JPS638133Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a semiconductor wafer movement detection device for detecting movement of a semiconductor wafer, for example, a semiconductor wafer being transferred from a cassette to a quartz board.
In particular, the present invention relates to a semiconductor wafer movement detection device that can also detect the passage of a semiconductor wafer in the opposite direction.

An example of detecting the movement of a wafer when transferring a conventional semiconductor wafer, for example, from the above-mentioned cassette to a quartz board, will be explained based on FIGS. 1 and 2. In FIG. Wafers, 2a and 2b, which are objects to be transferred
is a rail for rolling this wafer 1, 3
is a detector for detecting the passage of wafer 1; 4 is a detector for detecting the passage of wafer 1;
is the wafer that has completed the transfer.

FIG. 2 is a circuit diagram showing an example of a circuit for detecting confirmation of transfer when a wafer is transferred from position A to position B shown in FIG.

In FIG. 2, numeral 3 denotes a detector for detecting the passage of the wafer 1, which is the object to be transferred, shown in FIG. 1, and this corresponds to the detector 3 shown in FIG. 5 is an inverter that inputs the output of this detector 3 and inverts its polarity; 6 is this inverter 5;
7 is a two-input AND gate which receives the Q output of the D-type flip-flop 6 and the output of the inverter 5 and calculates the AND of both inputs.

Terminal D of the D-type flip-flop 6
is connected to a (+)5V power supply, and the terminal is configured so that a reset signal 8 is supplied from the outside.

Next, the operation of the circuit shown in FIG. 2 will be explained with reference to FIG. 3, which is a time chart showing waveforms at various parts.

First, when the detector 3 detects the passing of the wafer 1 shown in FIG. 1, the waveform of the output signal is as shown in FIG.
As shown in FIG. 3, the level changes from "L" (low level) to "H" (high level) when the wafer 1 passes, and then becomes "L" after passing. The inverter 5 which receives the output of the detector 3 as an input outputs a signal having a waveform that is an inversion of the waveform shown in a, as shown in FIG. 3b. When the inverter 5 changes the waveform from "L" to "H" as shown in FIG. 3b, the D-type flip-flop 6 receives a signal from the terminal Q whose waveform changes to "H" as shown in FIG. 3c. Output. AND gate 7 is the terminal Q of this D-type flip-flop 6.
The output from the inverter 5 is ANDed with the output from the inverter 5, and a matching signal having a waveform as shown in FIG. 3d is obtained at the output.

Conventionally, the "H" waveform of the AND gate 7 was used to confirm that the wafer 1 had been transferred normally.

However, in such a semiconductor wafer movement detection device, there is an inconvenience that if the output waveform of the detector 3 (see Fig. 3a) occurs even once due to the passage of the wafer, a normal signal is output. , wafer 1 is moved from position A to position B in FIG.
There was a drawback that it was impossible to detect a situation in which the camera moved to position A and then returned to position A.

In view of the above points, the present invention was devised to solve such problems and eliminate such drawbacks.The purpose of the present invention is to detect any abnormality in the movement of semiconductor wafers. An object of the present invention is to provide a semiconductor wafer movement detection device that can detect the movement of a semiconductor wafer.

In order to achieve this purpose, the present invention provides two detectors, a first and a second detector, in the passage of the semiconductor wafer, and detects when the semiconductor wafer passes in the forward direction and then in the reverse direction. It has been made possible.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 4 is a configuration diagram for explaining an embodiment of the semiconductor wafer movement detection device according to the present invention.

In FIG. 4, the same reference numerals as in FIG. 1 indicate corresponding parts, and 3 and 9 are first and second detectors for detecting passage of the wafer 1.

FIG. 5 is a block diagram showing an embodiment of a semiconductor wafer movement detection device according to the present invention, and only the parts necessary for explanation are shown.

In FIG. 5, the same reference numerals as in FIG. 4 indicate corresponding parts; 10 is a first inverter that receives the output of the first detector 3 and inverts its polarity; 11 is the first inverter 10; a first D-type flip-flop whose output is input to a terminal T;
12 is a second inverter which inputs the output of the second detector 9 and inverts its polarity; 13 is this second inverter;
A second D-type flip-flop 14 inputs the output of the inverter 12 at the terminal T.
This is a three-input AND gate which receives the Q output of the type flip-flop 13 and the outputs of the first and second inverters 10 and 12, and calculates the AND of these inputs.

This first D-type flip-flop 11
Terminal D is connected to the 5V power supply, and terminal Q is connected to the second
The terminal of the first D-type flip-flop 11 is connected to the terminal of the second D-type flip-flop 13. Further, the terminal of the second D-type flip-flop 13 receives an external reset signal 1.
5 is supplied.

Next, the operation of the embodiment shown in FIG. 5 will be explained with reference to FIG. 6. FIG. 6 is a time chart showing the waveforms of various parts when the wafer is transferred from position A to position B in FIG.

First, when the first detector 3 detects the passing of the wafer 1 shown in FIG. 4, the waveform of its output signal changes from "L" to "H" when the wafer 1 passes, as shown in FIG. 6a. After passing through, it becomes "L". The first inverter 10, which receives the output of the first detector 3 as an input, has a
Outputs a signal with a waveform that is an inversion of the waveform shown in . The first D-type flip-flop 11 changes from terminal Q to "H" as shown in FIG. 6c due to the change of the waveform of the first inverter 10 from "L" to "H" shown in FIG. 6b. Outputs a signal with a waveform that changes to . Then, from the AND gate 14, a signal having a waveform as shown in FIG. Output.

Further, when the second detector 9 shown in FIG. 5 detects the passing of the wafer 1 shown in FIG. 4, the waveform of the output signal becomes "L" as shown in FIG. 6 e. It becomes "H" from then on, and becomes "L" after passing through. The second inverter 12 which receives the output of the second detector 9 as an input outputs a signal having a waveform that is an inversion of the waveform shown in e, as shown in FIG. 6f. Then, a second D-type flip-flop 13
When the second inverter 12 changes from "L" to "H" in the waveform shown in FIG. 6(f), a signal whose waveform changes to "H" as shown in FIG. 6(g) is output from the terminal Q. At the same time, the first D-type flip-flop 11 is reset by a signal having a waveform as shown in FIG. 6h from the terminal. And this second
Based on the output of the D-type flip-flop 13, the AND gate 14 calculates the AND of the outputs of the first inverter 10, the second inverter 12, and the second D-type flip-flop 13, as shown in FIG. 6d. Outputs a signal with a waveform like this. Then, "H" as shown in FIG. 6d of this AND gate 14
The signal indicates that the wafer has been transferred normally.

Next, the operation when the wafer transfer is abnormal will be explained.

The reason why this wafer transfer becomes abnormal is considered to be as follows.

First, it does not move from position A to position B at all. Second, stuck between position A and position B. Third, move from position A to position B and back to position A.

The fact that there is no movement from the first position A to the position B can be detected by the output of the AND gate 14 becoming "L", and the fact that there is no movement from the first position A to the position B can be detected by the fact that the output of the AND gate 14 becomes "L". There is inverter 10
It can be detected that the output of the inverter 12 is "L".

Then, when moving from the third position A to position B and returning to position A, the timing is as shown in FIG. 7. In this FIG. 7, a, b, c...h are time charts showing the waveforms of each part in the embodiment of FIG. 5, respectively.

In this case, the second detector 9 shown in FIG.
Since the wafer detection signal of the second inverter 12 enters earlier in time than the wafer detection signal of the first detector 3 shown in FIG. 7a, the signal of the second inverter 12 shown in FIG. When changing to “H”, the second
Since the D terminal of the D-type flip-flop 13 is at "L", the output of the terminal Q does not change. Therefore, the output of the AND gate 14 becomes "L" as shown in FIG. 7d, and an abnormality in wafer transfer can be detected.

Furthermore, since the Q output of the first D-type flip-flop 11 remains at "H" as shown in FIG. 7c, it can be used as a signal indicating that the wafer has returned.

In this way, an abnormality in wafer transfer can be detected, and thereafter the second D-type flip-flop can be reset by the external reset signal 15.

As is clear from the above description, according to the present invention, the simple structure of providing two detectors, the first and second detectors, in the passage of the semiconductor wafer, without using complicated means, enables Since the passage of the semiconductor wafer in the opposite direction can also be detected, the practical effect is extremely large. Furthermore, it is extremely effective in that it is possible to reliably detect the transfer of semiconductor wafers.

[Brief explanation of the drawing]

Fig. 1 is a block diagram for explaining an example of a conventional semiconductor wafer movement detection device, Fig. 2 is a block diagram showing an example of a conventional semiconductor wafer movement detection device, and Fig. 3 is the operation of Fig. 2. A time chart showing waveforms of various parts for explanation, FIG. 4 is a configuration diagram for explaining an embodiment of the semiconductor wafer movement detection device according to the present invention, and FIG. 5 is an implementation of the semiconductor wafer movement detection device according to the present invention. A configuration diagram showing an example, and FIGS. 6 and 7 are time charts showing waveforms of various parts for explaining the operation of the embodiment shown in FIG. 1...Wafer, 3,9...Detector, 10,1
2... Inverter, 11, 13... D-type flip-flop, 14... AND gate.

Claims (1)

[Scope of utility model registration request] Two detectors, a first and a second detector, are provided in the passage of the semiconductor wafer, and the respective outputs of the first and second detectors are connected to the clock pulse terminals of the detectors via the first and second inverters, respectively. comprising first and second flip-flops as inputs, and an AND gate that receives the outputs of the first and second inverters and the Q output of the second flip-flop as inputs, and calculates the AND of these inputs; The Q output of the first flip-flop is connected to the D input of the second flip-flop, and the output of the second flip-flop is connected to the D input of the second flip-flop.
1. A semiconductor wafer movement detection device, characterized in that it is connected to an RD input to detect when the semiconductor wafer passes in a forward direction and then passes in a reverse direction.