JPH0421913A - Pattern forming method and thin film magnetic head formed by the method - Google Patents

Abstract

PURPOSE:To form a pattern having high accuracy by forming the prescribed pattern on a thin film to be worked by masking and etching the pattern of a second layer principally composed of carbon on a first layer containing silicon. CONSTITUTION:On a thin film 2 to be worked formed on a substrate 1, a layer 3 containing silicon, layer 4 principally composed of carbon and layer 5 containing silicon are successively formed. Next on the layer 5, a layer 6 is formed to sense light or radial rays. Continuously, this layer 6 is formed to the prescribed pattern and with this as the mask, the layer 6 is removed by patterning the layer 5. Next, with the layer 5 as the mask, the layer 4 is patterned and with the layer 4 as the mask, the layer 3 is patterned. Afterwards, with the layers 4 and 3 as the masks, the film 2 is patterned. Finally, the layers 4 and 3 are removed. Thus, since a material containing silicon is used for the layer 3, adhesion between the film 2 and the layer 4 is improved, and the pattern can be formed without any omission and lack or the like.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a pattern forming method for forming fine thin film patterns and a thin film magnetic head formed using this method, and particularly relates to adhesive properties of carbon films. The present invention relates to a pattern forming method suitable for eliminating pattern omission, chipping, or deformation caused by poor pattern formation, and a thin film magnetic head formed using this method.

[Prior art] As is well known, in the manufacturing process of thin film devices, so-called first film processing, which uses a resist for microfabrication of thin films, is known.
-Etching technology is mainly used. In particular, in recent years, as processing dimensions have become smaller, processing methods with less undercuts, such as reactive ion etching and ion milling, have come into use. However, although these methods have excellent dimensional accuracy, the resist is damaged by high-energy ions during etching, so a resist with high etching resistance is required. For this reason, various resist materials have been developed. For example, resists containing phenol novolac polymers as a main component have relatively high etching resistance.

However, as the demand for finer patterns increases, resists with increasingly superior etching resistance are required. For example, in the case of ion milling using Ar ion beer, the etching rate of known resists is 1 or more relative to the material to be processed, and usually a thin film that is twice or more thicker than the material to be processed is required. This causes poor processing accuracy.

In order to solve the above-mentioned problems, Japanese Patent Application Laid-Open No. 63-7643
No. 8 proposes a method of forming a pattern using a two-layer film consisting of a carbonaceous thin film and a silicon-containing organic polymer thin film.

Furthermore, Japanese Patent Application Laid-open No. 168810/1983 proposes a method of patterning the magnetic material of a thin film magnetic head using a two-layer film of carbon and photoresist.

[Problems to be Solved by the Invention] The prior art has a problem in that the adhesion between the carbonaceous thin film and the processed thin film is poor, and the carbonaceous thin film peels off during the processing process. For this reason, there was a problem that the pattern was missing, chipped, or deformed, resulting in poor pattern accuracy, and could not be put to practical use.

A first object of the present invention is to provide a pattern forming method that prevents peeling between a thin film to be processed and a carbonaceous thin film and prevents pattern omission, chipping, or deformation.

A second object of the present invention is to provide a pattern forming method capable of forming highly accurate patterns.

Furthermore, a third object of the present invention is to provide a pattern forming method that can remove the first layer and the second layer and form a pattern only on the thin film to be processed.

Furthermore, a fourth object of the present invention is to provide a pattern forming method capable of forming a highly accurate pattern without omission, chipping, or deformation even on a thin film to be processed having steps.

A fifth object of the present invention is to provide a thin film magnetic head having a highly accurate pattern using three layers of excellent adhesive material including a layer mainly composed of carbon.

[Means for Solving the Problems] The first object is to form a first layer containing silicon on a thin film to be processed on a substrate, and to form a second layer mainly composed of carbon on the first layer. forming a third layer containing silicon on the second layer; and forming a fourth layer made of an organic polymer sensitive to light or radiation on the third layer. a step of forming a predetermined pattern on the fourth layer; a step of patterning the third layer using the pattern formed on the fourth layer as a mask; and a step of removing the fourth layer. a step of patterning the second layer using the pattern formed on the third layer as a mask; and a step of patterning the first layer and the thin film to be processed using the pattern formed on the second layer as a mask. This is accomplished by a method that has.

The second purpose is to form a first layer made of a material with excellent adhesion to the thin film to be processed and the next second layer on the thin film to be processed on the substrate; forming a second layer made of a material whose ion milling rate is lower than that of the thin film to be processed and whose dry etching rate using oxygen is higher than that of the next third layer; forming a third layer made of a material whose dry etching rate is lower than that of the second layer; and forming a fourth layer made of an organic polymer sensitive to light or radiation on the third layer. , a step of forming a predetermined pattern on the fourth layer, a step of patterning the third layer using the pattern formed on the fourth layer as a mask, a step of removing the fourth layer, and a step of removing the fourth layer. A method comprising the steps of patterning the second layer using the pattern formed in the three layers as a mask, and patterning the first layer and the thin film to be processed using the pattern formed on the second layer as a mask. , achieved.

The third object is to use a method that includes the step of forming a predetermined pattern on the thin film to be processed using the pattern formed on the second layer as a mask, and then removing the first layer and the second layer. , achieved.

The fourth objective is achieved by forming a pattern on a thin film to be processed having steps.

The fifth object is achieved by patterning the 1-rack portion of the thin film magnetic head using a pattern forming method that achieves the first to fourth objects.

[Function] In the present invention, a resist pattern is transferred to a second layer mainly made of carbon, and etching is performed using the pattern of this second layer as a mask to form a predetermined pattern on a thin film to be processed. In this case, since the second layer is formed mainly of carbon, it has high resistance to high-energy ions such as those used in ion milling, and the thin film has a sufficient etching rate ratio (selectivity) to the thin film to be processed. I can do it. In addition, since the second layer is easily etched by oxygen plasma, by combining the third layer, which has a slow etching rate with oxygen plasma, and the fourth layer, which is a photosensitive layer, it is possible to easily pattern difficult-to-process materials with high precision. It can be achieved.

Furthermore, in the present invention, since a material containing silicon is used for the first layer, the adhesion between the thin film to be processed and the second layer (carbon) is improved. This makes it possible to form a pattern without omissions, chips, or deformations, and to perform photoetching with high precision.

Furthermore, according to the present invention, even on a thin film to be processed having steps, a highly accurate pattern can be formed without pattern omission, chipping, or deformation.

In addition, in the present invention, since the track portion of the thin film magnetic head is patterned using the pattern forming method of the present invention, it is possible to form a highly accurate pattern without passing through the track portion of the upper core and without chipping or deformation. .

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1(a) to 1(k) are diagrams showing an embodiment of the pattern forming method of the present invention in the order of steps.

As shown in FIG. 1, in this example, (a) to (k
) consists of processes.

In step (a), a first layer 3 containing silicon is formed on a thin film 2 to be processed formed on a substrate 1 .

This first layer 3 can be formed, for example, by a vapor deposition method. The vapor deposition method used in the present invention includes a chemical vapor deposition method such as plasma CVD using monosilane as a raw material, and a physical vapor deposition method such as sputtering using silicon as a target.

Next, in step (b), a second layer 4 mainly made of carbon is formed on the first phase 3. This second layer 4 can be formed by a vapor deposition method. For example, i) chemical vapor deposition methods such as plasma CVD, thermal CVD, and photo-CVD using vapors of organic compounds composed of carbon and hydrogen, carbon, hydrogen, and oxygen, or carbon, hydrogen, and nitrogen as raw materials, if) An ion beam deposition method in which the same raw material gas as in i) is ionized and the generated ions are accelerated by electrolysis and collided with a substrate to deposit; (2) a sputtering method using graphite as a target; and (iv) a graphite vapor deposition method. Can be mentioned.

Then, in the CQ) step, the (a) is applied on the second layer 4.
) The third layer 5 is formed in exactly the same manner as the step.

Next, in step (d), a fourth layer 6 made of an organic polymer sensitive to light or radiation is formed on the third layer 5. In order to form this fourth layer 6, a wet coating method in which a solution of the material to be made up of the layer is dissolved in an appropriate solvent is applied by a method such as spin coating, and then dried to form a film, or a wet coating method in which an organic polymer There are vapor phase deposition methods such as plasma polymerization method and vacuum evaporation method that use the vapor of When the thin film to be processed has a step difference, it is preferable to use the vapor phase deposition method because a uniform film thickness can be obtained, and therefore, for high-precision patterning.

The material used in the wet coating method is not limited as long as it is a so-called photoresist, but FOPR (manufactured by Tokyo Ohka Chemical Co., Ltd.) having a phenol novolak resin as a component is preferably used.

Furthermore, as an example of an organic compound that can form a photosensitive or radiation-sensitive polymer through plasma polymerization,
Methyl acrylate, methyl methacrylate, methyl isopropenyl ketone, styrene, p-chlorostyrene,
Examples include chloromethylstyrene, allyl acrylate, and glycidyl methacrylate.

Subsequently, in step (e), the fourth layer 6 is formed into a predetermined pattern by a normal lithography (exposure and development) process.

Furthermore, in step (f), the third layer 5 is patterned using the pattern formed on the fourth layer 6 as a mask. When the third layer 5 is made of silicon only, dry etching using CF4, for example, is preferably performed. Note that active ion etching (RIE) is preferable as the dry etching method using CF4 in order to form a highly accurate pattern.

Next, in step (g), the fourth layer 6 is removed.

It can be removed with a commonly used photoresist stripper.

Next, in step (h), the second layer 4 is patterned using the pattern formed on the third layer 5 as a mask.

A dry etching method using oxygen is used for this patterning. When the etching speed of the third layer 5 is faster than that of the second layer 4, the thickness of the third layer serving as a mask becomes thicker than the second layer 4 serving as the layer to be etched, and high-precision patterning becomes difficult. Because of this disadvantage, it is necessary that the etching rate of the third layer 5 is at least slower than that of the second layer 4.

Note that as the dry etching using oxygen, active ion etching (RIE) with excellent anisotropy is preferable.

Next, in step (i), the first layer 3 is patterned using the pattern formed on the second layer 4 as a mask. When the first layer 3 is made of silicon only, a pattern is formed by dry etching using CF, for example.

Subsequently, in step (j), the thin film 2 to be processed is patterned using the patterns formed on the second layer 4 and the first layer 3 as a mask. Ion etching or ion milling with excellent anisotropy is used for patterning. At this time, it is the second layer 4 mainly made of carbon that serves as a mask for the thin film 2 to be processed. Therefore, it is also possible to omit step (i) and simultaneously etch the first layer 3 and the thin film 2 to be processed using only step (j).

Finally, in step (K), the second layer 4 and first layer 3 are removed. Dry etching using oxygen is used to remove the second layer, and dry etching using CF4 or the like is effective for removing the first layer 3. Also, this (k)
If there is no problem in using the second layer and the first layer as they are without performing this step, step (k) can be omitted.

Next, specific examples will be given and explained.

[Example 1 A silicon wafer with a thickness of 1 inch was placed on a silicon wafer with a diameter of 3 inches as a co-substrate.
．． A permalloy (Ni-Fe) film of 5 μm was formed by sputtering to serve as a thin film to be processed.

Next, on the permalloy film, which is the thin film to be processed, a silicon film with a thickness of 0.1 μm is formed by a sputter leg method,
This was the first layer.

The second layer was created using the following procedure. That is, the electrode structure has a pair of disk-shaped parallel electrodes with a radius of 10G inside a stainless steel vacuum chamber, one of which is electrically connected to a high frequency power source via a matching box, and the other is installed together with the vacuum chamber. The substrate was placed on the high frequency application side electrode of a plasma CVD apparatus having a plasma CVD system, and the substrate was heated to 200°C.

After the vacuum chamber was evacuated to a degree of vacuum of I . Next, apply a frequency of 13.56M to the installation side electrode of the board.
Plasma was generated by applying high-frequency power of 200 W at Hz, and after maintaining this state for 20 minutes, the application of high-frequency power was stopped and the substrate was taken out. As a result, amorphous carbon with a thickness of 0.9 μm was formed as the second layer. A layer was formed.

Next, a silicon film having a thickness of 0.1 μm was formed on the second layer by sputtering to form a third layer.

Next, a commercially available positive photoresist (
After spin-coating the Tokyo Ohka layer 0FPR-800, 15CP), the solvent was allowed to develop to form a fourth layer with a thickness of 1 μm.

Ultraviolet light was applied to the substrate that had gone through the above process through a photomask with a 5 μm line and space pattern.
After irradiation with an energy of 0 m J /ryl (365 layer m), the film was developed by immersing it in a 2.8% aqueous solution of tetramethylammonium hydroxide for 2 minutes to obtain a third layer pattern.

Next, this substrate was placed on the same electrode side of the same vacuum device as when the second layer was formed, and after evacuation, CF4 (
(containing 5% oxygen) was introduced at a flow rate of 5 mΩ per minute, and the internal pressure was
The temperature was maintained at Pa, and high frequency power of 100 W was applied for 5 minutes. In this way, the exposed portion of the third layer was removed and the second layer was exposed.

Next, this substrate was coated with a stripping solution (Tokyo Ohka Layer S-1) at 80°C.
0) for 10 minutes, and the fourth layer pattern was removed.

Next, this substrate was placed in the same vacuum device and on the same electrode side as when forming the second layer, and after evacuation, oxygen gas was introduced at a rate of 5 mm per minute to set the internal pressure to 1.3 Pa, and high frequency power was 100 W. was applied for 30 minutes.

After that, the introduction of oxygen gas into the vacuum chamber was stopped, the vacuum chamber was once evacuated, CF4 was introduced at a rate of 5 m12 per minute, the internal pressure was maintained at 5 Pa, and high frequency power of 100 W was applied again for 5 m1 to form the first layer. The exposed portion was removed to expose the permalloy layer.

Next, ion milling of permalloy was performed as follows. Place the board in the board holder, accelerate the voltage to 700V,
Ion milling was performed for 20 minutes under the conditions of a deceleration voltage of 200 V, an arc voltage of 80 V, an Ar flow rate of 15 mfl/min, and an ion incidence angle of 0 degrees to remove the permalloy in the exposed portion.

When the substrate patterned as described above was observed under a microscope, no peeling was observed between permalloy and silicon, or between silicon and carbon.

Finally, the substrate is bonded to the second layer (carbon) and the first layer (carbon).
The second layer pattern was removed using the same equipment and under the same conditions as those used for patterning silicon (Si), and then the first layer pattern was removed.

After completing all the steps, the permalloy pattern width was measured and found that the distribution within the substrate was within the range of 5±0°2 μm, indicating excellent pattern accuracy. Furthermore, no omissions, chips, or deformations were observed over the entire surface of the pattern.

[Example 2] In exactly the same manner as in Example 1, a permalloy pattern with a thickness of 1.5 μm (width: 5 μm) was formed on a silicon wafer as a substrate.
m lines and spaces) were formed. However, in the case of this Example 2, after patterning the permalloy, the first layer (silicon) and the second layer (carbon) are not removed, but both layers are left, and the substrate is heated on top of the second layer. Al2O3 was formed to a thickness of 10 μm by sputtering at a temperature of 200°C.

In this Example 2, even after the substrate was returned to room temperature after the Al2O3 film was formed, no peeling phenomenon was observed between Permalloy and silicon, or between silicon and carbon. Further, the distribution of the permalloy pattern within the substrate was 5±0.3 μm, and had excellent accuracy.

[Example 3] A permalloy pattern was formed in the same manner as in Example 1 except for the formation and patterning of the fourth layer. As the fourth layer, an organic polymer layer sensitive to light or radiation, a resist film was formed by plasma polymerization. That is, using the same apparatus as that used to form the second layer (carbon) in Example 1, a third layer having a thickness of 0.5 μm was formed according to the procedure shown below.

The substrate was placed on the installation side electrode heated to 80°C, and the vacuum chamber was evacuated to 1xlo4Pa, then methyl isopropenyl ketone was supplied at 10mQ per minute in terms of atmospheric pressure, and the internal pressure was adjusted to 13.3Pa by adjusting the pumping speed. I kept it. Next, the frequency 1.3, 56MHz,
Plasma was generated by applying high frequency power of 80 W, and 20
Plasma polymerized for minutes.

The third layer was patterned as follows. That is, it was irradiated with deep ultraviolet rays (irradiation energy: 8000 mJ/d at 254 nm) through a quartz mask with a 5 μm line and space pattern, and developed by immersing it in a mixed solvent of water and isopropyl alcohol at a ratio of 1=4 (volume ratio). , a third layer pattern was obtained.

After completing all the steps in this Example 3, the permalloy pattern width was measured and found that the distribution within the substrate was 4.
．． It had an excellent pattern accuracy of 7±0.3 μm. Furthermore, no pattern omission, chipping, or deformation was observed over the entire surface of the substrate.

[Example 4] A 10 μm thick polyimide resin (Hitachi Chemical 1PrQ) was patterned with 5 μm lines and spaces on a silicon wafer, and this was used as a substrate to form a permalloy pattern in exactly the same manner as in Example 3. Obtained. Note that the polyimide pattern taper angle at this time was 37°±5°. Further, the permalloy pattern was formed perpendicularly to the polyimide resin pattern.

The pattern width of this Example 4 was 4.9±0.3 μm, and had excellent accuracy. Also, missing patterns,
No chipping or deformation was observed.

=20- [Example 5] Next, 1-rack width processing in manufacturing a thin film magnetic head will be described in detail below with reference to FIGS. 2 and 3.

Permalloy is sputtered to a thickness of 1.5 μm on the nonmagnetic substrate 7, and a lower core layer 8 is formed by photoetching. Next, A12o3 was added to 0 by sputtering.
．． The gap layer 9 is formed to have a thickness of 5 μm and is formed using a photoetching technique. Subsequently, a polyimide resin (PIQ manufactured by Hitachi Chemical Co., Ltd.) is spin-coated, then heated and cured, and patterned by photo-etching technology to form an insulating layer 10 with a thickness of 2 μm. Further, Cu is formed to a thickness of 1.5 μm by sputtering, and patterned into a spiral shape using photoetching technology to form the coil 11.

An insulating film made of polyimide resin was formed on this coil 11 to form an insulating layer 12 having a thickness of 2.5 μn1. Subsequently, permalloy was sputtered to a thickness of 1.5 μm to uniformly pattern the upper core layer 13 in exactly the same manner as in Example 3. That is, a pattern of silicon 3, C4, silicon 5, and plasma polymerized film 13 was formed. The width of the tip of the upper core layer 13 is the track width 14, and the variation within the substrate was 10±0.8 μm, indicating high processing accuracy. Furthermore, no missing, chipped, or deformed patterns were observed.

Finally, add 10μ of A12o3 as a protective film (not shown).
A thin film magnetic head was obtained by sputtering to a thickness of m. Even after the protective film is formed, the pattern may peel off, fall out, or
No chipping or deformation was observed.

[Comparative Example] A thin film magnetic head was produced in exactly the same manner as in Example 5 without forming the first layer of silicon. In the thin film magnetic head produced in this manner, some peeling occurred at the interface between the carbon and the upper core layer during ion milling of the upper core layer, and desired magnetic properties could not be obtained.

[Effects of the Invention] According to the invention described in claims 1 and 2 of the present invention described above, the problems caused by the poor adhesion of the carbon film that is the second layer can be solved by using a material with excellent adhesion. By using a first layer consisting of be.

Further, according to the third aspect of the present invention, the second
After the step of forming a predetermined pattern on the thin film to be processed using the pattern formed on the layer and the first layer as a mask,
Since the method includes the step of removing the first layer and the second layer, it is possible to remove the first layer and the second layer and form a pattern only on the thin film to be processed.

Furthermore, according to the invention set forth in claim 4 of the present invention, a thin film to be processed having a step is targeted, and
By applying the invention described in any one of the above, it is possible to form a highly accurate pattern in the thin film to be processed having the step without any omission, chipping or deformation.

According to the fifth aspect of the present invention, it is possible to provide a thin film magnetic head which is free from missing, chipped or deformed track portions of the thin film magnetic head and has a highly accurate pattern using a pattern forming method. I can do it.

[Brief explanation of drawings]

FIGS. 1(a) to (k) are process diagrams showing one embodiment of the pattern forming method of the present invention, and FIG. 2 is a partial vertical cross section showing an example of a thin film magnetic head formed using the pattern forming method of the present invention. 3 is an enlarged sectional view taken along the line AA' in FIG. 3, and FIG. 3 is a partial plan view of the thin film magnetic head. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Thin film to be processed, 3... First layer,
4...Second layer, 5...Third layer, 6...Fourth layer, 7
...Nonmagnetic substrate for forming a thin film magnetic head, 8.. Lower core layer, 9.. Gap layer, 10.. Insulating layer, 11.. Coil, 12.. Insulation. Layer, 13...
- Same upper core layer, 14 same 1-rack width.

Claims (5)

[Claims] 1. forming a first layer containing silicon on the thin film to be processed on the substrate; and forming a second layer mainly consisting of carbon on the first layer.
forming a third layer containing silicon on the second layer; and forming a fourth layer made of an organic polymer sensitive to light or radiation on the third layer. a step of forming a predetermined pattern on the fourth layer; a step of patterning the third layer using the pattern formed on the fourth layer as a mask; and a step of removing the fourth layer. Said third
patterning the second layer using the pattern formed on the layer as a mask; and patterning the first layer and the thin film to be processed using the pattern formed on the second layer as a mask. Characteristic pattern formation method. 2. forming a first layer made of a material with excellent adhesion to the thin film to be processed and the next second layer on the thin film to be processed on the substrate; forming a second layer made of a material whose dry etching rate using oxygen is slower than the thin film to be processed and faster than the next third layer; forming a third layer made of a material slower than the second layer; forming a fourth layer made of an organic polymer sensitive to light or radiation on the third layer; a step of patterning the third layer using the pattern formed on the fourth layer as a mask; a step of removing the fourth layer; and a step of forming the pattern formed on the third layer. A pattern forming method comprising the steps of patterning the second layer using a mask as a mask, and patterning the first layer and a thin film to be processed using a pattern formed on the second layer as a mask. 3. 3. The pattern forming method according to claim 1, wherein the first layer and the second layer are removed after the step of forming a predetermined pattern on the thin film to be processed using the pattern formed on the second layer as a mask. A pattern forming method comprising the steps of: 4. 4. The pattern forming method according to claim 1, wherein the pattern is formed on a thin film to be processed having steps. 5. A thin film magnetic head characterized in that track portions of the thin film magnetic head are patterned using the pattern forming method according to any one of claims 1 to 4.