JP3016637B2 - Direct joining method of sapphire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sapphire fixing method for directly joining two or more sapphire members by a thermal diffusion process.

[0002]

2. Description of the Related Art Conventionally, sapphire has been joined by a method of joining with an adhesive or a method of joining by applying a metallizing treatment to a joining surface. In the method of using an adhesive, a thermosetting or sapphire method is used. A joining method using a so-called organic adhesive such as an ultraviolet curing adhesive has been mainly used. What is bonded by this method is a permeable bonding surface, but there are difficulties in the heat resistance, chemical resistance, bonding strength, etc. of the adhesive after bonding, especially in the high temperature range because it is an organic material. The problem was that it could not be used.

[0003] As a method of performing metallization, a molybdenum-manganese (Mo-Mn) method is often used. However, a treatment at a high temperature of 1750 ° C and in a hydrogen atmosphere is required, and a metal (metal) phase is required in the treatment. However, there is a problem in the production method as a decorative sapphire-joined part reminiscent of integral molding, such as loss of transmission characteristics due to the precipitation of the metal, and the appearance of a metallized phase in a polished product.

[0004]

According to the present invention, two or more sapphire members are directly joined by thermal diffusion treatment of oxides and ions in bulk sapphire at the joint surface without using metallizing treatment or the like on the joint surface. The present invention relates to a method for fixing sapphire. In a bulk sapphire having a surface roughness Rmax of 0.1 μm or less and a flatness of 10 μm or less, ions capable of moving in the crystal are added by a doping material, and ions are added at a high temperature. Move directly in the crystal and in the joint interface to directly join sapphire.

[0005] As a doping material for bulk sapphire, a sapphire containing one or several oxides selected from the group IVa, Va, VIa, VIIa and VIII elements can be joined. If the surface roughness Rmax is finished to 0.1 μm or less, and the flatness of the bonding surface is a mirror surface of 10 μm or less, the bonding strength of the bonding portion can be sufficiently obtained. In other words, if the flatness is less than the accuracy (the flatness is 10 μm or more), the joint is not the whole plane, but only a partial plane that partially satisfies the flatness accuracy, and the bonding strength is sufficiently obtained. In some cases, flatness accuracy is an indispensable factor in obtaining sufficient bonding strength.

[0006] As a result of the experiment, it is effective that the treatment temperature is from 1000 ° C to 2000 ° C, which sufficiently activates the ion transfer of the doping material. At a treatment temperature of 1000 ° C or less, bonding does not occur. If the temperature exceeds 2000 ° C., there is a problem that the sapphire matrix is deformed. The concentration of the doping material in sapphire is the amount of ions that can move in the crystal.
Although good joining results were obtained in the range of 0.1 ppm to 5 wt%,
The bonding does not occur between bulk sapphires of less than pm, while if the doping material concentration exceeds 5 wt%, the strain depending on the impurities in the sapphire crystal and the presence of the second phase at the time of crystal growth influence, and the bonding after the bonding process is performed. It was confirmed that cracks occurred on the end face of the part. Further, it has been confirmed that it is essential that the joining surfaces of the individual sapphire to be joined are crystallographically superposed in the same orientation.

[0007]

EXAMPLE 1 An artificial sapphire containing 0.01 wt% of TiO ₂ as a doping material was grown by the Bernoulli method, and cut and polished so that the surface roughness Rmax of the C-plane was 0.1 μm or less and the flatness was 10 μm or less (approx. Two sapphires (φ30mm x 2mm thick) are superposed in the same orientation crystallographically on the joint surface,
Heat treatment was performed at 1500 ° C. to 1700 ° C. for 24 hours in the air and in a nitrogen atmosphere for bonding. As a result, a strong sapphire joint having a transparent colorless and transparent joint surface and a joint strength of 2 kg / mm ² or more was obtained.

In a similar method, the plane orientation is changed to C-plane and a-plane.
As a result of performing the bonding treatment by changing the bonding surface, the bonding state was such that cracks were present on the bonding surface, and sufficient bonding strength could not be obtained. Further, by changing the conditions, a bonding treatment was performed for a substrate having a flatness of 10 μm or more and a surface roughness of about 1 μm, but good bonding was not obtained.

[0009]

Embodiment 2 Using TiO ₂ and Fe ₂ O ₃ as doping materials,
Sapphire containing 0.2% by weight of iO _{2 and} 2% by weight of Fe ₂ O ₃ was grown by the Bernoulli method and subjected to a bonding treatment under the same conditions as in Example 1. As a result, a bonding strength of 2 kg / mm having a permeable bonding surface was obtained. ^Two
The above-mentioned strong bonding was obtained. Similar bonding results were obtained by performing a bonding process on sapphire in which the doping materials were changed to ZrO ₂ and CoO in the same procedure.

[0010]

Embodiment 3 On a sapphire joint surface having a surface roughness and flatness of which the impurity concentration in a bulk sapphire to which a doping material is not added is 0.1 ppm or less and the surface roughness and the flatness are finished under the above conditions, TiO ₂ is sputtered to a thickness of 0.5 μm. A thermal diffusion treatment was performed by superposing in the same orientation crystallographically as in Example 1. In the sapphire subjected to the bonding treatment, although the permeability of the bonding surface is somewhat reduced, a strong bonding without cracks or the like was obtained. The same result was obtained by forming one or several oxides of Zr, Cr, Mn, and Fe by a similar method and performing a bonding process.

[0011]

Embodiment 4 On a sapphire joint surface having a surface roughness and a flatness finished under the above-described conditions in which the impurity concentration in the bulk sapphire to which the doping material is not added is 0.1 ppm or less, Ti, Zr, Cr, Mn, Fe Each element was ion-implanted into the bonding surface in an amount of about 10 ¹⁷ / cm ² by the ion implantation method, and subjected to the same thermal diffusion treatment as described above. As a result, the same bonding strength as that of Examples 1 and 2 was obtained, and the bonding surface was transparent and had no problem in appearance.

[0012]

According to the present invention, a method for fixing sapphire in which two or more sapphire members are directly joined by thermal diffusion treatment of oxides and ions in bulk sapphire on the joining surface without using metallizing treatment or the like on the joining surface. Heat resistance, chemical resistance, bonding strength, and appearance, which were disadvantages in the method using an organic adhesive and the method of performing metallization treatment, which were conventionally performed as a method of bonding sapphire. With the above transmission characteristics, it has become possible to solve all such problems.

In particular, cracks due to thermal strain between the metal layer and sapphire in the high temperature region are completely eliminated, and it is suitable for window parts for heat treatment and decorative joint parts such as jewelry, precious metals, luxury watches, etc., which have excellent transmission characteristics. It has become possible to supply without deteriorating the appearance and appearance.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-115200 (JP, A) JP-A-59-233000 (JP, A) JP-A-3-97700 (JP, A) JP-A 62-115 162686 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C30B 1/00-35/00

Claims (3)

(57) [Claims] 1. A sapphire bonded surface having a surface roughness Rmax of 0.1
μm or less and a flatness of the joining surface is 10 μm or less, and one or several doping materials selected from the group IVa, Va, VIa, VIIa and VIII elements are 0.1 ppm to 5 wt%.
The artificial sapphire or natural sapphire contained, the joining surface is superimposed crystallographically in the same direction, 1000 ℃ ~ 2000 ℃
A direct joining method of sapphire, characterized by joining by a heat treatment. 2. The method according to claim 1, wherein one or several oxides selected from the group IVa, Va, VIa, VIIa and VIII elements are formed on the joint surface by sputtering or vacuum evaporation.
Joining method. 3. The bonding method according to claim 1, wherein one or several elements selected from the group IVa, Va, VIa, VIIa and VIII elements are formed on the bonding surface by ion implantation.