Sumitomo Mitsubishi Silicon Corporation

Fumio Kawahigashi

Hiroshi Asano

Takayuki Kubo

Manabu Nishimoto

Masahiko Okui

Shinichiro Miki

Naohiro Takaoka

Akira Tsujino

In the CZ process using a cooling member surrounding a single crystal, the cooling member is permitted to effectively serve to increase a pulling speed. Cracks of the single crystal due to excessive cooling are prevented to occur. A high crystal quality is acquired. In order to realize these objects, the temperature of the inner peripheral surface of the cooling member opposing to the outer peripheral surface of the single crystal is restricted to 500&deg; C. or below, even in the lower end, the temperature of which becomes the highest. To achieve this restriction, the thickness T of the cooling member is 10 to 50 mm. The height H of the cooling member is 0.1 to 1.5 times the diameter D of the single crystal

Crystal growth method

An apparatus for growing a crystal, using the cooler surrounding the single crystal for high speed pulling. The cooler is prepared using a copper-based metal and is water cooled. The supporting arm that supports the cooler is prepared using stainless steel or the like, which is higher in mechanical strength than copper-based metals and is inferior in thermal conductivity, and is detachably connected to the cooler . Excessive cooling of the supporting arm and disposition due to precipitation of silicon oxide are prevented, leading to improvement in disposition free pulling rate without the prevention of speed-up. The cost of manufacture of the cooler is saved. The support strength of the cooler is improved.

Crystal growth apparatus

In a high rate pulling with a cooler surrounding a single crystal steam explosion by leakage from the cooler is prevented. Flow rates La, Lb of cooling water are measured by flowmeters on a cooling water inflow side and cooling water outflow side of the cooler When flow rate difference &Dgr;L (La&minus;Lb) determined from the flow rates La, Lb exceeds 20 cc/minute, open/close valves are operated to stop water supply to the cooler and drain outward the cooing water in the cooler

Crystal growing apparatus

An apparatus is provided which is to be used in producing single crystals for silicon wafers useful as semiconductor materials and which can stably produce large-diameter, long-length and high-quality single crystals from which wafers limited in the number of grown-in defects can be taken. This silicon single crystal production apparatus comprises a cooling member surrounding the single crystal to be pulled up and having an internal surface coaxial with the pulling axis and thermal insulating members disposed outside the outer surface and below the bottom surface of the cooling member, the cooling member having an internal surface diameter of 1.20D to 2.50D (D being the diameter of the single crystal to be pulled up) and a length of not less than 0.25D, the distance from the melt surface to the bottom surface of the cooling member being 0.30D to 0.85D and the bottom side of the thermal insulating member below the cooling member having an inside diameter smaller than the inside diameter of the bottom of the cooling member.

Growing community of inventors

Tokyo, Japan

Fumio Kawahigashi