JPH04249319A - Grid for ion gun and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a one-sheet grid which can obtain a high current density at a low accelerating voltage and whose life is long by a method wherein its main constituent material is one out of Al2O3, Al2O3.TiC, ZrO2, BN and SiC and its surface is treated so as to be a conductor. CONSTITUTION:A one-sheet type grid 9 is used for an ion gun 1 of a type which generates a plasma in a thin gas state and which extracts thin-gas ions from it and is used for ion acceleration use and for ion extraction use. Its main constituent material of the grid is one selected out of Al2O3, Al2O3.TiC, ZrO2, BN and SiC and one side or both sides of its surface are treated so as be a conductor. For example, a single-sheet grid 9 for a Kaufmann-type gun 1 is manufactured as follows: a green sheet of Al2O3 or the like is baked; it is then cut to the size of the grid; a hole for screwing use is made; manu holes for the grid are made; the sheet is baked; and both faces are plated chemically with NiP to be in 10mum.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grid for an ion gun used in an ion beam sputtering device or an ion beam etching device used in the manufacture of semiconductors, and a method for manufacturing the same.

0002

[Prior Art] Ion beam sputtering equipment and ion etching equipment, which have become widely used in recent years to form fine patterns and produce magnetic films, generate inert gas ions and accelerate them to create targets and An ion gun is required to create an ion beam that collides with the object to be etched. Furthermore, recently, low-energy ion guns have been developed and used that are extremely effective in avoiding damage to the object to be etched and improving the properties of amorphous materials, especially in the production of acidic films. However, the commonly used two-plate grid cannot provide sufficient ion current density at low energy, i.e., low accelerating voltage, and it takes a long time to process the etched object. It took a long time to form a film, and it was not ready for industrial use. In order to avoid this, a two-piece grid can be used by using a single grid having many small holes with hole diameters of 0.2 mm to 0.4 mm, as previously disclosed in JP-A No. 63-124343. It was possible to obtain a higher ion current density than in the case where the etching process and film formation time were shortened.

[0003] As a typical example of such an ion gun, a Kaufmann type ion gun will be explained in detail. Figure 1 shows
This is a normal ion etching apparatus, and in the figure, 1 is a Kauffman type ion gun, and the ion gun 1 is installed above an etching chamber 2. The etching chamber 2 is provided with an exhaust port 3 connected to an exhaust system (not shown), and after the inside of the ion gun 1 is sufficiently evacuated, for example, argon gas is introduced from a gas inlet 5 provided in the case portion 4. ,
A dilute gas state with a gas pressure of about 0.1 mm Torr is created. The ion gun 1 is provided with a cathode 6 for emitting thermoelectrons and an anode 7 corresponding to the cathode 6. Furthermore, an electromagnet 8 is disposed on the outer side of the case portion 4 to cause the thermoelectrons emitted from the cathode 6 to spirally move. The cathode 6 and anode 7 constitute a discharge means, and the discharge means and the electromagnet 8 generate plasma in a dilute argon gas state to generate ions.

A single extractor grid 9 for extracting ions is provided on the front side of the ion gun 1, that is, on the etching chamber 2 side. A negative potential is applied to this single grid 9 with respect to the cathode 6, and it has the function of accelerating positive ions in the generated plasma and drawing them out into the etching chamber 2. In addition, 10 is a cathode power supply, 1
1 is an anode power supply, 12 is an acceleration power supply, and 13 is an extractor power supply. Note that a power source for driving the electromagnet 8 is not shown here. With the configuration of the ion gun as described above, the extracted argon ions strike the object to be etched 14 and physically etch it. In the case of ion beam sputtering, 14 is a target, and particles sputtered here are deposited on a substrate 15.

[0005] Single-sheet grids are usually made of stainless steel, such as SUS304, or molybdenum plate with a thickness of 1 mm or less, and pores with a diameter of 0.2 mm to 0.4 mm are formed in this to give an aperture ratio of 50% or more. It is manufactured by forming a mask on both sides so that a large number of masks can be manufactured, spraying a chemical etching solution on both sides, and drilling pores from both sides. These pores must penetrate from both sides of the plate to the opposite side perpendicular to the plate surface, but due to the characteristics of etching, it is inevitable that the pore diameter will be slightly smaller in the center of the plate. In order to avoid this, it is necessary to reduce the grid plate thickness. Furthermore, as disclosed in JP-A No. 63-124343, the thicker the grid plate is, the more difficult it is to obtain an ion beam current. There is a need to. However, the thinner the grid, the more the surface of the grid on the ion gun side is etched by ions, resulting in a shortened lifespan of the grid.

[0006] Another example of the conventional technology is to use photosensitive glass such as photoceram as the main constituent material, drill holes in it using photolithography, and chemically plate nickel on one or both sides of the glass. There was a one-piece grid that was applied. However, there were drawbacks such as the difficulty in making thin ones due to strength and the inability to increase the hole aperture ratio to 50% or more. In addition, there was a method of manufacturing a single grid using the ceramic material mentioned above, which involves drilling minute holes by machining and then plating or vapor depositing metal on one side. It took a lot of time to process and could not be widely used industrially.

[0007]

[Problems to be Solved by the Invention] This invention was proposed based on the above circumstances, and aims to provide a long-life single-piece grid that can obtain high current density at low acceleration voltage. .

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention is used in an ion gun that generates plasma in a diluted gas state and extracts diluted gas ions from it, and is used for ion acceleration and ion extraction. The single-piece grid used is made of Al2O as the main constituent material.
3, Al2 O3 ・TiC, ZrO2 , BN, S
The gist of the invention is a one-piece grid that is selected from iC and is characterized in that one or both surfaces of the grid are subjected to conductive treatment. Furthermore, in the present invention, the main constituent materials are Al2 O3, Al2 O3
・It is one of TiC, ZrO2, BN, and SiC, and is characterized by drilling holes, cutting out, and processing the curved surface of the grid surface in the green sheet state at the firing stage, and then subjecting it to conductive treatment after firing. The gist of the invention is a method for manufacturing a sheet grid.

[0009]

[Operation] According to the present invention, the main constituent materials of the ion gun grid are Al2 O3, Al2 O3 ・TiC,
It is made of ZrO2, BN, or SiC, and is processed by drilling etc. in the form of a green sheet, so it is easy to manufacture and has the effect of extending its life.

In other words, in the present invention, plasma is generated in a diluted gas state, and an ion beam is efficiently applied to the object or target to be etched with a high ion current density.
It is a one-piece grid for efficient etching or sputtering, and its characteristics are that the main constituent materials of the one-piece grid are Al2 O3 and Al2 O3.
・By using one ceramic material selected from TiC, ZrO2, BN, and SiC, the surface of the grid on the ion gun side becomes difficult to be etched by ions, so if the grid has the same dimensions as the conventional SUS304, A single-piece grid whose main constituent material is ceramic can have a significantly longer lifespan.

[0011]

[Example] Next, an example of the present invention will be described. It should be noted that the embodiments are merely illustrative, and it goes without saying that various changes and improvements can be made without departing from the spirit of the present invention.

[0012] Hereinafter, embodiments of the present invention will be described in the case of a single grid of a Kauffman type ion gun, and the main constituent materials of the substrate are Al2O3, Al2O3, TiC, ZrO2.
, BN, SiC, diameter 10cm, plate thickness 0.2m
A case will be described in which the hole diameter is 0.3 mm, the hole pitch is 0.35 mm, and the surface is chemically plated with NiP to a thickness of 10 μm. Generally, the lifespan of a grid material is proportional to the etching rate during ion beam etching, so the approximate lifespan can be estimated by comparing the etching rates of the main constituent materials. A ceramic material as the main constituent material was placed at position 14 in the configuration shown in FIG. 1, and its etching rate was measured under the conditions shown in Table 1, and the results shown in Table 2 were obtained.

[0013]

[0014]

[0015] From these results, since the etching rate of both ceramic materials is less than half that of SUS304, it is estimated that the lifespan of a one-piece grid is more than double that of SUS304. The lifespan of a single grid was measured as follows. SUS304 plate thickness 0.2
A grid with a hole pitch of 0.35 mm, a hole diameter of 0.3 mm, and an aperture ratio of 57% was attached to the position 9 in Fig. 1 using a chemical etching mask from both sides of the plate surface, and a copper target was etched in the figure. At position 14 in Table 1, perform ion beam sputtering for 5 hours using the conditions in Table 1, and perform sputtering again for 5 hours at intervals of 2 hours or more to calculate the cumulative time until the grid is worn out and becomes unusable. It depends on how you check the time. The lifespan of the SUS304 one-piece grid is 2
The time range was 0 to 25 hours. In other words, in the case of a one-piece grid whose main constituent material is the above-mentioned ceramic, it is certain that its lifespan is 100 hours or more.

By the way, a single-sheet grid is prepared as follows. In general, there are various types of molding methods for ceramic materials, such as pressurization, extrusion, and green sheet molding, and green sheet molding is used to produce thin sheet-like materials. After firing this formed sheet, it is cut to the size of a grid, holes for screw fixing are made, and a large number of holes for the grid are made by a method such as a stand bar or a drill, and then sintered to complete the sheet. Here, taking into account the amount of shrinkage due to sintering, we created a one-piece grid with a diameter of 10 cm, plate thickness of 0.2 mm, hole diameter of 0.3 mm, hole pitch of 0.35 mm, and aperture ratio of 57% after completion. do. These grids are completed after being coated with NiP chemical plating to a thickness of 10 μm on both sides.

In the case of the one-piece grid of the present invention, the NiP plating film applied to the ceramic surface will disappear within 10 hours on the ion-etched surface on the ion gun side, but this is not a problem and the ceramic material will be consumed after that. Compare the time until it becomes unusable. The plating film on the side of the chamber opposite to the ion gun side is connected to the extractor power supply, but it is rarely etched by ions and has a sufficient lifespan until it becomes unusable.

[0018] In order to manufacture the grid of the present invention, Al2 O3, Al2 O3 .Ti is used as the main constituent material.
Using either C, ZrO2, BN, or SiC, holes are drilled in the green sheet state, the grid surface is cut out and the curved surface is processed, then firing is performed, and after this, one or both surfaces are plated, sputtered, vapor-deposited, or CVD. Conductive processing is performed using methods such as the following.

Furthermore, regarding the manufacturing method of the one-piece grid of the present invention whose main constituent material is ceramic, since all processing such as drilling is performed in the green sheet state at the firing stage, laser or ultrasonic waves are not used after sintering. A long-life grid can be easily obtained without difficult processing such as

Furthermore, in the case of a single-piece ion gun, the ion beam irradiated from the ion gun is usually not a parallel beam near the target, but tends to spread out a little, but it is possible to make it conform to a concave or convex mold in a green sheet state. This allows the grid surface to have an appropriate curvature, and it is possible to easily obtain a convergent (focused) or diverging (defocused) single-sheet grid.

[0021]

[Effects of the Invention] As described above, according to the present invention, a one-piece grid for extracting a low-energy ion beam is manufactured using a main constituent material of Al2 O3, Al2 O3 ・Ti.
It is clear that the life of a one-piece grid made of one selected from C, ZrO2, BN, and SiC is more than twice that of conventional SUS304, and furthermore,
Since convergent and divergent curved surfaces can be easily processed, it has become possible to use the single-sheet grid in a wide range of industrial applications.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an ion beam etching apparatus according to the present invention.

[Explanation of symbols]

1 Ion gun 2 Etching chamber 3 Exhaust port 4 Case part 5 Gas inlet 6 Cathode 7 Anode 8 Electromagnet 9 Grid 10 Cathode power supply 11 Anode power supply 12 Acceleration power supply 13 Extractor power supply 14 Object to be etched 15　Substrate

Claims (2)

[Claims] Claim 1: A one-piece grid used for ion guns that generate plasma in a diluted gas state and extract diluted gas ions from it, and used for ion acceleration and ion extraction, the main constituent material being Al2
O3, Al2 O3 ・TiC, ZrO2 , BN,
A one-piece grid made of one selected from SiC, characterized in that one or both surfaces of the grid are subjected to conductive treatment. [Claim 2] Main constituent materials are Al2 O3, Al
2 O3 ・TiC, ZrO2, BN, or SiC, and is characterized by drilling holes, cutting out, and processing the curved surface of the grid surface in the green sheet state at the firing stage, and then subjecting it to conductor treatment after firing. A method for manufacturing a one-piece grid.