Method and system for shipping semiconductor wafers
According to one embodiment of the invention, an apparatus includes a plurality of coin stacks of semiconductor wafers. Each coin stack includes a plurality of semiconductor wafers separated from an adjacent wafer by a wafer separator disposed within a coin stack carrier. The apparatus also includes a shipping box having the plurality of coin stacks disposed therein such that each of the wafers in each of the coin stack carriers has a vertical orientation.
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This invention relates generally to semiconductor carriers and more particularly to a method and system for shipping semiconductor wafers.
BACKGROUND OF THE INVENTIONIn shipping semiconductor wafers, the wafers are often delivered in a container filled with the wafers in a horizontally stacked configuration. The containers are sometimes referred to as coin stacks or coin stack boxes. Typically there is a gap between the perimeter of the wafers and the inside of the coin box, which allows some movement of the wafers.
Many wafers have interconnection conductor material portions (e.g., solder bumps, bond pads, post-passivation interconnects) protruding from the wafer surface. These interconnection portions are subject to being damaged when shipped in coin stack boxes due to rubbing of one wafer against the other through movement of the wafers within the coin box. Damage may result in electrical short circuits on the wafers as well as other undesirable outcomes.
Another shipping method involves placing the wafers in a container that has a plurality of vertical slots, and shipping the wafers in a vertical configuration. This approach is often costly and results in bulky containers.
SUMMARY OF THE INVENTIONAccording to one embodiment of the invention, an apparatus includes a plurality of coin stacks of semiconductor wafers. Each coin stack includes a plurality of semiconductor wafers separated from an adjacent wafer by a wafer separator disposed within a coin stack carrier. The apparatus also includes a shipping box having the plurality of coin stacks disposed therein such that each of the wafers in each of the coin stack carriers has a vertical orientation.
Some embodiments of the invention provide numerous technical advantages. Some embodiments may benefit from some, none, or all of these advantages. According to one embodiment a method and apparatus are provided that allow shipping of semiconductor wafers with reduced likelihood of damage to the wafer. Such an advantage results, in one embodiment, from disposing coin stacks of wafers in a vertical orientation within a shipping box, which addresses undesired bending of the wafers that is likely to occur when the wafers are disposed horizontally. This results in more reliable wafers.
Other technical advantages may be readily ascertainable by one of skill in the art.
BRIEF DESCRIPTION OF THE DRAWINGSFor a more complete understanding of the invention, and for further features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:
Embodiments of the invention and its advantages are best understood by referring to
Damage may occur to wafers 16 rubbing against adjacent wafers or separators 18. Typically, each coin stack 12 is disposed in shipping box 10 in a horizontal fashion such that wafers 16 are stacked on top of each other as opposed to oriented vertically, as illustrated. Conventionally, separators were used between adjacent wafers to reduce wear on a protective overcoat on the wafers. More recently, particular separators have been invented to protect metallization features on the wafers extending beyond the protective overcoat. An example of such separators is also described in co-pending application entitled “Protective Interleaf for Stacked Wafer Shipping,” having a Ser. No. 10/417,499, filed Apr. 17, 2003. As described in that application, a ring-shaped separator 18 (shown best in
The teachings of the present invention recognize, however, that the use of such a ring-shaped separator 18 (or similarly-shaped separators) can result in damage to wafers 16 when coin stacks 12 are stored or shipped in a horizontal fashion, such as is illustrated in
This approach cuts against conventional wisdom, as heretofore coin stacks having been utilized and oriented in a horizontal configuration at least in part to address mechanical edge damage concerns that may result from disposing wafers vertically. The teachings of the invention recognize; however, that although coin stacks have been designed and used for the explicit purpose of horizontal shipping, that an improved shipping technique can benefit from the use of coin stacks in a vertical configuration. The teachings of the invention further recognize that the use of a ring-shaped separator, which can be effective, nevertheless may result in damage due to bending of the wafers, which are not supported at their center when stacked horizontally, and that this problem may be addressed through vertical stacking.
Additional details of one example separator 18 are described below; however, any suitable separator 18 may be used that reduces contact between adjacent wafers. As shown in
As shown in
Referring to
Although the present invention has been described in detail, it should be understood that the various changes, substitutions, and alterations can be made hereto without departing from the spirit and scope of the invention as defined by the appended claim.
Claims
1. A method for shipping semiconductor wafers each having metallization subject to damage comprising:
- providing a plurality of coin stacks, each coin stack comprising a plurality of semiconductor wafers separated from adjacent wafers by a ring-shaped wafer separator formed from plastic and disposed within a coin stack carrier, each semiconductor wafer having a plurality of interconnection conductor material portions, each coin stack further comprising first and second protection barriers formed from foam; and
- positioning each of the plurality of coin stack carriers in a shipping box such that each of the wafers in each of the coin stack carriers has a vertical orientation, the shipping box having a vertical arrow disposed thereon to indicate the orientation the shipping box should be maintained to maintain the wafers in a vertical orientation.
2. The method of claim 1, wherein the plurality of interconnection conductor material portions comprise a plurality of solder bumps.
3. The method of claim 1, wherein the plurality of interconnection conductor material portions comprise a plurality of flip chip bumps.
4. The method of claim 1, wherein the plurality of interconnection conductor material portions comprise a plurality of bond pads.
5. The method of claim 2, wherein the wafer separator comprises:
- a first surface;
- a first recessed portion formed in the wafer separator, the first recessed portion having an outer perimeter shape corresponding to an outer perimeter shape of the wafers, and the first recessed portion having a first depth from the first surface; and
- a second recessed portion formed in the wafer separator and located at least partially within the first recessed portion, the second recessed portion having a bottom surface at a second depth from the first surface, wherein the second depth is greater than the first depth.
6. A method for shipping semiconductor wafers comprising:
- providing a plurality of coin stacks, each coin stack comprising a plurality of semiconductor wafers each separated from an adjacent wafer by a wafer separator and also including first and second protection barriers disposed at opposite ends of the coin stack;
- positioning each of the plurality of coin stack carriers in a shipping box such that each of the wafers in each of the coin stack carriers has a vertical orientation; and
- providing visual indicia on the shipping box of the orientation in which the shipping box should be maintained to maintain the wafers in a vertical orientation.
7. The method of claim 6, wherein the plurality of wafer separators are ring-shaped.
8. The method of claim 6, wherein the first and second protection barriers are formed from foam.
9. The method of claim 6, wherein the coin stack carrier is formed from plastic.
10. The method of claim 6, wherein the visual indicia comprises an arrow pointing upwards.
11. The method of claim 6, wherein each of the semiconductor wafers comprises a plurality of interconnection conductor material portions.
12. The method of claim 11, wherein the plurality of interconnection conductor material portions comprise a plurality of solder bumps.
13. The method of claim 11, wherein the plurality of interconnection conductor material portions comprise a plurality of flip chip bumps.
14. The method of claim 11, wherein the plurality of interconnection conductor material portions comprise a plurality of bond pads.
15. The method of claim 11, wherein the wafer separator comprises:
- a first surface;
- a first recessed portion formed in the wafer separator, the first recessed portion having an outer perimeter shape corresponding to an outer perimeter shape of the wafers, and the first recessed portion having a first depth from the first surface; and
- a second recessed portion formed in the wafer separator and located at least partially within the first recessed portion, the second recessed portion having a second surface at a second depth from the first surface, wherein the second depth is greater than the first depth, and wherein the second depth minus the first depth is greater than a maximum height of the interconnection conductor material portions.
16. The method of claim 6, wherein the visual indication comprises writing.
17. An apparatus comprising:
- a plurality of coin stacks each comprising a plurality of semiconductor wafers disposed within a coin stack carrier, each coin stack comprising a plurality of semiconductor wafers separated from an adjacent wafer by a wafer separator; and
- a shipping box having the plurality of coin stacks disposed therein such that each of the wafers in each of the coin stack carriers has a vertical orientation.
18. The apparatus of claim 17, wherein the shipping box comprises visual indicia formed therein of the orientation in which the shipping box should be maintained to maintain the wafers in a vertical orientation.
19. The apparatus of claim 17, wherein the visual indicia comprises an arrow pointing upwards.
20. The apparatus of claim 17, wherein each of the semiconductor wafers comprises a plurality of flip chip bumps.
Type: Application
Filed: Oct 6, 2003
Publication Date: Apr 7, 2005
Applicant:
Inventors: Edgardo Hortzleza (Garland, TX), Rodel Arquisal
Application Number: 10/680,976