Tokyo Seimitsu Co., Ltd.

Takao Inaba

Minoru Numoto

Kenji Sakai

Manabu Satoh

Hisashi Terashita

Masaaki Oguri

A dresser of a wafer polishing apparatus according to this invention includes a grinding wheel head that is idly supported in such a manner as to be capable of moving up and down relative to a dresser main body , and an air bag interposed between the dresser main body and the grinding wheel head. The air pressure inside the air bag can be regulated so that the force pushing the grinding wheel head to the polishing cloth can be regulated. A washing tank for washing the grinding wheel head of the dresser is disposed adjacent to the platen , and a brush table having a brush implanted thereto is detachably provided to the bottom part of the washing tank

Wafer polishing apparatus

In a wafer polishing apparatus according to this invention, waiting units having upper-lower two-stage wafer placement tables each for temporarily keeping a wafer from a load/unload unit to a polishing head or vice versa are provided to a polishing unit , and the upper/lower stage wafer placement tables can move individually. A spindle-washing unit for washing polishing heads is disposed inside a lower space below the waiting units.

Polishing apparatus

A wafer polishing apparatus according to this invention has a polishing unit that includes three platens and two polishing heads. Injection ports are disposed between the platens. The two polishing heads can linearly move between the platens. In a two-step polishing process, while the polishing head holds a wafer after polishing by a platen, the wafer is transferred to a center platen which provides different polishing characteristics. In this instance, washing water from the injection ports washes away slurry, etc, adhering to the wafer. The wafer is then carried to the center platen beyond a waiting unit and is subjected to further polishing.

The present invention provides a wafer polishing apparatus capable of controlling the polishing quantity accurately. The wafer polishing apparatus comprises a rotatable polishing stool with a polishing cloth, a carrier for bringing a wafer into contact with the polishing cloth under a predetermined pressure, a pad arranged around the wafer in such a manner as to contact the polishing cloth under a predetermined pressure, a detector for detecting the change of the relative positions of the back of the wafer or the carrier and the pad, and a control unit for controlling the polishing operation in accordance with the polishing quantity computed from the detection signal of the detector, wherein an operating unit includes a sampling unit ( ) for sampling the detection signal of the detector with such a sampling period that the number of times sampled per rotation of the polishing stool is plural, a moving average calculating unit ( ) for calculating the moving average data by averaging the sampling data in the number equal to an integer multiple of the number of times sampled per rotation, and a polishing quantity computing unit ( ) for computing the polishing quantity from the moving average data.

Wafer grinder and method of detecting grinding amount

Sensors detect a stock removal of a wafer during polishing, and a CPU calculates the stock removal in accordance with information from the sensors. The CPU compares the actual stock removal detected by the sensors and a model stock removal stored in RAM, and determines timings for dressing and replacing said polishing pad in accordance with a difference between the actual stock removal and the model stock removal. The determination results are shown on a display.

A CMP machine of the invention includes first and second polishing bases and first and second wafer holding heads and a wafer loading unit a wafer unloading unit first and second head rotating mechanism rotating the first and second wafer holding heads so as to position then above the first and second polishing bases, wafer loading unit, or wafer unloading unit, a first transportation mechanism transporting an unpolished wafer to the wafer loading unit, and a second transportation mechanism, transporting a polished wafer from the wafer unloading unit. The first and second polishing bases are located mutually adjacently, the wafer loading unit and wafer unloading unit are located mutually adjacently, the first polishing base and wafer loading unit are located diagonally, the second polishing base and wafer unloading unit are located diagonally. Owing to this structure, transportation of a wafer to the wafer loading unit and transportation of a wafer from the wafer unloading unit are achieved by the different transportation mechanisms. This leads to a minimized adhesion of dust to an unpolished wafer.

Wafer polishing machine

According to the present invention, a floating mechanism of a load stage floats positioned wafers in concave parts, and then, the chucks hold the wafers by suction. Therefore, the chucks can easily hold the centered wafers.

Wafer machining apparatus

The polishing apparatus comprises a turn table, which polishes a semiconductor wafer, and a holding and pressing part, which holds and presses the semiconductor wafer against a polishing surface of the turn table. The holding and pressing part transmits a force from an air bag to the semiconductor wafer via a pressurized fluid layer to thereby press the semiconductor wafer against the polishing surface via the pressurized fluid layer, so that the semiconductor wafer can be polished. Thereby, it is possible to uniformly polish the semiconductor wafer.

A rubber sheet is arranged between a head body and a retainer ring of a wafer holding head. Two O-rings air-tightly close a space between the periphery of the rubber sheet, which is located above the retainer ring, and the head body. When a pump supplies the compressed air to the space, the periphery of the rubber sheet is elastically deformed to press the retainer ring under uniform pressure.

Wafer polishing apparatus with retainer ring

The first air guide groove is formed at the bottom of a carrier along the inner circumference of a circle whose radius corresponds to the maximum radius of a wafer. The air is supplied to the outer periphery of the wafer through the first air guide groove to form a pressure air layer between the carrier and the wafer. The formation of the pressure air layer makes the air pressure applied to the wafer uniform on the entire surface of the wafer, and thus, the wafer can be polished under a uniform pressure force. The second air guide groove is formed along the inner circumference of a circle whose radius corresponds to the minimum radius of the wafer, and therefore, the wafer with an orientation flat or notch can be polished under a uniform pressure force.

A polishing apparatus is provided with a turn table, on which an air passage is formed, and a polishing pad mount plate, on which a polishing pad is stuck. The polishing pad mount plate is detachably attached on the turn table. When the polishing pad mount plate is detached from the turn table, a separation fluid supplying part supplies air as separation fluid between the turn table and the polishing pad mount plate through the air passage.

The differential transformer is secured to the wafer holding table provided in the head, and the core of the differential transformer is secured to the rod member, which is provided to the head and freely projects and retracts from the face of the wafer. Then, the tip of the rod member is in contact with the polishing pad and keeps the core at a constant height from the polishing pad during polishing. When the head is displaced as polishing progresses with respect to the polishing pad, the differential transformer is displaced in connection with the displacement of the head. Therefore, the removed amount of the wafer can be determined by measuring the displacement amount of the differential transformer with respect to the core.

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Mitaka, Japan

Takao Inaba