JPH10308438A - Method of detecting carrier and wafer in carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a wafer detector from being an obstacle to carrier carriage by reducing the setting space of the wafer detector, and to surely detect the presence or absence of a wafer with high precision without being affected by the result of the optical precision of a carrier. SOLUTION: A carrier 10 is provided with a carrier main body 11 for housing plural wafers W with constant intervals and a cover 12 attached to the wafer fetching port of the carrier main body 11 so as to be attachable and detachable. Also, a protrusion for interposing each wafer W is provided on the inside face of the cover 12 corresponding to each wafer W, and each protrusion is provided with an optical path converting means 32, that is, half mirrors 12B and 12C for converting a parallel light beam L1 with the wafer W introduced in the carrier mail body 11 into a direction crossing each wafer W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier for transporting a semiconductor wafer used in a semiconductor manufacturing process and a method for detecting a wafer in the carrier.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, a carrier is used when a semiconductor wafer (hereinafter simply referred to as "wafer") is transferred between semiconductor manufacturing apparatuses and inspection apparatuses. For example, 25 or 13 wafers can be stored in the carrier. For example, wafers are stored in the carrier in lot units, and various processes are performed on the wafers for inspection. In addition, each semiconductor manufacturing apparatus receives a wafer in a carrier unit, takes out the wafer from the carrier in a state where the carrier is shut off from the outside, and performs a predetermined process, so it is directly determined whether or not all the wafers in the carrier have been taken out. Confirmation is required, but cannot be confirmed directly from outside.

For this reason, semiconductor manufacturing apparatuses are conventionally provided with a wafer detector that optically detects a wafer using, for example, a light emitting element and a light receiving element. One type of such a wafer detector has, for example, a light-emitting element and a light-receiving element that are arranged vertically or horizontally facing each other, and a carrier is installed between the two elements to detect a wafer in the carrier. (Hereinafter, referred to as a "confronting wafer detector"). In the case of the confronting type, a light beam such as an infrared ray is irradiated from the light emitting element to the light receiving element facing the light emitting element, and the presence or absence of the wafer in the carrier is detected by detecting the irradiation light beam in the light receiving element. Other models include, for example, a light-emitting element and a light-receiving element arranged on the same side, and a reflecting mirror arranged at a position facing both of them (hereinafter, "reflective wafer detector"). ). In the case of the reflection type, a light beam is emitted from the light emitting element toward the reflecting mirror, and the presence or absence of the wafer in the carrier is detected by detecting whether or not the light receiving element detects the reflected light from the reflecting mirror.

At present, 6 inches or 8 inches of wafers are the mainstream, but there is a tendency to shift to 12 inches (300 mm) wafers at a stretch. Along with this, a semiconductor manufacturing apparatus corresponding to a 12-inch wafer is being developed. In this case, not only does the wafer increase in diameter and weight but also the line width of the integrated circuit formed on the wafer becomes an ultra-fine structure of sub-quarter microns or less. It is becoming more and more important for the semiconductor technology and the inspection technology to reduce the space of the semiconductor technology and the automatic wafer transport technology. As described above, as the diameter of a wafer becomes larger, automation of semiconductor manufacturing is further promoted, and the situation in which an operator intervenes is reduced, the importance of a wafer detector is increased more than before.

[0005] The conventional carrier itself cannot be applied as it is. For example, up to an 8-inch wafer, it is common practice to transport the carrier with the wafer upright when transporting the wafer between each process, and to level the wafer when loading and unloading the semiconductor manufacturing equipment in each process. there were. However, in the case of a 12-inch (300 mm) wafer, if the wafer is transported while standing, the lower end of the wafer may be damaged due to its own weight or vibration during transport, so the carrier is transported while the wafer is horizontal. However, when carrying in and out of the semiconductor manufacturing apparatus in each process, it is performed in a horizontal state as it is. At present, as a carrier for a 12-inch wafer, for example, an open type carrier and a closed type pod (e.g., a closed type pod in which the carrier is housed in a pod and covered) are roughly divided.
Unified Pod) is being considered.

Regardless of which carrier is used, if the size of the carrier increases with the wafer, a measure for the large carrier is required in a semiconductor manufacturing apparatus and an inspection apparatus. In particular, it is important whether all wafers are processed without missing any wafers in the carrier, and it is necessary to more reliably detect wafers in the carrier than ever before.

[0007]

However, in the conventional wafer detecting method using a confronting wafer detector, the light emitting element and the light receiving element face each other at the top and bottom or at the right and left of the carrier transport path or the installation location. In such a case, the wafer detector may hinder the transfer of the carrier. Further, the carrier is not formed with high gloss glossiness, and the optical axis may be distorted, and there is no guarantee that the irradiation light can be accurately received. Furthermore, since the light-emitting element and the light-receiving element are arranged to face each other, a unique space must be allocated to each of the light-emitting element and the light-receiving element, and in consideration of future space saving, a space specific to each element must be allocated. Is not preferred. On the other hand, in the case of a conventional wafer detection method using a reflection-type wafer detector, it is impossible to distinguish between reflected light from a reflecting mirror and reflected light from a wafer, and the presence or absence of a wafer is erroneously detected. There is a fear.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and does not hinder the carrier conveyance by reducing the installation space for the wafer detector, and is influenced by the optical precision of the carrier. It is an object of the present invention to provide a carrier capable of reliably detecting the presence or absence of a wafer without high accuracy and a method for detecting a wafer in the carrier.

[0009]

According to a first aspect of the present invention, there is provided a carrier body for accommodating a plurality of wafers at regular intervals, and a detachably mounted wafer outlet of the carrier body. In a carrier having a lid, a projection that sandwiches each of the wafers is provided on the carrier body or the lid in correspondence with each of the wafers, and a parallel light beam with the wafer that is introduced into the carrier body is irradiated with each of the wafers. An optical path changing means for converting light in a direction crossing the wafer is provided on each of the protrusions.

According to a second aspect of the present invention, there is provided the carrier according to the first aspect, wherein the optical path changing means is formed by a pair of tapered surfaces formed in directions intersecting each other at the tips of the projections. And a half mirror formed on each tapered surface.

According to a third aspect of the present invention, in the carrier according to the first or second aspect, the light emitting element for irradiating a light beam toward the optical path changing means is provided on the carrier body or the lid. And a light receiving element for receiving the reflected light beam whose optical path has been converted by the optical path changing means on both sides of the optical path changing means is provided on the carrier body or the lid.

According to a fourth aspect of the present invention, there is provided a method for detecting a wafer in a carrier, wherein the carrier body accommodating a plurality of wafers at predetermined intervals, and the wafer is detachably attached to a wafer outlet of the carrier body. Detecting a wafer in a carrier having a cover provided thereon, and sequentially irradiating a parallel light beam with the wafer to an optical path changing means provided at a tip end of a protrusion sandwiching each wafer on the carrier body or the cover. The irradiation light beam is converted by the optical path changing means in a direction crossing the wafer, and the presence or absence of the converted light beam is detected to detect the presence or absence of the wafer.

According to a fifth aspect of the present invention, there is provided a method for detecting a wafer in a carrier according to the fourth aspect of the present invention, wherein a pair of tapered surfaces formed in directions intersecting with each other at the tips of the projections are provided. The parallel light beam is applied to the optical path changing means comprising a half mirror formed on each tapered surface.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. Carrier 1 of the present embodiment
0 is, for example, 12 inches (3
13 mm or 25 mm)
It is configured as a closed pod formed of a synthetic resin such as polycarbonate and PEEK (polyetheretherketone). The carrier 10 is, for example, as shown in FIG. 1, formed of a transparent material made of the above-described material and accommodating thirteen wafers W at regular intervals, and a carrier outlet 11 of the carrier body 11. And an optically transparent lid 12 detachably mounted. A gripper 13 is attached to the upper wall 11A of the carrier body 11, and the gripper 13 is gripped by a carrier transporting device (not shown) arranged on the ceiling to transfer the carrier 10 between the respective semiconductor manufacturing apparatuses. It is automatically transported. Further, the carrier 10 is filled with, for example, nitrogen gas to prevent natural oxidation of the wafer as much as possible and to make the inside clean.

The carrier 10 is installed in, for example, a semiconductor manufacturing apparatus 20 shown in FIGS. 2 and 3, and performs a predetermined process on a wafer W in the carrier 10.
The carrier-related portion of the semiconductor manufacturing apparatus 20 is, for example, as shown in FIG.
It is configured as shown in FIG. 2 is a perspective view from the outside of the semiconductor manufacturing apparatus 20, and FIG. 3 is a perspective view of the state of FIG.
That is, as shown in each figure, an opening 22 into which the lid 12 of the carrier 10 is fitted is formed in the front panel 21 of the semiconductor manufacturing apparatus 20, and the carrier mounting portion corresponding to the opening 22 is formed in the front panel 21. A part 23 is provided. The carrier mounting portion 23 is configured to be able to move back and forth (in the direction of the arrow in each drawing) on the base 24 via a drive mechanism (not shown). A positioning member (not shown) is provided on the upper surface of the carrier mounting portion 23, and the carrier 10 can be automatically positioned at a predetermined position via the positioning member. Accordingly, when the carrier 10 is placed on the carrier placing portion 23 while being positioned by the positioning member and is advanced to the opening 22, the lid 12 of the carrier 10 is fitted into the opening 22 and the state shown in FIG. Become.

As shown in FIG. 3, for example, the semiconductor manufacturing apparatus 20 includes an opener 25 for opening and closing the lid 12 of the carrier 10 fitted to the opening 22 of the front panel 21.
And all the wafers W in the carrier main body 11 via a wafer transfer mechanism disposed in a relay chamber (not shown) for the wafers W.
Are collectively transferred into the relay room. Then, for example, the wafer detector 3 shown in FIG.
0, and the wafer detector 30 detects the wafer W in the carrier main body 11.

The wafer detector 30 is orthogonal to the lid 12 of the carrier 10 and
A plurality of light emitting elements 31 for irradiating light rays parallel to the light from the outer surface of the lid 11, and a plurality of light receiving elements 33 for receiving light rays radiated by these light emitting elements 31 through optical path conversion means 32 formed on the lid 12 And these two optical elements 31, 3
And a sensor controller 34 for controlling the sequence of the wafers 3 in order to detect the wafers W in the carrier body 11 one by one. Further, as shown in FIG. 1, the sensor controller 34 is a controller 2 of the semiconductor manufacturing apparatus 20.
7 is controlled. The light emitting element 31 and the light receiving element 33 are connected to the sensor array 35.
And are vertically arranged in tandem with the 13 wafers W in the carrier body 11. The sensor array 35 is arranged such that the light beam L1 emitted from one light emitting element 31 is vertically
The light is received by the light receiving elements 33.

The optical path changing means 32 is formed on the inner surface of the lid 12. That is, as shown in FIG. 1, each wafer W stored in the carrier main body 11 is placed on the inner surface of the lid 12.
Are formed so as to protrude horizontally corresponding to each wafer W, and the cross-sectional shape of each protrusion 14 is formed in a comb shape. For example, a pair of upper and lower tapered surfaces 14A, 1A, 1
4B are formed, and each of the tapered surfaces 14A and 14B is formed as a half mirror serving as the optical path changing means 32. Therefore, the tapered surface is hereinafter referred to as a half mirror.

Therefore, the light emitting element 31 outside the lid 12
The light beam L1 horizontally incident on the projection 14 from FIG.
As shown in the figure, half mirrors 14A above and below the projection 14,
The optical path is changed by 90 degrees by 14B, and the light travels in a direction crossing the wafer W (up and down directions). Part of the reflected light L2 from the upper half mirror 14A is
After transmitting through the lower half mirror 14B of the same protrusion 14 and transmitting through the upper half mirror 14A of the lower protrusion 14, the light path is changed by 90 ° by the lower half mirror 14B of the same protrusion 14, and the light passes through the lid 12 to emit light. Light receiving element 3 below element 31
3 is received. Similarly, the reflected light L3 from the lower half mirror 14B is transmitted through the lid 12 through the half mirrors 14B and 14A of the projection 14 on the upper side and received by the light receiving element 33 on the upper side.

Next, an embodiment of a wafer detecting method using the carrier 10 of the present embodiment will be described. For example, the carrier 10 is transported while holding the gripped portion 13 by the carrier transport device, and the carrier mounting portion 2 of the semiconductor manufacturing apparatus 20 is transported.
When mounted on the carrier 3, the carrier mounting portion 23 advances toward the front panel 21, and the lid 12 of the carrier 10 fits into the opening 22 of the front panel 21. Thereafter, the opener 25 (not shown) of the semiconductor manufacturing apparatus 30 is driven to drive the lid 1
2 is removed from the carrier body 11 to open the wafer outlet. Next, the wafer transfer mechanism in the relay chamber (not shown) is driven to collectively transfer all the wafers W in the carrier 10 from the carrier 10 to the relay chamber. Thereafter, the wafer detector 30 operates to detect whether or not the wafer W remains in the carrier 10. Before the transfer of the wafer W into the transfer room, the carrier main body 1 using the wafer detector 30 is used.
By detecting all the wafers W in the carrier 1, the carrier 10
It is also possible to create a wafer mapping by detecting the wafer W in each slot in the.

That is, after the wafer W in the carrier body 11 is transferred to the relay room via the wafer transfer mechanism,
5 is driven to attach the lid 12 to the carrier body 11 and close the wafer outlet. Thereafter, when a light beam L1 parallel to the wafer W is emitted from the uppermost light emitting element 31 of the sensor tray 35, the light beam L1 is transmitted through the optically transparent lid 12 of the carrier body 11 and received as shown in FIG. The light enters the half mirrors 14A and 14B above and below the projection 14 corresponding to the element 31. The incident light L1 is the half mirror 1 above and below the projection 14.
The optical path is reflected by 4A and 14B, respectively, and the optical path is 90 °.
It is converted and proceeds in a direction crossing the wafer W.

A part of the light L2 reflected by the upper half mirror 14A passes through the lower half mirror 14B, enters the projection 14 from the lower half mirror 14A next to the lower half mirror 14B, and further converts the optical path by 90 ° by the lower half mirror 14B. Then, the light beam L1 returns to the incident direction, and is received by the light receiving element 33 below the light emitting element 31 that has irradiated the light. On the other hand, the light L3 reflected by the lower half mirror 14B is transmitted through the upper half mirror 14A, enters the projection 14 from the lower half mirror 14B adjacent to the upper half mirror 14A, and further, the optical path is changed by 90 ° by the upper half mirror 14A, and the light L1 Returns to the direction in which the light is incident, and is received by the light receiving element 33 adjacent to and above the uppermost light emitting element 31.

A series of these operations allows the carrier body 1
If the wafer W remains at one or both of the uppermost stage and the lower stage of the wafer 1, one or both of the reflected lights L2 and L3 are blocked by the wafer W, and the corresponding light receiving elements No reflected light is received by 33,
The remaining wafer W can be detected. Thereafter, by sequentially irradiating the light beam L1 from the remaining light emitting elements 31 under the control of the sensor controller 34, the presence or absence of another wafer W can be detected, and thus the presence or absence of the wafer W in the carrier body 11 can be detected. can do.

As described above, according to the present embodiment, the projections 14 sandwiching the wafer W are provided on the inner surface of the lid 12 of the carrier 10 in correspondence with each wafer W, and the wafer detector 30 is provided.
Optical path conversion means 32 (upper and lower half mirrors 14A, 14A) for converting a parallel ray L1 from the light emitting element 31 to the wafer W introduced into the carrier main body 11 in a direction crossing each wafer W.
Since 14B) is provided at the tip of each projection 14, the presence or absence of the wafer W in the carrier main body 11 is reliably detected by whether or not the light receiving elements 33 receive the reflected light L2, L3 from the upper and lower half mirrors 14A, 14B. Therefore, there is no possibility of erroneously detecting the presence or absence of the wafer W. Further, since the sensor array 35 can be mounted in the opener 25, there is no need to devote a dedicated space to the wafer detector 30, and there is no hindrance to wafer transfer. Furthermore, since the distance of the irradiation light L1 from the light emitting element 31 to the light receiving element 33 is short, the presence or absence of the wafer W can be reliably detected without being affected by the optical accuracy of the lid 12.

In the above embodiment, the case where the sensor array 35 is provided on the opener 25 of the semiconductor manufacturing apparatus 20 has been described. However, the sensor array 35 may be provided on the carrier 10 side, for example, on the lid 12 or the carrier body 11. Lid 12
In the case where the carrier body 1 is provided, the projection 14 sandwiching the wafer W can be used as it is.
In the case where the projections are provided at 1, the projections need to be provided at positions corresponding to the positions of the sensor array 35. For example, when the sensor array is provided on the side wall of the carrier main body 11, each wafer support groove formed on the inner surface of the optically transparent side wall of the carrier main body can be used as a projection. When the sensor array is provided on the carrier 10 side, the sensor controller 34 is also provided on the carrier 10 and a circuit element for recognizing the lot number of the light receiving element 33 is provided. The presence or absence of a wafer can be detected. In this case, by providing communication means with the semiconductor manufacturing apparatus and the inspection apparatus, it is possible to notify the semiconductor manufacturing apparatus and the inspection apparatus of a wafer map or presence / absence in the carrier. Further, in the above embodiment, the light emitting element 31 and the light receiving element 33 are provided corresponding to each projection 14 of the lid 12, but the light emitting element and the light receiving element corresponding to the light emitting element are provided one by one on a wafer. The wafer W in each slot in the carrier 10 may be detected one by one by scanning in the W storage direction.

[0026]

According to the first to fifth aspects of the present invention, it is possible to reduce the installation space for the wafer detector so as not to hinder the carrier conveyance and to improve the optical accuracy of the carrier. It is possible to provide a carrier capable of reliably detecting the presence or absence of a wafer with high accuracy without being affected by the condition, and a method of detecting a wafer in the carrier.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a relationship between a carrier and a wafer detector according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state where the carrier shown in FIG. 1 is installed on a carrier mounting portion of a semiconductor manufacturing apparatus.

FIG. 3 is a perspective view showing a state where a lid is removed from a carrier main body using an opener of the semiconductor manufacturing apparatus shown in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Carrier 11 Carrier main body 12 Lid 14 Projection 14A, 14B Half mirror (optical path conversion means) 32 Optical path conversion means W Wafer

Claims (5)

[Claims] 1. A carrier having a carrier body for accommodating a plurality of wafers at predetermined intervals, and a lid detachably attached to a wafer outlet of the carrier body. Protrusions sandwiching the respective wafers are provided corresponding to the respective wafers, and each of the protrusions is provided with an optical path changing means for converting a parallel ray with the wafer introduced into the carrier main body in a direction crossing the respective wafers. A carrier characterized by that. 2. A pair of tapered surfaces formed in a direction intersecting each other at the tip of the projection,
The carrier according to claim 1, comprising a half mirror formed on each tapered surface. 3. A light-emitting element for irradiating a light beam toward the optical path changing means is provided on the carrier body or the lid, and a light receiving element for receiving a reflected light beam whose path has been changed by the optical path changing means on both sides of the optical path changing means. The carrier according to claim 1, wherein an element is provided on the carrier body or the lid. 4. A method for detecting a wafer in a carrier having a carrier body for accommodating a plurality of wafers at regular intervals, and a lid detachably attached to a wafer outlet of the carrier body. A parallel light beam with the wafer is sequentially radiated to the optical path conversion means provided at the tip of the projection that sandwiches each wafer on the carrier body or the lid, and the irradiated light beam is traversed by the light path conversion means in a direction traversing the wafer. A method for detecting a wafer in a carrier, wherein the presence or absence of the wafer is detected based on whether or not the converted light beam is detected. 5. Irradiating said parallel light beam to said optical path changing means comprising a pair of tapered surfaces formed in a direction intersecting each other at the tip of said projection and a half mirror formed on each of said tapered surfaces. 5. The method for detecting a wafer in a carrier according to claim 4, wherein: