Optical sensor circuit combining functions of open and close type optical sensor circuits

An optical sensor circuit comprises an optical sensor adapted to sense a position of a component in a semiconductor manufacturing apparatus according to the presence or absence of a flag and output a signal indicative of the position. A position sensing driver receives the signal via a path selected by a plurality of switches and then drives an output signal in response to the signal. The path selected by the plurality of switches causes the optical sensor circuit to act as either a close-type optical sensor circuit or an open-type optical sensor circuit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an optical sensor circuit for a semiconductor manufacturing device. More particularly, the invention relates to an optical sensor circuit that combines the functions of both “open-type” and “close-type” optical sensor circuits into a single optical sensor circuit.

A claim of priority is made to Korean Patent Application No. 10-2004-0110967 filed Dec. 23, 2004, the disclosure of which is hereby incorporated by reference in its entirety.

2. Discussion of Related Art

Optical sensors are commonly used to detect the positions and/or orientations of various components within a piece of semiconductor manufacturing equipment. For instance, optical sensors may be used to detect whether a printed circuit board is properly positioned or whether parts of the equipment such as doors, valves, and so forth, are properly positioned (e.g., open, closed, tilted, rotated, etc.). The optical sensors are generally coupled to or associated with actuators such as pivot motors, door motors, and air springs, which are used to adjust the positions and/or orientations of the various components.

An ion-implantation apparatus is one type of equipment that uses optical sensors. In an ion implantation apparatus, components such as isolation valves, faradays, and load lock chambers, are monitored by optical sensors. For example, the optical sensors may detect whether the load lock chambers or the or the isolation valves are properly opened or closed. In addition, the optical sensors may be used to determine whether an ion source or a substrate is in a proper position for ion-implantation to take place.

In a “close-type” optical sensor circuit, when an obstruction, or “flag”, prevents a light emitting diode (LED) from transmitting light to a light receiving transistor, the optical sensor circuit outputs a signal with a logic state “low” (i.e., a “low signal”). In contrast, in an “open-type” optical sensor circuit, when a flag prevents the LED from transmitting light to the light receiving transistor, the optical sensor circuit outputs a signal with a logic state “high” (i.e., a “high signal”).

FIG. 1is a circuit diagram of a conventional “close-type” optical sensor circuit andFIG. 2is a circuit diagram of a conventional “open-type” optical sensor circuit.

Referring toFIG. 1, the conventional close-type optical sensor circuit comprises an optical sensor10, a position sensing driver12, and a LED “LED1”. The close-type optical sensor circuit further comprises a first resistor R1and a second resistor R2connected to optical sensor10.

Optical sensor10comprises a LED D1and a light receiving transistor TR1that is turned on in response to light emitted from LED D1. A flag “FLAG” is inserted or input between LED D1and light receiving transistor TR1to prevent the light emitted from LED D1from turning on light receiving transistor TR1.

Position sensing driver12comprises a transistor12having a base connected to an emitter of light receiving transistor TR1, a collector connected to an output of LED “LED1”, and an emitter connected to an output of the close-type optical sensor circuit.

The operation of the close-type optical sensor circuit is as follows. Where flag “FLAG” is not interposed between LED D1and light receiving transistor T1, the emitter of light receiving transistor T1assumes logic state “high”, causing transistor Q1to turn on. Accordingly, current flows through LED “LED1”, causing it to turn on, and as a result, the emitter of transistor Q1assumes logic state “high”. In contrast, where flag “FLAG” is interposed between LED D1and light receiving transistor T1, the emitter of light receiving transistor T1assumes logic state “low”, causing transistor Q1to turn off. Accordingly, no current flows through LED “LED1”, and as a result, the emitter of transistor Q1assumes logic state “low”.

The operation of the close-type optical sensor circuit is illustrated by Table 1 below.

Referring now toFIG. 2, the open-type optical sensor circuit comprises an optical sensor20, a position sensing driver22, a LED “LED2”, and first and second resistors R1and R12. Optical sensor20comprises a LED “D2” and a light receiving transistor TR2that is turned on in response to light emitted by LED D2. A flag “FLAG” is inserted or input between LED D2and light receiving transistor TR2to prevent the light emitted from LED D2from turning on light receiving transistor TR2. Position sensing driver22comprises a transistor Q2having a base connected to a collector of light receiving transistor TR2, a collector connected to an output of LED “LED2”, and an emitter connected to an output of the open-type optical sensor.

The operation of the open-type optical sensor circuit is as follows. Where flag “FLAG” is not interposed between LED D2and light receiving transistor T2, the collector of light receiving transistor T2assumes logic state “low”, causing transistor Q2to turn off. Accordingly, no current flows through LED “LED2”, and as a result, the emitter of transistor Q2assumes logic state “low”. In contrast, where flag “FLAG” is interposed between LED D2and light receiving transistor T2, the collector of light receiving transistor T2assumes logic state “high”, causing transistor Q1to turn on. Accordingly, current flows through LED “LED2”, thus turning it on, and as a result, the emitter of transistor Q2assumes logic state “high”.

The operation of the close-type optical sensor circuit is illustrated by Table 2 below.

In the description above, the close-type optical sensor circuit outputs a high signal when no flag is input to optical sensor10, and the open-type optical sensor circuit outputs a low signal when no flag is input to optical sensor20. Conversely, where a flag is input to optical sensor10, the close-type optical sensor circuit outputs a low signal and where a flag is input to optical sensor20, the open-type optical sensor circuit outputs a high signal.

The output of the closed or open type optical sensor generally provides an indication of the state of some component in a semiconductor manufacturing device. For example, the output may represent whether a door in the device is open or closed. The optical sensor typically detects the state of the component by the presence or absence of the flag.

The optical sensor circuits described above are commonly employed in semiconductor manufacturing equipment. For example, in a semiconductor manufacturing apparatus comprising a processing chamber and a plurality of load lock chambers connected to the process chamber, optical sensor circuits may be used to determine whether the load-lock chambers are properly closed or whether an air bearing in the processing chamber is properly oriented.

Where a close-type or open-type optical sensor circuit is used in the load lock chambers of a semiconductor manufacturing apparatus, malfunctions in one optical sensor circuit can be addressed without interrupting semiconductor manufacturing processes in the processing chamber. This can be accomplished, for example, by removing the malfunctioning optical sensor circuit from its respective load lock chamber and using a different load lock chamber to perform process steps. However, where a close-type or open-type optical sensor circuit is used in the processing chamber, malfunctions in the optical sensor circuit cannot be addressed without interrupting semiconductor manufacturing processes performed therein.

SUMMARY OF THE INVENTION

According to one embodiment of the invention, an optical sensor circuit adapted for use in a semiconductor manufacturing apparatus is provided. The optical sensor circuit comprises an optical sensor adapted to sense a position of a component in the semiconductor manufacturing apparatus according to the presence or absence of a flag and output a signal indicative of the position, and a position sensing driver receiving the signal via a path selected by a plurality of switches and driving an output signal in response to the signal.

According to another embodiment of the invention, another optical sensor circuit adapted for use in a semiconductor manufacturing apparatus is provided. The optical sensor circuit comprises an optical sensor adapted to sense a position of a component in the semiconductor manufacturing apparatus according to the presence or absence of a flag, a pull-up resistor connected between a power supply and the optical sensor, and a pull-down resistor connected between the optical sensor and ground. The optical sensor circuit further comprises a first switch connected between the power supply and the optical sensor, a second switch connected between the optical sensor and ground, a position sensing driver comprising a transistor having a base, an emitter, and a collector, a third switch connected between the optical sensor and the base of the transistor, and a fourth switch connected between the base of the transistor and the optical sensor.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the invention are described below with reference to the corresponding drawings. These embodiments are presented as teaching examples. The actual scope of the invention is defined by the claims that follow.

FIG. 3is a diagram of an optical sensor circuit combining the functions of a close-type and open-type optical sensor circuit according to one embodiment of the present invention.

Referring toFIG. 3, the optical sensor circuit comprises an optical sensor30, a position sensing driver32, a LED “LED11”, first and second pull-up resistors R1and R2, a pull down resistor R3, and first through fourth switches SW1through SW4. The optical sensor circuit further comprises a connecter J1connecting the optical sensor circuit to a power supply Vcc (1), an output terminal (2), and ground (3).

Optical sensor30comprises a LED D11connected between first pull-up resistor R1and ground. Optical sensor30further comprises a light receiving transistor TR11having an emitter and a collector and turning on in response to light emitted by LED D11. A flag “FLAG” is inserted or input between LED D11and light receiving transistor TR11to prevent the light emitted from LED D11from turning on light receiving transistor TR11.

Position sensing driver32comprises a negative-positive-negative (NPN) bipolar transistor Q11connected between an output of LED LED11and the output terminal. Transistor Q11has a base connected to switch SW3, a collector connected to the output of LED LED11, and an emitter connected to the output terminal.

InFIG. 3, first pull-up resistor R1is connected between the power supply and LED D11, second pull-up resistor R2is connected between the power supply and the collector of light receiving transistor TR11, and pull-down resistor R3is connected between the emitter of light receiving transistor TR11and ground.

First switch SW1is connected between the power supply and the collector of light receiving transistor TR11, second switch SW2is connected between the emitter of light receiving transistor TR11and ground, third switch SW3is connected between the collector of light receiving transistor TR11and the base of transistor Q11, and fourth switch SW4is connected between the emitter of light receiving transistor TR11and the base of transistor Q11.

By selectively closing (or turning on) first through fourth switches SW1through SW4, the optical sensor circuit ofFIG. 3can perform the functions of the close-type optical sensor circuit ofFIG. 1or the functions of the open-type optical sensor circuit ofFIG. 2. As illustrated by the following table 3, the optical sensor circuit ofFIG. 3acts as an open-type optical sensor circuit when second and third switches SW2and SW3are on and first and fourth switches SW1and SW4are off. The optical sensor circuit ofFIG. 3acts as a close-type optical sensor circuit when first and fourth switches SW1and SW4are turned on and second and third switches SW2and SW3are turned off.

Where the optical sensor circuit ofFIG. 3functions as the close-type optical sensor circuit, the output terminal receives a high signal whenever flag “FLAG” is not interposed between LED D11and light receiving transistor TR11, and the output terminal receives a low signal whenever flag “FLAG” is interposed between LED D11and light receiving transistor TR11. On the other hand, where the optical sensor circuit ofFIG. 3functions as the open-type optical sensor circuit, the output terminal receives a low signal whenever flag “FLAG” is not interposed between LED D11and light receiving transistor TR11, and the output terminal receives a high signal whenever flag “FLAG” is interposed between LED D11and light receiving transistor TR11.

Where the optical sensor circuit acts as the closed-type optical sensor circuit and flag “FLAG” is not interposed between LED D11and light receiving transistor TR11, light receiving transistor TR11is turned on, and fourth switch SW4connects the emitter of light receiving transistor TR11to the base of transistor Q11to turn on transistor Q11. Current then flows through LED11and transistor Q11to output a high signal on the output terminal.

Where the optical sensor circuit acts as the closed-type optical sensor circuit and flag “FLAG” is interposed between LED D11and light receiving transistor TR11, light receiving transistor TR11is turned off, and fourth switch SW4connects the base of transistor Q11to ground through pull-down resistor R3. Therefore, no current flows through LED11and transistor Q11, and therefore a low signal is output to the output terminal.

Where the optical sensor circuit acts as the open-type optical sensor circuit and flag “FLAG” is not interposed between LED D11and light receiving transistor TR11, light receiving transistor TR11is turned on, and third switch SW3connects the base of transistor Q11to a low voltage to turn transistor Q11off. Accordingly, no current flows through LED11and therefore transistor Q11outputs a low signal on the output terminal.

Where the optical sensor circuit acts as the open-type optical sensor circuit and flag “FLAG” is interposed between LED D11and light receiving transistor TR11, light receiving transistor TR11is turned off, and third switch SW3connects the base of transistor Q11to the power supply through second pull-up resistor R2. Accordingly, transistor Q11is turned on and current flows through LED11. As a result, a high signal is sent to the output terminal.

Because the optical sensor circuit shown inFIG. 3is capable of acting as both a close-type optical sensor circuit and an open-type optical sensor circuit, semiconductor manufacturing processes do not necessarily have to be terminated when a part of the optical sensor circuit malfunctions. Accordingly, the productivity of semiconductor manufacturing processes are greatly enhanced in the face of optical sensor circuit malfunctions.

Although the optical sensor circuit shown inFIG. 3contains bi-polar NPN transistors, transistors with other polarities (i.e., PNP transistors) could also be used instead, and the polarities of signals could be modified accordingly to produce output signals in accordance with the desired functionality of the optical sensor circuit.

Various types of switches could be used to form the circuit shown inFIG. 3. For example, dual in-line package (DIP) switches, transistors, and the like could be used. In general, the switches are turned on and off by a control circuit (not shown) so that either switches SW1and SW4are on at the same time while switches SW2and SW3are off in order to perform like a close-type optical sensor circuit or switches SW2and SW3are on at the same time while switches SW1and SW4are off in order to perform like an open-type optical sensor circuit.

The foregoing preferred embodiments are teaching examples. Those of ordinary skill in the art will understand that various changes in form and details may be made to the exemplary embodiments without departing from the scope of the present invention which is defined by the following claims.