The present disclosure relates generally to the field of integrated circuit (IC), and more particularly, to IC die transport apparatus and methods.
Tape and reel systems for transporting integrated circuit (IC) dies typically involve positioning a die in a pocket of a carrier tape. The pockets are shaped specifically to match the form factor of the dies therein, and the carrier tape is sealed with a cover tape to keep the dies contained.
Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. Embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.
Die transport apparatus and methods are disclosed herein. For example, in some embodiments, a die transport apparatus may include: a plurality of regularly arranged adhesive areas, wherein individual adhesive areas have a die contact surface; and a relief area recessed from the die contact surfaces.
Various ones of the embodiments disclosed herein may be particularly useful for bare die transportation and storage where existing technologies have failed. In particular, the rising demand for small electronic devices (e.g., smartphones, tablets, and wearables) has driven the development of low packaging and three dimensional stacking packaging. However, as chips grow thinner and increasingly complex, they may become more vulnerable during handling and transportation. Previously adequate conventional approaches to die handling, such as tape and reel, may experience multiple different failure modes as chips grow thinner.
One such failure mode may be referred to as “die migration” or “die out-of-pocket.” Die migration may occur when the carrier tape experiences vibration or shock during transportation. If there is enough space between the carrier tape and the cover tape, the dies may migrate out of the pocket through the gap between the carrier tape and the cover tape (and possibly get stuck between the carrier tape and the cover tape outside of the pocket). The likelihood of die migration increases as the height of the die decreases (due to the increased ability for the die to fit between the carrier tape and the cover tape outside of the pocket). The result may be significant downstream yield loss.
Another failure mode is die damage (e.g., die crack). Die damage may occur as the die is jostled against the carrier tape and the cover tape during transport. The damage may also occur when the die is “tilted” in the pocket (instead of sitting “flat”) and a chip attach module feeder attempts to engage and pick the die during assembly; the impact between the chip attach module feeder in the improperly positioned die may lead to die damage.
Conventional transportation and storage techniques may also be not adequate for the next generation of chip testing technology. For example, testing dies after they have been singulated from a wafer (referred to herein as “singulated die testing”), rather than when the dies are still joined at the wafer level (referred to herein as “wafer-level testing”), may be less expensive (since entire wafers need not be handled during testing) and more precise (because dies can be evaluated and rejected/accepted individually). However, some singulated die testing techniques may require open and random access to dies during processing so that a component placement system (e.g., a tape and reel die sort (TRDS) system) can pick and re-pick the same die for multiple tests without having to repeatedly peel and reseal a cover tape covering multiple dies.
Moreover, as noted above, conventional tape and reel systems and other conventional pocketed media, such as Joint Electronic Device Engineering Council (JEDEC) trays and waffle packs, include pockets for dies that are sized specifically for dies of a particular form factor. Each new or different die form factor thus requires a new pocketed media design and corresponding material development, tooling, material management, and training.
Various ones of the embodiments disclosed herein provide a “pocketless” transport apparatus which can accommodate substantially all die footprints and thicknesses. Use of such embodiments may not only substantially reduce the costs associated with introducing new and different dies to a manufacturing process, but may also enable the use of more advanced and precise testing techniques to improve manufacturing efficiency and yield.
Various embodiments of the apparatus disclosed herein may include an open and uniform surface to accommodate a wide range of die footprints and thicknesses so the apparatus is not specific to a particular die size. Dies may be randomly accessed without having to peel away a cover tape, and a single die can be picked and placed multiple times, providing process flexibility. Various embodiments disclosed herein may be picked and re-picked more than 250 times without exhibiting any degradation of the die transport apparatus. Various embodiments of the material adhesion and surface geometry for the apparatus disclosed herein may enable the apparatus to hold dies securely “horizontally” while releasing the die relatively easily when a component placement system applies a “vertical” picking force. Because the dies are adhesively fixed to the apparatus, the die crack and die migration risk associated with thin dies is mitigated or eliminated. Additionally, various embodiments of the apparatus disclosed herein may be cleanable and/or reusable, reducing the waste associated with disposable tape and reel systems.
In some embodiments, the adhesive areas 102 may be regularly arranged. For example, in the embodiment illustrated in
The dimensions of the footprints 178 of the adhesive areas 102 and the spacing between adhesive areas 102 may take any suitable values. For example, the spacing between adhesive areas 102 may be selected based on the size of the dies that will be transported by the die transport apparatus 100 so that a die disposed on transport apparatus 100 will contact two or more die contact surfaces 124. In some embodiments, a center of an adhesive area 102 may be spaced away from a center of a nearest neighbor adhesive area by a distance 106 between 0.5 millimeters and 3 millimeters.
Although
In some embodiments, individual adhesive areas 102 may have a profile with a curved portion. For example, the individual adhesive areas 102 of the die transport apparatus 100 depicted in
In some embodiments, the curved portion 118 of the adhesive areas 102 may be an upper portion of a profile of the adhesive areas 102. For example, in the embodiment of the die transport apparatus 100 illustrated in
Although
As discussed above, the dimensions of various components of the die transport apparatus may be selected to take any suitable values. For example, in some embodiments, the curved portion 118 may have the shape of the top half of an ellipse, the width 114 may be 1.2 millimeters, the height 120 may be 75 microns, the height 116 may be 75 microns, and the distance 106 may be 2 millimeters. In another example, the curved portion 118 may have the shape of the top half of an ellipse, the width 114 may be 1.2 millimeters, the height 120 may be 75 microns, the height 116 may be 75 microns, and the distance 106 may be 1.5 millimeters. In another example, the curved portion 118 may have the shape of the top half of an ellipse, the width 114 may be 0.8 millimeters, the height 120 may be 75 microns, the height 116 may be 75 microns, and the distance 106 may be 1.5 millimeters. In another example, the curved portion 118 may have the shape of the top half of an ellipse, the width 114 may be 0.8 millimeters, the height 120 may be 75 microns, the height 116 may be 75 microns, and the distance 106 may be 1.1 millimeters. These are simply examples, and other suitable dimensions may be used.
The selection of a profile for an adhesive area may depend on the amount and distribution of force desired on the dies transported by the die transport apparatus 100. Having a curved portion 118 for the die contact surface 124 of an adhesive area 102 (e.g., a concave curvature) may result in a reduced contact area between the die contact surface 124 and a die relative to an adhesive area with a broad “flat” die contact surface 124. Additionally, the maximum contact area between the die transport apparatus 100 and a transported die is limited because the relief area 104 is recessed away from the die during transport, and thus is not in contact with the die. Since the area of contact between a die and the die transport apparatus 100 is limited to a die contact surface 124 of desired geometry, the maximum adhesion between the die and the die transport apparatus 100 is also limited. The amount of force applied to a die during picking may be adjusted by changing the acceleration with which the die is picked (with higher accelerations corresponding to higher pick forces, but reduced process time). Example accelerations may be between 1000 millimeters per squared second and 12000 millimeters per squared second.
This selective contact between the die and the die transport apparatus 100 avoids the continuous wetting across the whole die that would occur if the die were placed on a continuous “flat” adhesive surface. If the die were in continuous “flat” contact with an adhesive, the picking force applied to the die by a component placement system when the die is picked up is distributed over the entire adhesive area and debonding only occurs when a “crack” unpredictably occurs between the die and the adhesive surface. Debonding in such a scenario is, therefore, unpredictable and difficult, and existing technologies that utilize adhesion (such as die picking from a mylar dicing tape) typically employ an additional release mechanism, such as using a die ejector to “poke” the tape from underneath the die while vacuum is applied to the dicing tape is partially delaminated from the die to facilitate pick up of the die via the vacuum nozzle.
When the adhesive contact surface is “patterned” as discussed herein with reference to the adhesive areas 102 and the relief area 104, the initial debonding crack is hardwired into the design and occurs at an edge of the contact area between the die and the adhesive areas 102. The picking force applied to the die is, therefore, concentrated into the crack region, leading to a well-controlled debonding process. The use of the apparatus and methods disclosed herein may provide improved debonding performance relative to conventional continuous wetting approaches in a manner analogous to the ease with which a piece of adhesive tape may be removed from a surface by peeling from an end relative to pulling the adhesive tape vertically from the middle.
In use, one or more dies may be disposed on the die transport apparatus 100 such that each individual die is in contact with one or more of the die contact surfaces 124 of the adhesive areas 102 but are not in contact with the relief area 104. The strength of the adhesive of the die contact surfaces 124 may be high enough to substantially prevent lateral and vertical movement of one or more dies during transport, but may be low enough to permit one or more dies to be removed from the die transport apparatus 100 by a component placement system (e.g., a pick-and-place machine or other piece of die handling manufacturing equipment. The strength of the adhesive of the adhesive areas 102 may be characterized by the peak tack force of the adhesive. In some embodiments, the individual adhesive areas 102 may have a peak tack force between 15 and 150 grams. In some embodiments, the individual adhesive areas 102 may have a peak tack force between 30 and 100 grams.
As indicated above, the base 122 of the die transport apparatus 100 may take any of a number of forms.
In the embodiment of the die transport apparatus 100 depicted in
In some embodiments, the continuous adhesive material 130 may be formed of TPE. Material properties of the continuous adhesive material 130 may be selected as suitable. For example, in some embodiments, the continuous adhesive material 130 may have a tensile strength between 7 and 10 megaPascals, and a hardness of 29 to 39 shore A. In some embodiments in which the continuous adhesive material is formed of TPE, the TPE may include styrene ethylene butylene styrene (SEBS), polyolefin (PO), and/or mineral oil.
In embodiments including the support film 136, the support film 136 may provide mechanical support for the adhesive material on “top” of the support film 136. In some embodiments, the adhesive material may be relatively elastic on its own (e.g., “rubbery”), and the support film 136 may be “rigid” enough to mechanically support the adhesive material to keep the adhesive material from deforming as it is handled and as forces are applied. The support film 136 may be formed of any suitable material, such as polyethylene terephthalate (PET) and/or PET/polyethylene (PE) dual layer with PE as an adhesion promoter (PE). The support film 136 may have any suitable thickness. For example, in some embodiments, the support film 136 may have a thickness of approximately 4.3 thousandths of an inch (e.g., +/−.2 millimeters).
In embodiments including the second adhesive material 142, the second adhesive material 142 may couple two non-adhesive surfaces together. For example, as discussed below with reference to
The tray 152 may take any suitable form for use in die transport and storage applications. For example, in some embodiments, the tray 152 may be formed from a polycarbonate material (e.g., a carbon nanotube material). For example, the tray 152 may be a carbon nanotube reinforced polycarbonate, which may be selected based on a mechanical strength requirements of the tray 152 and/or an electrostatic discharge (ESD) requirement. The tray 152 may be substantially rigid and may be formed of materials that do not significantly flake during handling. The tray 152 may also be electrically passive so that it does not store static electricity that may discharge and damage the dies transported by the die transport apparatus 100. In some embodiments, the tray 152 may have the dimensions of existing trays used in die handling systems to facilitate the use of the die transport apparatus 100 in legacy systems. For example, the tray 152 may be a JEDEC tray.
As noted above, the footprints 178 of the adhesive areas 102 may take any suitable shape. For example,
As noted above, the profiles of the adhesive areas 102 may take any suitable shape. For example,
In some embodiments, the assembly 1500 may further include a coversheet to protect the continuous adhesive material 130 after manufacture but prior to use in transporting dies. The coversheet may be formed of any suitable material, such as PET.
In some embodiments, the die transport apparatus 100 of
At 2302, an IC die disposed on a die transport apparatus 100 may be provided. The die transport apparatus 100 may include multiple regularly arranged adhesive areas, wherein individual adhesive areas have a die contact surface. The die transport apparatus 100 may include relief areas recessed from the die contact surfaces. The IC die may be disposed on the die transport apparatus 100 such that the IC die is in contact with the die contact services of more than one of the multiple adhesive areas.
At 2304, the IC die may be picked off the die transport apparatus 100. The IC die may be picked off the die transport apparatus 100 by applying a force to the IC die in a direction opposite to an adhesive force between the IC die and the die contact surfaces of the more than one of the multiple adhesive areas.
At 2402, a sheet of adhesive material may be patterned with multiple regularly arranged adhesive areas and a relief area. Individual adhesive areas may have a die contact surface and the release area may be recessed from the die contact surfaces. In some embodiments, patterning the sheet of adhesive material may include embossing a texture onto a first face of the sheet of adhesive material.
At 2404, the patterned sheet of adhesive material (formed at 2402) may be coupled to a second material. The second material may include a second adhesive material (e.g., the second adhesive material 142, coupled to the patterned sheet of adhesive material via a support film 136) or a tray (e.g., the tray 152). In some embodiments, the patterned sheet of adhesive material may be coupled directly to a tray. In some embodiments, the patterned sheet of adhesive material may be coupled to a tray via one or more intermediate layers (e.g., a support film 136 and a second adhesive material 142). In some embodiments, the patterned sheet of adhesive material may not be coupled to a tray.
In some embodiments, the die transport apparatus 100 may be cleanable to remove silicon and other debris from any adhesive or non-adhesive surfaces of the die transport apparatus 100. Examples of cleaning techniques that may be used with various embodiments include an air blow to dislodge foreign material, deionized water cleaning (with optional fine brushing), and tack roller cleaning (in which a stronger adhesive is used to “stick” away foreign material from adhesive surfaces of the die transport apparatus 100).
The following paragraphs provide examples of various ones of the embodiments disclosed herein.
Example 1 may include a die transport apparatus, comprising: a plurality of regularly arranged adhesive areas, wherein individual adhesive areas have a die contact surface; and a relief area recessed from the die contact surfaces.
Example 2 may include the die transport apparatus of example 1, wherein the plurality of adhesive areas and the relief area are different portions of a continuous adhesive material.
Example 3 may include the die transport apparatus of example 2, wherein the continuous adhesive material has a first face and a second face opposite the first face, the plurality of adhesive areas are located at the first face, and the die transport apparatus further comprises a support film coupled to the second face.
Example 4 may include the die transport apparatus of example 3, wherein the continuous adhesive material is formed of a first adhesive material, the support film has a first face and a second face opposite the first face of the support film, the first face of the support film is in contact with the second face of the continuous adhesive material, and the die transport apparatus further comprises a second adhesive material coupled to the second face of the support film.
Example 5 may include the die transport apparatus of example 4, wherein the second adhesive material has a first face and a second face opposite the first face of the second adhesive material, the first face of the second adhesive material is in contact with the second face of the support film, and the die transport apparatus further includes a tray coupled to the second face of the second adhesive material.
Example 6 may include the die transport apparatus of example 2, wherein the continuous adhesive material has a first face and a second face opposite the first face, the plurality of adhesive areas are located at the first face, and the die transport apparatus further comprises a tray coupled to the second face.
Example 7 may include the die transport apparatus of any of examples 1-6, wherein the relief area is not adhesive.
Example 8 may include the die transport apparatus of any of examples 1-6, wherein the relief area is adhesive.
Example 9 may include the die transport apparatus of any of examples 1-6, wherein individual adhesive areas have a profile with a curved portion.
Example 10 may include the die transport apparatus of example 9, wherein the curved portion has a height between 25 microns and 150 microns.
Example 11 may include the die transport apparatus of example 9, wherein the curved portion has a width between 0.5 millimeters and 2 millimeters.
Example 12 may include the die transport apparatus of example 9, wherein the curved portion is an upper portion and the profiles of the individual adhesive areas have lower portions including side walls.
Example 13 may include the die transport apparatus of example 12, wherein the vertical side walls have a height between 25 microns and 150 microns.
Example 14 may include the die transport apparatus of any of examples 1-6, wherein centers of the individual adhesive areas are spaced away from centers of their nearest neighbor adhesive areas by a distance between 0.5 millimeters and 3 millimeters.
Example 15 may include the die transport apparatus of any of examples 1-6, wherein the individual adhesive areas are hexagonally arranged.
Example 16 may include the die transport apparatus of any of examples 1-6, wherein the individual adhesive areas have a peak tack force between 15 and 150 grams.
Example 17 may include a transport arrangement for an integrated circuit (IC) die, comprising: a die transport apparatus, including: a plurality of regularly arranged adhesive areas, wherein individual adhesive areas have a die contact surface, and a relief area recessed from the die contact surfaces; and the IC die disposed on the die transport apparatus such that the IC die is in contact with the die contact surfaces of more than one of the plurality of adhesive areas.
Example 18 may include the transport arrangement of example 17, wherein the IC die is a first IC die, and wherein the transport arrangement further comprises: at least one additional IC die.
Example 19 may include the transport arrangement of example 18, wherein the first IC die has a first length and a first width, and wherein the at least one additional IC die includes at least one IC die having a length or a width that is different from the first length or the first width, respectively.
Example 20 may include a method of processing an integrated circuit (IC) die, comprising: providing an IC die disposed on a die transport apparatus, wherein: the die transport apparatus includes a plurality of regularly arranged adhesive areas, wherein individual adhesive areas have a die contact surface, the die transport apparatus includes a relief area recessed from the die contact surfaces, and the IC die is disposed on the die transport apparatus such that the IC die is in contact with the die contact surfaces of more than one of the plurality of adhesive areas; and picking the IC die off the die transport apparatus by applying a force to the IC die in a direction opposite to an adhesive force between the IC die in the die contact surfaces of the more than one of the plurality of adhesive areas.
Example 21 may include the method of example 20, further comprising: after picking the IC die off the die transport apparatus, repositioning the IC die on the die transport apparatus such that the IC die is in contact with the die contact surfaces of more than one of the plurality of adhesive areas; and after repositioning the IC die on the die transport apparatus, re-picking the IC die off the die transport apparatus; wherein the die contact services of the die transport apparatus are continuously exposed during the picking, repositioning, and re-picking.
Example 22 may include a method of manufacturing a die transport apparatus, comprising: patterning a sheet of adhesive material with a plurality of regularly arranged adhesive areas and a relief area, wherein individual adhesive areas have a die contact surface and the relief area is recessed from the die contact surfaces; and coupling the patterned sheet of adhesive material to a second material, wherein the second material includes a second adhesive material or a tray.
Example 23 may include the method of example 22, wherein patterning the sheet of adhesive material includes embossing a texture onto a first face of the sheet of adhesive material, wherein the sheet of adhesive material has a second face opposite the first face and wherein the sheet of adhesive material has a support film coupled to the second face.
Example 24 may include the method of example 23, wherein the second material includes the second adhesive material, and wherein coupling the patterned sheet of adhesive material to the second adhesive material includes performing a conversion process to couple the patterned sheet of adhesive material to the second adhesive material and to couple the second adhesive material to a release liner.