Wafer protective cassette

The invention claimed is:




1. A substrate carrier for securing plurality semiconductor substrates, comprising: carrier having, axially opposed end partitions laterally opposed arcuate side panels which are connected with said end partitions form four-sided box structure; spacing said arcuate side panels by said end partitions form substrate entrance top said carrier, narrowed substrate support opening bottom side said carrier; said arcuate side panels having inner surface thereof, with aligned train substrate support channels for holding substrates spaced parallel relation, said channels are formed having two side surfaces bottom surface, said substrate support channels having curbing member formed one side surface each channel, said curbing member having lead-in profile that sloped truncated enabling circular substrate slide into substrate support channel past said curbing member there-in-after securing said substrate between channel support surface said curbing member.


2. The substrate carrier according claim 1 wherein said substrate support channels are configured secure substrates vertical or horizontal orientation.


3. The substrate carrier according claim 1 wherein said surfaces said substrate support channels provide stress free containment fragile substrate by providing lateral movement within channels while said curbing member prevents said substrate jutting beyond said substrate entrance.


4. The substrate carrier according claim 3 wherein said substrate support channels having “U” shape intended prevent wedging said substrate's brittle edges, thereby reducing chipping said brittle edges.


5. The substrate carrier according claim 1 wherein said sloped truncated profile said curbing member prevents substrates jutting beyond said curbing member.


6. The substrate carrier according claim 1 wherein bottom edge said sloped profile formed give substrate freedom move laterally.


7. A method for protecting plurality semiconductor substrates substrate carrier, comprising steps of: providing carrier having, axially opposed end partitions laterally opposed arcuate shaped side panels which are connected said end partitions form four-sided box structure; spacing said arcuate shaped side panels by said end partitions form substrate entrance top said carrier, narrowed substrate support opening bottom side said carrier; said side panels having inner surface thereof, with train parallel substrate support channels for supporting substrates spaced parallel relation, said channels are formed having two side surfaces bottom surface, said substrate support channels having curbing member disposed one side surface each channel, said curbing member, having sloped truncated profile enabling circular substrate slide into substrate support channel, past said curbing member, there-in-after securing said substrate between said substrate support surface said curbing member.


8. A method according claim 7 wherein said upper entrance said substrate support opening providing liquid chemical access all surfaces contained substrates.


9. A method according claim 7 wherein said substrate support channel surfaces are planar thereby permitting unrestrained freedom substrates during wet processes during handling.


10. A method according claim 7 wherein said shape said curbing member operation with said substrate support channel, restricts said substrate jutting towards said carrier entrance during handling.


11. A method according claim 7 wherein all substrate support channels are formed contain circular disk given diameter, said substrate support channels are equally spaced one another.


12. A method according claim 7 wherein said substrate support channels are configured hold substrates vertical orientation.


13. A method according claim 7 wherein said surfaces said substrate support channels provide stress free containment fragile substrate by providing lateral movement within channels while said curbing member secures said substrate within said substrate support channel.


14. A method according claim 13 wherein said substrate support channels having “U” shape prevent wedging said substrate's brittle edges, thereby reducing perimeter chipping.


15. A method according claim 7 wherein said sloped truncated profile said curbing member prevents substrates jutting beyond said curbing member.


16. A method according claim 7 wherein bottom edge said sloped profile said curbing member formed give substrate with known physical attributes, freedom move laterally.

BACKGROUND OF THE INVENTION

(1) Technical Field

The present invention relates wafer cassette which holds plurality semiconductor substrates more particularly cassette for containing supporting plurality thin substrates such semiconductor wafers for storing handling fragile wafers, each which are loaded unloaded numerous times during forming integrated circuits therein.

(2) Description Prior Art

A cassette been conventionally used for storing supporting plurality fragile semiconductor substrates. The stored substrates, each which are loaded unloaded times during manufacturing process, both manually automatically, are susceptible damage. Cassettes are typically molded one-piece container described with reference FIGS. 1, 2 3 , prior art. The cassette 120 made form open container having only four sides with wide opening top for inserting removing substrates, narrower opening, relative outside dimensions substrate bottom cassette. This allows maximum exposure process fluids while securely containing each substrate. The four sides include two side panels 121 , 122 two end panels 123 , 124 . Each side panel straight upper portion curved lower portion with grooves that elongated V shaped cross-section 125 formed within its interior surfaces. Each curved portion converges inward forming narrower opening for bottom; this best illustrated FIG. 1. In this conventional cassette 120 having aforementioned configuration, plurality substrates 10 are contained parallel with each other while guided retained elongated V grooves 125 .

The substrates are usually loaded or unloaded when cassette vertical position shown FIG. 3 illustrating cross-sectional side view cassette 120 showing common problem substrates 10 protruding out beyond front opening 130 cassette. When cassette placed vertical position, any vibration that may caused by myriad disturbances easily cause substrates slide out inside cassette position exposure damage by interfering with substrate handling hardware. This always been problem with conventional cassettes when handling fragile substrates. During automatic handling substrates, by robots like, fragile substrates are vulnerable breakage during insertion or removal because this protrusion problem.

BACKGROUND OF THE RELATED ART

The present invention concerned with substrate damage during transportation. A plurality substrates contained cassette held place only if cassette placed horizontal position. The substrates are reasonably secure provided by grooves that elongated V shaped cross-section. The V grooves are formed opposing inner sides cassette provide means hold support plurality substrates various process steps throughout manufacturing. If cassette placed vertical position, any source vibration, caused by myriad disturbances, effect position substrates within cassette. The substrates may jut out exposed damage by interfering with handling hardware, shown FIG. 2. This always been problem with conventional cassettes when handling fragile substrates.

Typically, substrates are arranged within cassette outside semiconductor process operation. The cassette thereafter transported, with its compliment substrates inside, processing station. Some processing stations are designed process substrates while cassettes. Therefore, list primary goals for providing universal cassette design follows: a) safely contain substrates stacked space saving array. b) Allow much access each substrate without inhibiting processing fluids making contact with all surfaces substrate. c) Have reasonable spacing between substrates for accessing each for removal insertion. d) Choose cassette material that compatible with processing chemicals with its contents while maintaining dimensional integrity between cassettes.

Accordingly, primary object present invention provide curbing member that substantially reduces substrate movement jutting forward when cassette placed vertical position bumped.

Another object present invention provide channel design that allows freedom movement for substrate, one that does not induce stresses by overly constraining. This common prior art when substrate moves against inner apex groove promoting breakage or chipping highly stressed edges.

Still another object present invention provide cassette design that does not change overall cassette dimensions or its spacing between substrates.

SUMMARY OF THE INVENTION

Accordingly, present invention provides solution eliminate abovementioned problems. To achieve foregoing objects, accordance with first object present invention, there provided substrate cassette that embodies grooves, each with curbing member that prevents substrates jutting forward when cassette placed vertical position bumped.

The present invention relates wafer cassette which holds plurality semiconductor substrates more particularly cassette for containing supporting plurality thin substrates such semiconductor wafers for storing handling fragile wafers, each which are loaded unloaded numerous times during forming integrated circuits therein.

The cassette molded one piece made form open container having only four sides with wide opening top for inserting removing substrates, narrower opening, relative outside dimensions substrate, bottom cassette. This allows maximum exposure process fluids while securely containing each plurality substrates. The four sides include two side panels two end panels. Each side panel straight upper portion curved lower portion curved portions converge inward forming narrower opening for bottom. A plurality substrate supporting channels molded into each interior panel surface. The channels are provided each side panels cassette parallel alignment with supporting channels opposite side. The supporting channels slight open draft angle about three degrees. Each channel molded curbing member disposed preventing substrate jutting forward when cassette placed vertical position bumped.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 top perspective view cassette showing saw tooth groove pattern prior art.

FIG. 2 schematic side cross-sectional view plurality wafers cassette prior art illustrating problem wafers protruding out cassette.

FIG. 3 cross-section drawing end view cassette showing substrate retained by curbing members, invention.

FIG. 4 sectional fragmented view cassette shown FIG. 3, invention.

FIG. 5 perspective illustration cassette invention.

FIG. 6 perspective illustration showing left side panel invention.

FIG. 7 development layout construction curbing member invention.

FIG. 8 illustration invention showing enlarged fragmented front view invention.

FIG. 9 front view illustration cassette invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention concerned with substrate damage, cassette because movement during transportation. Refer now FIGS. 1 2 prior art. A plurality substrates 10 contained cassette 120 are held place only if cassette placed horizontal position, substrates are reasonably secure by their weight by grooves 125 that elongated V shaped cross-sections. The grooves are formed opposing inner sides cassette provide means hold support plurality substrates various process steps throughout manufacturing. When cassette placed vertical position, illustrated FIG. 2, vibration caused by myriad disturbances, may cause substrates project out position within cassette 120 into position 130 interference with substrate handling hardware. This always been problem with conventional cassettes when handling fragile substrates.

Typically, substrates are arranged within cassette outside semiconductor process operation. The cassette thereafter transported, with its compliment substrates inside, processing station. Some processing stations are designed process substrates while cassettes. The primary goals for universal cassette design are follows: a) safely contain substrates stacked space saving array. b) Allow access each substrate without inhibiting process fluids making contact with all surfaces substrate. c) Have repeatable precise spacing between substrates for accessing each for removal insertion. d) Choose cassette material that compatible with process chemicals temperatures while maintaining dimensional integrity between cassettes. e) Provide proper drainage process fluids by having no fluid traps.

In following particular embodiment substrate cassette, present invention, described detail by making reference accompanying drawings.

Referring now FIGS. 3–8, invention, substrate cassette 20 conventional form factor, that is, open container having upper entrance 29 lower cassette support opening 28 formed by two side panels 21 22 two end panels 23 24 . A preferred embodiment invention includes first side panel 21 having inner surface 38 thereof, train 31 substrate supporting “␣” shaped channels 40 molded with left surface 41 , right surface 42 bottom surface 43 , left right side surfaces are within about two degrees being perpendicular bottom surface that provides slight open angle for withdrawal molding tooling. A second side panel 22 opposite alignment first side panel 21 , also with inner surface 39 matching train 37 substrate supporting channels 40 .

Referring FIGS. 5 6 arcuate curbing member 30 disposed left surface 41 each ␣ shaped substrate supporting channels 40 , including top end having thinner sloped portion 36 facing upper open entrance cassette 20 letting substrate pass down through thinner sloped profile under stepped bottom end. The stepped end perpendicular inner surface 38 prevents substrate jutting forward, see FIG. 8. The placement arcuate curbing member 30 relative substrate 10 shown construction layout FIG. 7. The arcuate curvatures 32 33 curbing member 30 are same radii periphery substrate 10 . The location stepped bottom end placed so that substrate does not jut out beyond top edge cassette. The edge sloped profile determined permit substrate freedom move limit X direction which offset (the difference X offset wafer diameter). The inner surfaces 41 , 42 , 43 substrate supporting channels 40 are perpendicular each other planar.

FIG. 9 illustrates front view cassette 20 vertical position showing substrate 10 cassette behind curbing members 30 , all which are horizontal supporting channel planar surfaces. The space 35 between substrates shown consistently uniform for following reason. Since supporting channel serves horizontal reference plane, substrate over-constraint posed by v slot shown FIG. 1, prior art not factor. The planar surface allows substrate horizontal by definition, therefore, exposure stress fracturing or chipping reduced when bumped case when restrained by converging apex v shaped slot. The supporting channel design its arcuate curbing member applicable all substrate sizes.

While invention been particularly shown described with reference preferred embodiment, it understood by those skilled art that various changes form details may made without departing spirit scope inventions.