JPH0316287Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an apparatus for counting the number of wafers mounted on a carrier in a semiconductor manufacturing process.

Prior Art In the semiconductor manufacturing process, wafers are subjected to various treatments in a clean room, but during processes such as etching and water washing, wafers are placed in a carrier C as shown in Figure 3. They are lined up inside, loaded and processed. In such a carrier C, grooves 9 are formed at predetermined intervals, and each groove 9 has one wafer W, which normally holds about 25 wafers (Fig. 3 shows a carrier for 8 wafers). ) are lined up at predetermined intervals for processing, but the wafers themselves are extremely thin (cleaning, approx.
(250 to 400 μm), the wafer may break during liquid processing or centrifugal drying. In such a case, it is necessary to check the number of wafers because broken debris may adhere to other wafers or the balance will be lost if centrifugal drying is continued.

Problems that the invention aims to solve Conventionally, this work of counting the number of wafers was done by humans, but since it is not desirable for humans to enter the clean room, the number of wafers in the carrier is automatically counted. There was a demand for the development of a device. As such an automatic counting device, it is possible to use a mechanical detection device that detects by bringing a contact lever into contact, or an optical detection device that detects by using an optical sensor.

However, when using a mechanical detection device, the contact lever must come into contact with the wafer, which poses a problem of contaminating or scratching the wafer. Further, in the case of using an optical detection device, there is a problem that the optical sensor malfunctions due to clouding of the optical sensor due to vapor of the processing liquid or the like.

The present invention was devised in view of the current situation, and its purpose is to clean the wafer during the carrier without contaminating or damaging the wafer, and without being affected by processing liquid vapor. An object of the present invention is to provide an apparatus capable of counting the number of wafers.

Means for Solving the Problem The above object is a device for counting the number of wafers aligned and loaded in a carrier, which includes a nozzle that can scan in the direction in which the wafers are aligned while ejecting gas at a predetermined pressure. , a device for counting the number of wafers in a carrier, comprising a detection unit for detecting gas pressure in the nozzle, and counting the number of wafers in the carrier based on a change in the detected gas pressure. It is achieved by doing so.

Function: In the device for counting the number of wafers in a carrier according to the present invention, when the nozzle is scanned over the wafers in the wafer alignment direction while ejecting gas at a predetermined pressure, the gas pressure inside the nozzle increases Since the gas pressure value is low where there is no wafer and high where there is a wafer, the gas pressure value comes to exhibit a pulse train in which each pulse corresponds to each wafer as a result of the above scanning. Therefore, by counting the number of pulses, the number of wafers in the carrier can be counted.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a perspective view of an embodiment of the wafer number counting device according to the present invention. The device of this embodiment is
This is used in the process of treating a wafer with an etching solution and then washing the wafer with water. In the figure, 1 is a processing tank, 2 is a washing tank, and 3 is a transport device. The transport device 3 holds the carrier C at the lower ends of four hanging fittings 32 provided on the lifting arm 31, and the drive device 3 is provided in the hollow part 42 of the wall 4.
3, a comb-shaped slot 41 is formed in the wall 4.
The carrier C is moved vertically and horizontally along the wafer C, and the carrier C is placed in the processing tank 1 for a predetermined period of time to perform the etching process on the wafer W.
are sequentially put into the washing tanks 2 and 2 to wash the wafers W with water. A series of operations of these transport devices 3 are controlled by a control device 5.

A gas ejection nozzle 61 and a gas pressure detection unit 62 of the counting device 6 of this embodiment are attached to the conveyance device 3, and are, for example, a gas supply source G that supplies gas such as dry N ₂ gas at a predetermined pressure Po. When the side valve 63 is opened, gas is sent to the gas ejection nozzle 61 via the gas pressure detection section 62. The nozzle 61 is moved in the alignment direction of the wafers W by an air cylinder 64 attached to the transfer device 3 so that its tip passes over the wafers W while keeping a constant distance from the wafers W aligned in the carrier C. be moved to.

In this embodiment, the gas pressure detection section 62 is
As shown in FIG. 1a, it has a first gas pressure detection device A and a second gas pressure detection device B,
Both detection devices A and B include thin films A1 and B1 whose deflection amount changes in proportion to the gas pressure inside the nozzle 61;
Microswitches A2 and B2 are provided, respectively, which are turned on when the amount of deflection of the thin films A1 and B1 exceeds a certain set value, and turned off when the amount of deflection is less than that. Here, the relationship between the working gas pressure value PA of the micro switch A2 of the first gas pressure detecting device A and the working gas pressure value PB of the micro switch B2 of the second gas pressure detecting device B is PA>PB. It is set to be.

As shown in Figure 1a, micro switch A
2, one electrode of B2 is connected to a DC constant voltage source (not shown), and the other electrode is connected to an AND circuit 65.
It is connected to the counter 67 via. Also,
The other electrode of micro switch A2 is connected to counter 6.
6 is also connected.

For example, when the processing step is completed and the conveyance device 3 is activated and the carrier C is raised, the air cylinder 6
4 is activated, and the nozzles 61 ejecting gas are scanned at a constant interval over the wafers W aligned and mounted in the carrier C in the direction of the arrow in the figure. In this case, the third wafer in carrier C is damaged and has completely fallen from carrier C, and the fifth wafer, W5, is damaged and only a portion of length b is missing. Assume that it is missing.

Here, when the opening end of the nozzle 61 is directed toward the part where the wafer W is not present, as described above, there is no obstacle to the ejected gas, so the nozzle 6
The gas pressure in 1 is approximately the same as the supply pressure Po, but
During scanning, when the opening end of the nozzle 61 is pointing toward a healthy wafer, for example, wafer W1, the wafer becomes an obstacle to the gas ejection, so the gas pressure inside the nozzle 61 increases to Pa. do.
On the other hand, the nozzle opening end is partially missing.
When the direction is directed to the th wafer W5,
The wafer also becomes an obstacle to gas ejection, so the gas pressure inside the nozzle 61 increases, but the degree of the obstacle is smaller than that of a healthy wafer, so the gas pressure inside the nozzle at this time is Pb (Pb<Pa). Become. The relationship between the gas pressure within the nozzle and the scanning distance of the nozzle 61 is illustrated as a pulse train as shown in FIG. 1b.

The working gas pressure value PA of micro switch A2 is
Set the working gas pressure value PB of micro switch B2 to a value slightly lower than the gas pressure Pa.
If you set it to a value slightly lower than Pb, nozzle 6
When wafer 1 is on top of the first and second wafers W1 and W2, the gas pressure inside the nozzle is Pa, so
Micro switch A2 is turned on and counter 66
A signal is sent to the counter 66, and the counter 66 is counted up. Even when the nozzle 61 is directed to the position where the third wafer was placed, the gas pressure inside the nozzle 61 does not increase as described above, so both microswitches A2 and B2 remain OFF, and both counters 66, 67 does not work. The counter 66 is counted up by the fourth wafer W4. Partially missing 5th wafer W5
At the position, as mentioned above, the gas pressure inside the nozzle only rises to Pb, so only micro switch B2 is turned on, and micro switch A2 is turned on.
It remains OFF. Therefore, only the counter 67 is counted up. For the sixth wafer W6, the counter 66 is incremented. Thereafter, similarly, the nozzle 61 is connected to the carrier C.
When the entire area is scanned, the count value of the counter 66 is the number of healthy wafers, and the count value of the counter 67 is the number of wafers that are damaged and missing.

If the number of healthy wafers counted is less than the number of wafers loaded on the carrier, it means that there is a damaged wafer, so this is to prevent other wafers from being damaged by the damaged debris. , appropriate measures will be taken, such as stopping the operation of the cleaning equipment. Furthermore, since the counting device of this embodiment can also count the number of damaged wafers, more appropriate measures can be taken.

Incidentally, as shown in FIG. 5, the wafer usually has an orientation flat (hereinafter referred to as "OF") 7 formed on one side for positioning. If such wafers W are loaded randomly on the carrier C, OF7 will be placed in the nozzle 61.
If you continue counting as described above, there is a risk that OF7 will incorrectly count wafers that are facing the nozzle as damaged wafers. There is. To prevent this,
For example, when loading wafer W onto carrier C,
As shown in FIG. 6a, when the roller 8 disposed at the bottom of the carrier C is rotated while contacting the end surface of the wafer W, the roller 8 stops contacting the wafer W at the position OF7 and the wafer W stops rotating. (see FIG. 6b), it is possible to prevent the wafer W from being loaded onto the carrier with the OF7 still at the top.

Effects of the invention As is clear from the above explanation, the device of the invention does not come into mechanical contact with the wafers when counting the number of wafers loaded on the carrier, so it does not damage or damage the wafers. Since there is no damage and no optical means is used, accurate counting can be performed without being affected by vapor of processing liquid or the like.

[Brief explanation of drawings]

Figures 1a and b are explanatory diagrams of an embodiment of the present invention, Figure 2 is an explanatory diagram of an example of the use of this embodiment, Figure 3 is a perspective view of an example of a carrier, and Figure 4 is a wafer attached to this carrier. FIG. 5 is a plan view of the wafer, and FIGS. 6a and 6b are illustrations of how to orient the wafer. A...First gas pressure detection device, B...Second gas pressure detection device, C...Carrier, G...Gas supply source, W, W1 to W8...Wafer, 6...Gas pressure detection unit , 61... Nozzle.

Claims (1)

[Scope of utility model registration request] A device that counts the number of wafers aligned and loaded in a carrier, including a nozzle that scans in the wafer alignment direction while ejecting gas at a predetermined pressure, and a detection unit that detects the gas pressure in the nozzle. 1. A device for counting the number of wafers in a carrier, comprising: a device for counting the number of wafers in the carrier based on a detected change in gas pressure.