JPH04323388A - Ion beam etching method - Google Patents

Abstract

PURPOSE:To simultaneously dry-etch the exposed parts of a thin metal film and a patterned resist mask and to make the angular parts of a formed pattern free from scrapes causing trouble in practical use when the thin metal film coated with the resist mask is dry-etched with ion beams. CONSTITUTION:When a thin metal film 2 coated with a patterned resist mask 3 is dry-etched with ion beams, the surface of the resist mask 3 is inclined by 30-75 deg. from a direction S perpendicular to the direction X of radiation of ion beams.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of dry etching a thin metal film covered with a patterned resist mask using an ion beam.

0002

[Prior Art] For example, in the field of magnetic recording, when manufacturing magnetic heads used for reading and writing records, a thin metal film covered with a patterned resist mask is used to form coils and magnetic paths. A dry etching method using an ion beam irradiated from an ion source is used.

In this case, an ion beam is irradiated perpendicularly to the resist mask surface and the metal thin film surface, and after etching the exposed portion of the metal thin film not covered by the resist mask,
A method is known in which the remaining resist mask is removed by a separate chemical treatment or the like, and another method is also considered in which the resist mask is also removed by etching with an ion beam.

0004

However, the method of removing the resist mask by separate chemical treatment has a problem in that the chemical treatment is a separate process and requires time and effort. In comparison, the method of removing the resist mask with an ion beam is simple, but some of the corners of the resist mask are etched rounded due to the diagonal component of the ion beam, and therefore There is a problem in that even the corners of the desired pattern are etched round.

Taking as an example the formation of a coil section, which is one of the steps in manufacturing a thin film magnetic head, as shown in FIG. A resist mask 3 is formed on the copper thin film to obtain a predetermined copper coil pattern, and an etching target 4 is prepared. Then, this is vertically irradiated with an ion beam such as an argon ion beam, and the exposed portion 21 of the copper thin film and the resist mask 3 are etched, thereby forming a copper coil pattern 20 as shown in FIG. However, in the process, as shown in FIG. 5, the corner portions 31 of the mask 3 are etched to be rounded, and when the etching of the mask is completed, the corner portions 22 of the coil pattern 20 are also rounded. As a result, the cross-sectional area of the coil becomes smaller, resulting in disadvantages such as a resistance value greater than a predetermined value.

Accordingly, the present invention provides an ion beam etching method for dry etching a metal thin film on which a patterned resist mask is placed using an ion beam.
An object of the present invention is to provide an ion beam etching method that can dry-etch an exposed portion of a metal thin film and a resist mask at the same time, and does not cause scraping, which is a practical problem, at the corners of a target pattern.

[0007]

[Means for Solving the Problem] As a result of research to achieve the above object, the present inventor has found that if the resist mask surface is tilted not perpendicularly to the ion beam irradiation direction but more inclined than the ion beam irradiation direction, the resist mask The etching rate of the surface can be made approximately the same as the etching rate of the corners of the resist mask, which is partially etched by the oblique component of the ion beam, thereby preventing the occurrence of rounding of the corners of the mask. The present invention was completed based on the discovery that the etching process time can be shortened as a whole.

That is, in accordance with the above object, the present invention provides an ion beam etching method in which a metal thin film on which a patterned resist mask is placed is dry etched using an ion beam. The present invention provides an ion beam etching method characterized by tilting at an angle of 75° to 75°.

[0009] If the angle at which the resist mask surface is tilted from the direction perpendicular to the ion beam irradiation direction is smaller than 30° or larger than 75°, the etching rate of the resist mask surface will be low and the corners of the resist mask will be It is inevitable that roundness will occur, which is a problem in practice. Note that the ion beam may be an ion beam of an inert gas such as argon.

[0010] Furthermore, as the resist, various types such as COP electron beam resist, AZ1350 resist, etc. can be employed depending on the type of metal thin film.

[0011]

[Operation] According to the method of the present invention, the etching rate increases on the resist mask surface that is tilted by 30° to 75° with respect to the ion beam irradiation direction, so the corners of the mask that are also etched by the oblique component of the ion beam. The etching rate becomes almost the same as that of the mask, and as a result, it is possible to avoid the occurrence of roundness at the corners of the mask, which is a practical problem. Furthermore, as a result, the corners of the pattern under the resist mask that appear after the etching of the resist mask is completed do not suffer from roundness or scraping, which would be a problem in practice.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the method of the present invention will be described below, taking as an example a case where an etching object 4 shown in FIG. 2 is etched using an etching apparatus 5 whose schematic configuration is shown in FIG. Figure 1
The apparatus 5 includes a vacuum chamber 51 for etching processing.
, a vacuum generator 52 connected to the chamber, an argon ion beam source 53 provided in the chamber, and a support device 54 for the object to be etched.

The support device 54 has a support rod 541 and a holder 542 attached thereto. The rod 541 is moved in the original irradiation direction X of the ion beam by a driving means (not shown).
It is rotated around an axis parallel to the The direction Y perpendicular to the holder 542 can be adjusted in angle with respect to the ion beam irradiation direction X within a range of at least θ=30° to 75°.

The object to be etched 4 shown in FIG. 2 is placed in a holder 54 with its resist mask 3 facing the ion beam source 53.
2, and the upper end surface of the mask is tilted at θ=40° from the direction S perpendicular to the ion beam irradiation direction X. In other words, the direction Y perpendicular to the upper end surface of the mask is set to be inclined by θ=40° in the longitudinal direction of the upper end surface with respect to the ion beam irradiation direction X. Then slowly rotate the holder, while
The inside of the chamber 51 is vacuumed by a vacuum generator 52 of approximately 2×10 −4
Torr], and the ion beam source 53 is in a vacuum state of 0.
．． When the target object 4 was irradiated with an argon planar ion beam (about 100 mm in diameter) 531 having a current density of 5 mA/cm2, the exposed portion 21 of the copper thin film and the resist mask 3 were etched at the same time, as shown in FIG. As shown in FIG. 4, the corners 31 of the mask 3 do not have the roundness that would be a problem, and by completing the etching of the mask 3, as shown in FIG. A coil pattern 200 was formed. Moreover,
Compared to the case where the upper end surface of the resist mask is arranged in the direction S perpendicular to the ion beam irradiation direction X, the etching time is 10
It was shortened by about %.

[0015]

As explained above, according to the present invention, there is provided an ion beam etching method in which a metal thin film on which a patterned resist mask is placed is dry etched using an ion beam, and the exposed portion of the metal thin film and the resist mask are simultaneously etched. It is possible to provide an ion beam etching method that allows dry etching and does not cause scraping, which is a practical problem, at the corners of a target pattern.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an example of an ion beam etching apparatus that implements the method of the present invention.

[Figure 2] (A) is a cross-sectional view of an example of an object to be etched, (B)
is a sectional view taken along line P-P in Figure (A).

3(A) is a sectional view of the object in FIG. 2 during etching by the method of the present invention, and FIG. 3(B) is a sectional view taken along the line Q--Q in FIG. 3(A).

4 is a cross-sectional view of the object of FIG. 2 after etching according to the invention; FIG.

FIG. 5 is a cross-sectional view of the object in FIG. 2 during etching by a conventional method.

6 is a cross-sectional view of the object of FIG. 2 after etching by a conventional method; FIG.

[Explanation of symbols]

1 Substrate 2 Copper thin film 3 Resist mask 4 Etching object 5 Etching device 51 Vacuum chamber 52 Vacuum generator 53 Ion beam source 531 Planar ion beam X Ion beam irradiation direction S Direction Y perpendicular to ion beam irradiation direction X Upper end surface of resist mask Direction perpendicular to 54 Support device 541 Rotation support rod 542 Holder

Claims (1)

[Claims] 1. In an ion beam etching method in which a metal thin film on which a patterned resist mask is placed is dry etched using an ion beam, the resist mask surface is tilted by 30° to 75° from a direction perpendicular to the ion beam irradiation direction. Characteristic ion beam etching method.