1. A method, comprising:
providing a substrate having a plurality of conductive pads;
placing a plurality of semiconductor dies on the plurality of conductive pads in a manner such that an entire bottom surface of each of the semiconductor dies is placed on a respective conductive pad;
placing a mold device on the substrate, the mold device having a plurality of recesses, wherein the placing the mold device includes covering each of the semiconductor dies by a respective one of the recesses; and
thereafter bonding the semiconductor dies to the conductive pads.
2. The method of claim 1, wherein the placing the mold device substantially restricts movement of the semiconductor dies that are covered by recesses in the mold device.
3. The method of claim 2, wherein the placing the mold device includes restricting a movement range of each semiconductor die covered by the recess to be less than about 5 microns in any lateral direction.
4. The method of claim 1, wherein the placing the mold device includes securing the mold device with respect to the substrate, so that the mold device is substantially free of lateral movement with respect to the substrate.
5. The method of claim 1, wherein the placing the mold device includes applying pressure to the semiconductor dies through the mold device.
6. The method of claim 1, wherein the recesses each have a sloped profile.
7. The method of claim 1, wherein the bonding includes heating the substrate, the semiconductor dies, and the mold device in a reflow oven.
8. The method of claim 1, further including:
applying a flux material on each of the conductive pads before the semiconductor dies are placed on the conductive pads; and
aligning each of the recesses of the mold device with a respective one of the semiconductor dies before the mold device is placed on the substrate.
9. The method of claim 1, wherein the semiconductor dies include light-emitting diode (LED) devices.
10. A method of light-emitting diode (LED) packaging, comprising:
providing a sub-mount having a plurality of bonding pads disposed thereon;
coupling a plurality of LED dies to the plurality of bonding pads, wherein each LED die is coupled to a respective one of the bonding pads through direct surface contact;
providing a mold apparatus, the mold apparatus including a plurality of concave recesses;
placing the mold apparatus over the sub-mount, wherein each LED die is housed in a respective one of the recesses; and
thereafter heating the sub-mount, the LED dies, and the mold apparatus in a thermal reflow process, thereby causing the LED dies to be bonded to the bonding pads, respectively;
wherein each recess substantially restricts a positional shift of the LED die below with respect to the bonding pad coupled thereto during the heating.
11. The method of claim 10, wherein the placing the mold apparatus includes positionally securing the mold apparatus relative to the sub-mount.
12. The method of claim 10, wherein the placing the mold apparatus includes applying a predetermined amount of pressure to the LED dies through the mold apparatus.
13. The method of claim 10, wherein the placing the mold apparatus includes aligning the recesses with the LED dies through an optical positioning process.
14. The method of claim 10, wherein the recesses of the mold apparatus each have a non-uniform cross-sectional profile.
15. A method of light-emitting diode (LED) packaging, comprising:
providing a sub-mount having a plurality of conductive elements disposed thereon;
providing a mold having a plurality of concave recesses;
placing a plurality of LED dies to the plurality of conductive elements, wherein each LED die is placed to a different one of the conductive elements, and wherein a lateral dimension of each LED die is smaller than a lateral dimension of the conductive element to which the LED die is coupled;
thereafter covering the plurality of LED dies with the mold over the sub-mount, wherein the plurality of LED dies is aligned with the plurality of recesses, respectively, such that each recess restricts movements of the LED die underneath; and
performing a heating process to the sub-mount, the LED dies, and the mold, thereby causing the plurality of LED dies to be bonded to the plurality of conductive elements, respectively.
16. The method of claim 15, further comprising: securing the mold to the sub-mount before the performing the heating process, such that the mold is free of lateral movement relative to the sub-mount.
17. The method of claim 15, further comprising: applying a downward force to the mold after the covering the plurality of LED dies.
18. The method of claim 15, wherein the covering the plurality of LED dies is performed at least in part through an optical positioning process.
19. The method of claim 15, wherein the recesses of the mold each have a non-uniform cross-sectional profile.
20. The method of claim 19, wherein at least some of the recesses each have a trapezoidal cross-sectional profile.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process for forming a composite sheet comprising a substrate adhesively laminated to a nanoweb, the process comprising:
(a) providing a carrier layer having a collection surface;
(b) forming a nanoweb on the collection surface of the carrier layer;
(c) providing a flexible porous substrate having two major surfaces;
(d) applying a layer of adhesive to at least a portion of one surface of the substrate;
(e) contacting the adhesive layer with the nanoweb and bonding the nanoweb to the substrate; and
(f) optionally removing the carrier layer, thus forming the composite sheet.
2. The process of claim 1 wherein the carrier layer is selected from the group consisting of spunlaced nonwovens and spunbond nonwovens.
3. The process of claim 1 wherein the substrate is selected from the group consisting of spunbond nonwovens, airlaid nonwovens, carded nonwovens, spunlaced nonwovens, felts, spunbond-meltblown-spunbond composite nonwovens and woven fabrics.
4. The process of claim 1 wherein the layer of adhesive comprises a solvent-based adhesive, a melt adhesive or a high temperature binding agent.
5. The process of claim 1 wherein the step of contacting the adhesive layer with the nahoweb is by means of nip rolls.
6. A filter element for separating particulate matter from a gas stream comprising a filter medium comprising a substrate having two major surfaces wherein the substrate is adhesively laminated over one of the major surfaces to a first nanoweb having a basis weight less than about 2 gsm.
7. A filter element for separating particular matter from a gas stream comprising a filter medium comprising exactly one substrate having two major surfaces wherein the substrate is adhesively laminated to a first nanoweb over one of the major surfaces in a face-to-face relationship having a basis weight less than about 2 gsm.
8. The filter element of claim 6 or 7 wherein the substrate is selected from the group consisting of spunbond nonwovens, spunlaced nonwovens, airlaid nonwovens, carded nonwovens, felts, spunbond-meltblown-spunbond composite nonwovens, and woven fabrics.
9. The filter element of claim 6 or 7 wherein the first nanoweb and the substrate are laminated by means of a solvent-based adhesive, a melt adhesive or a high temperature binding agent.
10. The filter element of claim 6 or 7 wherein the substrate and the first nanoweb remain bonded after the filter element has been subjected to VDI 3926 for at least 30 cycles.
11. The filter element of claim 6 or 7 wherein the substrate and the first nanoweb remain bonded after the filter element has been subjected to a complete test according to VDI 3926.
12. The filter element of claim 6 or 7 wherein the first nanoweb has a basis weight of between about 0.7 gsm and about 2 gsm.
13. A process for removing particulate matter from a gas stream, comprising passing the particle-laden gas stream through the filter medium of the filter element of claim 6 or 7 such that the gas stream enters the filter medium on the surface of the filter medium having the first nanoweb bonded thereto in a face to face relationship and the filtered gas stream exits the,filter medium from the surface of the filter medium opposite the first nanoweb.