JP2000164556A - Wafer drying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a wafer from being directly or indirectly damaged or cracked by a method wherein adjacent wafers are restrained from coming into contact with each other due to the deformation of a wafer carrier caused by a centrifugal force induced in rotation. SOLUTION: Adjacent wafers are restrained from coming into contact with each other due to the deformation of a wafer carrier caused by a centrifugal force induced in rotation. The wafer carrier holds the periphery of the wafer by a groove, the groove is restrained from applying stress on the periphery of the wafer due to the deformation of the wafer carrier caused by a centrifugal force induced by the rotation of the wafer carrier. The wafer carrier is formed of plastic material and holds the wafer by the periphery with its groove. When the wafer carrier is rotated to dry out a wafer taking advantage of a centrifugal force, the wafer carrier is enhanced in rigidity by an adapter so as to be less deformed by a centrifugal force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer drying apparatus for centrifugally drying a wafer, and more particularly to a wafer drying apparatus for reducing the crack of a wafer even when a wafer carrier is rotated at a high speed for centrifugal drying.

[0002]

2. Description of the Related Art In the electronic parts and other industries, there are extremely many steps of drying a work in a manufacturing process. Especially in the electronic component industry, so-called wafers are washed in multiple steps,
In addition, it is necessary to dry many wafers at a time because they are processed by chemicals. Here, the word wafer is not necessarily limited to a semiconductor wafer, but generally refers to a wafer made of a ceramic material, a wafer made of a glass material, a wafer made of a metal material, and a wafer made of a composite material thereof. In any case, these wafers are as small as 1 cm in diameter to as large as several meters in diameter. The shape is not uniform, and the shape is not limited to a circular shape, but also a variety of shapes such as a rectangular shape and an irregular shape. However, what can be said in common for these various types of wafers is that each wafer is a thin plate. Therefore, these wafers generally have a low mechanical strength and are often damaged during the drying process.

[0003] Among these wafer drying processes, there is a so-called centrifugal drying process in which liquid adhering to the wafer is shaken off by centrifugal force. The centrifugal drying process is a process that is extremely frequently used as a pre-process for drying at a high temperature or as a pre-process for the next liquid treatment, and is intended to remove the liquid on the wafer to an invisible degree. .
The basic principle of centrifugal drying is that the liquid on the wafer is shaken out of the wafer by centrifugal force, so that the rotational acceleration is applied to the liquid while the wafer is held and fixed by the wafer carrier. By moving to.

That is, in order to perform centrifugal drying, it is necessary to rotate the wafer while fixing it against centrifugal force. The fixing of the wafer is generally performed by a wafer carrier. As the name implies, the wafer carrier is for carrying wafers, but generally, treatment with a chemical solution, washing with water, centrifugal drying and the like are performed for each wafer carrier.

[0005] Therefore, the wafer carrier is required to be portable and to carry a large number of wafers at a time, and is made of a light material, and is packed with many wafers.

Therefore, in a state where a wafer is stored in a wafer carrier, the distance between the wafers is often at most about 1 mm (as the case may be). For example, in a process of manufacturing a semiconductor device, a wafer carrier as shown in 3 is used. The wafer carrier includes a pair of holding members 32 having a plurality of grooves 31, 31, 31,.
32 is configured such that the sides having grooves are opposed to each other, and the peripheral portions of the wafer 42 are held in the opposed grooves 41, 41 as shown in FIG.

[0007]

As described above, when a wafer is centrifugally dried, the wafer is housed in a wafer carrier, and the wafer carrier is rotated at high speed to shake off the liquid on the wafer. Wafer carriers are designed so that wafers are housed tightly but do not come into contact with each other, and there is no design that something hits the wafer or wafer carrier during rotation . Therefore, the wafer should not be damaged during centrifugal drying.

However, in reality, cracks occur in the wafer during centrifugal drying. Although this depends on the strength of the material, for example, in the case of a defect in the manufacturing process of a fragile material, such as gallium wafer, most of the failure is caused by wafer breakage during centrifugal drying.

Therefore, we conducted factor analysis to investigate the cause of wafer cracking during centrifugal drying. The primary factors are equipment failure, drying method, material failure, and operator inadequacy.Secondary factors related to equipment failure include excessive vibration of equipment and excessive centrifugal force due to too fast rotation. As a secondary factor relating to the method, excessive vibration and excessive centrifugal force, as a secondary factor relating to the material, damage to the wafer from the previous process, and as a secondary factor relating to the operator, a variation in the wafer set position, including chipping. A set of wafers was mentioned. Further, the tertiary factors and the like were also examined, and finally, the most suspicious factors were narrowed down to the bad shape of the wafer carrier or the bad wafer setting method.

[0010] Based on the above circumstances, it was determined that there was a problem with the deformation of the carrier during centrifugal drying and the state of the wafer during centrifugal drying. In conclusion, the characteristics of the wafer carrier indicate that it is generally made of a light material and therefore has relatively low rigidity and causes slight deformation due to centrifugal force. It has been found that since the wafers are stored close to each other, deformation of the wafer carrier may cause contact between adjacent wafers.

This contact state leads to the destruction of the fine structure formed on the wafer, and in extreme cases, the destruction of the wafer itself. When a part of a wafer rotating at a high speed together with the wafer carrier is damaged in this way, the debris collides with other wafers, causing damage to other wafers, and a series of these causes many defects. Results.

For example, when there is a groove or the like for supporting the peripheral portion of a wafer, adjacent wafers come into contact with each other with such a strength as to cause damage if the direction of the groove changes due to deformation of the wafer carrier. There is. In addition, even if the wafer carrier is not deformed by the deformation of the wafer carrier, a force is applied to a part of the wafer to generate a stress state. It is easier to break than when fragments come into contact with the wafer in the state.

Further, even if a simple stress is applied, the fine structure formed on the wafer may be adversely affected by the residual stress. The stress applied to the wafer by the deformation of the wafer carrier is as follows.

In a wafer carrier having a structure for holding a wafer by a groove, the grooves 51, 51, 51... Hold the wafer in parallel with each other when there is no centrifugal force as shown in FIG. However, the holding members 52, 52 in which grooves are formed by centrifugal force are deformed on a drum,
At 53, stress is applied to the peripheral portion of the wafer from the groove itself in the portion of the groove which changes its direction toward the center and is greatly deformed, as shown in FIG.

In addition, at the bottom of the wafer carrier, particularly, the distance between the grooves in the central portion is widened, so that when the centrifugal force is applied, the wafer slips toward the bottom side, that is, the direction in which salt vision is applied, and the rotation ends. When the centrifugal force disappears in this state, the distance between the grooves becomes narrow, and a stress due to the restoring force of the wafer carrier is applied to that portion of the wafer that has been slipped.

In any case, the deformation of the wafer carrier due to the application of the centrifugal force generates a stress state in the wafer, which directly or indirectly causes damage to the wafer and lowers reliability.

[0017]

Means for Solving the Problems The present inventors provide the following means to solve this problem.

2. A wafer drying apparatus according to claim 1, wherein the wafer carrier holding a plurality of wafers is rotated to shake off and dry the liquid on the wafer by centrifugal force, wherein the wafer carrier is rotated by centrifugal force during rotation. A wafer drying device wherein adjacent wafers do not come into contact with each other due to bending of a wafer carrier.

A wafer drying apparatus according to claim 2, wherein the wafer carrier holding a plurality of wafers is rotated to shake off and dry the liquid on the wafer by centrifugal force.
The wafer carrier holds the periphery of the wafer with a groove,
A wafer drying apparatus in which the grooves do not apply stress to the periphery of the wafer due to bending of the wafer carrier due to centrifugal force during rotation of the wafer carrier.

4. A wafer drying apparatus according to claim 3, wherein the wafer carrier holding a plurality of wafers is rotated to shake off and dry the liquid on the wafer by centrifugal force, wherein the wafer carrier is made of a plastic material, The wafer drying apparatus according to claim 1, wherein a periphery of the wafer is held by a groove.

5. A wafer drying apparatus according to claim 4, wherein the wafer carrier holding a plurality of wafers is rotated to shake off and dry the liquid on the wafer by centrifugal force, wherein the wafer carrier is made of a plastic material. 3. The wafer drying apparatus according to claim 1, wherein when the wafer carrier is rotated to perform centrifugal drying of the wafer, the rigidity of the wafer carrier is increased by an adapter to reduce deflection due to centrifugal force.

A wafer drying apparatus according to claim 5, wherein the wafer carrier holding a plurality of wafers is rotated to shake off and dry the liquid on the wafer by centrifugal force, wherein the wafer carrier is made of a plastic material. 3. The wafer drying device according to claim 1, wherein a portion of the wafer carrier is held by a high-rigidity member in order to reduce the deflection of the wafer carrier due to centrifugal force when the wafer carrier is rotated for centrifugal drying of the wafer. apparatus.

A pair of holding members having a plurality of grooves according to claim 6 with the sides having the grooves facing each other, and a wafer carrier for holding a peripheral portion of a wafer in the opposed grooves, and the holding member is connected to the holding member. A rotating mechanism that rotates so that the grooves face in the direction of the substantially rotational acceleration, and in order to reduce the pair of holding members from bending outward due to the rotation acceleration, during rotation, the bottom of the holding member or Wafer drying device with upper part sandwiched by reinforcing members. 6 as above
Is provided.

[0024]

Embodiments of the present invention will be described below. The specific embodiments described below do not narrow the technical scope of the present invention at all, but are described only as examples.

First, according to the first aspect of the present invention,
A wafer drying apparatus for rotating a wafer carrier holding a plurality of wafers to shake off and dry the liquid on the wafer with centrifugal force as described above, wherein the wafer carrier is rotated by the bending of the wafer carrier due to centrifugal force. A wafer drying apparatus in which adjacent wafers do not contact each other.

According to the present invention, it has been found that bending of the wafer carrier due to centrifugal force causes damage to the wafer during rotation. This deflection was found by strobing and analyzing the state of the wafer carrier during centrifugal drying, and was the trigger for the present invention. Specifically, the carrier is rotated with the lid of the normally closed drying device opened, and the flashing speed of the strobe light is synchronized with the rotation speed of the carrier to facilitate deformation of the carrier. To be able to confirm. Although the deformation of the wafer carrier cannot be easily recognized visually, a transparent acrylic plate was placed instead of the lid with the strobe light blinking, and the width of the wafer carrier was measured with a vernier caliper from above. As a result, it was found that the wafer carrier was expanded by about 2 mm in the horizontal direction, that is, in the rotation direction.

At the same time, when the wafers housed in the carrier were observed, it was found that the wafers came into contact with each other. From these facts, it was found that the crack of the wafer generated during the centrifugal drying was largely caused by the deformation of the wafer carrier due to the centrifugal force. Thus, the invention described in claim 1 of the present case was born.

[0028] Next, as to the invention of claim 2, as described above, the present invention relates to a wafer drying apparatus for rotating a wafer carrier holding a plurality of wafers to shake off and dry the liquid on the wafers by centrifugal force. Wherein the wafer carrier holds the periphery of the wafer with a groove, and the groove does not apply stress to the periphery of the wafer due to bending of the wafer carrier due to centrifugal force during rotation of the wafer carrier.

The present invention has been made by paying particular attention to the deformation of the groove holding the wafer among the deformations of the wafer carrier due to the centrifugal force. As described above, the wafer carrier is deformed by the centrifugal force. As one mode of the deformation, the groove is directed toward the center of the wafer carrier as described above.

In this case, the groove provided in the central portion has almost no change in the direction, but the groove provided in the portion close to both sides faces the central side, so that the groove provided for the wafers to be arranged in parallel. Gives stress. The present invention has been made based on such findings.

Next, a third aspect of the present invention is directed to a wafer drying apparatus for rotating a wafer carrier holding a plurality of wafers as described above to shake off and dry the liquid on the wafers by centrifugal force. 3. The wafer drying apparatus according to claim 1, wherein the wafer carrier is made of a plastic material, and the periphery of the wafer is held by a groove. As shown in the figure, the shape is similar to that of the conventional wafer carrier described in the related art.
For example, as shown in FIG.

As described in the prior art, the wafer carrier is often made of a plastic material from the viewpoint of easy carrying, and not corroded or deteriorated by chemicals. However, plastic materials have relatively low mechanical strength, so that deformation due to centrifugal force is relatively large. However, the deformation of the wafer carrier due to centrifugal force has been overlooked as a problem in the past, and a structure using a plastic material and having reduced deformation due to centrifugal force is suitable for such a wafer carrier or a centrifugal drying device. I have. That is, conventionally, the problem of deformation due to centrifugal force was not recognized, and there is no wafer carrier made of a plastic material having a structure that reduces deformation due to centrifugal force. This is because reducing this deformation and reducing the weight of the carrier were inconsistent unless otherwise noted.

The specific structure is also clarified in the invention described in the other claims, but here, if another example is given, for example, a holding member provided with a plurality of grooves as described above is used. In the case of deformation like a drum, the deformation can be reduced by providing a beam that passes the holding members facing each other at the center where displacement is large. It is also conceivable to use a band or the like to prevent the holding members from bulging. It is also good to provide a wall on the part that holds the wafer carrier to prevent the wafer carrier from bulging like a drum. As described above, the present invention is not limited to these.

Next, a fourth aspect of the present invention will be described. As described above, the present invention is a wafer drying apparatus for rotating a wafer carrier holding a plurality of wafers to shake off and dry the liquid on the wafer by centrifugal force, wherein the wafer carrier is made of a plastic material. 3. The wafer drying apparatus according to claim 1, wherein when the wafer is centrifugally dried by rotating the wafer carrier, the rigidity of the wafer carrier is increased by an adapter to reduce the bending due to the centrifugal force. In the invention according to the third aspect, the device for reducing the deformation of the wafer carrier due to the centrifugal force has been described. In the present invention, the adapter is used as the deformation preventing means. FIGS. 1 and 2 show the use state of this adapter.
It is. FIG. 1 shows a state in which an adapter 12 is mounted on a wafer carrier 11 of the present invention.
FIG. 2A shows a state in which the adapter is mounted on the wafer carrier when viewed from the wafer insertion side of the wafer carrier, and FIG. 2B shows only the adapter from the same direction. FIG. In the case of this adapter, holding grooves 21 and 21 for securely holding the bottom portions of the two holding members on the bottom portion of the wafer carrier are formed in the adapter.
The advantage of using the adapter as the deformation preventing means is that the adapter used to increase the mechanical strength of the wafer carrier by a member separate from the wafer carrier, that is, the adapter used to increase the rigidity may be removed when the wafer carrier is carried,
The point is that it can be made lighter.

An adapter may be attached for centrifugal drying. This adapter is for increasing the rigidity of the wafer carrier, and may be any adapter that increases the rigidity in a direction that prevents deformation due to centrifugal force and, if reduced, a force based on rotational acceleration. For example, a highly rigid plastic material, a metal material, or the like disposed along the holding members to prevent the pair of holding members from bending is considered.

Next, according to a fifth aspect of the present invention,
A wafer drying apparatus for rotating a wafer carrier holding a plurality of wafers to shake off and dry the liquid on the wafer by centrifugal force as described above, wherein the wafer carrier is made of a plastic material, and the wafer carrier is rotated. 3. The wafer drying apparatus according to claim 1, wherein when the wafer is subjected to centrifugal drying, a part of the wafer carrier is held by a high-rigidity member to reduce deflection of the wafer carrier due to centrifugal force.

This high-rigidity material not only includes the above-mentioned adapter, but also does not need to be attached separately, for example, such as the wall existing in the part of the drying device holding the wafer carrier. May be something.

Finally, according to a sixth aspect of the present invention, as described above, a pair of holding members having a plurality of grooves are opposed to each other on the side having the grooves, and the peripheral portion of the wafer is held in the opposed grooves. A carrier, and a rotation mechanism for rotating the wafer carrier such that the holding member has a groove oriented substantially in the direction of the rotational acceleration, and in order to reduce the pair of holding members from bending outward due to the rotational acceleration, This is a wafer drying device that holds the bottom or the top of the holding member with a reinforcing member during rotation. The present invention according to claims 1 to 5 is further embodied.

As a material of the above-described wafer carrier or adapter, vinyl chloride or polypropylene is suitable. In addition, the rigidity of the structure is increased by using these materials at minimum, such as man-shaped beams used in building structures.
In other words, it is better if a measure is taken to increase the sectional quadratic coefficient.

[0040]

As described above, according to the present invention, since the deformation of the wafer carrier during centrifugal drying can be reduced, the wafers come into contact with each other even when the wafers are densely packed in the wafer carrier. And the stress received from the wafer carrier itself can be reduced, so that the damage to the wafer can be reduced directly, and the wafer can be hardly cracked indirectly, and the wafer can be damaged due to residual stress. It is possible to reduce the deterioration of the provided elements, reduce the mechanical strength of the wafer itself due to the residual stress, and improve the yield of the wafer in many drying steps.

[0041]

[Brief description of the drawings]

FIG. 1 is a view showing a state in which a wafer carrier of a wafer drying apparatus according to the present invention is inserted into an adapter. (A) A perspective view showing an inserted state. (B) A conceptual sectional view showing a state of being inserted.

FIG. 2 is a plan view for explaining an adapter of the wafer drying apparatus according to the present invention. (A) A plan view showing a state where a wafer carrier is inserted into an adapter. (B) A plan view showing a state of an adapter alone.

FIG. 3 is a perspective view showing a wafer carrier of a conventional wafer drying apparatus.

FIG. 4 is a perspective view showing a state where a wafer is stored in a conventional wafer drying apparatus.

FIG. 5 is a conceptual plan view showing a problem of a wafer carrier of a conventional wafer drying apparatus.

[Explanation of symbols]

 11 Wafer carrier 12 Adapter

Claims (6)

[Claims] 1. A wafer drying device for rotating a wafer carrier holding a plurality of wafers to shake off and dry the liquid on the wafer by centrifugal force, wherein the wafer carrier is bent by centrifugal force during rotation. A wafer drying apparatus in which adjacent wafers do not come into contact with each other. 2. A wafer drying apparatus for rotating a wafer carrier holding a plurality of wafers to shake off and dry a liquid on the wafer by centrifugal force, wherein the wafer carrier holds a periphery of the wafer with a groove, A wafer drying apparatus in which the grooves do not apply stress to the periphery of the wafer due to bending of the wafer carrier due to centrifugal force during rotation of the wafer carrier. 3. A wafer drying device for rotating a wafer carrier holding a plurality of wafers to shake off and dry the liquid on the wafers by centrifugal force, wherein the wafer carrier is made of a plastic material, and a periphery of the wafer is formed. 3. The wafer drying apparatus according to claim 1, wherein the wafer is held by a groove. 4. A wafer drying apparatus for rotating a wafer carrier holding a plurality of wafers to shake off and dry the liquid on the wafer by centrifugal force, wherein the wafer carrier is made of a plastic material, and the wafer carrier is rotated. 3. The wafer drying apparatus according to claim 1, wherein when the wafer is subjected to centrifugal drying, the rigidity of the wafer carrier is increased by an adapter to reduce deflection due to centrifugal force. 5. A wafer drying apparatus for rotating a wafer carrier holding a plurality of wafers to shake off and dry the liquid on the wafer by centrifugal force, wherein the wafer carrier is made of a plastic material, and the wafer carrier is rotated. 3. The wafer drying apparatus according to claim 1, wherein when the wafer is subjected to centrifugal drying, a part of the wafer carrier is held by a high-rigidity member to reduce deflection of the wafer carrier due to centrifugal force. 6. A wafer carrier for holding a pair of holding members having a plurality of grooves on the side having the grooves, and holding a peripheral portion of the wafer in the opposed grooves. A rotation mechanism for rotating the holding member so that the grooves face in the direction, and in order to reduce the pair of holding members from bending outward due to the rotational acceleration, the bottom or top of the holding member is reinforced during rotation. Wafer drying device sandwiched by.