US20030132135A1

US20030132135A1 - Protective wafer storage system, device, and method

Info

Publication number: US20030132135A1
Application number: US10/047,589
Authority: US
Inventors: Stephen Natale; Scott Limb
Original assignee: Analog Devices Inc
Current assignee: Analog Devices Inc
Priority date: 2002-01-14
Filing date: 2002-01-14
Publication date: 2003-07-17

Abstract

A protective insert is used to secure a wafer cassette within a storage box and reduce mechanical stresses transmitted from the storage box to the wafer cassette. The protective insert is formed from at least one mechanical stress reducing material in such a way that the protective insert can secure the wafer cassette within the storage box and reduce mechanical stresses transmitted from the storage box to the wafer cassette.

Description

FIELD OF THE INVENTION

The present invention relates generally to wafer storage, and more particularly to a protective wafer storage system and apparatus.

BACKGROUND OF THE INVENTION

In today's technological age, extremely small devices are often formed on large wafers. For example, extremely small electrical, electromechanical, and optoelectromechanical devices are often formed on large silicon wafers. The devices can be formed using a variety of techniques, including etching components into the wafer or depositing components onto the wafer. It is common for hundreds or thousands of devices to be formed on a single wafer. The completed wafers are extremely valuable.

Completed wafers are often stored so they can be subsequently processed by automated wafer processing machines. Typically, a number of wafers are placed into a cassette that can be used by the automated wafer processing machines, and the cassette is placed into a storage box. The boxes facilitate transportation and storage of the wafers.

Unfortunately, the devices are often extremely sensitive to mechanical stresses such as shock and vibration. This is particularly true for electromechanical and optoelectromechanical devices, such as optical Micro-Electromechanical System (MEMS) devices having mirrors that are suspended by very small and sensitive tethers. Even small mechanical stresses can often damage the fragile mechanical structures of such a device, effectively destroying the device. Furthermore, the damaged mechanical structures can often separate from the device and contaminate other devices on the same wafer or on different wafers, effectively destroying the entire box of wafers.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, a protective insert is used to secure a wafer cassette within a storage box and reduce mechanical stresses transmitted from the storage box to the wafer cassette. The protective insert is formed from at least one mechanical stress reducing material in such a way that the protective insert can secure the wafer cassette within the storage box and reduce mechanical stresses transmitted from the storage box to the wafer cassette.

In accordance with another aspect of the invention, a protective wafer storage system includes a cassette for holding at least one wafer, a storage box for holding the cassette, and a protective insert for securing the cassette within the storage box and reducing mechanical stresses transmitted from the storage box to the cassette. The protective insert may reduce mechanical stresses such as shock and vibration. The protective insert may be formed from a single material, such as a pliable plastic sheeting, or from multiple materials. The protective insert may be inexpensive and/or washable.

In accordance with yet another aspect of the invention, an apparatus is formed from at least one mechanical stress reducing material for securing a cassette within a storage box and reducing mechanical stresses transmitted from the storage box to the cassette in a protective wafer storage system. The apparatus may reduce mechanical stresses such as shock and vibration. The apparatus may be formed from a single material, such as a pliable plastic sheeting, or from multiple materials. The apparatus may be inexpensive and/or washable.

In accordance with still another aspect of the invention, a method for securing a cassette within a storage box and reducing mechanical stresses transmitted from the storage box to the cassette in a protective wafer storage system involves obtaining a protective insert comprising at least one mechanical stress reducing material formed to secure the cassette within the storage box and reduce mechanical stresses transmitted from the storage box to the cassette and introducing the protective insert between the cassette and the storage box for securing the cassette within the storage box and reducing mechanical stresses transmitted from the storage box to the cassette. The method may also involve subjecting the storage box to a mechanical stress sufficient to damage contents of the cassette without the protective insert but insufficient to damage the contents of the cassette with the protective insert. The method may also involve removing the protective insert from between the cassette and the storage box and discarding the protective insert. The method may also involve removing the protective insert from between the cassette and the storage box and washing the protective insert, in which case the protective insert may be re-used.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings: [0009]
FIG. 1 shows a representation of an exemplary wafer, cassette, and protective insert in accordance with an embodiment of the present invention; [0010]
FIG. 2 shows the cut-outs and fold lines for forming a protective insert from a single piece of pliable plastic sheeting in accordance with an embodiment of the present invention; [0011]
FIG. 3 shows a front perspective of an exemplary protective insert formed from a single piece of pliable plastic sheeting sheeting in accordance with an embodiment of the present invention; [0012]
FIG. 4 shows a top perspective of an exemplary protective insert formed from a single piece of pliable plastic sheeting sheeting in accordance with an embodiment of the present invention; [0013]
FIG. 5 shows a back perspective of an exemplary protective insert formed from a single piece of pliable plastic sheeting sheeting in accordance with an embodiment of the present invention; [0014]
FIG. 6 shows a bottom perspective of an exemplary protective insert formed from a single piece of pliable plastic sheeting sheeting in accordance with an embodiment of the present invention; [0015]
FIG. 7 shows a side perspective of an exemplary protective insert formed from a single piece of pliable plastic sheeting sheeting in accordance with an embodiment of the present invention; [0016]
FIG. 8 shows a representation of an alternative protective insert for securing the cassette and wafer within the storage box in accordance with an embodiment of the present invention; [0017]
FIG. 9 shows a representation of a storage box for storing the cassette in accordance with an embodiment of the present invention; and [0018]
FIG. 10 describes a method for securing a cassette within a storage box and reducing mechanical stresses transmitted from the storage box to the cassette in accordance with an embodiment of the present invention.[0019]

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

In an embodiment of the present invention, a protective insert is used to reduce mechanical stresses transmitted to the wafer cassette during transportation and storage. The protective insert is placed between the cassette and the box such that the cassette fits within the protective insert and the protective insert fits within the box. The protective insert reduces mechanical stresses by securing the cassette within the box and/or absorbing mechanical stresses such as shock and vibration. [0020]
FIG. 1 shows a representation of an [0021] exemplary wafer 110, cassette 120, and protective insert 130, in accordance with an embodiment of the present invention. The cassette 120 typically holds multiple wafers, and is designed to fit within a certain storage box (not shown). In an exemplary embodiment of the present invention, the cassette 120 and the storage box are commercially available from EMPAK(TM). The protective insert 130 is designed so as to secure the cassette 120 within the box and absorb mechanical stresses transmitted from the box to the cassette 120.
The exemplary [0022] protective insert 130 is approximately 6.5 inches wide, 4 inches deep, and 3.25 inches high overall, and is typically formed from a single piece of pliable plastic sheeting approximately one-eighth of an inch thick. FIG. 2 shows the cut-outs and fold lines for forming the exemplary protective insert 130 from a single piece of pliable plastic sheeting 200. Shown are the back 206, the left side 202, the left bottom 224, the right side 210, and the right bottom 214 panels that are formed from the single piece of pliable plastic sheeting 200. The fold lines 204, 208, 212, and 226 represent v-shaped grooves that are cut into the single piece of pliable plastic sheeting 200 so as to leave an approximately 45 degree bevel panel edge. An approximately 45 degree bevel is also formed on the edges 216, 218, 220, and 222. The protective insert is formed by joining the left side panel 202 to the back panel 206 along the fold line 204, joining the left bottom panel 224 to the left side panel 202 along the fold line 226, joining the edge 222 of the left bottom panel 224 to the edge 220 of the back panel 206, joining the right side panel 210 to the back panel 206 along the fold line 208, joining the right bottom panel 214 to the right side panel 210 along fold line 212, and joining the edge 216 of the right bottom panel 214 to the edge 218 of the back panel 206. The panels can be joined using heat, glue, or some other technique.
FIG. 3 shows a front perspective of an exemplary protective insert. Shown are the [0023] back 206, left side 202, right side 210, left bottom 224, and right bottom 214 panels.
FIG. 4 shows a top perspective of an exemplary protective insert. Shown are the [0024] back 206, left side 202, right side 210, left bottom 224, and right bottom 214 panels.
FIG. 5 shows a back perspective of an exemplary protective insert. Shown is the [0025] back panel 206.
FIG. 6 shows a bottom perspective of an exemplary protective insert. Shown are the [0026] back 206, left side 224, and right side 214 panels.
FIG. 7 shows a side perspective of an exemplary protective insert. The protective insert looks substantially the same from both the left side perspective (left side panel [0027] 202) and right side perspective (right side panel 210).
FIG. 8 shows a representation of an alternative [0028] protective insert 830 for securing the cassette 120 and wafer 110 within the storage box (not shown). The protective insert 830 differs in shape from the protective insert 130, but performs essentially the same function as the protective insert 110.
FIG. 9 shows a representation of a [0029] storage box 900 for storing the cassette 120. A protective insert, such as the protective insert 130 or the protective insert 830, is introduced between the cassette 120 and the storage box 900 for securing the cassette 120 within the storage box 900 and reducing mechanical stresses transmitted from the storage box 900 to the cassette 120.
In a typical embodiment of the present invention, the [0030] storage box 900 and cassette 120 are cleaned after each use. This is because the storage box 900 and cassette 120 can become contaminated from wafer/device material that could in turn contaminate a subsequent box of wafers. Because the protective insert (130, 830) can also become contaminated from wafer/device material, the protective insert (130, 830) is typically discarded or washed after each use. Therefore, it is desirable for the protective insert (130, 830) to be made from a material that is inexpensive and/or washable.
FIG. 10 describes a method for securing the [0031] cassette 120 within the storage box 900 and reducing mechanical stresses transmitted from the storage box 900 to the cassette 120. Beginning in block 1002, the method involves obtaining a protective insert, in block 1004, and introducing the protective insert between the cassette 120 and the storage box 900, in block 1006. The method may also involve subjecting the storage box 900 to a mechanical stress sufficient to damage contents of the cassette 120 without the protective insert but insufficient to damage the contents of the cassette 120 with the protective insert, in block 1008. The method may also involve removing the protective insert from between the cassette 120 and the storage box 900, in block 1012. The method may also involve discarding the protective insert or washing and re-using the protective insert, in block 1012. The method terminates in block 1099.
It should be noted that the present invention is in no way limited to any particular form of protective insert. The protective insert is preferably formed so as to secure the cassette within the storage box and reduce mechanical stresses transmitted from the storage box to the cassette. Exemplary [0032] protective inserts 130 and 830 are shown in FIG. 1 and FIG. 8, respectively.
It should also be noted that the present invention is in no way limited to any particular type of wafer. Wafers are available in a variety of materials, shapes, and sizes. [0033]
It should also be noted that the present invention is in no way limited to any particular type of device formed on the wafers. Devices can include small electrical, electromechanical, optoelectromechanical, and other devices formed on the wafers. [0034]
It should also be noted that the present invention is in no way limited to any particular cassette or storage box. Wafer storage cassettes and storage boxes are available in different sizes and shapes from a variety of manufacturers. [0035]
It should also be noted that the present invention is in no way limited to any particular protective insert material(s). The protective insert is preferably made from one or more materials that enable the protective insert to secure the cassette within the storage box and/or reduce mechanical stresses transmitted from the storage box to the cassette. Although the above embodiments describe a protective insert made from a pliable plastic sheeting, the protective insert can be made from virtually any material that will enable the protective insert to secure the cassette within the storage box and/or reduce mechanical stresses transmitted from the storage box to the cassette. For example, a protective insert can be made from materials such as styrofoam, corrugated cardboard, or other material. [0036]
The present invention may be embodied in other specific forms without departing from the true scope of the invention. The described embodiments are to be considered in all respects only as illustrative and not restrictive. [0037]

Claims

What is claimed is:

1. A protective wafer storage system comprising:

a cassette for holding at least one wafer;

a storage box for holding the cassette; and

a protective insert operably coupled to secure the cassette within the storage box and reduce mechanical stresses transmitted from the storage box to the cassette.

2. The protective wafer storage system of claim 1, wherein the protective insert is operably coupled to reduce shock transmitted from the storage box to the cassette.

3. The protective wafer storage system of claim 1, wherein the protective insert is operably coupled to reduce vibration transmitted from the storage box to the cassette.

4. The protective wafer storage system of claim 1, wherein the protective insert is formed from a single material.

5. The protective wafer storage system of claim 4, wherein the single material comprises a pliable plastic sheeting.

6. The protective wafer storage system of claim 1, wherein the protective insert is formed from a plurality of materials.

7. The protective wafer storage system of claim 1, wherein the protective insert is formed from an inexpensive material.

8. The protective wafer storage system of claim 1, wherein the protective insert is formed from a washable material.

9. An apparatus comprising at least one mechanical stress reducing material formed to secure a cassette within a storage box and reduce mechanical stresses transmitted from the storage box to the cassette in a protective wafer storage system.

10. The apparatus of claim 9, wherein the at least one mechanical stress reducing material reduces shock transmitted from the storage box to the cassette.

11. The apparatus of claim 9, wherein the at least one mechanical stress reducing material reduces vibration transmitted from the storage box to the cassette.

12. The apparatus of claim 9, wherein the at least one mechanical stress reducing material comprises a pliable plastic sheeting.

13. The apparatus of claim 9, wherein the at least one mechanical stress reducing material is inexpensive.

14. The apparatus of claim 9, wherein the at least one mechanical stress reducing material is washable.

15. A method for securing a cassette within a storage box and reducing mechanical stresses transmitted from the storage box to the cassette in a protective wafer storage system, the method comprising:

obtaining a protective insert comprising at least one mechanical stress reducing material formed to secure the cassette within the storage box and reduce mechanical stresses transmitted from the storage box to the cassette; and

introducing the protective insert between the cassette and the storage box for securing the cassette within the storage box and reducing mechanical stresses transmitted from the storage box to the cassette.

16. The method of claim 15, further comprising:

subjecting the storage box to a mechanical stress sufficient to damage contents of the cassette without the protective insert but insufficient to damage the contents of the cassette with the protective insert.

17. The method of claim 15, further comprising:

removing the protective insert from between the cassette and the storage box; and

discarding the protective insert.

18. The method of claim 15, further comprising:

washing the protective insert.

19. The method of claim 17, further comprising:

re-using the protective insert after washing the protective insert.