US3467242A - Storage unit for wafer-like articles - Google Patents

Description

p 6, 1969 o. E. DE ROUSSE 3,467,242

STORAGE UNIT FOR WAFER-LIKE ARTICLES Filed March 4, 1968 2 sheetss heetl oponwaowo can P a INVENTOR. DALE EDEROUSSE 36 BY ATTORNEYS Sept. 16, 1969 n. E. DE ROUSSE 3,467,242

STORAGE UNIT FOR WAFER'LIKE ARTICLES Filed March 4, 1968 2 Sheqts-Sheet 2 IN .V ENTOR.

,DALE E. DEROUSSE ATTORNEYS United States Patent 0,

U.S. Cl. 206-1 15 Claims ABSTRACT OF THE DISCLOSURE A storage unit for wafer-like articles, such as disks of semiconductor material adapted for use in making integrated circuit chips. The storage unit is comprised of a tray having a bottom and wall means cooperating with the bottom to define a plurality of compartments for receiving wafer-like articles. The wall means is constructed to engage such an article only at specific points on its outer periphery when the article is supported on edge on the tray bottom. A lid is used to cover the compartment and has flange means movable into sealing engagement with a lip on the upper margin of the tray. Means is provided to apply a predetermined downward force to an article in a compartment of the tray when the lid covers the compartment and stacking means on the tray and lid is provided to position a plurality of covered trays in a vertical stack.

This invention relates to improvements in article handling and storage containers and, more particularly, a storage container for wafer-like articles, such as disks of semiconductor material for use in making integrated circuit chips.

While the present invention is adapted for storing a wide variety of articles, it is specifically adapted for use in handling and storing semiconductor disks of the type described wherein a large number of such disks must oftentimes be moved from place to place and on which a number of operations are performed prior to the cutting of the disks into small pieces to define what is known in the trade as integrated circuit chips. Such disks are of the order of one to two inches in diameter and from to 20 mils in thickness and are quite frangible. Thus, extreme care must be taken to assure that the disks will not be fractured during handling and/or storage and also that the sides of the disks remain clean at all times and untouched by the hands or by tools. Even contact between adjacent disks can mar the side surfaces of the disks sufficiently to cause the disks to be rejected for their intended purpose.

Storage containers heretofore utilized in the handling of semiconductor disks have generally been undesirable for several reasons, one of which is that they do not properly isolate the disks from each other when the disks are in the container. Thus, adjacent disks may contact each other due to relative movement between the disks and the container when the latter is handled and damage to the disk side surfaces can result. Moreover, conventional containers generally make no provision to keep the side surfaces of the disks out of contact with adjacent wall structure in the containers so as to avoid damage to the side surfaces of the disks.

The present invention is directed to an improved handling and storage container for disks of the type described to circumvent the problems associated with conventional containers used in this field. To this end, the present invention includes a tray having a number of open top compartments for receiving and supporting a number of wafer-like articles on edge in a manner such that the articles are only in point contact at their outer periphery with the adjacent structure of the tray so as to leave the surfaces of the articles substantially untouched during handling and storage. Also, the tray is made so that ad- 3,467,242 Patented Sept. 16, 1969 ICC jacent articles generally remain out of contact with each other. The tray can be molded to form a one-piece construction to simplify the construction and minimize its expense. Also, the material of the tray can be translucent to permit articles to be observed therein when the tray is closed or it can be light-tight for use with articles having photosensitive surfaces.

A further important feature of the invention is the provision of structure for applying a predetermined downward force to the vertically disposed articles in the compartments of the tray when the latter is covered by a lid. This feature assures substantially no relative movement between the articles and the tray when the storage unit is handled, i.e., moved about from place to place. Such downward force applied to the articles can be chosen to prevent such relative movement between the articles and the tray while assuring that the articles will not be stressed to the limit at which structural damage to the disks occurs.

A further important feature of the invention is the provision of an improved seal on the upper margin of the tray and the outer margin of the lid wherein a lip on the tray is receivable within a pair of spaced flanges rigid to and extending downwardly from the lid itself. The spacing between the flanges is less than the transverse thickness ofthe lip and one of the flanges is resilient so that, when the lip is forced into the space between the flanges, the one flange will be displaced from its equilibrium position and will be biased toward the lip. Thus, the flanges will be in sealing engagement with the lip on opposed sides of the same to thereby assure that dust, dirt and other foreign matter will not enter the tray at this junction.

Still another aspect of the present invention is the provision of stacking means on the bottom of the tray and the top of the lid whereby a number of storage units, each comprised of a tray covered by a lid, can be vertically stacked in a manner to avoid any substantial lateral or longitudinal movement of the units. To this end, each tray has projections which mate with a plurality of stacking devices on a lid therebelow, the stacking devices providing abutments for the inner extremities of the projections and stops for the adjacent side faces of the projections. Thus, the tray of each storage unit is effectively held against lateral or longitudinal movement with respect to the lid of the storage unit immediately therebelow.

The primary object of this invention is, therefore, to provide an improved handling and storage unit for use with wafer-like articles wherein the articles are stored in a tray on edge and engaged by the structure of the tray only at spaced, outer peripheral points to thereby leave the opposed surfaces of the articles substantially untouched and to assure effective isolation of the articles with respect to each other.

Another object of this invention is to provide a storage unit of the type described wherein structure is utilized to apply a predetermined downward force to the articles in the compartments of the tray when a lid covers the same to thereby prevent any relative movement of the articles in the compartments and thereby more assuredly provide for damage-free handling of the articles.

A further object of this invention is to provide a storage unit of the type described which has an improved Other objects of this invention will become apparent as the following specification progresses, reference being had to the accompanying drawings for a preferred embodiment of the storage unit of the invention.

FIG. 1 is a top plan view of the tray forming a part of the storage unit of the present invention;

FIG. 2 is a cross-sectional view taken along line 22 of FIG. 1;

FIG. 3 is a fragmentary cross-sectional view taken along line 33 of FIG. 2;

FIG. 4 is a side elevational view, partly broken away, of the tray with a packing tube disposed therewithin and with the lid removed from the tray;

FIG. 5 is an end elevational view, partly in section, of the tray and lid thereon, showing the way in which the packing tube is disposed to hold articles in the compartments of the tray;

FIG. 6 is a perspective view of the tray and lid show ing the stacking means therefor;

FIG. 7 is a fragmentary end elevational view of a pair of stacked trays with the bottom tray having a lid thereon; and

FIG. 8 is an enlarged, fragmentary cross-sectional view of the lid, showing the sealing means therefor.

The storage unit of the present invention is broadly denoted by the numeral 10 and includes an open top tray 12 and a lid 14 for movement into coupled relationship with tray 12 for covering the same. Tray 12 is provided with a plurality of open top compartments 16 for receiving wafer-like articles 18 therewithin when the articles are inserted into the tray through the open top thereof.

Tray 12 has a bottom 20, a pair of spaced, generally parallel sidewalls 22 and a pair of opposed end walls 24 spanning the distance between sidewalls 22. Bottom 20 and walls 22 and 24 are substantially imperforate so that, when the open top of the tray is closed by lid 14, articles 18 within the tray are closed to the atmosphere.

For purposes of illustration only, tray 12 is provided with two rows of compartments 16 with the compartment rows extending substantially parallel to sidewalls 22. To this end, a central partition 26 spans the distance between end walls 24 and is also parallel to sidewalls 22. Other tray configurations can be utilized, if desired. For instance, only a single compartment row may be provided or more than two such rows can be provided.

Bottom 20 in the vicinity of each compartment row is transversely V-shaped, as shown in FIG. 2, to define a pair of inner bottom, support surfaces 28 and 30 which converge toward each other as the lowermost extremity 32 of bottom 20 is approached. Also, the upper extremities of inner surfaces 30 converge toward each other as partition 26 is approached, whereby the portion of bottom 20 in the vicinity of surfaces 30 defines an inverted V-shaped recess 34 as shown in FIG. 2. Surfaces 28 and 30 are disposed for supporting an article 18 on edge with the outer periphery of the article being in substantially point contact relationship to surfaces 28 and 30.

Tray 12 has a plurality of spaced walls 36 extending upwardly from bottom 20 and defining respective compartments 16. Each wall 36 has a first side section 38, a second side section 40 and a central section 42 interconnecting the bottom margins of side sections 38 and 40, the latter having inner edges 44 and 46, respectively, which converge toward each other as central section 42 is approached. Thus, edges 44 and 46 define stretches extending upwardly relative to surfaces 30 and 28, respectively, for each compartment row and provide for the open top feature of the corresponding compartment.

Central portion 42 has a post 48 which is rigid to each side thereof respectively, posts 48 of each central portion 42 extending upwardly from the adjacent lowermost extremity 32 of bottom 20. Wall 36 is adapted to contact an article 18 only at spaced points on the outer periphery thereof when the article is supported on bottom surfaces 28 and 30. To this end, there is a three-point contact of an article 18 in the manner shown in FIGS. 2 and 3 when the article is disposed within a particular compartment 16. As shown in FIG. 2, article 18 in the left compartment row contacts the corresponding wall 36 at points 50 and 52 While the bottom extremity or peripheral margin of the article contacts post 48 of the next adjacent wall 36 as shown in FIG. 3. Thus, the article is in a slightly inclined position and is contacted by the structure of tray 12 at five points, all of which points are on the outer periphery or edge of the article itself. Thus, the opposed surfaces of the article are substantially out of engagement with the adjacent structure of tray 12.

The V-shaped configuration defined by bottom surfaces 28 and 30, when taken in conjunction with walls 36, allows tray 12 to receive and store articles 18 of different diameters as shown in FIG. 2. In each case, there will be a substantially five-point contact of the structure of the tray with the article and the article will generally assume the angularity shown in FIG. 3. The only difference will be that articles of different sizes will contact different points of tray 12. As shown in FIG. 2, the smaller article 18 on the right will contact points on bottom 20, wall 36 and post 48 which are lower than the corresponding points contacted by the larger diameter article 18 on the left. Regardless of the diameter of the article, the five-point contact will be achieved. A maximum diameter of the article will be determined by the width of each compartment 16.

Tray 12 is preferably formed with all of its components molded together, whereby the tray can define a one-piece construction through the use of well-established molding techniques. If molded, the tray construction will be relatively inexpensive to manufacture and can be formed from any one of a number of different materials, such as polypropylene or polyethylene. Moreover, the material can be colored, can be translucent or can be light-impervious for situations where articles 18 have photosensitive outer surfaces.

The configuration of tray 12 is suitable to permit articles 18 to be inserted and removed from the tray by vacuum holding techniques. The shapes of edges 44 and 46 of each wall 36 allow the upper outer periphery of each article to be disposed for engagement by a vacuum lifter and the latter can gently raise and lower an article without causing the article to engage the adjacent walls 36.

Lit 14 is imperforate and is preferably formed from the same material and in the same manner as tray 12. The lid thickness is substantially uniform throughout and its color can be the same or different from that of tray 12. It may be translucent for easy identification of contents without removing the lid and the lid can be made available in relatively soft material, such as polyethylene for use where the lid must be removed often. On the other hand, the lid can be of relatively rigid material, such as polypropylene, where the lid is to be removed only a relatively few number of times.

The lid has a pair of continuous, spaced flanges 54 and 56 adjacent to its outer periphery. These flanges depend from the lower surface 58 of lid 14 and are adapted to cooperate with a continuous lip 60 on the uppermost margin of tray 12 to provide an effective seal when lid 14 covers tray 12.

Flange 54 has a pair of side faces 62 and 64 of different lengths to present an edge 66 at the lowermost extremity of side face 64. The spacing between faces 62 and 64 is such that flange 54 is resilient, i.e., can be displaced from the full line position in FIG. 8 to the dashed line position.

Flange 56 has an inner face provided with a pair of surface segments 68 and 70 which converge toward each other to form an edge 72 substantially aligned with edge 66 of flange 54. The spacing between edges 66 and 72 is less than the transverse width of lip 60 as shown in FIG. 8 so that, when the lip is forced between flanges 54 and 56, flange 54 will be displaced to the dashed line position and the edge 66 will bite" into the inner surface 74 of lip 60. Thus, the lip will, in effect, be squeezed between the flanges and thereby be sealed by the engagement of the flanges with the lip.

Surface segment 70 of flange 56 is substantially complemental to the outer surface 76 of lip 60. Also, the uppermost and outermost edge 78 of lip 60 is in engagement with flange 56 at a location 80 (FIG. 8) adjacent to the junction between lid 14 and flange 56. Thus, flanges 54 and 56 are in sealing engagement with lip 60 at three points to provide a positive seal at all times when the lid covers the tray while flanges 54 and 56 form a labyrinthine path which is closed at the three points. Since flange 54 is resilient, it will return to its equilibrium position when the lid is removed from the tray.

Lid 14 is provided with stacking devices 82 on upper surface 84 (FIGS. 5 and 6) which position stacking feet or projections 86 rigidly connect to bottom 20 of tray 12. To this end, each projection 86 extends into recess 34 from the adjacent lowermost extremity 32 of bottom 20 as shown in FIG. 2, the projection being provided with fiat sides as shown in FIG. 4.

Each device 82 has a first section 88 which is to be disposed proximal to and alongside the outer side of a corresponding projection 86. A second section 90 is disposed at right angles to section 88 and is adapted to abut the innermost end 92 of the corresponding projection. Devices 82 are spaced apart in accordance with the spacing of projections 86 so that, when a tray 12 is placed on lid 14, projections 86 will be immediately disposed in the proper positions alongside sections 88 and abutting sections 90.

Means may be supplied to provide a downward force to articles 18 in compartments 16 when lid 14 closes tray 12 to thereby hold the article substantially immovable in the compartment. To this end, a plastic, resilient packing tube 92 may be positioned on the articles in the compartments and be of a size suflicient to cause deformation of the tube from a transversely circular or other configuration to the configuration shown in FIG. 5. As shown in FIG. 4, the unflexed tube projects above the lip 60 of tray 12. However, when lid 14 is placed on the tray, the lid deforms the tube and pushes the latter into the tray and against the outer peripheries of articles 18 which are disposed on edge in compartments 16. Thus, the articles are subjected to individual downward forces and are held generally in fixed locations in respective compartments. Thus, storage unit 10 can be subjected to shock and acceleration forces of relatively high values without causing damage to the articles in the tray.

Preferably, tube 92 is formed from a suitable thermoplastic material and has a restoring force selected to apply a substantially uniform downward force to the upper edges of a number of articles 18 of a given diameter or falling in a given range of diameters. Since the tube is loosely received in the tray on the articles, it will be readily removable from the tray when lid 14 has been removed therefrom.

In use, tray 12 is positioned to receive articles 18 and such articles can be deposited on edge by a vacuum lifter in the respective compartments. After the articles have been placed in the tray, the packing tubes 92 can be put on the articles, followed by the placing of lid 14 on the tray. The lid is forced downwardly so that lip 60 is forced in to the space between flanges 54 and 56. Flange 54 will deflect inwardy and will be biased against the inner surface 74 of lip 60 to thereby releasably hold the lip between the flanges. The storage unit 10 is then complete and a number of such storage units can be vertically stacked in the manner shown in FIG. 7 due to the provision of stacking devices 82 and projections 86.

When stored in tray 12, articles 18 will contact adjacent wall structure only at the fixed points on the outer peripheries of the article. Thus, the side faces of each article remain substantially untouched at all times so that the articles can be subjected to operations which require perfectly unmarred surfaces.

While one embodiment of the invention has been shown and described, it will be apparent that other adaptations and modifications of this device can be made without departing from the true spirit and scope of the invention.

What is claimed is:

1. A tray for wafer-like articles comprising: a receptacle having a bottom and means cooperating with said bottom to define therewith a plurality of compartments with each compartment adapted to receive a wafer-like article, said bottom being substantially V-shaped to present a pair of bottom surfaces for each compartment respectively with each pair of bottom surfaces converging toward each other as the lowermost extremity of the bottom is approached, said cooperating means including a pair of spaced stretches adjacent to each bottom surface respectively with the stretches extending upwardly relative to respective bottom surfaces, the stretches of each pair being spaced from the stretches of an adjacent pair by a dis tance greater than the thickness of a wafer-like article in the corresponding compartment with each stretch being disposed to engage the outer periphery of the article in point contacting relationship with respect thereto when the article is supported on the corresponding bottom surfaces.

2. A storage unit for wafer-like articles comprising: a tray having an upper margin and means therewithin defining a plurality of compartments with each compartment being generally vertically disposed and adapted to receive a wafer-like article on edge; a lid movable into coupled relationship to said upper margin and into covering relationship to said compartments; and means engageable with the lid and extending laterally from the upper extremity of a wafer-like article in a compartment for applying a predetermined downward force to said upper extremity of the article when the lid covers the compartment to thereby cause the article to be held in a generally fixed location in the compartment.

3. A storage unit as set forth in claim 2, wherein said force applying means includes a resilient device having a restoring force responsive to the coupled relationship between said tray and said lid.

4. A storage unit as set forth in claim 3, wherein said compartments are disposed in a row, force applying means including a resilient tube disposed above and longitudinally of said row.

5. In a storage unit for wafer-like articles comprising: a tray adapted to receive a plurality of wafer-like articles and having an upper margin defining a lip; a lid movable into covering relationship to said tray; and a pair of spaced flanges carried by said lid and disposed for receiving said lip therebetween when said lid covers said tray, one of said flanges being resilient and the spacing between the flanges being less than the thickness of the lip therebetween, whereby said one flange will be displaced with respect to its equilibrium position and will be biased toward said lip to thereby cause said flanges to be in sealing engagement with the lip when the lid covers the tray.

6. In a storage unit as set forth in claim 5, wherein said lip has an inner surface and an outer surface, said inner and outer surfaces flaring outwardly as the uppermost extremity of said lip is approached, the flange adjacent to said inner surface of the lip being resilient, the other flange having an inner face substantially complemental to said outer surface of the lip.

7. In a storage unit as set forth in claim 6, wherein the outer face of the inner flange is angularly disposed relative to said inner surface of the lip to present an edge in substantially line contact with said inner surface, said lip having an uppermost edge engageable with said other flange adjacent to its junction with said lid, whereby the lid has a three-point engagement with said flanges.

8. In a storage unit for wafer-like articles comprising: a tray adapted to receive a plurality of wafer-like articles and having a bottom provided with an inverted V-shaped outer surface to define a pair of relatively convergent surface segments; a pair of spaced projections secured to each surface segment respectively and extending outwardly therefrom toward the other surface segment; a lid movable into closing relationship to said tray; and a pair of stacking devices on said lid for the projections on each surface segment respectively, each of said devices extending upwardly from said lid and having a first, generally flat section proximal to the outer side of corresponding projection and a second, generally flat section abutting the outer end of the corresponding projection when the tray is supported on said lid, whereby the tray is rendered substantially immovable laterally and longitudinally of said p'rojections.

9. In a storage unit as set forth in claim 8, wherein said projections are generally parallel to each other and are molded to said tray, said devices being molded to said lid, the sections of each device being generally perpendicular to each other.

10. A storage unit for Wafer-like articles comprising: a tray having a bottom, a sidewall provided with a lip on its upper margin, and means cooperating with said bottom to define therewith a plurality of generally vertically disposed compartments with each compartment adapted to receive a wafer-like article on edge, said bottom being substantially V-shaped to present a pair of inner bottom surfaces for each compartment respectively with each pair of inner bottom surfaces converging toward each other as the lowermost extremity of said bottom is approached, said cooperating means including a pair of spaced stretches adjacent to each bottom surface respectively with the stretches extending upwardly relative to respective bottom surfaces, the stretches of each pair being spaced apart a distance greater than the thickness of a wafer-like article in the corresponding compartment with each stretch being disposed to engage the outer periphery of the article in point contacting relationship with respect thereto when the article is supported on the corresponding bottom surfaces; means in each compartment respectively adjacent to said bottom for engaging the lowermost margin of an article in the respective compartment in point contacting relationship with respect thereto; a lid movable onto said tray and into closing relationship to said compartments; a pair of spaced flanges carried by said lid and disposed for receiving said lip therebetween with said flanges being in sealing engagement to said lip; means engageable with the lid for applying a predetermined force to the upper extremity of a wafer-like article in a compartment when the lid covers the same; said bottom having an outer surface defining a recess; a pair of spaced projections for each side of said recess respectively, each pair of projections extending into said recess and toward the other side of the same; and a pair of stacking devices for each pair of projections respectively, each device being secured to and extending upwardly from said lid and having a first section proximal to the outer side of a corresponding projection and a second section abutting the outer end of the corresponding projection when the tray is supported on said lid to render the tray substantially immovable laterally and longitudinally of said projections.

11. A tray for wafer-like articles comprising: a receptacle having a bottom and means cooperating with said bottom to define therewith a plurality of compartments with each compartment adapted to receive a wafer-like article, said bottom being substantially V-shaped to present a pair of bottom surfaces for each compartment respectively with each pair of bottom surfaces converging toward each other as the lowermost extremity of the bottom is approached, said cooperating means including a plurality of spaced walls, each wall forming one boundary of an adjacent compartment and having a pair of spaced, innermost edges adjacent to and extending upwardly relative to respective bottom surfaces, each pair of adjacent walls being spaced apart a distance greater than the thickness of a wafer-like article in the corresponding compartment with the edges of each wall being disposed to engage the outer periphery of the article in point contacting relationship with respect thereto when the article is supported on the corresponding bottom surfaces.

12. A tray as set forth in claim 11, wherein each wall has a section extending upwardly from a respective bottom surface and is provided with means interconnecting the sections thereof adjacent to said lowermost extremity of said bottom.

13. A tray for wafer-like articles comprising: a receptacle having a bottom and means cooperating with said bottom to define therewith a plurality of compartments with each compartment adapted to receive a wafer-like article, said bottom being substantially V-shaped to present a pair of bottom surfaces for each compartment respectively with each pair of bottom surfaces converging toward each other as the lowermost extremity of the bottom is approached, said cooperating means including a pair of spaced stretches adjacent to each bottom surface respectively with the stretches extending upwardly relative to respective bottom surfaces, the stretches of each pair being spaced from the stretches of an adjacent pair by a distance greater than the thickness of a wafer-like article in the corresponding compartment with each stretch being disposed to engage the outer periphery of the article in point contacting relationship with respect thereto when the article is supported on the corresponding bottom surfaces; and means in each compartment, respectively, adjacent to said bottom for engaging the lowermost margin of an article in the respective compartment in point contacting relationship with respect thereto.

14. A tray as set forth in claim 13, wherein said cooperating means includes a plurality of walls with each wall forming one boundary of an adjacent compartment, said engaging means including a post secured to each wall respectively and being disposed above and extending upwardly relative to said lowermost extremity of said bottom.

15. A tray for wafer-like articles comprising: a receptacle having a bottom and means cooperating with said bottom to define therewith a plurality of compartments with each compartment adapted to receive a wafer-like article, said bottom being substantially V-shaped to present a pair of bottom surfaces for each compartment respectively with each pair of bottom surfaces converging toward each other as the lowermost extremity of the bottom is approached, said cooperating means including a number of spaced walls, each wall forming one boundary of an adjacent compartment and having a pair of spaced stretches adjacent to each bottom surface, respectively, with the stretches extending upwardly relative to respective bottom surfaces and being in alignment with the stretches of the walls, whereby said compartments are disposed in a row, the stretches of each pair being spaced from the stretches of an adjacent pair by a distance greater than the thickness of a wafer-like article in the corresponding compartment with each stretch being disposed to engage the outer periphery of the article in point contacting relationship with respect thereto when the article is supported on the corresponding bottom surfaces, said receptacle having a pair of spaced sides extending upwardly from said bottom, said sides, said bottom and said walls being molded together to form a one-piece construction.

References Cited UNITED STATES PATENTS 2,795,430 6/1957 Broad 206--72 3,349,937 10/1967 Duff et al. 206--1 3,346,137 10/1967 Ricci 220-97 JAMES B. MARBERT, Primary Examiner

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