WO2003082769A1

WO2003082769A1 - Silicon monoxide sintered product and sputtering target comprising the same

Info

Publication number: WO2003082769A1
Application number: PCT/JP2003/003894
Authority: WO
Inventors: Yoshitake Natsume; Tadashi Ogasawara; Munetoshi Watanabe; Kazuomi Azuma; Toshiharu Iwase
Original assignee: Sumitomo Titanium Corporation
Priority date: 2002-04-02
Filing date: 2003-03-27
Publication date: 2003-10-09
Also published as: JP4235114B2; AU2003220872A1; TWI276696B; JPWO2003082769A1; TW200304954A

Abstract

A silicon monoxide sintered product prepared through forming a raw material powder which consists of 20 to 80 mass % of a silicon powder doped with boron, phosphorus or antimony and the balanced amount of silicon monoxide or a mixture of silicon monoxide and silicon dioxide, wherein the content of silicon monoxide in the mixture is 20 % or more; and a sputtering target using the silicon monoxide sintered product. The sputtering target can be used for securing a satisfactorily high rate of film formation while providing a film reduced in variations of film characteristics, and thus can be widely and advantageously used for forming a silicon oxide thin film as a protective film for optical use, for example, for use in the prevention of gas permeation in a transparent plastic and the prevention of dissolution of Na from a glass and the protection of the surface of a lens.

Description

Specification

Sintered silicon monoxide and sputtering target comprising the same

The present invention relates to a silicon monoxide sintered body and a sputtering target comprising the same, and more particularly, to an optical protective film for preventing gas permeation of transparent plastic, preventing Na elution of glass, or protecting a lens surface. The present invention relates to a silicon monoxide sintered body to be used and a sputtering target comprising the same. Background art

Silicon oxide-based thin films such as SiO ₂ film or SiO ₂ (1 <X <2) film have excellent electrical insulation and high mechanical strength, so they are used as barrier films for various optical components. It is also used as a protective film to prevent gas permeation of transparent plastic because it is transparent and has excellent gas barrier properties. Such S i O ₂ film or S i O x film when forming a film on the substrate material, silicon and (S i), silicon monoxide (S io) and silicon dioxide (S io ₂₎ a sputtering target Reactive sputtering is performed. 'As the reactive sputtering method, a bipolar direct current reactive sputtering method and a high frequency reactive sputtering method are used as typical methods. First, in order to form a thin film by the bipolar DC reactive sputtering method, N ₂ and O ₂ are mixed and introduced into an inert gas such as Ar under reduced pressure, and a DC high voltage is applied between the electrodes. To discharge (global discharge).

Due to such discharge, the inert gas is ionized and collides with the cathode side at a high speed, causing the substance (target) disposed on the cathode to fly out. The protruding substance becomes nitride or oxide and deposits on the surface of the substrate. To form a thin film.

On the other hand, the high-frequency reactive sputtering method generates a high-frequency glow discharge by applying a high-frequency voltage of 50 kHz or more instead of the DC high voltage applied in the two-pole DC reactive sputtering method, This is a method of forming a thin film on the surface of the substrate in the same manner as described above.

The above-described bipolar direct-current reactive sputtering method has the advantages of simple equipment and operation and a high film formation rate. However, when a high-resistance substance or an insulator is used as a target, the target is exposed to positive ions. Charging makes sputtering impossible.

On the other hand, the above-described high-frequency reactive sputtering method uses high-frequency discharge, so that even when an insulator or the like is used as a target, the glow discharge is maintained, so that a thin film can be formed. However, the high-frequency reactive sputtering method has a lower deposition rate than the two-pole DC reactive sputtering method, and has a complicated power supply configuration, which results in high equipment production costs. I am worried about the reliability and maintainability of the For this reason, this method has a problem that it is difficult to stably obtain a high-frequency current.

In order to cope with such a problem, an attempt has been made to form a film by a DC reactive sputtering method on an insulating base material which has been conventionally formed by a high frequency reactive sputtering method. For example, there is known a method of performing DC reactive sputtering by removing a part (oxygen component) of a main material (PLZT / PZT system) to lower the resistance.

Furthermore, in order to reduce the resistance of the sintered body, a method of mixing a conductive substance with an insulating substance, sintering to obtain a highly conductive sintered body, and performing DC reactive sputtering is used. It has been proposed (Japanese Patent Application Laid-Open No. 2000-246731, Japanese Patent Application Laid-Open No. 2000-58771). However, among the above-mentioned methods, in the method of providing conductivity to the sintered body by oxygen deficiency, substances to which this method can be applied are limited, and the present invention is applicable to silicon oxide-based materials. Can not. In addition, in the proposed method of obtaining a sintered body having high conductivity by mixing and sintering an insulating material and a conductive material, a heterogeneous material is mixed at the time of sputtering because the sintered body is made of a mixture of different materials. Films are formed at the same time, and the film characteristics change. Furthermore, since it is a mixed sintered body, the specific resistance of the sputtering target is not uniform, and problems such as unstable film formation occur. Disclosure of the invention

As described above, in forming a thin film of silicon oxide is, S i, S i O and S i 0 ₂ reactive sputtering a sputtering target to crack line. However, Si can be easily reduced in resistance by doping boron (B), phosphorus (P), or antimony (Sb) at the stage of growing a single crystal.

For this reason, usually, the doped Si powder can be formed into a film by a DC reactive sputtering method while introducing oxygen using a DC sputtering apparatus. In contrast, in the case of using S io, the sintered body S i O ₂ in the sputtering target, because there is no conductive material is deposited by RF reactive sputtering method.

When a film is formed by a DC reactive sputtering method using doped Si, the film forming rate is increased, but the conditions of the reactive sputtering are easily changed, and as a result, the silicon oxide film formed is formed. The characteristics will vary. In addition, at the time of high power input, there is a problem that the doped Si is easily broken.

On the other hand, when forming a SiO x (1 <X <2) film or a SiO film, if Sio and SiO ₂ close to the film composition are used as targets, Since the amount of oxygen introduced can be reduced, the film characteristics can be homogenized. As described above, S io, S io ₂ because conductivity is lowered insulating material, it is necessary to use a high-frequency reactivity Supattari ing device. For this reason, there is a problem that the film formation rate is slower than the DC reactive sputtering method, and it is difficult to increase the size of the sintered body.

The present invention has been made in view of the problem when a conventional silicon oxide-based thin film is formed by a reactive sputtering method. It can be applied to equipment, secures the deposition rate, stabilizes the characteristics of the deposited film, and enables the deposition of a thin film of a single composition without using different materials. It is an object of the present invention to provide a silicon monoxide sintered body and a sputtering target comprising the same.

The present inventors have conducted various studies on a method of forming a silicon oxide-based thin film in order to solve the above-mentioned problem. As a result, if a conductive silicon monoxide sintered body can be manufactured, We focused on the fact that by using it as a sputtering target, a silicon oxide-based thin film could be formed by applying a sputtering device using a DC power supply.

As a result, the stability of the characteristics of the film to be formed can be ensured, and at the same time, the film forming speed can be increased to improve the productivity, and a good sputtering rate (film forming efficiency) can be obtained.

In consideration of the above, S i powder and S i O powder doped or during sintering by mixing a mixed powder of S i O and S io _2,, "S i in the interior or on the surface of the S io powder It was found that part of “O” thermally decomposed into “S i + S i〇 ₂ ”.

In other words, by mixing and sintering Si doped with heavily doped SiO as a conductor, good conductivity can be obtained by the interaction of the mixed Si with the thermally decomposed Si. Will be. Furthermore, a silicon oxide film having the same composition can be formed regardless of whether it is a mixture of sintering, or any of Si, SiO, and SiO ₂ powders by reactive sputtering. It does not affect the properties of the film. As a result, it is possible to solve the problem of the conventional mixed sintering, that is, the change in the film characteristics and the non-uniformity of the specific resistance of the sputtering target.

The present invention has been completed based on the above findings, and includes the following (1) to

The gist of the present invention is a sputtering target comprising a silicon monoxide sintered body of (4) and a silicon monoxide sintered body of (5).

(1) A silicon monoxide sintered body characterized in that a raw material powder is formed by combining a silicon powder doped with boron, phosphorus or antimony and a silicon monoxide powder.

(2) the mass ^_0/0, boron (B), Li down (P) or antimony (S b). 20 to 80% is contained doped silicon powder (S i), and the balance being silicon monoxide (S i This is a silicon monoxide sintered body obtained by molding a raw material powder of O).

(3) Mass ⁰ /. Containing 20 to 80% of silicon powder (S i) doped with boron (B), phosphorus (P) or antimony (S b), with the balance being silicon monoxide (S i O) or silicon monoxide. A material powder comprising a mixture of silicon dioxide (S i O and S i O ₂ ) having a content of silicon monoxide (S i O) of 20% or more in the mixture is formed. It is a silicon sintered body.

It is desirable that the silicon monoxide sintered body of the above (1) to (3) has a bulk density of 95% or more after sintering.

(4) The specific resistance is 8 Ω · c π! A silicon monoxide sintered body you characterized in that - a 4 X 10 one ^{3 Ω} · cm.

(5) It is characterized by comprising the silicon monoxide sintered body of (1) to (4). Sputtering target. BEST MODE FOR CARRYING OUT THE INVENTION

The silicon monoxide sintered body of the present invention is characterized by containing 20 to 80% by mass of Si powder doped with B, P or Sb. More preferably, the content is 30 to 60%. By containing the doped Si powder, the sintered body has conductivity, and thus can be used as a target of a DC power source sputtering apparatus.

When used as a cathode (target) of a sputtering apparatus during reactive sputtering, the characteristics of the formed film are less scattered, and a good sputter rate can be obtained.

By including doped Si powder, some parts of the Sio powder come into contact with each other and exhibit conductivity, but during mixed sintering, part of the Sio is thermally decomposed inside or on the surface of the Sio powder. I do.

At this time, the doped element B, B,

The thermal conductivity of P or Sb further improves the electrical conductivity. This point can be confirmed from the results of experiments conducted by the inventors, in which the specific resistance of the sintered body rapidly decreases as the sintering temperature is increased.

In the sintered body of the present invention, when the content of the doped Si powder is less than 20%, the specific resistance of the sintered body does not sufficiently decrease even when sintered at a high temperature. This is because the particle distribution of the doped Si powder becomes too "coarse". For this reason, the lower limit of the content of the doped Si powder is set to 20%, preferably 30%.

On the other hand, if the content of the doped Si powder exceeds 80%, the characteristics of SiO 2 will be lost, and the characteristics of the deposited film will vary, as in the case of the Si target. Disadvantages occur. Therefore, doped S i The upper limit of the powder content was set to 80%, and preferably 60%.

Achieving the bulk density of 95% required for the target even when mixing and sintering doped Si powder and Sio ₂ powder without mixing Sio during mixed sintering Can not.

However, if the SiO 2 powder is present during hot pressing, a bulk density of 95% or more can be sufficiently achieved. Since S i O has a low sublimation temperature of about 1200 ° C., it becomes glassy with hot pressing. Therefore, if S i O is mixed with the raw material powder, S i O powder or S i O It is presumed that this is because SiO ₂ penetrates into the gaps between the powders and forms a glassy sintered body.

From the above, in the sintered body of the present invention, it is essential to mix the Si powder and the SiO powder doped as the raw material powder. However, in order to adjust the oxygen concentration of the target, the mixed material of S i powder and S i O powder doped it is effective for mixing the S i 0 ₂ powder. Even in this case, in order to make the film characteristics of the target uniform without losing the characteristics of SiO,

The content of Sio powder must be 20% or more. Desirably, it is 30% or more.

In addition, it is desirable that the average particle diameter of the raw material powder of the silicon monoxide sintered body be reduced from the viewpoint of improving the sinterability, making the conductive properties uniform, and making the film composition uniform. On the other hand, if the raw material powder becomes too fine, a problem of poor mixing occurs. Therefore, it is desirable that the average particle size of the raw material powder is in the range of 0.1 to 20 μπι.

The specific gravity of the doped Si powder contained in the silicon monoxide sintered body of the present invention is 0.01 Ω · cm (high resistivity) to 0,000 lQ'cm (low resistance). Rate) is desirable. If the resistance is too high, sufficient conductive properties cannot be secured, and if the resistance is too low, the material cost becomes too expensive. The doping method using B, P, or Sb is not particularly limited, and may be any method that is usually employed in the stage of growing a silicon single crystal. The doping amount of B, P or Sb is added so that the grown Si single crystal satisfies the above specific resistance.

The silicon monoxide sintered body of the present invention is a powder mainly composed of SiO 2, that is,

S i O powder or S i O and S i 0 ₂ mixed powder S i powder doped by containing 20-80% in the, sufficiently mixed, the resulting powder was 100 kg Zc m ² or more Preferably, it is manufactured by firing under pressure at a temperature of 1250 to 1400 ° C while pressurizing at a pressure of 1250 ° C.

If the sintering temperature is too high, the S の powder dissolves and a good sintered body cannot be obtained. On the other hand, if the sintering temperature is too low, the sintering is insufficient and the dose of B and P Insufficient thermal diffusion of the dopant element occurs. For this reason, in the production of the silicon monoxide sintered body of the present invention, the sintering temperature is preferably set to 1250 to 1400 ° C, more preferably 1300 to 1400 ° C.

(Example)

The effect of using the silicon monoxide sintered body of the present invention will be described based on specific examples.

In the example, Si powder whose specific resistance was adjusted to 0.0004 Ω · cm by doping with B was used. Both the Si powder and the Sio powder were pulverized until the average particle diameter became 10 µm or less. This S i powder is contained in a range of 10 to 90% in the S i O Powder, while applying a pressure of the resulting powder 9. 8 MP a (1 00 kgf / cm 2), 1400 ° C After sintering under pressure for 2 hours, it was machined to <) 6 inches X t 5 mm to obtain a sputtering target.

The surface resistivity and the density ratio of each sintered body obtained under the above conditions were measured, and further, using this sintered body as a target, performing reactive sputtering using a DC power supply to perform monoxide oxidation Form a silicon film (SiO film) and hit for unit time The sputter rate of the film thickness was measured, and variations in film characteristics were observed.

The surface resistivity was measured by a four-terminal method, and the density ratio was indicated by (bulk density theoretical density) X I 00%. Variations in the film characteristics are observed from the measurement results of the transmittance and the refractive index. The above measurement results and observation results are shown in Table 1.

From the results in Table 1, as specified in the present invention, by including the doped Si powder in the Sio powder in the range of 20 to 80%, the variation in the film characteristics as well as the sputter rate is reduced. It turns out that it is good. Further, as a reference test, with the S I_〇 ₂ powder above the same conditions to prepare a sintered body, and machining the sintered body obtained, and Supattari Ngutage' bets, the S i 0 ₂ thin film formed I let it. At this time, although one line the same measurements and observations, the surface resistivity of the sintered body is 1 0 ⁷ Ω · cm or more, the sputtering rate is poor, as in the case of Table 1 Test N o. 1 It is confirmed that it is.

As described above, according to the silicon monoxide sintered body of the present invention, the resistivity of the sintered body can be reduced to be applied to a DC reactive sputtering apparatus, and a stable film characteristic can be secured while securing a film forming rate. be able to. Industrial applicability

When the silicon monoxide sintered body of the present invention is used, the resistivity of the sintered body can be reduced to directly Because it can be applied to flow reactive sputtering equipment, it secures the deposition rate and stabilizes the characteristics of the deposited film.Furthermore, it does not use different materials and forms a thin film with a single composition. be able to. Therefore, if a sputtering target made of this silicon monoxide sintered body is used, a good sputtering rate and a sputtering reaction with little variation in film characteristics are guaranteed. As a result, it can be widely applied as an optical protective film for preventing gas permeation of transparent plastic, preventing Na elution of glass, or for forming a silicon oxide-based thin film used as a protective film on a lens surface.

Claims

The scope of the claims

1. A silicon monoxide sintered body obtained by mixing a silicon powder doped with boron, phosphorus or antimony and a silicon monoxide powder to form a raw material powder.

2. The silicon monoxide sintered body according to claim 1, wherein the sintered body has a bulk density of 95% or more.

3. The silicon monoxide sintered body according to claim 1, wherein the raw material powder has an average particle diameter of 1 to 20 / m.

4. A silicon monoxide sintered body containing 20 to 80% by mass of a silicon powder doped with boron, phosphorus or antimony, and the remainder being formed from a raw material powder of silicon monoxide.

5. The silicon monoxide sintered body according to claim 4, wherein the sintered body has a bulk density of 95% or more.

6. Contain 20 to 80% by weight of silicon powder doped with boron, phosphorus or antimony, and the balance consists of silicon monoxide or a mixture of silicon monoxide and silicon dioxide. A silicon monoxide sintered body obtained by molding a raw material powder having a content of 20% or more.

7. The silicon monoxide sintered body according to claim 6, wherein the sintered body has a bulk density of 95% or more.

8. The specific resistance is 8 Ω ·. π! Silicon monoxide sintered body, which is a ^{~ 4 X 1 0- 3 Ω ·} cm.

9. A sputtering target comprising the silicon monoxide sintered body according to any one of claims 1 to 8.

10. The sputtering target according to claim 9, which is used for reactive sputtering using a DC power supply.