TWM551615U - Single and dual stage wafer cushion and wafer separator - Google Patents

Description

Single and dual wafer cushions and wafer spacers

The present invention is a buffer device for damping and dividing a wafer in a wafer carrier, in particular, a ring formed by molding or folding, and having a composite curved surface to provide various degrees of buffering. Buffer device.

Generally, when wafers are placed in a wafer carrier for transportation, the wafers are not pressed against the wall of the wafer carrier. In any case, the wafers are likely to partially or completely Wafers are subject to wear and tear, and some manufacturers use buffers such as patent-pending separators, gasket rings or bubble rings to support the outer edges of the wafers and absorb shocks and movements during transit.

The key to preventing wear on the wafer surface during transport of the wafers is to limit their radial movement. The buffer device can be used for wafers with or without circuits on the surface, and may or may not be stacked on the spacers. Solder wafers are also suitable for such buffers because the spacers only touch the periphery of the wafer and cannot move radially into the area containing the solder joints. If a wafer carrier that reduces the radial movement of the wafer is used, the buffer is used. The device can enhance the protection of the wafers.

If a solid separator is used, the wafer may be damaged and the wafer may not be sufficiently isolated to prevent movement. If a bubble separator is used, damage and aging may occur, and some buffer products and patents have been sold on the market. Patents for such products are disclosed in the text.

For example, U.S. Patent No. 3,392, 824, issued July 16, 1968, and U.S. Patent No. 5,366,079, issued Nov. 22, 1994, both of which disclose a circuit wafer buffer packaging system in which the wafer buffer system is a Bellville type. A shallow disc or a shallow disc cushion having a fixed foot. The cushion of the buffer system of the wafer disclosed in these patents causes radial movement on the outer surface of the wafer and collides with the wafer carrier. This in turn causes damage to the wafers.

For example, U.S. Patent No. 6,926,150, issued on Aug. 9, 2005, and U.S. Patent No. 7,530, 462, issued on May 12, 2009, both of which are incorporated herein by reference. Related to the spacers between the wafers, which provide a cushion and a gap spacer, and in some cases, a bubble pad is placed over the entire wafer surface or only on the outer edge of the wafer.

For example, U.S. Patent No. 7,423,362, issued on Sep. 16, 2008, and U.S. Patent No. 7,611,766, issued on Nov. 3, 2009, the disclosure of each of the entire disclosures of And the gap between the wafer carriers, the pads can be made from a variety of materials, from plastic to paper, and are available in a variety of shapes to accommodate the gap between the wafer and the wafer carrier.

For example, U.S. Patent No. 6,926,150, issued on Aug. 9, 2005, U.S. Patent No. 7,317,312 issued on Jan. 08, 2008, and U.S. Patent No. 2002/0144927, filed on Oct. 10, 2002, both patents disclose Buffer pad or ring of the wafer in the buffer box. The main variable of the strength of the bubble pad is the life of the bubble. If the structure of the bubble pad is broken, the bubble pad can also become the cause of pollution. It can also become a contaminant smear wafer, and in some cases, the bubble pad contacts the entire wafer surface and causes wafer deformation.

In summary, the wafer container requires a buffer device that has various degrees of buffering and can be adapted to slight variations in the top and bottom of the wafer.

One purpose of the present single-stage and dual-stage wafer cushions is to cooperate with a wafer carrier that can be placed on the bottom of the wafer carrier or on the top of the wafer in the carrier. The circular cushion can be expanded and contracted to accommodate variations in wafer thickness and variations in the transport housing. The thickness variation of individual wafers can be small, and when the variations are accumulated, the gap will be larger than expected. The circular cushion provides minimal force on the wafer and housing, making the housing easy to open and further limiting the movement of the wafer within the wafer carrier.

The purpose of the present single-stage and dual-stage wafer cushions is to be fabricated into a casing that fits into a wafer carrier. The shape of the wafer cushion is a pair of folded rings whose outer diameter is Open, the outer edge of the ring provides maximum expansion, so that only the outer edge of the ring will contact the outer edge of the wafer, minimizing the contact area of the wafer, allowing any axial load On the outer peripheral surface of the wafer, particularly when a wafer is placed on a separator disk, damage to the inner surface of the wafer can be minimized and shrinkage at the center of the wafer can be minimized.

One purpose of the present wafer spacer is to provide separation between a stack of wafers to prevent damage to the wafers and parts placed or bonded to the wafer.

One purpose of the inventive wafer spacer is to provide a plurality of venting holes around the outer edge of the wafer spacer, allowing air flow between the wafers, which reduces the flat wafers to be placed together or pulled apart from each other. The pressure or vacuum, the number and shape of the vents may vary depending on the size of the wafer or other factors.

Another purpose of the single-stage and dual-stage wafer cushions is that the material of the wafer cushion is shrinkable and shock-absorbing before the vibration is transmitted to the wafer. The material can be molded, padded, cast or vulcanization.

Another purpose of the single-stage and double-stage wafer cushions is that only half of the "V" of the wafer cushion cross-sectional shape is a ring fit, joint or clip to the bottom or bottom cover, thus The cover provides the missing half of the "V" limit feature. This design features a single or dual segment feature that allows single or multiple arms or "V-ring" stacks to take up excess space in the box.

Another purpose of the present single-stage and dual-stage wafer cushions is that the wafer cushion is made of a non-absorbent material to prevent debris or contaminants from entering the wafer cushion.

Another purpose of the present single-stage and dual-stage wafer cushion is that the wafer cushion uses an edge folding portion as a first segment cushion and a second intermediate portion as a second segment cushion. Two different buffering forces are applied, and the buffering force is linear with respect to the amount of compression applied to the outer surface of the wafer cushion relative to the use of a single-segment design.

First, please refer to the drawings and the second figure, which are respectively a perspective view and a perspective sectional view of a preferred embodiment of the present invention. As shown in the figure, it discloses a single-stage and two-stage wafer cushion. 20, the single-stage and dual-stage wafer cushion 20 is a ring-shaped wafer cushion, and the inside of the wafer cushion 20 is open, as shown in the second figure. In the embodiment, the crystal The circular cushion 20 is placed on a plurality of wafers 40, and the wafers 40 are stacked one on another, and a plurality of annular spacers 50 are placed on the wafers. Between 40, each of the spacers 50 can be electrically connected to the final product or an external circuit through a plurality of wafer substrates having small solder balls. The wafer substrates generally have a solid height, and the spacers 50 that cannot be adjusted. It is placed between the wafers 40 to prevent adjacent wafers 40 from contacting each other and causing damage to the solder balls.

In the embodiment, the wafer cushion 20 is a spacer design using a double elastic modulus or a variable elastic coefficient. The wafer cushion 20 is sequentially defined with a first segment and a ㄧ in the radial direction from the inside to the outside. In the second segment, the first segment has a coefficient of elasticity that makes it easy to load and close the top of the wafer carrier (not shown). Conversely, the second segment has a higher modulus of elasticity if the wafer carrier falls or is improper By transporting, energy can be absorbed to protect the wafers 40 or the wafer substrates.

The wafer cushion 20 is a V-ring structure having a V-shaped cross section and having the elasticity or buffering effect of protecting the wafer 40. This design is suitable for injection molding, vulcanization or the like. In the manufacturing method of the profiled section, the two free ends of the wafer cushion 20 are respectively defined as an upper end portion 23 and a lower end portion 34, and the upper end portion 23 has contact with the wafer 40 and the wafer carrier 21 If the wafer carrier 21 has excess space, a plurality of wafer cushions 20 may be disposed. The wafer cushion 20 has the advantage that only the upper end portion 23 and the lower end portion 34 contact the crystal. The periphery of the circle 40, when used for soldering wafers, generally has a 3 mm 保留 retention area for the circuit or solder joint to extend inwardly from the periphery of the wafer 40. In this embodiment, the wafer 40 contact point has a slight a protruding circular area (not shown), but this feature is not necessary, and the upper end portion 23 of the wafer cushion 20 has a slightly protruding area to provide an additional gap of any solder joint near the forbidden area, as shown in the second figure. Showing two separate wafer cushions 20, including an upper buffer wafer And a wafer cushion, wherein the lower wafer cushion is placed in the wafer carrier 21 and located below the wafer 40, and the lower wafer cushion upper end 23 passes through the bottom surface thereof. The 22 series can support the gap of the bottom surface of the wafer carrier 21.

At least part of the weight of the wafer 40 and the spacers 50 is carried by the lower wafer cushion, that is, the wafers 40 at least partially compress the lower wafer cushion, so that the lower wafer buffer The first segment of the pad or the folded portion 31 of the inner diameter 30 of the lower wafer cushion is at least partially compressed. As shown in the second figure, the gap of the second segment still sees the intermediate surface 32 when the first segment is compressed. Internal and external, and as shown in the second figure, the outer edge of the lower end 34 of the upper wafer cushion contacts the outer edge of the wafer 40, and the remaining inner diameter of the wafer cushion 20 The surface is suspended above the wafer 40 and is not in contact with the surface of the wafer 40. If a cover (not shown) is mounted over the wafer carrier 21, the upper cover compresses the wafer buffer. The upper surface 35 of the pad is loaded with pressure by the lower wafer cushion, so that the upper and lower wafer cushions can mutually buffer external forces.

Referring to the third embodiment, which is a perspective view of a second preferred embodiment of the present invention, in the embodiment, the wafer cushion 20 has an inner edge 60 for reinforcing the structural strength of the folded portion 65. Further, a ㄧ clip surface is provided to facilitate removal of the wafer cushion 20, and the wafer cushion 20 defines an outer diameter 64, the length of which enables the wafer carrier 20 to be mounted in the wafer carrier 21, the crystal The two free ends of the circular cushion 20 respectively define an upper surface 61 and a lower surface 62. The upper surface 61 and the lower surface 62 have a small axial curve to maintain the upper and lower edges of the wafer 40. The surface contact, in addition, considers that one end portion 66 of the wafer cushion 20 can be cut, has a sawtooth mark or a curved zigzag shape toward the folded portion 65 of the inner edge 60. In this embodiment, the end portion 66 is empty. The area includes the upper and lower edges of the wafer cushion 20 or the arm, and the wafer cushion 20 can be made to have only one arm interrupted, and the remaining arm is continuous. When the first stage is compressed, the area is compressed. The inner surface of the outer diameter 64 of the wafer cushion 20 contacts and remains from the folded portion 65 to the outer surface Gap, the second section may provide a cushioning effect.

Please refer to the fourth embodiment, which is a perspective view of a third preferred embodiment of the present invention. The figure only briefly illustrates the third preferred embodiment. For a more detailed description, please refer to the fifth to the tenth drawings. As shown in the embodiment, the wafer cushion 20 is extended with a plurality of bendable arms at the folding portions 70, 75. When the wafer cushion 20 is mounted in the wafer carrier 21, the wafer is Above and below the buffer pad 20, the upper surface 71 is in contact with the upper surface and the lower surface of the wafer 40, and the outer diameter 73 of the wafer cushion is sized so that it can be moved only slightly within the wafer carrier 21. Or no movement, as shown in the fifth and sixth figures, the wafer cushion 20 is expanded in the wafer carrier 21 and subjected to the first stage of compression.

Please refer to the fifth and sixth figures, which are perspective views and another perspective view of the third embodiment of the present invention, respectively, showing that the single-stage and dual-stage wafer cushions are mounted on the folded wafer and the wafer. The carrier is uncovered and the single-stage and dual-stage wafer cushions are mounted on the folded wafer and the wafer carrier is covered. As shown in the fifth and sixth figures, the lower wafer cushion is compressed. The bottom surface 22 contacts the wafer carrier 21, and the upper end portion 23 contacts the lowermost wafer 40, and the wafers 40 are separated by a spacer 50 located between the wafers 40, as shown in FIG. When the upper wafer cushion is uncompressed, the first section of the wafer cushion is uncompressed and the extension arms 76, 77 are not in contact, and the lower bottom surface 72 of the upper wafer cushion contacts the uppermost wafer 40. The outer surface of the wafer cushion and the lower surface 71 provide a straight line for the tangential curved surface to contact the wafer 40 and the upper cover 25 or the wafer carrier 21. The outer edges 74 and 78 of the cushion Near the outer diameter of the wafer 40.

When the lower portion of the upper cover 25 contacts the wafer cushion, since the folding portion 70 causes the extension arms 76, 77 of the cushion to be brought together, if the wafer carrier 21 and the upper cover 25 are interlocked with each other, the upper cover 25 will press the outer edge 26 of the wafer cushion, and the intermediate portions of the extension arms 76, 77 will contact each other and form a first length of cushion.

As shown in the seventh figure, a side cross-sectional view of a third preferred embodiment of the present invention, wherein the wafer cushion is uncompressed, as shown in the eighth figure, another side view of the third preferred embodiment of the present creation A cross-sectional view in which the wafer cushion is initially compressed. As shown in FIG. 9 , a side view of the third preferred embodiment of the present invention, wherein the wafer cushion is partially compressed, as shown in FIG. As shown, a further side sectional view of the third preferred embodiment of the present invention, in which the wafer cushion is fully compressed; from the seventh drawing, the wafer cushion 20 is in an uncompressed natural condition without any The external forces 100 and 101 cause the wafer cushion 20 to compress, and the folded portions 70, 75 form a curve to maintain the extension arms 76, 77 as separate U-shaped or V-shaped structures, and the upper surface of the wafer cushion 20 The lower surface 71 has a maximum width, and the outer edges 74, 78 of the wafer cushion 20 are of equal length, but it is also considered that they may have different radii. The center position or the second section of the extension arms 76, 77 is Separate and no contact.

As shown in the eighth figure, the external forces 100 and 101 cause the extension arms 76, 77 to compress and the inner range to begin to compress. As shown in the ninth figure, the ends 70, 73 of the wafer cushion 20 and the extensions The upper bend portion or folds 70, 75 of the arms 76, 77 are curved as the force increases until the inner surfaces of the extension arms 76, 77 contact each other, the external forces 100, 101 creating a first load or elastic constant surface.

Since the length of the arm of the extension arms 76, 77 has been shortened, the elastic resistance of the segment causes a buffer change. In this embodiment, the contact between the extension arms 76, 77 is shown at the midpoint, but the middle must be considered. The contact causes a different buffering force curve at any point of the extending arms 76, 77. As shown in the ninth figure, the wafer carrier 21 is closed and the normal shipping mode is known from the shape of the wafer cushion 20. Referring to the ninth and tenth drawings, an additional external force 102, 103 is additionally applied between the external forces 100, 101 to provide a second load or elastic constant, and is applied to the seventh to ninth figures. The elastic load constant of the wafer cushion 20 is different, and the elastic constant may be according to the shape, the angle of the wafer cushion 20, and the constant or variable thickness of the folded portion or the foot section. Linearly upgraded or nonlinear elastic constant.

As shown in the tenth figure, a possible impact load condition is displayed, such as a fall or impact of the wafer carrier 21, which continues to push the outer ends of the extension arms 76, 77, the extension arms The outer ends of 76, 77 are compressed in the radial direction. It must be noted that even if such a load forms a gap 79, the wafer cushion 20 can still be further buffered, and the wafer cushion 20 is still located therein. Component gaps on wafer 40.

Please refer to the tenth and twelfth drawings, which are a perspective sectional view and another perspective sectional view of the fourth preferred embodiment of the present invention, and the twelfth figure shows the wafer cushion connection. The wafer carrier 21 has no wafer 40 mounted thereon.

The "unilateral cushion" is an embodiment of the wafer cushion 29 shown in the above illustration, which has a half V-shaped cross section, wherein the wafer cushion 29 is fixed or clamped. Fixed to an upper cover or bottom cover, so that it has another half V-shaped limiting function. This design can be implemented as a single-stage or double-segment. This design allows multiple V-type wafer cushions to be placed in the design. The excess space in the wafer carrier 21, the bottom 90 of the wafer cushion 29 can be coupled to the wafer carrier 21 (or the upper cover 25). Although the single-sided wafer cushion 29 has only one arm, Having similar structures, such as folds 91, 92 and intermediate bends 93 to form a separation point between the first and second sections of the wafer cushion 29, the wafer cushion 29 having a ridge outer edge 95, The size of the wafer carrier 21 extends along the peripheral wall of the wafer carrier 21 and is formed with a gap for free movement and bending. The upper edge 96 of the wafer cushion 29 is contactable with the wafer spacer or wafer (not shown). If the wafer 40 overlaps most of the surface of the wafer cushion 29, the wafer cushion 29 Edge 94 may provide additional cushioning of shocks.

In this embodiment, the wafer cushion 29 is made of a suitable material, and the hardness may be between Shore and D hardness of 10 to 70, and other hardnesses are based on the buffer material and the height and weight of the wafers. In addition, it is also considered that the upper and lower wafer cushions are installed in the wafer carrier 21, have different properties, structures and weights, or the wafers 40 are placed on the wafer cushion 29. Above or below the fact that the surface shape from the middle bend to the outer contact can be curved, or have different cross sections, or multiple steps, planes, bends or bends to achieve non-linear buffering or multi-segment wafers. Cushion.

The thirteenth drawing is a plan view of the wafer spacer 110, the fourteenth embodiment is a bottom view of an embodiment of the wafer spacer 110, and the fifteenth drawing is a cross-sectional view of the dicing line 15-15 of the wafer spacer 110, the sixteenth The wafer spacer 110 has an open central portion and an outer peripheral portion. In this embodiment, the outer peripheral portion is an outer lip 111, and The outer lip 111 has a bottom surface 117 and a top surface 118. The bottom surface 117 and the top surface 118 provide space between adjacent wafers 40 (as shown in the first figure). The wafer 40 is placed. On the intermediate surface 116, the wafer spacer 110 further has an intermediate wall. In the embodiment, the intermediate wall is an intermediate lip 113 for mitigating the axial load impact of the wafers 40. Again, the lower bottom surface 117 and the intermediate surface 116 are slightly angled from the inner diameter 112 to the outer diameter 111 to provide placement and clamping of the wafers 40.

The intermediate face 116 provides between adjacent wafers 40 for the wafer initial face on the wafer 40, the space of the part, the bond pads, the solder bumps, the solder balls, the chemically immutable interconnections, and the wires. The lower bottom surface 117 of the wafer spacer 110 (as shown in FIG. 14) has a plurality of vent holes 114 sized to form an air cushion chamber under the wafer 40, and the space The venting opening 114 extends from the inner diameter 112 to the outer diameter 111. The venting opening 114 is V-shaped, U-shaped, square-shaped, rectangular, or a combination thereof, when a wafer 40 is removed from or placed on a stack of wafers 40. The venting opening 114 allows air to pass under the wafer 40 to reduce vacuum and pressure, and in this embodiment has 12 venting holes 114, but is not limited, depending on the size of the wafer 40. The venting holes 114 may have a geometry of more than 12, and a circular aperture 115 is formed on the outer side of the wafer spacer 110 to disperse the exhausted air to prevent concentrated airflow. The wafer spacer 110 does not have to correspond to the circulation. Direction, so the wafer spacer 110 can be placed Circulation directions are not necessarily aligned with the vent hole arrangement 114.

The single-stage and double-stage wafer cushions and wafer spacers described above are only the preferred embodiments of the present invention. When the scope of implementation is not limited thereto, the simple scope of the patent scope and the description of the invention is as follows. Equivalent changes and modifications are still covered by this creation patent.

20‧‧‧ Wafer cushion
21‧‧‧ wafer carrier
22‧‧‧ bottom
23‧‧‧Upper end
25‧‧‧Upper cover
26‧‧‧ outer edge
29‧‧‧ Wafer cushion
30‧‧‧Inner diameter
31‧‧‧Folding Department
32‧‧‧Intermediate surface
34‧‧‧Bottom
35‧‧‧ upper surface
40‧‧‧ wafer
50‧‧‧Parts
60‧‧‧ inner edge
61‧‧‧ upper surface
62‧‧‧ lower surface
64‧‧‧ outside diameter
65‧‧‧Folding
66‧‧‧End
70‧‧‧Folding Department
71‧‧‧Upper and lower surfaces
72‧‧‧ underside
73‧‧‧ outside diameter
74‧‧‧ outer edge
75‧‧‧Folding
76‧‧‧Extension arm
77‧‧‧Extension arm
78‧‧‧ outer edge
79‧‧‧ gap
90‧‧‧ bottom
91‧‧‧Folding
92‧‧‧Folding
93‧‧‧Bending
94‧‧‧ lower edge
95‧‧‧ outer edge
96‧‧‧Upper edge
100‧‧‧ External force
101‧‧‧External force
102‧‧‧External force
103‧‧‧External force
110‧‧‧ Wafer dividers
111‧‧‧Outer lip
112‧‧‧Inner diameter
113‧‧‧Intermediate lip
114‧‧‧ventilation holes
115‧‧‧ hole
116‧‧‧Interface
117‧‧‧ underside
118‧‧‧ top surface

The first picture is a perspective view of the single-stage and dual-stage wafer cushions. The second figure is a cross-sectional view of the single-stage and double-stage wafer cushions. The third figure is a schematic diagram of a second embodiment of the authored single-stage and dual-stage wafer cushion. The fourth figure is a schematic diagram of a third embodiment of the authored single-stage and dual-stage wafer cushion. The fifth figure is a schematic diagram of a single-stage and two-stage wafer cushion on a stack of wafers. The wafer carrier is not equipped with a top cover. The sixth figure is a schematic view of a single stack of wafers with a dual-segment wafer cushion mounted on a stack of wafers. The seventh figure is a cross-sectional view of the created single-stage and dual-stage wafer cushions in an uncompressed state. The eighth figure is a cross-sectional view of the original single-stage and double-stage wafer cushions in a state in which the creation is initially compressed. The ninth figure is a cross-sectional view of the portion in which the single-stage and double-stage wafer cushion portions are compressed. The tenth figure is a cross-sectional view of the created single-stage and two-stage wafer cushions in a compressed state. The eleventh figure is a schematic view of a fourth embodiment of the present single-stage and dual-stage wafer cushion. The twelfth figure is the fourth embodiment of the present invention, the single-stage and two-stage wafer cushions are combined with the bottom case, and no wafer is mounted on the wafer cushion. A thirteenth view is a top plan view of an embodiment of a wafer spacer. Figure 14 is a bottom plan view of an embodiment of a wafer spacer. The fifteenth view is a cross-sectional view of the wafer divider tangent 15-15. Figure 16 is an external side view of the wafer divider tangent 16-16.

110‧‧‧ Wafer dividers

111‧‧‧Outer lip

112‧‧‧Inner diameter

113‧‧‧Intermediate lip

116‧‧‧Interface

Claims (19)

A wafer spacer comprising: an outer peripheral portion; the outer peripheral portion having a top surface and a bottom surface; a wafer cushion substantially in the shape of a ring; an intermediate surface having a diameter smaller than the outer peripheral portion and disposed in the Between the top surface and the bottom surface, a wafer is placed, and the intermediate surface is angled; the intermediate surface extends to an inner diameter to provide an open central region; and at least one venting hole is disposed on the bottom surface, The vent hole extends from the inner diameter to the outer peripheral portion; thereby, when the wafer is placed on the wafer spacer, only the top surface of the outer peripheral portion contacts the wafer. A wafer separator according to claim 1, wherein the at least one vent hole is sized to form an air-cushion chamber under the wafer. A wafer spacer according to claim 1, wherein the open central region provides a space for the parts on the wafer, the bonding pads, the solder bumps, the solder balls, and the chemical changes. Connections and wires. A wafer spacer according to claim 1, wherein the open central region provides a space for a part on an adjacent wafer, a bonding pad, a solder bump, a solder ball, and no chemical change. Connected to each other and wires. A wafer separator according to claim 1, wherein the wafer is 200 or 300 mm. A wafer spacer according to claim 1, wherein the wafer is stacked on the top surface and the bottom surface without any load placed on the wafer. A wafer separator according to claim 1, wherein the at least one venting hole is V-shaped, U-shaped, square, rectangular, or a combination thereof. A wafer spacer according to claim 1, wherein the outer peripheral portion is sized to fit within a wafer carrier. A wafer separator according to claim 1, wherein the at least one venting hole is a plurality of venting holes, and the venting holes are circumferentially disposed at an equal interval. A wafer separator according to claim 9, wherein the vent holes are variable according to a diameter of the outer peripheral portion. A wafer separator according to claim 9, wherein the vent holes are variable according to a gas flow rate under the wafer. A wafer separator according to claim 1, wherein the at least one venting hole extends radially from the inner diameter to the outer peripheral portion. A wafer spacer according to claim 1, wherein the bottom surface is angled. A wafer spacer according to claim 1, wherein the wafer spacer is made of a material having a Shore D hardness of 10 to 70. A wafer separator according to claim 1, wherein the vent hole end point is a radial shape or a circular shape at the outer peripheral portion. A wafer spacer according to the above aspect of the invention, further comprising an intermediate wall disposed between the outer peripheral portion and the inner diameter. A wafer separator according to claim 16, wherein the intermediate wall size corresponds to an outer diameter of a wafer. The wafer spacer of claim 1, wherein the venting hole is disposed between a bottom surface of a first wafer spacer and a top surface of a second wafer spacer for exhausting, Exhausting on a surface of a wafer. A wafer separator according to claim 1, wherein the spacer has no circulation direction.