Microelectronics package assembly tool and method of manufacture therewith

A method of manufacturing a microelectronic package comprising, in one embodiment, providing a package substrate, coupling a device substrate to the package substrate, and assembling a bifurcated mold around the device and package substrates, the bifurcated mold including a seal. The method also includes encapsulating the device and package substrates employing the bifurcated mold.

BACKGROUND

The present disclosure relates generally to microelectronics packaging and, more specifically, to manufacturing a microelectronics package with a sealed bifurcated mold.

Flip-chip ball grid array (FCBGA) packaging generally employs a plurality of solder bump balls that may be coupled between bond pads of a microelectronics device substrate and a package substrate. An encapsulant is typically applied to back-fill the bonded device substrate and BGA while the package is housed in a mold. However, during encapsulation, encapsulant or flash mold material can leak from the mold, the package/substrate interface and/or other gaps/cracks. The mold material is difficult to remove and can deteriorate proximate electrical contacts. The excess encapsulate is also difficult to remove from the mold, therefore requiring frequent cleaning.

Accordingly, what is needed in the art is a device and manufacturing method that addresses the above discussed issues.

DETAILED DESCRIPTION

Referring toFIG. 1, illustrated is a sectional view of one embodiment of a microelectronic package assembly tool100during assembly of a microelectronic package110according to aspects of the present disclosure. The assembly tool100is bifurcated, having a base or foundation (hereafter collectively referred to as the base)120and a body130. The microelectronic package110includes a device substrate112and a package substrate114. Although any means for coupling the device and package substrates112,114are within the scope of the present disclosure, a ball grid array (BGA)116is employed to couple the substrates in the illustrated embodiment. The BGA116includes a plurality of solder bump balls or other electrically conductive members that may have a substantially spherical shape before and possibly after a reflow process employed to couple the substrates112,114via the BGA116.

The device substrate112may comprise one or more microelectronic devices, such as transistors, electrically programmable read only memory (EPROM) cells, electrically erasable programmable read only memory (EEPROM) cells, static random access memory (SRAM) cells, dynamic random access memory (DRAM) cells and other microelectronic devices, which may be interconnected to form one or more integrated circuits. The device substrate112contemplates one or more substrates on or in which one or more conventional or future-developed microelectronic devices may be formed.

The package substrate114may comprise a die lead frame, a printed circuit board (PCB), a multiple chip package substrate or other types of substrates. The bulk of the device substrate112and/or the package substrate114may be a silicon-on-insulator (SOI) substrate and/or may comprise silicon, gallium arsenide, strained silicon, silicon germanium, carbide, diamond and other materials.

The base120of the assembly tool100is configured to fix the orientation or otherwise support the package substrate114during assembly of the microelectronic package110. For example, as in the illustrated embodiment, the base120may comprise a recess140configured to receive the package substrate114, wherein the inner profile of the recess140may be substantially similar to the outer profile of the package substrate114. The recess140may be configured such that the package substrate114extends from the recess140above the base120(relative to the illustration) or, alternatively, such that the package substrate114is substantially coplanar with the base120. Of course, coupling means other than or in addition to the recess140may be employed to couple the package substrate114to the base120. The base120may also be adjustable to allow for different sizes and shapes of the package substrate114. The base120may comprise a thermally conductive material, such as stainless steel, aluminum, nickel, copper, alloys thereof and/or other materials.

The body130is configured to receive or otherwise house the device substrate112, such that the inner profile of the body130may be substantially similar to or, as in the illustrated embodiment, larger than the outer profile of the device substrate112. The body130is also configured to form a cavity132in conjunction with the base120(and possibly the package substrate114). As such, the body may have a plate or other substantially planar member (hereafter collectively referred to as a plate)134and a frame136extending from the plate134. The frame136and the plate134may be discrete components formed separately and subsequently coupled together, such as by mechanical fasteners, adhesive, welding and/or other processes. The frame136and the plate134may also be formed integrally, such as by machining a bulk material, injection-molding, casting and/or other processes. The body130, including the frame136, plate134and/or other portions of the body130, may comprise a thermally conductive material, such as stainless steel, aluminum, nickel, copper, alloys thereof and/or other materials.

During assembly of the microelectronic package110, an encapsulant may be injected or otherwise deposited in the cavity132formed by the base120and the body130. The encapsulant may comprise a low viscosity epoxy resin material with a solid filler material, wherein the solid filler material may comprise silicon, quartz and/or other materials, including materials having a particle size ranging between about 0.01 microns and about 50 microns. In an effort to confine the encapsulant within the cavity132until the encapsulant is allowed to cure or otherwise solidify, a clamping force may be applied to the base120and the body130. The body130may also include one or more ports configured to inject encapsulant into the cavity132. The body130may also include one or more apertures or other vents to allow air or other gases to escape the cavity132as the cavity is filled with the encapsulant.

The body130also includes a seal138. In the illustrated embodiment, the seal138extends around a substantial portion of an inner perimeter of the frame136. In one embodiment, the seal138comprises a trench139filled with a seal material. The trench139may be formed by machining or otherwise removing material from the body130. In other embodiments, the trench139may be formed simultaneous to forming the body130, such as when the body130is formed by molding or casting. The seal material employed to form the seal138may comprise graphite, Teflon® (a product of DuPont of Wilmington, Del.), Kalrez® (a product of DuPont of Wilmington, Del.) and/or other materials. The seal138may also comprise multiple seals stacked vertically (relative to the illustration) and/or radially. In one embodiment, the seal138may have a depth D ranging between about 0.5 mm and about 4 mm.

Referring toFIG. 2, illustrated is a bottom view of an embodiment of the body130shown inFIG. 1, herein designated with the reference number200. The body200may be employed in the simultaneous assembly of more than one microelectronic package100(shown inFIG. 1). For example, the body200may include a first cavity210and a second cavity220separated by a dividing portion230of the body200. Of course, the body200(and the body130shown inFIG. 1) may have more than two cavities, within the scope of the present disclosure. For example, in one embodiment, the shape or outer profile of the body200may be substantially similar to or otherwise encompass the surface area of a semiconductor wafer employed in the simultaneous fabrication of multiple semiconductor or other microelectronic devices. In such an embodiment, the body200may include a cavity for each of the microelectronic devices fabricated on the wafer. The body200may also include a trench240corresponding to each cavity. The trenches240may each be substantially similar to the trench139shown inFIG. 1.

Referring toFIGS. 1 and 2collectively, the bodies130,200may each have a substantially rectangular shape. However, the shapes of the bodies130,200and the trenches139,240are not limited by the scope of the present disclosure, such that other shapes may also be employed therefor, including squares, ellipses, circles, polygons, combinations thereof and/or other geometries. The trenches139,240may also have a width W ranging between about 0.5 mm and about 4 mm.

Referring toFIG. 3, illustrated is a sectional view of another embodiment of the microelectronic package assembly tool100shown inFIG. 1, herein designated with the reference number300. The tool300is bifurcated, having a base310and a body320. The base310is substantially similar to the base120shown inFIG. 1. The body320includes a plate330which is substantially similar to the plate134shown inFIG. 1. The body320also includes a seal340extending from the plate330. The seal340may be substantially similar in size and shape to the frame136shown inFIG. 1, and has a composition that is substantially similar to the seal138shown inFIG. 1. The seal340is coupled to the plate330by mechanical fasteners, adhesive, bonding and/or other means.

Referring toFIG. 4, illustrated is a sectional view of another embodiment of the microelectronic package assembly tool100shown inFIG. 1, herein designated with the reference number400. The tool400is bifurcated, having a base410and a body420. The base410is substantially similar to the base120shown inFIG. 1. However, as shown inFIG. 4, the base410may also include a seal430. The seal430is substantially similar to the seal138shown inFIG. 1. The body420is substantially similar to the body130shown inFIG. 1. For example, the body420includes a seal138. However, in one embodiment, the tool400includes one or more seals in only one of the base410and the body420. That is, in one embodiment, the base410includes one or more seals430although the body420does not include the seal138.

Thus, the present disclosure introduces a method of manufacturing a microelectronic package comprising, in one embodiment, providing a package substrate, coupling a device substrate to the package substrate, and assembling a bifurcated mold around the device and package substrates, the bifurcated mold including a seal. The method also includes encapsulating the device and package substrates employing the bifurcated mold.

A bifurcated microelectronic package assembly tool is also provided in the present disclosure. In one embodiment, the tool includes a foundation configured to fix an orientation of a package substrate. The tool also includes a body configured to house a device substrate coupled to the package substrate. The tool also includes a seal coupled to one of the foundation and the body.

The present disclosure also provides a microelectronic package assembly tool comprising, in one embodiment, a substantially planar base and at least one wall extending from a surface of the base, the base and the at least one wall defining a cavity configured to receive a microelectronic device. The too also includes a seal inlayed in an interior edge of the wall distal from the base.