Through via nub reveal method and structure

Information

  • Patent Grant
  • 8324511
  • Patent Number
    8,324,511
  • Date Filed
    Tuesday, April 6, 2010
    14 years ago
  • Date Issued
    Tuesday, December 4, 2012
    11 years ago
Abstract
A method includes applying a backside passivation layer to an inactive surface of an electronic component and to enclose a through via nub protruding from the inactive surface. The method further includes laser ablating the backside passivation layer to reveal a portion of the through via nub. The backside passivation layer is formed of a low cost organic material. Further, by using a laser ablation process, the backside passivation layer is removed in a controlled manner to reveal the portion of the through via nub. Further, by using a laser ablation process, the resulting thickness of the backside passivation layer is set to a desired value in a controlled manner. Further, by using a laser ablation process, the fabrication cost is reduced as compared to the use of chemical mechanical polish.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention


The present application relates to the field of electronics, and more particularly, to methods of forming electronic component structures.


2. Description of the Related Art


To allow backside contact to an electronic component such as an integrated circuit die, electrically conductive through vias are formed in the electronic component. The through vias extend entirely through the electronic component from the active surface to the inactive surface of electronic component.


The inactive surface of the electronic component is etched to reveal through via nubs, i.e., portions, of the through vias. A chemical vapor deposition (CVD) inorganic dielectric layer such as a plasma enhanced chemical vapor deposition (PECVD) silicon oxide is deposited on the inactive surface of the electronic component and completely encloses the through via nubs. Unfortunately, formation of a CVD inorganic dielectric layer is relatively expensive thus increasing the fabrication cost.


The inorganic dielectric layer is thinned using chemical mechanical polish (CMP) to reveal the ends of the through via nubs. More particularly, the inorganic dielectric layer and a portion of the through via nubs are thinned such that the exposed ends of the through via nubs are parallel to and coplanar with the exterior surface of the inorganic dielectric layer. Unfortunately, chemical mechanical polish is relatively expensive thus increasing the fabrication cost.


SUMMARY OF THE INVENTION

In accordance with one embodiment, a method includes applying a backside passivation layer to an inactive surface of an electronic component and to enclose a through via nub protruding from the inactive surface. The method further includes laser ablating the backside passivation layer to reveal a portion of the through via nub.


In one embodiment, the backside passivation layer is formed of a low cost organic material. By forming the backside passivation layer of an organic material, the fabrication cost is reduced as compared to the formation of a relatively expensive CVD inorganic dielectric layer.


Further, by using a laser ablation process, the backside passivation layer is removed in a controlled manner to reveal the portion of the through via nub. Further, by using a laser ablation process, the resulting thickness of the backside passivation layer is set to a desired value in a controlled manner. Further, by using a laser ablation process, the fabrication cost is reduced as compared to the use of chemical mechanical polish.


These and other features of the present invention will be more readily apparent from the detailed description set forth below taken in conjunction with the accompanying drawings.





BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1 is a block diagram of a through via nub reveal method in accordance with one embodiment;



FIG. 2 is a cross-sectional view of an array including a substrate including a plurality of electronic components in accordance with one embodiment;



FIG. 3 is a cross-sectional view of the array of FIG. 2 at a later stage during fabrication in accordance with one embodiment;



FIG. 4 is a perspective views of the region IV of the array of FIG. 3 in accordance with one embodiment;



FIG. 5 is a cross-sectional view of the array of FIG. 3 at a later stage during fabrication in accordance with one embodiment;



FIG. 6 is a cross-sectional view of the array of FIG. 5 at a later stage during fabrication in accordance with one embodiment;



FIG. 7 is a cross-sectional view of the region VII of the array of FIG. 6 at a later stage during fabrication in accordance with one embodiment;



FIG. 8 is a cross-sectional view of the array of FIG. 5 at a later stage during fabrication in accordance with another embodiment; and



FIG. 9 is a cross-sectional view of the region IX of the array of FIG. 8 at a later stage during fabrication in accordance with one embodiment.





In the following description, the same or similar elements are labeled with the same or similar reference numbers.


DETAILED DESCRIPTION

As an overview and in accordance with one embodiment, referring to FIG. 5, a backside passivation layer 550 is applied to an inactive surface 212 of an electronic component 204 and to enclose through via nubs 344 protruding from inactive surface 212. Referring to FIG. 6, backside passivation layer 550 is laser ablated to reveal top portions 656 of through via nubs 344.


In one embodiment, backside passivation layer 550 is formed of a low cost organic material. By forming backside passivation layer 550 of an organic material, the fabrication cost is reduced as compared to the formation of a relatively expensive CVD inorganic dielectric layer.


Further, by using a laser ablation process, backside passivation layer 550 is removed in a controlled manner to reveal top portions 656 of through via nubs 344. Further, by using a laser ablation process, the resulting thickness of backside passivation layer 550 is set to a desired value in a controlled manner. Further, by using a laser ablation process, the fabrication cost is reduced as compared to the use of chemical mechanical polish.


Now in more detail, FIG. 1 is a block diagram of a through via nub reveal method 100 in accordance with one embodiment. FIG. 2 is a cross-sectional view of an array 200 including a substrate 202 including a plurality of electronic components 204 in accordance with one embodiment.


In one embodiment, substrate 202 is a silicon wafer. Substrate 202 includes a frontside, e.g., first, surface 206 and an opposite backside, e.g., second, surface 208.


Substrate 202 includes electronic components 204 integrally connected to one another. For simplicity, the term substrate 202 shall be used herein and it is to be understood that this term generally includes electronic components 204.


In one embodiment, electronic components 204 are integrated circuit chips, e.g., active components. However, in other embodiments, electronic components 204 are passive components such as capacitors, resistors, or inductors.


In accordance with this embodiment, electronic components 204 include active surfaces 210 and opposite inactive surfaces 212. Active surfaces 210 and inactive surfaces 212 generally define frontside surface 206 and backside surface 208 of substrate 202, respectively. For simplicity, the terms frontside surface 206 and backside surface 208 shall be used herein and it is to be understood that these terms generally include active surfaces 210 and inactive surfaces 212, respectively. Electronic components 204 further includes bond pads 214 formed on active surfaces 210.


Electronic components 204 are delineated from one another by singulation streets 216. Substrate 202 is singulated, e.g., sawed, along singulation streets 216 to separate electronic components 204 from one another at a later stage during fabrication.


Referring now to FIGS. 1 and 2, in a form through vias operation 102, through vias 218 are formed though electronic components 104. Through vias 218 include dielectric through via passivation linings 220 and electrically conductive through via columns 222.


Illustratively, through via apertures 224 are formed, e.g., by laser drilling, into electronic components 104 from frontside surface 206. Through via passivation linings 220, e.g., silicon oxide (SiO2), are formed on the sidewalls of through via apertures 224. In one embodiment, the silicon of substrate 202 exposed within through via apertures 224 is oxidized to form through via passivation linings 220. In another embodiment, a dielectric material is deposited within through via apertures 224 to form through via passivation linings 220. In one embodiment, through via passivation linings 220 are 0.15 μm thick although have other values in other embodiments.


Through via columns 222 are formed within through via passivation linings 220. Illustratively, an electrically conductive material, e.g., copper or tungsten, is deposited, e.g., plated, within through via passivation linings 220 to form through via columns 222. Through via passivation linings 220 electrically isolate through via columns 222 from substrate 202.


Substrate 202 is then thinned, sometimes called backgrinded, to expose through vias 218 at backside surface 208 of substrate 202. In one embodiment, the pitch of through vias 218 is in the range of 10 μm to 30 μm although the pitch has other values in other embodiments.


Through via passivation linings 220 are hollow cylinders and through via columns 222 are solid cylinders formed within through via passivation linings 220.


Through vias 218 are cylindrical in shape although may taper slightly between frontside surface 206 and backside surface 208. More particularly, referring to a first through via 218A of the plurality of through vias 218, through via 218A include a cylindrical outer surface 226, a circular active surface end 228, and a circular inactive surface end 230.


Cylindrical outer surface 226 is defined by the cylindrical outer surface of through via passivation lining 220 of through via 218A. Cylindrical outer surface 226 has a longitudinal axis L perpendicular to frontside surface 206 and backside surface 208. Cylindrical outer surface 226 extends from active surface end 228 to inactive surface end 230. Although the terms parallel, perpendicular, and similar terms are used herein to describe various features, in light of this disclosure, those of skill in the art will understand that the features may not be exactly parallel or perpendicular but only substantially parallel or perpendicular to within accepted manufacturing tolerances.


Active surface end 228 is circular in accordance with this embodiment. Active surface end 228 is coplanar with and parallel to frontside surface 206 of substrate 202.


Active surface end 228 includes a circular active surface column end 232 surrounded by an annular active surface passivation lining end 234. Active surface column end 232 is the lower end of through via column 222 and thus is electrically conductive. Active surface passivation lining end 234 is the lower end of through via passivation lining 220 and thus is a dielectric.


Similarly, inactive surface end 230 is circular in accordance with this embodiment. Inactive surface end 230 is coplanar with and parallel to backside surface 208 of substrate 202.


Inactive surface end 230 includes a circular inactive surface column end 236 surrounded by an annular inactive surface passivation lining end 238. Inactive surface column end 236 is the upper end of through via column 222 and thus is electrically conductive. Inactive surface passivation lining end 238 is the upper end of through via passivation lining 220 and thus is a dielectric.


Although only a single through via 218A is described in detail, in light of this disclosure, those of skill in the art will understand that all of the through vias 218 include cylindrical outer surfaces 226, active surface ends 228, inactive surface ends 230, active surface column ends 232, active surface passivation lining ends 234, inactive surface column ends 236, and inactive surface passivation lining ends 238 in a similar manner.


As illustrated in FIG. 2, frontside surface 206 of substrate 202 is mounted to a carrier 240, e.g., a silicon carrier, by an adhesive 242. In one embodiment, the thickness of carrier 240 is 700 μm although has other values in other embodiments.



FIG. 3 is a cross-sectional view of array 200 of FIG. 2 at a later stage during fabrication in accordance with one embodiment. FIG. 4 is a perspective views of the region IV of array 200 of FIG. 3 in accordance with one embodiment. Referring now to FIGS. 1, 2, 3, and 4 together, from form through vias operation 102, flow moves to an etch backside surface to expose nubs of through vias operation 104.


In etch backside surface to expose nubs of through vias operation 104, backside surface 208 of substrate 202 is blanket etched, i.e., removed, to expose through via nubs 344 of through vias 218. In one embodiment, backside surface 208 is removed using a selective etch that etches substrate 202, e.g., silicon, but does not etch through vias 218, e.g., silicon oxide and copper.


Generally, in etch backside surface to expose nubs of through vias operation 104, substrate 202 is thinned from backside surface 208. Stated another way, a portion of substrate 202 at backside surface 208 as illustrated in FIG. 2 is removed to form a recessed backside surface 346 as illustrated in FIG. 3.


Accordingly, after performance of etch backside surface to expose nubs of through vias operation 104, substrate 102 includes a recessed backside surface 346. Inactive surfaces 212 generally define recessed backside surface 346. For simplicity, the term recessed backside surface 346 shall be used herein and it is to be understood that this term generally include inactive surfaces 212.


The distance D2 between recessed backside surface 346 and frontside surface 206 as illustrated in FIG. 3 is less than the distance D1 between backside surface 208 and frontside surface 206 as illustrated in FIG. 2. Stated another way, substrate 202 is thinned from an initial thickness equal to distance D1 (FIG. 2) to a final thickness equal to distance D2 (FIG. 3).


In one embodiment, distance D1 is 50 μm and distance D2 is 48 μm although distances D1, D2 have other values in other embodiments.


However, through vias 218 are not thinned and thus through via nubs 344 are exposed as illustrated in FIG. 3. Through vias 218 are sometimes said to stand proud of recessed backside surface 346.


Through via nubs 344 are the upper portions of through vias 218 including the upper portions of through via passivation linings 220 and through via columns 222 exposed and uncovered by substrate 202. Through via nubs 344 are cylindrical protrusions protruding upwards from recessed backside surface 346.


Referring again to through via 218A, through via nub 344 includes a cylindrical nub outer surface 348 and inactive surface end 230. Cylindrical nub outer surface 348 is the upper, e.g., first, portion of cylindrical outer surface 226 of through via 218A exposed from substrate 202. A cylindrical enclosed, e.g., second, portion 349 of cylindrical outer surface 226 of through via 218A remains enclosed within and in contact with substrate 202.


Inactive surface end 230 is spaced above recessed backside surface 346. More particularly, a distance D3 exists between inactive surface end 230 and recessed backside surface 346. Distance D3 is equal to the difference between the initial thickness (distance D1 as illustrated in FIG. 2) of substrate 202 prior to performance of etch backside surface to expose nubs of through vias operation 104 and the final thickness (distance D2) of substrate 202 after performance of etch backside surface to expose nubs of through vias operation 104, i.e., D3=D1-D2. In one embodiment, distance D3 is 2 μm although distance D3 has other values in other embodiments.


Although only a single through via 218A is described in detail, in light of this disclosure, those of skill in the art will understand that all of the through vias 218 include through via nubs 344 including cylindrical nub outer surfaces 348 in a similar manner.



FIG. 5 is a cross-sectional view of array 200 of FIG. 3 at a later stage during fabrication in accordance with one embodiment. Referring now to FIGS. 1 and 5 together, from etch backside surface to expose nubs of through vias operation 104, flow moves to an apply backside passivation layer operation 106. In apply backside passivation layer operation 106, a backside passivation layer 550 is applied to recessed backside surface 346 of substrate 202 and through via nubs 344.


Backside passivation layer 550 includes a lower, e.g., first, passivation layer surface 552 attached to recessed backside surface 346. Backside passivation layer 550 further includes an opposite upper, e.g., second, passivation layer surface 554, which is planar. Backside passivation layer 550 is a dielectric material.


In one embodiment, backside passivation layer 550 is formed from an organic material such as polyimide (PI), polybutyloxide (PBO), benzocyclobutene (BCB), a polymer, or other carbon containing material. By forming backside passivation layer 550 of an organic material, the fabrication cost is reduced as compared to the formation of a relatively expensive CVD inorganic dielectric layer. In one embodiment, backside passivation layer 550 is formed by spinning or spraying an organic material onto recessed backside surface 346.


Backside passivation layer 550 has a thickness equal to a distance D4 between lower passivation layer surface 552 and upper passivation layer surface 554. In one embodiment, distance D4 is in the range of 3 μm to 4 μm with a thickness control of ±0.1 μm although distance D4 has other values in other embodiments.


Distance D4 is greater than the distance D3 that through via nubs 344 protrude above recessed backside surface 346. Accordingly, through via nubs 344 including cylindrical nub outer surface 348 and inactive surface ends 230 are completely enclosed within backside passivation layer 550. More particularly, backside passivation layer 550 exists between inactive surface ends 230 of through vias 218 and upper passivation layer surface 554.



FIG. 6 is a cross-sectional view of array 200 of FIG. 5 at a later stage during fabrication in accordance with one embodiment. Referring now to FIGS. 1, 5, and 6 together, from apply backside passivation layer operation 106, flow moves to a laser ablate backside passivation layer to reveal portions of through via nubs operation 108. In laser ablate backside passivation layer to reveal portions of through via nubs operation 108, backside passivation layer 550 is laser ablated to reveal top, e.g., first, portions 656 of through via nubs 344.


In accordance with this embodiment, a laser, e.g., an excimer laser, is directed at upper passivation layer surface 554 of backside passivation layer 550. This laser laser-ablates, i.e., removes, upper passivation layer surface 554 to expose top portions 656 of through via nubs 344 of through vias 218. Upper passivation layer surface 554 is laser-ablated, sometimes call global or mass ablated, while through via nubs 344 are not removed.


In one embodiment, the laser used during the laser ablation process selectively laser-ablates backside passivation layer 550 and does not laser ablate through via nubs 344 even though the laser is directed at through via nubs 344. In another embodiment, the laser used during the laser ablation process is directed only at backside passivation layer 550 to avoid laser ablation of through via nubs 344.


Generally, in laser ablate backside passivation layer to reveal portions of through via nubs operation 108, backside passivation layer 550 is thinned from upper passivation layer surface 554. Stated another way, a portion of backside passivation layer 550 at upper passivation layer surface 554 as illustrated in FIG. 5 is removed to form a recessed upper passivation layer surface 658 as illustrated in FIG. 6.


Accordingly, after performance of laser ablate backside passivation layer to reveal portions of through via nubs operation 108, backside passivation layer 550 includes a recessed upper passivation layer surface 658. The distance D4 between upper passivation layer surface 554 and lower passivation layer surface 552 as illustrated in FIG. 5 is greater than the distance D5 between recessed upper passivation layer surface 658 and lower passivation layer surface 552 as illustrated in FIG. 6. Stated another way, backside passivation layer 550 is thinned from an initial thickness equal to distance D4 (FIG. 5) to a final thickness equal to distance D5 (FIG. 6).


However, through vias 218 are not thinned and top portions 656 of through via nubs 344 are exposed. Top portions 656 of through via nubs 344 are the upper portions of through via nubs 344 including the upper portions of through via passivation linings 220 and through via columns 222 exposed and uncovered by backside passivation layer 550. Top portions 656 of through via nubs 344 are cylindrical protrusions protruding upwards from recessed upper passivation layer surface 658.


Referring again to through via 218A, top portion 656 of through via nub 344 of through via 218A includes a cylindrical top portion outer surface 660 and inactive surface end 230. Cylindrical top portion outer surface 660 is the upper, e.g., first, portion of cylindrical nub outer surface 348 of through via nub 344 of through via 218A exposed from backside passivation layer 550. A cylindrical enclosed, e.g., second, portion 662 of cylindrical nub outer surface 348 of through via nub 344 of through via 218A remains enclosed within and in contact with backside passivation layer 550.


Inactive surface end 230 is spaced above recessed upper passivation layer surface 658. More particularly, a distance D6 exists between inactive surface end 230 and recessed upper passivation layer surface 658. Distance D6 is equal to the difference between the distance D3 which through via nubs 344 protrude above lower passivation layer surface 552 and distance D5 between lower passivation layer surface 552 and recessed upper passivation layer surface 658, i.e., D6=D3−D5.


Although only a single through via 218A is described in detail, in light of this disclosure, those of skill in the art will understand that all of the through vias 218 include top portions 656, cylindrical top portion outer surfaces 660 and cylindrical enclosed portions 662 in a similar manner.


By using a laser ablation process, backside passivation layer 550 is removed in a controlled manner around top portions 656 of through via nubs 344. Further, by using a laser ablation process, the resulting thickness (equal to distance D5) of backside passivation layer 550 is set to a desired value in a controlled manner, e.g., to within +0.1 μm. Further, by using a laser ablation process, the fabrication cost is reduced as compared to the use of chemical mechanical polish.


In one embodiment, any residue on recessed upper passivation layer surface 658 and top portions 656 of through via nubs 344 is removed, e.g., using a soft etch, plasma clean, or combination of these techniques.



FIG. 7 is a cross-sectional view of the region VII of array 200 of FIG. 6 at a later stage during fabrication in accordance with one embodiment. Referring now to FIGS. 1 and 7 together, from laser ablate backside passivation layer to reveal portions of through via nubs operation 108, flow moves to a form circuit pattern on backside passivation layer operation 110.


In form circuit pattern on backside passivation layer operation 110, an electrically conductive circuit pattern 764 is formed on backside passivation layer 550. More particularly, circuit pattern 764 is formed on recessed upper passivation layer surface 658 of backside passivation layer 550. Backside passivation layer 550 electrically isolates circuit pattern 764 from substrate 202, i.e., from recessed backside surface 346.


Circuit pattern 764 is electrically connected to through vias 218. More particularly, circuit pattern 764 contacts and is electrically connected to inactive surface column ends 236 of through via columns 222 of through vias 218. As top portions 656 of through via nubs 344 protrude above recessed upper passivation layer surface 658, electrical interconnection between circuit pattern 764 and through vias 218 is facilitated.


In one embodiment, circuit pattern 764 includes terminals and/or traces. Illustratively, a terminal, sometimes called pad, provides an electrically conductive area to which other electrical conductors, e.g., solder balls, are mounted. A trace is a long yet narrow electrical conductor extending in a horizontal direction substantially parallel to recessed upper passivation layer surface 658 that electrically interconnects other electrical conductors, e.g., terminals of circuit pattern 764, with one another. Although terminals and traces are set forth as examples of features of circuit pattern 764, in light of this disclosure, those of skill in the art will understand that circuit pattern 764 is formed with other electrically conductive features in other embodiments depending upon the particular application.



FIG. 8 is a cross-sectional view of array 200 of FIG. 5 at a later stage during fabrication in accordance with another embodiment. Referring now to FIGS. 1, 5, and 8 together, from apply backside passivation layer operation 106, flow moves to laser ablate backside passivation layer to reveal portions of through via nubs operation 108. In laser ablate backside passivation layer to reveal portions of through via nubs operation 108, backside passivation layer 550 is laser ablated to reveal contact area, e.g., first, portions 866 of inactive surface ends 230 of through via nubs 344.


In accordance with this embodiment, a laser is directed at upper passivation layer surface 554 of backside passivation layer 550. This laser laser-ablates, i.e., removes, selective portions of upper passivation layer surface 554 to reveal contact area portions 866 of inactive surface ends 230 of through via nubs 344 of through vias 218. Upper passivation layer surface 554 is laser-ablated, i.e., removed, while through via nubs 344 are not removed.


Generally, in laser ablate backside passivation layer to reveal portions of through via nubs operation 108, circuit pattern apertures 868 are formed in backside passivation layer 550 to expose contact area portions 866 of inactive surface ends 230 of through via nubs 344 of through vias 218. Circuit pattern apertures 868 extend between upper passivation layer surface 554 and contact area portions 866. Circuit pattern apertures 868 have a diameter DIA1 less than a diameter DIA2 of through vias 218. In one embodiment, diameter DIA2 of through vias 218 is less than or equal to 20 μm, e.g., is in the range of 5 μm to 10 μm, although diameter DIA2 has other values in other embodiments.


Accordingly, contact area portions 866 of inactive surface ends 230 are the portions of inactive surface ends 230 exposed and uncovered by circuit pattern apertures 868. Further, enclosed area, e.g., second, portions 870 of inactive surface ends 230 of through via nubs 344 of through vias 218 remain enclosed within and covered by backside passivation layer 550.


In one embodiment, contact area portions 866 are inactive surface column ends 236 of through via columns 222 of through vias 218. In accordance with this embodiment, enclosed area portions 870 are inactive surface passivation lining ends 238 of through via passivation linings 220 of through vias 218.


In light of this disclosure, those of skill in the art will understand that in various embodiments a contact area portion 866 includes (1) a portion of inactive surface column end 236 only; (2) the entire inactive surface column end 236; (3) the entire inactive surface column end 236 and a portion of inactive surface passivation lining end 238; or (4) a portion of inactive surface column end 236 and a portion of inactive surface passivation lining end 238, depending upon the diameter of the circuit pattern aperture 868 and the tolerance in alignment of the circuit pattern aperture 868 with the through via 218.


By using a laser ablation process, circuit pattern apertures 868 are formed in backside passivation layer 550 in a controlled manner to expose contact area portions 866 of through via nubs 344. Further, by using a laser ablation process, the fabrication cost is reduced as compared to the use of chemical mechanical polish.



FIG. 9 is a cross-sectional view of the region IX of array 200 of FIG. 8 at a later stage during fabrication in accordance with one embodiment. Referring now to FIGS. 1 and 9 together, from laser ablate backside passivation layer to reveal portions of through via nubs operation 108, flow moves to form circuit pattern on backside passivation layer operation 110.


In form circuit pattern on backside passivation layer operation 110, an electrically conductive circuit pattern 964 is formed on backside passivation layer 550. More particularly, circuit pattern 964 is formed on upper passivation layer surface 554 and within circuit pattern apertures 868 of backside passivation layer 550. Backside passivation layer 550 electrically isolates circuit pattern 964 from substrate 202, i.e., from recessed backside surface 346.


Circuit pattern 964 is electrically connected to through vias 218. More particularly, circuit pattern 964 contacts and is electrically connected to contact area portions 866 of through vias 218.


In one embodiment, circuit pattern 964 includes terminals and/or traces in a manner similar to that described above regarding circuit pattern 764 of FIG. 7 and so is not repeated here.


Referring again to FIGS. 6 and 8, array 200 is singulated on singulation streets 216 to form a plurality of individual electronic component packages 600, 800, respectively. More particularly, substrate 202 and backside passivation layer 550 are cut, e.g., using a laser, mechanical sawing, or other singulation technique to form electronic component packages 600, 800. However, in other embodiments, array 200 is singulated at later stages during manufacture.


Although formation of a plurality of electronic component packages 600, 800 simultaneously in array 200 is described above, in other embodiments, electronic component 204 are processed individually (after singulation of substrate 202) using the methods as described above.


The drawings and the forgoing description gave examples of the present invention. The scope of the present invention, however, is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of the invention is at least as broad as given by the following claims.

Claims
  • 1. An electronic component package comprising: an electronic component comprising: an active surface; andan inactive surface,a through via comprising: an active surface end coplanar with the active surface; anda through via nub protruding from the inactive surface, wherein the through via nub comprises:a cylindrical nub outer surface; andan inactive surface end; anda backside passivation layer on the inactive surface, wherein a top portion comprising a first portion of the cylindrical nub outer surface of the through via nub is exposed from the backside passivation layer.
  • 2. The electronic component package of claim 1 wherein the backside passivation layer comprises an organic material.
  • 3. The electronic component package of claim 1 wherein a second portion of the cylindrical nub outer surface is enclosed within the backside passivation layer.
  • 4. The electronic component package of claim 1 wherein the top portion comprises the inactive surface end.
  • 5. The electronic component package of claim 1 further comprising a circuit pattern on the backside passivation layer and electrically connected to the inactive surface end.
  • 6. The electronic component package of claim 5 wherein the through via comprises an electrically conductive through via column, the inactive surface end comprising an inactive surface column end of the through via column, the circuit pattern contacting the inactive surface column end.
  • 7. An electronic component package comprising: an electronic component comprising an inactive surface;a through via extending through the electronic component, the through via comprising a through via nub protruding from the inactive surface; anda backside passivation layer on the inactive surface, wherein a top portion of the through via nub is exposed from the backside passivation layer, the top portion comprising:a cylindrical top portion outer surface being a first portion of a cylindrical nub outer surface of the through via nub; andan inactive surface end.
  • 8. The electronic component package of claim 7 wherein the top portion is a cylindrical protrusion protruding from the backside passivation layer.
  • 9. The electronic component package of claim 7 wherein the through via comprises through a through via passivation lining and a through via column.
  • 10. The electronic component package of claim 9 wherein the through via passivation lining comprises a dielectric material.
  • 11. The electronic component package of claim 9 wherein the through via column comprises a conductive material.
  • 12. The electronic component package of claim 7 wherein a second portion of the cylindrical nub outer surface of the through via nub is enclosed within the backside passivation layer.
  • 13. The electronic component package of claim 7 further comprising a circuit pattern on the backside passivation layer and electrically connected to the inactive surface end.
  • 14. An electronic component package comprising: an electronic component comprising an inactive surface;a through via comprising a through via nub protruding from the inactive surface, the through via nub comprising: a cylindrical nub outer surface; andan inactive surface end; anda backside passivation layer comprising a lower passivation layer surface on the inactive surface, the backside passivation layer further comprising an upper passivation layer surface, wherein a distance between the inactive surface end and the upper passivation layer surface is equal to the difference between a distance that the through via nub protrudes above the lower passivation layer surface and a distance between the lower passivation layer surface and the upper passivation layer surface, wherein a top portion comprising a first portion of the cylindrical nub outer surface of the through via nub is exposed from the backside passivation layer.
  • 15. The electronic component package of claim 14 further comprising a circuit pattern on the upper passivation layer surface.
  • 16. The electronic component package of claim 15 wherein the backside passivation layer electrically isolates the circuit pattern from the inactive surface.
US Referenced Citations (408)
Number Name Date Kind
2596993 Gookin May 1952 A
3435815 Forcier Apr 1969 A
3734660 Davies et al. May 1973 A
3838984 Crane et al. Oct 1974 A
4054238 Lloyd et al. Oct 1977 A
4189342 Kock Feb 1980 A
4258381 Inaba Mar 1981 A
4289922 Devlin Sep 1981 A
4301464 Otsuki et al. Nov 1981 A
4332537 Slepcevic Jun 1982 A
4394712 Anthony Jul 1983 A
4417266 Grabbe Nov 1983 A
4451224 Harding May 1984 A
4499655 Anthony Feb 1985 A
4530152 Roche et al. Jul 1985 A
4541003 Otsuka et al. Sep 1985 A
4646710 Schmid et al. Mar 1987 A
4707724 Suzuki et al. Nov 1987 A
4727633 Herrick Mar 1988 A
4729061 Brown Mar 1988 A
4737839 Burt Apr 1988 A
4756080 Thorp, Jr. et al. Jul 1988 A
4812896 Rothgery et al. Mar 1989 A
4862245 Pashby et al. Aug 1989 A
4862246 Masuda et al. Aug 1989 A
4907067 Derryberry Mar 1990 A
4920074 Shimizu et al. Apr 1990 A
4935803 Kalfus et al. Jun 1990 A
4942454 Mori et al. Jul 1990 A
4987475 Schlesinger et al. Jan 1991 A
5018003 Yasunaga et al. May 1991 A
5029386 Chao et al. Jul 1991 A
5041902 McShane Aug 1991 A
5057900 Yamazaki Oct 1991 A
5059379 Tsutsumi et al. Oct 1991 A
5065223 Matsuki et al. Nov 1991 A
5070039 Johnson et al. Dec 1991 A
5087961 Long et al. Feb 1992 A
5091341 Asada et al. Feb 1992 A
5096852 Hobson Mar 1992 A
5118298 Murphy Jun 1992 A
5122860 Kikuchi et al. Jun 1992 A
5134773 LeMaire et al. Aug 1992 A
5151039 Murphy Sep 1992 A
5157475 Yamaguchi Oct 1992 A
5157480 McShane et al. Oct 1992 A
5168368 Gow, III et al. Dec 1992 A
5172213 Zimmerman Dec 1992 A
5172214 Casto Dec 1992 A
5175060 Enomoto et al. Dec 1992 A
5200362 Lin et al. Apr 1993 A
5200809 Kwon Apr 1993 A
5214845 King et al. Jun 1993 A
5216278 Lin et al. Jun 1993 A
5218231 Kudo Jun 1993 A
5221642 Burns Jun 1993 A
5229647 Gnadinger Jul 1993 A
5245751 Locke et al. Sep 1993 A
5250841 Sloan et al. Oct 1993 A
5252853 Michii Oct 1993 A
5258094 Furui et al. Nov 1993 A
5266834 Nishi et al. Nov 1993 A
5268310 Goodrich et al. Dec 1993 A
5273938 Lin et al. Dec 1993 A
5277972 Sakumoto et al. Jan 1994 A
5278446 Nagaraj et al. Jan 1994 A
5279029 Burns Jan 1994 A
5281849 Singh Deo et al. Jan 1994 A
5294897 Notani et al. Mar 1994 A
5327008 Djennas et al. Jul 1994 A
5332864 Liang et al. Jul 1994 A
5335771 Murphy Aug 1994 A
5336931 Juskey et al. Aug 1994 A
5343076 Katayama et al. Aug 1994 A
5353498 Fillion et al. Oct 1994 A
5358905 Chiu Oct 1994 A
5365106 Watanabe Nov 1994 A
5381042 Lerner et al. Jan 1995 A
5391439 Tomita et al. Feb 1995 A
5394303 Yamaji Feb 1995 A
5406124 Morita et al. Apr 1995 A
5410180 Fuji et al. Apr 1995 A
5414299 Wang et al. May 1995 A
5417905 Lemaire et al. May 1995 A
5424576 Djennas et al. Jun 1995 A
5428248 Cha Jun 1995 A
5432677 Mowatt et al. Jul 1995 A
5435057 Bindra et al. Jul 1995 A
5444301 Song et al. Aug 1995 A
5452511 Chang Sep 1995 A
5454905 Fogelson Oct 1995 A
5474958 Djennas et al. Dec 1995 A
5484274 Neu Jan 1996 A
5493151 Asada et al. Feb 1996 A
5508556 Lin Apr 1996 A
5517056 Bigler et al. May 1996 A
5521429 Aono et al. May 1996 A
5528076 Pavio Jun 1996 A
5534467 Rostoker Jul 1996 A
5539251 Iverson et al. Jul 1996 A
5543657 Diffenderfer et al. Aug 1996 A
5544412 Romero et al. Aug 1996 A
5545923 Barber Aug 1996 A
5576517 Wojnarowski et al. Nov 1996 A
5578525 Mizukoshi Nov 1996 A
5581122 Chao et al. Dec 1996 A
5592019 Ueda et al. Jan 1997 A
5592025 Clark et al. Jan 1997 A
5594274 Suetaki Jan 1997 A
5595934 Kim Jan 1997 A
5604376 Hamburgen et al. Feb 1997 A
5608264 Gaul Mar 1997 A
5608265 Kitano et al. Mar 1997 A
5608267 Mahulikar et al. Mar 1997 A
5619068 Benzoni Apr 1997 A
5625222 Yoneda et al. Apr 1997 A
5633528 Abbott et al. May 1997 A
5639990 Nishihara et al. Jun 1997 A
5640047 Nakashima Jun 1997 A
5641997 Ohta et al. Jun 1997 A
5643433 Fukase et al. Jul 1997 A
5644169 Chun Jul 1997 A
5646831 Manteghi Jul 1997 A
5650663 Parthasarathi Jul 1997 A
5661088 Tessier et al. Aug 1997 A
5665996 Williams et al. Sep 1997 A
5673479 Hawthorne Oct 1997 A
5683806 Sakumoto et al. Nov 1997 A
5689135 Ball Nov 1997 A
5696666 Miles et al. Dec 1997 A
5701034 Marrs Dec 1997 A
5703407 Hori Dec 1997 A
5710064 Song et al. Jan 1998 A
5723899 Shin Mar 1998 A
5724233 Honda et al. Mar 1998 A
5726493 Yamashita et al. Mar 1998 A
5736432 Mackessy Apr 1998 A
5736448 Saia et al. Apr 1998 A
5745984 Cole, Jr. et al. May 1998 A
5753532 Sim May 1998 A
5753977 Kusaka et al. May 1998 A
5766972 Takahashi et al. Jun 1998 A
5769989 Hoffmeyer et al. Jun 1998 A
5770888 Song et al. Jun 1998 A
5776798 Quan et al. Jul 1998 A
5783861 Son Jul 1998 A
5786238 Pai et al. Jul 1998 A
5801440 Chu et al. Sep 1998 A
5814877 Diffenderfer et al. Sep 1998 A
5814881 Alagaratnam et al. Sep 1998 A
5814883 Sawai et al. Sep 1998 A
5814884 Davis et al. Sep 1998 A
5817540 Wark Oct 1998 A
5818105 Kouda Oct 1998 A
5821457 Mosley et al. Oct 1998 A
5821615 Lee Oct 1998 A
5834830 Cho Nov 1998 A
5835988 Ishii Nov 1998 A
5841193 Eichelberger Nov 1998 A
5844306 Fujita et al. Dec 1998 A
5856911 Riley Jan 1999 A
5859471 Kuraishi et al. Jan 1999 A
5859475 Freyman et al. Jan 1999 A
5866939 Shin et al. Feb 1999 A
5871782 Choi Feb 1999 A
5874770 Saia et al. Feb 1999 A
5874784 Aoki et al. Feb 1999 A
5877043 Alcoe et al. Mar 1999 A
5886397 Ewer Mar 1999 A
5886398 Low et al. Mar 1999 A
5894108 Mostafazadeh et al. Apr 1999 A
5897339 Song et al. Apr 1999 A
5900676 Kweon et al. May 1999 A
5903049 Mori May 1999 A
5903050 Thurairajaratnam et al. May 1999 A
5909053 Fukase et al. Jun 1999 A
5915998 Stidham et al. Jun 1999 A
5917242 Ball Jun 1999 A
5937324 Abercrombie et al. Aug 1999 A
5939779 Kim Aug 1999 A
5942794 Okumura et al. Aug 1999 A
5951305 Haba Sep 1999 A
5959356 Oh Sep 1999 A
5969426 Baba et al. Oct 1999 A
5973388 Chew et al. Oct 1999 A
5976912 Fukutomi et al. Nov 1999 A
5977613 Takata et al. Nov 1999 A
5977615 Yamaguchi et al. Nov 1999 A
5977630 Woodworth et al. Nov 1999 A
5981314 Glenn et al. Nov 1999 A
5982632 Mosley et al. Nov 1999 A
5986333 Nakamura Nov 1999 A
5986885 Wyland Nov 1999 A
6001671 Fjelstad Dec 1999 A
6013947 Lim Jan 2000 A
6018189 Mizuno Jan 2000 A
6020625 Qin et al. Feb 2000 A
6025640 Yagi et al. Feb 2000 A
6031279 Lenz Feb 2000 A
RE36613 Ball Mar 2000 E
6034423 Mostafazadeh et al. Mar 2000 A
6040626 Cheah et al. Mar 2000 A
6043430 Chun Mar 2000 A
6060768 Hayashida et al. May 2000 A
6060769 Wark May 2000 A
6072228 Hinkle et al. Jun 2000 A
6075284 Choi et al. Jun 2000 A
6081029 Yamaguchi Jun 2000 A
6084310 Mizuno et al. Jul 2000 A
6087715 Sawada et al. Jul 2000 A
6087722 Lee et al. Jul 2000 A
6100594 Fukui et al. Aug 2000 A
6113474 Shih et al. Sep 2000 A
6114752 Huang et al. Sep 2000 A
6118174 Kim Sep 2000 A
6118184 Ishio et al. Sep 2000 A
RE36907 Templeton, Jr. et al. Oct 2000 E
6130115 Okumura et al. Oct 2000 A
6130473 Mostafazadeh et al. Oct 2000 A
6133623 Otsuki et al. Oct 2000 A
6140154 Hinkle et al. Oct 2000 A
6143981 Glenn Nov 2000 A
6168969 Farnworth Jan 2001 B1
6169329 Farnworth et al. Jan 2001 B1
6177718 Kozono Jan 2001 B1
6181002 Juso et al. Jan 2001 B1
6184465 Corisis Feb 2001 B1
6184573 Pu Feb 2001 B1
6194250 Melton et al. Feb 2001 B1
6194777 Abbott et al. Feb 2001 B1
6197615 Song et al. Mar 2001 B1
6198171 Huang et al. Mar 2001 B1
6201186 Daniels et al. Mar 2001 B1
6201292 Yagi et al. Mar 2001 B1
6204554 Ewer et al. Mar 2001 B1
6208020 Minamio et al. Mar 2001 B1
6208021 Ohuchi et al. Mar 2001 B1
6208023 Nakayama et al. Mar 2001 B1
6211462 Carter, Jr. et al. Apr 2001 B1
6214525 Boyko et al. Apr 2001 B1
6218731 Huang et al. Apr 2001 B1
6222258 Asano et al. Apr 2001 B1
6222259 Park et al. Apr 2001 B1
6225146 Yamaguchi et al. May 2001 B1
6229200 Mclellan et al. May 2001 B1
6229205 Jeong et al. May 2001 B1
6239367 Hsuan et al. May 2001 B1
6239384 Smith et al. May 2001 B1
6242281 Mclellan et al. Jun 2001 B1
6256200 Lam et al. Jul 2001 B1
6258192 Natarajan Jul 2001 B1
6258629 Niones et al. Jul 2001 B1
6261918 So Jul 2001 B1
6281566 Magni Aug 2001 B1
6281568 Glenn et al. Aug 2001 B1
6282095 Houghton et al. Aug 2001 B1
6285075 Combs et al. Sep 2001 B1
6291271 Lee et al. Sep 2001 B1
6291273 Miyaki et al. Sep 2001 B1
6294100 Fan et al. Sep 2001 B1
6294830 Fjelstad Sep 2001 B1
6295977 Ripper et al. Oct 2001 B1
6297548 Moden et al. Oct 2001 B1
6303984 Corisis Oct 2001 B1
6303997 Lee Oct 2001 B1
6307272 Takahashi et al. Oct 2001 B1
6309909 Ohgiyama Oct 2001 B1
6316822 Venkateshwaran et al. Nov 2001 B1
6316838 Ozawa et al. Nov 2001 B1
6323550 Martin et al. Nov 2001 B1
6326243 Suzuya et al. Dec 2001 B1
6326244 Brooks et al. Dec 2001 B1
6326678 Karnezos et al. Dec 2001 B1
6335564 Pour Jan 2002 B1
6337510 Chun-Jen et al. Jan 2002 B1
6339255 Shin Jan 2002 B1
6348726 Bayan et al. Feb 2002 B1
6355502 Kang et al. Mar 2002 B1
6365974 Abbott et al. Apr 2002 B1
6369447 Mori Apr 2002 B2
6369454 Chung Apr 2002 B1
6373127 Baudouin et al. Apr 2002 B1
6379982 Ahn et al. Apr 2002 B1
6380048 Boon et al. Apr 2002 B1
6384472 Huang May 2002 B1
6388336 Venkateshwaran et al. May 2002 B1
6395578 Shin et al. May 2002 B1
6396148 Eichelberger et al. May 2002 B1
6396153 Fillion et al. May 2002 B2
6400004 Fan et al. Jun 2002 B1
6406934 Glenn et al. Jun 2002 B1
6410979 Abe Jun 2002 B2
6414385 Huang et al. Jul 2002 B1
6420779 Sharma et al. Jul 2002 B1
6429508 Gang Aug 2002 B1
6429509 Hsuan Aug 2002 B1
6437429 Su et al. Aug 2002 B1
6444499 Swiss et al. Sep 2002 B1
6448633 Yee et al. Sep 2002 B1
6448661 Kim et al. Sep 2002 B1
6452279 Shimoda Sep 2002 B2
6459148 Chun-Jen et al. Oct 2002 B1
6464121 Reijnders Oct 2002 B2
6476469 Hung et al. Nov 2002 B2
6476474 Hung Nov 2002 B1
6482680 Khor et al. Nov 2002 B1
6498099 McLellan et al. Dec 2002 B1
6498392 Azuma Dec 2002 B2
6507096 Gang Jan 2003 B2
6507120 Lo et al. Jan 2003 B2
6521530 Peters et al. Feb 2003 B2
6524885 Pierce Feb 2003 B2
6534849 Gang Mar 2003 B1
6545332 Huang Apr 2003 B2
6545345 Glenn et al. Apr 2003 B1
6559525 Huang May 2003 B2
6566168 Gang May 2003 B2
6573461 Roeters et al. Jun 2003 B2
6577013 Glenn et al. Jun 2003 B1
6583503 Akram et al. Jun 2003 B2
6593645 Shih et al. Jul 2003 B2
6603196 Lee et al. Aug 2003 B2
6608371 Kurashima et al. Aug 2003 B2
6624005 DiCaprio et al. Sep 2003 B1
6667546 Huang et al. Dec 2003 B2
6671398 Reinhorn et al. Dec 2003 B2
6727576 Hedler et al. Apr 2004 B2
6730857 Konrad et al. May 2004 B2
6740964 Sasaki May 2004 B2
6780770 Larson Aug 2004 B2
6831371 Huemoeller et al. Dec 2004 B1
6838776 Leal et al. Jan 2005 B2
6845554 Frankowsky et al. Jan 2005 B2
6853572 Sabharwal Feb 2005 B1
6873054 Miyazawa et al. Mar 2005 B2
6905914 Huemoeller et al. Jun 2005 B1
6919514 Konrad et al. Jul 2005 B2
6921975 Leal et al. Jul 2005 B2
6930256 Huemoeller et al. Aug 2005 B1
7015075 Fay et al. Mar 2006 B2
7022609 Yamamoto et al. Apr 2006 B2
7041534 Chao et al. May 2006 B2
7129158 Nakai Oct 2006 B2
7151009 Kim et al. Dec 2006 B2
7190062 Sheridan et al. Mar 2007 B1
7192807 Huemoeller et al. Mar 2007 B1
7208838 Masuda Apr 2007 B2
7223634 Yamaguchi May 2007 B2
7242081 Lee Jul 2007 B1
7247523 Huemoeller et al. Jul 2007 B1
7272444 Peterson et al. Sep 2007 B2
7345361 Mallik et al. Mar 2008 B2
7361533 Huemoeller et al. Apr 2008 B1
7372151 Fan et al. May 2008 B1
7420272 Huemoeller et al. Sep 2008 B1
7572681 Huemoeller et al. Aug 2009 B1
7632753 Rusli et al. Dec 2009 B1
7692286 Huemoeller et al. Apr 2010 B1
7714431 Huemoeller et al. May 2010 B1
7777351 Berry et al. Aug 2010 B1
7843052 Yoo et al. Nov 2010 B1
7843072 Park et al. Nov 2010 B1
7932595 Huemoeller et al. Apr 2011 B1
20010008305 McLellan et al. Jul 2001 A1
20010011654 Schmidt et al. Aug 2001 A1
20010012704 Eldridge Aug 2001 A1
20010014538 Kwan et al. Aug 2001 A1
20020017710 Kurashima et al. Feb 2002 A1
20020024122 Jung et al. Feb 2002 A1
20020027297 Ikenaga et al. Mar 2002 A1
20020030245 Hanaoka et al. Mar 2002 A1
20020061642 Haji et al. May 2002 A1
20020140061 Lee Oct 2002 A1
20020140068 Lee et al. Oct 2002 A1
20020163015 Lee et al. Nov 2002 A1
20030013232 Towle et al. Jan 2003 A1
20030030131 Lee et al. Feb 2003 A1
20030038344 Palmer et al. Feb 2003 A1
20030064548 Isaak Apr 2003 A1
20030073265 Hu et al. Apr 2003 A1
20030134455 Cheng et al. Jul 2003 A1
20030207566 Forbes et al. Nov 2003 A1
20040004293 Murayama Jan 2004 A1
20040026781 Nakai Feb 2004 A1
20040046244 Nakamura et al. Mar 2004 A1
20040056277 Karnezos Mar 2004 A1
20040061212 Karnezos Apr 2004 A1
20040061213 Karnezos Apr 2004 A1
20040063242 Karnezos Apr 2004 A1
20040063246 Karnezos Apr 2004 A1
20040113260 Sunohara et al. Jun 2004 A1
20040192033 Hara Sep 2004 A1
20040251554 Masuda Dec 2004 A1
20050029630 Matsuo Feb 2005 A1
20050046002 Lee et al. Mar 2005 A1
20050104181 Lee et al. May 2005 A1
20050242425 Leal et al. Nov 2005 A1
20050263869 Tanaka et al. Dec 2005 A1
20050282314 Lo et al. Dec 2005 A1
20070007639 Fukazawa Jan 2007 A1
20070273049 Khan et al. Nov 2007 A1
20070290376 Zhao et al. Dec 2007 A1
20080230887 Sun et al. Sep 2008 A1
20080277799 Benson et al. Nov 2008 A1
20090020865 Su Jan 2009 A1
20090039527 Chan et al. Feb 2009 A1
20100008058 Saen et al. Jan 2010 A1
20120018868 Oganesian et al. Jan 2012 A1
Foreign Referenced Citations (68)
Number Date Country
197 34 794 Jul 1998 DE
0 393 997 Oct 1990 EP
0 459 493 Dec 1991 EP
0 720 225 Jul 1996 EP
0 720 234 Jul 1996 EP
0 794 572 Sep 1997 EP
0 844 665 May 1998 EP
0 936 671 Aug 1999 EP
0 989 608 Mar 2000 EP
1 032 037 Aug 2000 EP
55-163868 Dec 1980 JP
57-045959 Mar 1982 JP
59-208756 Nov 1984 JP
59-227143 Dec 1984 JP
60-010756 Jan 1985 JP
60-116239 Jun 1985 JP
60-195957 Oct 1985 JP
60-231349 Nov 1985 JP
61-039555 Feb 1986 JP
62-009639 Jan 1987 JP
63-033854 Feb 1988 JP
63-067762 Mar 1988 JP
63-188964 Aug 1988 JP
63-205935 Aug 1988 JP
63-233555 Sep 1988 JP
63-249345 Oct 1988 JP
63-289951 Nov 1988 JP
63-316470 Dec 1988 JP
64-054749 Mar 1989 JP
01-106456 Apr 1989 JP
01-175250 Jul 1989 JP
01-205544 Aug 1989 JP
01-251747 Oct 1989 JP
02-129948 May 1990 JP
03-069248 Jul 1991 JP
03-177060 Aug 1991 JP
04-098864 Mar 1992 JP
05-129473 May 1993 JP
05-166992 Jul 1993 JP
05-283460 Oct 1993 JP
06-092076 Apr 1994 JP
06-140563 May 1994 JP
06-260532 Sep 1994 JP
07-297344 Nov 1995 JP
07-312405 Nov 1995 JP
08-064634 Mar 1996 JP
08-083877 Mar 1996 JP
08-125066 May 1996 JP
08-222682 Aug 1996 JP
08-306853 Nov 1996 JP
09-008205 Jan 1997 JP
09-008206 Jan 1997 JP
09-008207 Jan 1997 JP
09-092775 Apr 1997 JP
09-293822 Nov 1997 JP
10-022447 Jan 1998 JP
10-163401 Jun 1998 JP
10-199934 Jul 1998 JP
10-256240 Sep 1998 JP
2000-150765 May 2000 JP
2000-556398 Oct 2000 JP
2001-060648 Mar 2001 JP
2002-043497 Feb 2002 JP
1994-0001979 Jan 1994 KR
10-0220154 Jun 1999 KR
2002-0049944 Jun 2002 KR
WO 9956316 Nov 1999 WO
WO 9967821 Dec 1999 WO