergo a crosslinking reaction or chemical change, making it impossible to remove it.

Therefore, the ion energy to make etching proceed as quickly as possible without causing such a reaction is so
There is a distribution where o (eV) to ao o (eV) are selected. However, even in this ion energy range, ion etching poses a problem called the redeposition effect. This will be explained with reference to FIG. Atoms and particles ejected by Ar ions entering from the direction of the arrow, such as the gold shown by 6 ◆ Different atoms and atoms constituting the photoresist shown by 7,
The particles re-adhere around the sample according to probability.

This is called the redeposition effect, and in this phenomenon, if the energy of the incident ions is high, the energy of the redeposited atoms and particles will also be high, and they will sink into the film rather than stick. In this state, it becomes very difficult to remove it.

Experiments have shown that this occurs even when the ion energy is around 500 (sV).

An electron microscope photograph of the portion in this state is shown in FIG. The particles indicated by 8 in the figure are reattached particles. If this re-deposition phenomenon occurs at the beginning of etching, it can be expected that the film will be etched again, but there is no way to avoid it near the end of etching.

OBJECTS AND SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for manufacturing a thin film magnetic head that prevents the phenomenon of re-deposition of removed particles when manufacturing a thin film magnetic head using a dry etching process. do.

This object of the present invention is to form a two-layer structure by backing the metal thin film to be etched with another base material of a different material, and to generate a signal representing the characteristics of the two-layer structure, such as m-power atoms, during the etching process. This is achieved by a method characterized in that the etching process number is controlled by detecting the signal and sweet-backing this signal.

In particular, when etching approaches its end point, the etching rate is reduced by taking advantage of the fact that the fully refracted thin film layer partially penetrates, exposing the underlying foreign base material, and the detected characteristics suddenly change. This avoids particle redeposition phenomena.

3. Detailed Description of the Invention The present invention will be described in detail below with reference to specific examples. The following example shows the detection obtained by mass spectrometry of the particles released when a bilayer structure is etched by ions, and the sudden change in detected mass (i.e., chemical species) when the substrate is exposed at the end of etching. This will be described in connection with the method of feeding back the signal to the ion source, but other detection methods may also be used.
1゜The material to be etched in the present invention is/gumalloy (F
These are materials such as metal thin films of magnetic permeability such as e-Ni alloy), spacer thin films thereof, and conductive thin films such as AI and Cu. Also,
The material of the base material used for the backing (if this is used permanently as a substrate for a magnetic metal thin film), Ti, Cr, etc.
Materials such as -1° are preferred, and this example is also preferred in terms of good adhesion to the magnetic metal film, λ. The material of the base material is selected relative to the thin film layer 4 of gold, and may be selected as appropriate in consideration of detection efficiency and other factors.

A second embodiment of the present invention will be described in detail with reference to FIGS. 6 and 7. In FIG. 6, 1 is a substrate made of glass, silicon, silicon, or a magnetic material, and 2 is a substrate made of Cu, A
3 is a metal thin film for a conductor such as I, or a magnetic thin film for a core such as permalloy or sendust, and 3 is a photoresist film on which a desired etching pattern is formed by photolithography. According to the present invention, a thin film 9 of TlXCr or the like is interposed between the metal thin film 2 and the substrate 1 to form a backing layer for the metal thin film 2. Ti5Cr and the like improve the adhesion between layers in addition to the prescribed functions of the present invention.

The laminate pretreated as described above is loaded into the etching apparatus shown in FIG. 7 and subjected to the etching process according to the present invention. In FIG. 7, 10 is a vacuum chamber for ion etching, 11 is a mass detector for performing, for example, mass spectrometry, 12 is the sample to be etched shown in FIG. 6, and 13 is 1
2 is attached, 14 is an ionization chamber for ionizing and accelerating Ar, 15 is a circuit that performs switching to reduce the ion acceleration voltage based on the detection result by the detection device, 16 is a power source for accelerating voltage, 17 is an amplifier and 18 is a mass discrimination circuit.

In operation, the sample 12 is mounted on the rotation stage 13 in a vacuum chamber, the vacuum chamber is filled with Ar gas at a predetermined pressure, and the power supply 16 is activated via the switching circuit 15 on the high pressure side. As a result, ions are emitted from the ion source 14 and impact the surface of the sample 12 to start etching. In this case, the accelerating voltage may be sufficiently high so that the above-mentioned re-deposition of the particles may occur. However, since the accelerating voltage is high, the etching rate is high. The metal thin film 2 (see FIG. 6) bombarded with ions emits constituent metal particles, some of which are detected by the mass detector 11. For example, if the mass spectra of the metal thin film 2 and the base material 9 are shown by waveforms 17 and 18, respectively, as shown in FIG. Near the end, a portion of the substrate 9 is exposed and the component of the waveform 18 indicated by the dotted line begins to increase rapidly. At this time, the discrimination circuit 18 is activated, detects the point in time when the lever increases rapidly, and thereby switches the switching circuit to the low voltage side. As a result, etching is continued by low-energy ions, and by the end of etching, redeposited particles are completely removed, resulting in a metal pattern with excellent etching characteristics.

As described above, according to the present invention, a method for manufacturing a thin film head that can form a high-quality etching pattern with little re-deposition phenomenon and that requires a short processing time can be provided.

Figure 1 is a cross-sectional view showing conventional wet etching technology;
The figure is a cross-sectional view showing conventional dry etching technology, and Figure 3 is a graph showing ion energy and processing time MfM.
FIG. 4 is a cross-sectional view showing the re-deposition phenomenon in dry etching, FIG. 5 is an enlarged plan view showing the re-deposition phenomenon, FIG. 6 is a cross-sectional view showing the structure of the sample used in the method of the present invention, and FIG. The figure is a schematic diagram of the apparatus of the present invention, and FIG. 8 is a graph showing an example of a mass spectrum. The main parts in the figure are as follows.

2: Metal thin film 3 Near odd resist film 9: Base material layer 10: Vacuum chamber 11: Purchase detector 122 samples 13: Rotating stage 14: Ionization chamber 15 Ni switching circuit 16: Accelerating voltage power supply 18: Mass discriminator Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. In the dry etching process of a metal thin film in the production of a thin film magnetic head made through a thin film process, the metal thin film to be etched is lined with a base material of a different material to form a two-layer structure, and the etching progresses. A method for manufacturing a thin film magnetic head, comprising: detecting a signal representing characteristics of the base material according to the characteristics of the base material, and controlling etching by feeding back the signal. 2. The method for manufacturing a thin film magnetic head as described in item 1 above, wherein the characteristics of the base material are chemical characteristics. Etching is performed using ions, and the chemical property is the mass property of the atoms released by the ionic bombardment of the ions. 4. A 1V film magnetic head manufactured through a thin film process In the equipment used in the dry etching process of the metal frame thin film in the production of
The apparatus includes a base material made of a different material that supports the metal thin film from the back side, an ion source that injects etching ions into the metal thin film, and detects the characteristics of the base material that are exposed to the ions and determines the characteristics. A method for manufacturing a thin film magnetic head, comprising: a detection means for generating a corresponding signal; and a control means for controlling the flow of ions emitted from the ion source in accordance with the detected signal. 4. The method for manufacturing a thin film magnetic head according to item 3 above, wherein the detection means is a mass spectrometer.