WO2014189739A1

WO2014189739A1 - Front opening unified pod (foup) cassette container

Info

Publication number: WO2014189739A1
Application number: PCT/US2014/038034
Authority: WO
Inventors: Joseph Arthur Kraus; Joseph Michael HALLISEY; Joseph Mack
Original assignee: Veeco Instruments Inc.
Priority date: 2013-05-22
Filing date: 2014-05-15
Publication date: 2014-11-27
Also published as: TW201509768A

Abstract

A front opening unified pod (FOUP) cassette container includes a container housing. A wafer cassette housing that includes at least one cavity for positioning a wafer cassette is movably attached to the container housing so that the wafer cassette housing moves relative to a surface of the container housing to allow wafers cassettes to be loaded and removed. A latching mechanism secures the wafer cassette housing to the container housing.

Description

Front Opening Unified Pod (FOUP) Cassette Container

[0001] The section headings used herein are for organizational purposes only and should not to be construed as limiting the subject matter described in the present application in any way.

Introduction

[0002] Material processing systems typically store substrates in cassettes before and after processing. Many of these material processing systems include substrate carriers for supporting and sometimes transporting substrates during processing. The substrate is often a disc of silicon or other semiconductor crystalline material that is commonly called a wafer. The terms

"substrate" and "wafer" as used herein are equivalent. One such type of material processing system is a vapor phase epitaxy (VPE) system. Vapor phase epitaxy is a type of chemical vapor deposition (CVD), which involves directing one or more gases containing chemical species onto a surface of a substrate so that the reactive species react and form a film on the surface of the substrate. For example, VPE systems can be used to grow compound semiconductor materials on substrates.

[0003] Materials are typically grown by injecting at least one precursor gas and, in many processes, at least a first and a second precursor gas into a process chamber containing the crystalline substrate. Compound semiconductors, such as III-V semiconductors, can be formed by growing various layers of semiconductor materials on a substrate using a hydride precursor gas and an organometalic precursor gas. Metalorganic vapor phase epitaxy (MOVPE) is a vapor deposition method that is commonly used to grow compound semiconductors using a surface reaction of metalorganics and hydrides containing the required chemical elements. For example, indium phosphide could be grown in a reactor on a substrate by introducing trimethylindium and phosphine.

[0004] Alternative names for MOVPE used in the art include organometallic vapor phase epitaxy (OMVPE), metalorganic chemical vapor deposition (MOCVD), and organometallic chemical vapor deposition (OMCVD). In these processes, the gases are reacted with one another at the growth surface of a substrate, such as a sapphire, Si, GaAs, InP, InAs or GaP substrate, to form a III-V compound of the general formula In_xGa_YAl_zNAAsBPcSbD, where X+Y+Z equals approximately one, and A+B+C+D equals approximately one, and each of X, Y, Z, A, B, C, and D can be between zero and one. In various processes, the substrate can be a metal,

semiconductor, or an insulating substrate. In some instances, bismuth may be used in place of some or all of the other Group III metals.

[0005] Compound semiconductors, such as III-V semiconductors, can also be formed by growing various layers of semiconductor materials on a substrate using a hydride or a halide precursor gas process. In one halide vapor phase epitaxy (HVPE) process, Group III nitrides (e.g., GaN, A1N) are formed by reacting hot gaseous metal chlorides (e.g., GaCl or AlCl) with ammonia gas (NH₃). The metal chlorides are generated by passing hot HC1 gas over the hot Group III metals. One feature of HVPE is that it can have a very high growth rate, up to 100 μιη per hour for some state-of-the-art processes. Another feature of HVPE is that it can be used to deposit relatively high quality films because films are grown in a carbon free environment and because the hot HC1 gas provides a self-cleaning effect.

[0006] In these processes, the substrate is maintained at an elevated temperature within a reaction chamber. The precursor gases are typically mixed with inert carrier gases and are then directed into the reaction chamber. Typically, the gases are at a relatively low temperature when they are introduced into the reaction chamber. As the gases reach the hot substrate, their temperature, and hence their available energy for reaction, increases. Formation of the epitaxial layer occurs by final pyrolysis of the constituent chemicals at the substrate surface. Crystals are formed by a chemical reaction on the surface of the substrate and not by physical deposition processes. Consequently, VPE is a desirable growth technique for thermodynamically metastable alloys. Currently, VPE is commonly used for manufacturing laser diodes, solar cells, and light emitting diodes (LEDs).

Summary of the Invention

[0007] A front opening unified pod (FOUP) cassette container, according to the present teaching, includes a container housing and a wafer cassette housing comprising at least one cavity for positioning a wafer cassette. In various embodiments, the cassette housing is positioned so that a robotic arm can pick and place wafers out of and into the cassette housing. In many embodiments, the wafer cassette housing comprises a plurality of cavities adapted to position a corresponding plurality of wafer cassettes. The wafer cassette housing is movably attached to the container housing so that the wafer cassette housing moves relative to a front surface of the container housing. This geometry allows wafer cassettes to be easily loaded and removed. In some embodiments, the container housing comprises a mating surface that forms an airtight seal with the wafer cassette housing.

[0008] A latching mechanism secures the wafer cassette housing to the container housing. In one embodiment, the latching mechanism is a spring loaded latching mechanism. In some embodiments, the wafer cassette housing includes an H-Bar interface that secures the wafer cassette to the wafer cassette housing. In various embodiments, the container housing includes at least one carry handle for the operator to manually transport the container housing. For example, a carry handle can be positioned on a top surface of the container housing.

[0009] The container housing according to the present teaching can take various forms.

In some embodiments, at least one of the container housing and the wafer cassette housing is formed of a resin material that is strong and inexpensive. Also, in some embodiments, at least one of the container housing and the wafer cassette housing is formed of aluminum.

[0010] In some embodiments, the wafer cassette housing is movably attached to the container housing with a hinging mechanism that rotates the wafer cassette housing relative to the container housing. For example, the hinging mechanism can include at least one bearing. In other embodiments, the wafer cassette housing is movably attached to the container housing with a sliding mechanism. The sliding mechanism can include at least one bearing.

[0011] The FOUP cassette of the present teaching can be adapted to accommodate various wafer sizes. For example, in some embodiments, the wafer cassette housing includes a first cavity that is dimensioned to receive a first wafer cassette that supports wafers having a first diameter and a second cavity for positioning a second wafer cassette that supports wafers having a second diameter. Also, in some embodiments, the wafer cassette housing supports at least one wafer cassette adapted to support at least two of four-inch wafers, six-inch wafers, and eight-inch wafers. One skilled in the art will appreciate that various FOUP cassettes of the present teaching can be configured in numerous different ways to accommodate various wafer sizes. Brief Description of the Drawings

[0012] The present teaching, in accordance with preferred and exemplary embodiments, together with further advantages thereof, is more particularly described in the following detailed description, taken in conjunction with the accompanying drawings. The skilled person in the art will understand that the drawings, described below, are for illustration purposes only. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating principles of the teaching. The drawings are not intended to limit the scope of the Applicant's teaching in any way.

[0013] FIG. 1 A illustrates a perspective front-view of a front opening unified pod

(FOUP) cassette container of the present teaching in the wafer cassette loaded position.

[0014] FIG. IB illustrates a perspective back-view of a front opening unified pod

[0015] FIG. 2 illustrates a perspective front-view of a front opening unified pod (FOUP) cassette container of the present teaching in the wafer cassette unloaded position.

[0016] FIG. 3 illustrates a flow chart of a method of loading wafer cassettes in a processing system according to the present teaching.

[0017] FIG. 4 illustrates a flow chart of a method of unloading processed wafer cassettes in a processing system according to the present teaching.

Description of Various Embodiments

[0018] Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the teaching. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

[0019] It should be understood that the individual steps of the methods of the present teachings may be performed in any order and/or simultaneously as long as the teaching remains operable. Furthermore, it should be understood that the apparatus and methods of the present teachings can include any number or all of the described embodiments as long as the teaching remains operable.

[0020] The present teaching will now be described in more detail with reference to exemplary embodiments thereof as shown in the accompanying drawings. While the present teachings are described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives, modifications and equivalents, as will be appreciated by those of skill in the art. Those of ordinary skill in the art having access to the teaching herein will recognize additional implementations, modifications, and embodiments, as well as other fields of use, which are within the scope of the present disclosure as described herein.

[0021] The present teaching relates to methods and apparatus for loading and unloading wafer cassettes in a processing system. Although some aspects of the present teaching are described in connection with semiconductor substrate handling for VPE systems, one skilled in the art will appreciate that the methods and apparatus of the present invention can be applied to any type of processing system that includes a substrate carrier for supporting any type of substrate. In addition, the methods and apparatus of the present teaching are independent of the substrate or wafer size.

[0022] Many material processes require very high throughput to be competitive in the industry. For example, it is highly desirable to achieve a high process throughput of LED and semiconductor laser devices in order for these devices to be cost competitive in the industry today. Furthermore, there is currently a need in the industry to achieve completely automated or near completely automated cassette-to-cassette substrate handling of substrates for various processes, such as VPE substrate processes to manufacture LED and semiconductor laser devices. Also, there is a current need in the industry to significantly increase the substrate throughput, which is measured in substrates processed per hour. The present teaching can increase the mechanical throughput of substrates in an automated cassette-to-cassette substrate handling system.

[0023] FIG. 1 A illustrates a perspective front-view of a front opening unified pod

(FOUP) cassette container 100 of the present teaching in the wafer cassette loaded position. FIG. IB illustrates a perspective back- view of a front opening unified pod (FOUP) cassette container 100 of the present teaching in the wafer cassette loaded position. Referring to both FIGS. 1A and IB, the FOUP cassette container 100 includes a container housing 102 and a wafer cassette housing 104. In many embodiments, there is a mating surface that creates a seal between the container housing 102 and the wafer cassette housing 104 as described in connection with FIG. 2. The wafer cassette housing 104 includes at least one cavity 106, which is shown more clearly in FIG. 2, dimensioned to support a wafer cassette 108. Wafer cassettes 108 can be manually picked and placed from and to the container housing 102. Alternatively, robotic arms can be used to pick and place wafer cassettes 108 from and to the container housing 102. [0024] In some embodiments, the wafer cassette housing 104 includes an industry standard H-Bar interface that secures industry standard H-Bar wafer cassettes to the wafer cassette housing 104. Wafers can be picked and placed by a robotic arm out of and into the wafer cassettes 108. Also, in various embodiments, the container housing 102 includes at least one carry handle to assist the operator in manually transporting the container housing 102. For example, the wafer cassette housing 104 can include a top cover 112 with a carry handle 114 secured to the top cover 112. Other carry handles 114' can also be positioned on the side of the container housing 102 as shown in FIGS. 1A and IB to allow the operator to use both hands when transporting the FOUP cassette container 100.

[0025] The wafer cassette housing 104 is movably attached to the container housing 102 so that the wafer cassette housing 104 moves relative to a surface of the container housing 102. In some embodiments, the wafer cassette housing 104 rotates away from a top surface of the container housing 102 as described in connection with FIG. 2. For example, in various embodiments, the wafer cassette housing 104 moves relative to the surface of the container housing 102 on a bearing assembly or on one of numerous types of hinge mechanisms. In one specific embodiment, a hinge pin is built into the wafer cassette housing 104 and the hinge pin is inserted into a bearing assembly in the container housing 102 such that the hinge pin rotates on bearing surfaces.

[0026] A latching mechanism 110 secures the wafer cassette housing 104 to the container housing 102 while under operation. In the embodiment shown in FIGS. 1A and IB, the latching mechanism 110 is a fastener, such as a bolt. In other embodiments, the latching mechanism 110 is a positive locking mechanism with a quick release, such as a spring loaded latching mechanism. [0027] The container housing 102 according to the present teaching can take various forms. In some embodiments, at least one of the container housing 102 and the wafer cassette housing 104 is formed of a resin material. Numerous types of resin materials can be used to form wafer cassette housings according to the present teaching. Forming the wafer cassette housings from resin materials is relatively inexpensive and can have substantially the same mechanical properties as wafer cassette housings machined or stamped out of metals. Also, in some embodiments, at least one of the container housing 102 and the wafer cassette housing 104 is formed of aluminum or an aluminum alloy material.

[0028] FIG. 2 illustrates a perspective front-view of a front opening unified pod (FOUP) cassette container 100 of the present teaching in the wafer cassette unloaded position. As shown in FIG. 2, the FOUP wafer cassette housing 104 folds back relative to the container housing 102 in order to allow access to the wafer cassettes 108 positioned in the wafer cassette housing 104 for insertion or removal. In one embodiment, the wafer cassette housing 104 folds back 90 degrees so that the wafer cassette housing 104 rests against the bottom of the container housing 102 as shown in FIG. 2. In some embodiments, the container housing 102 comprises a mating surface 116 that forms an air tight seal with a corresponding mating surface 116' of the wafer cassette housing 104.

[0029] The unloaded position shown in FIG. 2 allows wafer cassettes 108 to be easily loaded and removed from the plurality of cavities 106. In various methods of loading and unloading wafer cassettes 108 from the wafer cassette housing 104 according to the present teaching, the wafer cassette housing 104 can be positioned so that a robotic arm can pick and place wafers out of and into the wafer cassette housing 104. In many embodiments, the wafer cassette housing 104 comprises a plurality of cavities 106 that are dimensioned to support a corresponding plurality of wafer cassettes 108.

[0030] The cavities 106 can all be the same size or one or more of the cavities can be a different size to accommodate numerous wafer sizes and shapes as well as numerous types of wafer cassettes. In general the cavities 106 are dimensioned and designed to allow the wafer cassettes 108 to be easily dropped into the cavities. Thus, the FOUP cassette container of the present teaching can be adapted to accommodate various wafer sizes. For example, in some embodiments, the wafer cassette housing 104 includes a first cavity that is dimensioned to receive a first wafer cassette 108 that supports wafers having a first diameter and a second cavity for positioning a second wafer cassette 108 that supports wafers having a second diameter. Also, in some embodiments, the wafer cassette housing 104 supports at least one wafer cassette 108 adapted to support at least two of four-inch wafers, six-inch wafers, and eight-inch wafers. One skilled in the art will appreciate that the FOUP cassette of the present teaching can be configured in numerous different ways to accommodate various wafer sizes.

[0031] In some embodiments, the wafer cassette housing 104 is movably attached to the container housing 102 with a hinging or sliding mechanism that rotates the wafer cassette housing 104 relative to the container housing 102. The hinging mechanism can include a bearing assembly to reduce wear and to assist the operator in loading and unloading wafer cassettes 108. Numerous types of hinging or sliding mechanisms can be used.

[0032] The FOUP container 100 described in connection with FIGS. 1A, IB, and 2 can be used in many different substrate handling architectures. For example, the FOUP container 100 can be used in 300 mm or greater diameter fully automated wafer handling and processing systems. Also, in some embodiments of the present teaching, the FOUP container 100 is used to feed multiple process tools. For example, the FOUP container can be used to feed a cluster of MOCVD process tools. In some embodiments, the FOUP container can be used in a central substrate carrier loader that is used to load wafer cassettes with unprocessed substrates and to unload wafer cassettes with processed substrates.

[0033] FIG. 3 illustrates a flow chart 300 of a method of loading wafer cassettes 108 in a processing system according to the present teaching. Referring to FIGS. 1 A, IB, 2 and 3, in a first step 302 a FOUP container 100 comprising a container housing 102 and a wafer cassette housing 104 that is movably attached to the container housing 102 is provided. In a second step 304, the wafer cassette housing 104 is moved relative to a surface of the container housing 102 to expose at least one cavity 106 in the wafer cassette housing 104 that is dimensioned to receive wafer cassettes.

[0034] In a third step 306, at least one wafer cassette 108 is inserted into the at least one cavity 106 in the wafer cassette housing 104. The insertion of the at least one wafer cassette 108 into the at least one cavity 106 in the wafer cassette housing 104 can be performed with any one of numerous types of robotic arms. In various embodiments, two or more wafer cassettes 108 supporting different size wafers can be inserted into at least one cavity 106 in the wafer cassette housing 104. For example, a first wafer cassette 108 supporting wafers having a first dimension and a second wafer cassette 108 supporting wafers having a second dimension can be inserted.

[0035] In a fourth step 308, the wafer cassette housing 104 including at least one wafer cassette 108 is then moved relative to the surface of the container housing 102. In some methods of the present teaching, the moving the wafer cassette housing 104 relative to the surface of the container housing 102 includes rotating the wafer cassette housing 104 relative to the container housing 102. Also, in some methods according to the present teaching, the moving the wafer cassette housing 104 relative to the surface of the container housing 102 includes translating the wafer cassette housing 104 relative to the container housing 102.

[0036] In a fifth step 310, the wafer cassette housing 104 is secured to the container housing 102. In some methods, an airtight seal is formed between the wafer cassette housing 104 and the container housing 102 when they are secured. In various methods according to the present teaching, the securing the wafer cassette housing 104 to the container housing 102 can include fastening with fasteners, such as bolts or screws or can include latching.

[0037] FIG. 4 illustrates a flow chart 400 of a method of unloading processed wafer cassettes 108 in a processing system according to the present teaching. Referring to FIGS. 1A, IB, 2 and 4, in a first step 402 a FOUP container 100 comprising a container housing 102 and a wafer cassette housing 104 that is movably attached to the container housing 102 is retrieved from a processing system, such as an MOCVD processing system.

[0038] In a second step 404, the wafer cassette housing 104 is moved relative to a surface of the container housing 102 to expose at least one wafer cassette 108 with processed wafers positioned in at least one cavity 106 in the wafer cassette housing 104. In some methods according to the present teaching, moving the wafer cassette housing 104 relative to the surface of the container housing 102 includes rotating the wafer cassette housing 104 relative to the container housing 102. Also, in some methods according to the present teaching, moving the wafer cassette housing 104 relative to the surface of the container housing 102 includes translating the wafer cassette housing 104 relative to the container housing 102.

[0039] In a third step 406, at least one wafer cassette 108 is then removed from the at least one cavity 106. The removing at least one wafer cassette 108 from the at least one cavity 106 can be performed with a robotic arm. In various embodiments, two or more wafer cassettes 108 supporting different size wafers can be removed from the at least one cavity 106 in the wafer cassette housing 104. For example, a first wafer carrier supporting wafers having a first dimension and a second wafer carrier supporting wafers having a second dimension can be removed.

Equivalents

[0040] While the applicant's teaching is described in conjunction with various embodiments, it is not intended that the applicant's teaching be limited to such embodiments. On the contrary, the applicant's teaching encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art, which may be made therein without departing from the spirit and scope of the teaching.

Claims

claimed is:

A front opening unified pod (FOUP) cassette container comprising: a) a container housing; and b) a wafer cassette housing that is movably attached to the container housing so that the wafer cassette housing moves relative to a surface of the container housing to allow wafer cassettes to be loaded and removed, the wafer cassette housing comprising at least one cavity dimensioned to support a wafer cassette; and c) a latching mechanism that secures the wafer cassette housing to the container housing.

The FOUP cassette container of claim 1 , wherein the container housing comprises a mating surface that forms an airtight seal with the wafer cassette housing.

The FOUP cassette container of claim 1 , wherein at least one of the container housing and the wafer cassette housing is formed of a resin material.

The FOUP cassette container of claim 1 , wherein at least one of the container housing and the wafer cassette housing is formed of aluminum.

The FOUP cassette container of claim 1 , wherein the wafer cassette housing is movably attached to the container housing with a hinging mechanism that rotates the wafer cassette housing relative to the container housing.

6. The FOUP cassette container of claim 5, wherein the hinging mechanism comprises at least one bearing.

7. The FOUP cassette container of claim 1 , wherein the wafer cassette housing is movably attached to the container housing with a sliding mechanism.

The FOUP cassette container of claim 7, wherein the sliding mechanism comprises at least one bearing.

9. The FOUP cassette container of claim 1 , wherein the wafer cassette housing comprising a plurality of cavities for positioning a corresponding pluralities of wafer cassettes.

The FOUP cassette container of claim 1 , wherein the wafer cassette housing comprises a first cavity that is dimensioned to receive a first wafer cassette that supports wafers having a first diameter and a second cavity for positioning a second wafer cassette that supports wafers having a second diameter.

The FOUP cassette container of claim 1 , wherein the wafer cassette housing supports at least one wafer cassette adapted to support at least two of four-inch wafers, six-inch wafers, and eight-inch wafers.

The FOUP cassette container of claim 1 , wherein the cassette housing is positioned so that a robotic arm can pick and place wafers out of and into the cassette housing.

The FOUP cassette container of claim 1 , wherein the cassette housing comprises at least one spring loaded latching mechanism that secures the wafer cassette to the cassette housing.

The FOUP cassette container of claim 1 , wherein the cassette housing comprises an H-Bar interface that secures the wafer cassette to the cassette housing.

The FOUP cassette container of claim 1 , wherein the container housing further comprising at least one carry handle.

The FOUP cassette container of claim 15, wherein the carry handle is positioned on a top surface of the container housing.

The FOUP cassette container of claim 1 , wherein the latching mechanism comprises a spring.

A method of loading wafer cassettes in a processing system, the method comprising: a) providing a front opening unified pod (FOUP) cassette container comprising a container housing and a wafer cassette housing that is movably attached to the container housing; b) moving the wafer cassette housing relative to a surface of the container

housing to expose at least one cavity in the wafer cassette housing that is dimensioned to receive wafer cassettes; c) inserting at least one wafer carrier into the at least one cavity in the wafer cassette housing; and d) moving the wafer cassette housing comprising the at least one wafer carrier relative to the surface of the container housing so that the wafer cassette housing is secured to the container housing.

The method of claim 18, wherein the inserting the at least one wafer carrier into the at least one cavity in the wafer cassette housing is performed with a robotic arm.

The method of claim 18, wherein the moving the wafer cassette housing relative to the surface of the container housing comprises rotating the wafer cassette housing relative to the container housing.

The method of claim 18, wherein the moving the wafer cassette housing relative to the surface of the container housing comprises translating the wafer cassette housing relative to the container housing.

The method of claim 18, further comprising forming an airtight seal between the wafer cassette housing and the container housing.

The method of claim 18, wherein the inserting the at least one wafer carrier into the at least one cavity in the wafer cassette housing comprises inserting a first wafer carrier supporting wafers having a first dimension and inserting a second wafer carrier supporting wafers having a second dimension.

A method of unloading wafer cassettes in a processing system, the method comprising: a) providing a front opening unified pod (FOUP) cassette container comprising a container housing and a wafer cassette housing that is movably attached to the container housing; b) moving the wafer cassette housing relative to a surface of the container

housing to expose at least one wafer cassette positioned in at least one cavity in the wafer cassette housing; and c) removing the at least one wafer cassette from the at least one cavity.

25. The method of claim 24, wherein the removing the at least one wafer cassette from the at least one cavity is performed with a robotic arm.

26. The method of claim 24, wherein the moving the wafer cassette housing relative to the surface of the container housing comprises rotating the wafer cassette housing relative to the container housing.

27. The method of claim 24, wherein the moving the wafer cassette housing relative to the surface of the container housing comprises translating the wafer cassette housing relative to the container housing.

28. The method of claim 24, wherein the removing the at least one wafer carrier from the at least one cavity in the wafer cassette housing comprises removing a first wafer carrier supporting wafers having a first dimension and a second wafer carrier supporting wafers having a second dimension.