Method for removing metal impurity from quartz component part used in heat processing apparatus of batch type

A method for using a heat processing apparatus of a batch type, the apparatus comprising

• a holder member configured to hold a plurality of product substrates, on which semiconductor devices are to be formed, at intervals in a vertical direction,
• a process container configured to accommodate the holder member with the product substrates held thereon and to form a heat process atmosphere therein, the process container including a quartz inner surface to be exposed to the heat process atmosphere,
• a heater configured to heat an interior of the process container,
• an exhaust system configured to exhaust gas from inside the process container,
• a process gas supply system configured to supply into the process container a process gas for performing a main heat process to form the semiconductor devices, and
• a baking gas supply system configured to supply into the process container a baking gas for performing a baking process to remove the metal impurity, and
• the method comprising
• performing a preparatory process for removing aluminum present as a metal impurity from the quartz inner surface of the process container in the process container with no product substrates placed therein, and
• performing the main heat process on the product product substrates held on the holder member in the process container after the preparatory process,
• wherein the preparatory process comprises
• holding a plurality of dummy substrates including a silicon surface for the metal impurity to be deposited thereon on the holder member and placing the holder member with the dummy substrates held thereon inside the process container;
• then, supplying hydrogen chloride gas and water vapor as the baking gas into the process container, while setting a ratio of the hydrogen chloride gas relative to a sum total of the hydrogen chloride gas and the water vapor at 0.5 to 30 vol %, and heating the quartz inner surface of the process container at a process temperature of 550° C. to 1,050° C., thereby applying the baking process onto the quartz inner surface to discharge the metal impurity from the quartz inner surface and deposit the metal impurity onto the dummy substrates;
• and
• then, unloading the holder member along with the dummy substrates with the metal impurity deposited thereon from the process container, without performing the main heat process on the dummy substrates,
• wherein the preparatory process further comprises
• measuring a concentration of aluminum deposited on an unloaded dummy substrate, and repeatedly applying the baking process onto the quartz inner surface of the processing container while replacing the dummy substrates with new ones every time after said measuring a concentration until the concentration becomes lower than a predetermined value before performing the main heat process on the product substrates in the process container, and
• stopping supply of the hydrogen chloride gas and the water vapor and purging the interior of the process container with oxygen gas every time after the baking process, and then purging the interior of the process container with nitrogen gas and cooling the process container to an unload temperature to perform said unloading.

A method for using a heat processing apparatus of a batch type, the apparatus comprising

• a holder member configured to hold a plurality of product substrates, on which semiconductor devices are to be formed, at intervals in a vertical direction,
• a process container configured to accommodate the holder member with the product substrates held thereon and to form a heat process atmosphere therein,
• a predetermined member including a quartz portion to be exposed to the heat process atmosphere,
• a heater configured to heat an interior of the process container,
• an exhaust system configured to exhaust gas from inside the process container,
• a process gas supply system configured to supply into the process container a process gas for performing a main heat process to form the semiconductor devices, and
• a baking gas supply system configured to supply into the process container a baking gas for performing a baking process to remove the metal impurity,
• the method comprising
• performing a preparatory process for removing aluminum present as a metal impurity from the quartz portion of the predetermined member in the process container with no product substrates placed therein, and
• performing the main heat process on the product substrates held on the holder member in the process container after the preparatory process,
• wherein the preparatory process comprises
• holding a plurality of dummy substrates including a silicon surface for the metal impurity to be deposited thereon on the holder member and placing the predetermined member along with the holder member with the dummy substrates held thereon inside the process container;
• then, supplying hydrogen chloride gas and water vapor as the baking gas into the process container, while setting a ratio of the hydrogen chloride gas relative to a sum total of the hydrogen chloride gas and the water vapor at 0.5 to 30 vol %, and heating the quartz portion of the predetermined member at a process temperature of 550° C. to 1,050° C., thereby applying a baking process onto the quartz portion to discharge the metal impurity from the quartz portion and deposit the metal impurity onto the dummy substrates;
• and
• then, unloading the holder member along with the dummy substrates with the metal impurity deposited thereon from the process container, without performing the main heat process on the dummy substrates,
• wherein the preparatory process further comprises
• measuring a concentration of aluminum deposited on an unloaded dummy substrate, and repeatedly applying the baking process onto the quartz portion of the predetermined member while replacing the dummy substrates with new ones every time after said measuring a concentration until the concentration becomes lower than a predetermined value before performing the main heat process on the product substrates by use of the predetermined member, and
• stopping supply of the hydrogen chloride gas and the water vapor and purging the interior of the process container with oxygen gas every time after the baking process, and then purging the interior of the process container with nitrogen gas and cooling the process container to an unload temperature to perform said unloading.

A method for removing aluminum present as a metal impurity from a holder member configured to hold a plurality of product substrates, on which semiconductor devices are to be formed in a heat processing apparatus of a batch type, at intervals in a vertical direction and including a quartz portion, the method being performed in a baking apparatus dedicated to the holder member and different from the heat processing apparatus of a batch type,

• the baking apparatus comprising
• a process container configured to accommodate the holder member and to form a heat process atmosphere therein,
• a heater configured to heat an interior of the process container,
• an exhaust system configured to exhaust gas from inside the process container, and
• a baking gas supply system configured to supply into the process container a baking gas for performing a baking process to remove the metal impurity,
• the method being preset to take place in the process container with no product substrates placed therein before performing a main heat process to form the semiconductor devices on the product substrates by use of the holder member, and comprising:
• holding a plurality of dummy substrates including a silicon surface for the metal impurity to be deposited thereon on the holder member and placing the holder member with the dummy substrates held thereon inside the process container;
• then, supplying hydrogen chloride gas and water vapor as the baking gas into the process container, while setting a ratio of the hydrogen chloride gas relative to a sum total of the hydrogen chloride gas and the water vapor at 0.5 to 30 vol %, and heating the quartz portion of the holder member at a process temperature of 550° C. to 1,050° C., thereby applying a baking process onto the quartz portion to discharge the metal impurity from the quartz portion and deposit the metal impurity onto the dummy substrates;
• and
• then, unloading the holder member along with the dummy substrates with the metal impurity deposited thereon from the process container, without performing the main heat process on the dummy substrates,
• wherein the method further comprises
• measuring a concentration of aluminum deposited on an unloaded dummy substrate, and repeatedly applying the baking process onto the quartz portion of the holding member while replacing the dummy substrates with new ones every time after said measuring a concentration until the concentration becomes lower than a predetermined value before performing the main heat process on the product substrates by use of the holder member, and
• stopping supply of the hydrogen chloride gas and the water vapor and purging the interior of the process container with oxygen gas every time after the baking process, and then purging the interior of the process container with nitrogen gas and cooling the process container to an unload temperature to perform said unloading.