Integrated circuit packaging system with leadframe and method of manufacture thereof

A method of manufacture of an integrated circuit packaging system includes: forming a paddle having an indented planar surface intersecting an outwardly extending planar surface at an angle of approximately 135 degrees plus 25 degrees or minus 5 degrees; mounting an integrated circuit over the paddle; and forming an encapsulation over the integrated circuit and under the extension void free.

TECHNICAL FIELD

The present invention relates generally to an integrated circuit packaging system, and more particularly to a system for an integrated circuit packaging system with leadframe.

BACKGROUND ART

Integrated circuits are used in many portable electronic products, such as cell phone, portable computers, voice recorders, etc. as well as in many larger electronic systems, such as cars, planes, industrial control systems, etc. Across virtually all applications, there continues to be demand for reducing the size and increasing performance of the devices. The intense demand is no more visible than in portable electronics that have become so ubiquitous.

As electronic devices have become smaller and thinner, the packages for protecting and interconnecting IC chips particularly power IC have the same trend, too.

The goals in designing and manufacturing semiconductor devices have been to make the devices smaller, more complex, with higher densities, and to include additional features. One method that improves the features and the densities of the semiconductor devices is to shrink the line sizes used in the lithographic process step in fabricating semiconductor devices. For example, each one-half reduction in line width of the circuits of the semiconductor device corresponds to a four-fold increase in chip density for the same size device.

Unfortunately, increasing density simply through improved lithographic techniques is limited because of physical limits and the cost factor of scaling down the dimensions of the semiconductor device. Accordingly, many attempts to increase semiconductor device density have been pursued. One such alternative has been the stacking of multiple semiconductor devices.

DISCLOSURE OF THE INVENTION

The present invention provides a method of manufacture of an integrated circuit packaging system including: forming a paddle having an indented planar surface intersecting an outwardly extending planar surface at an angle of approximately 135 degrees plus 25 degrees or minus 5 degrees; mounting an integrated circuit over the paddle; and forming an encapsulation over the integrated circuit and under the extension void free.

The present invention provides an integrated circuit packaging system, including: a paddle having an indented planar surface intersecting an outwardly extending planar surface at an angle of approximately 135 degrees plus 25 degrees or minus 5 degrees; an integrated circuit over the paddle; and an encapsulation over the integrated circuit and under the extension void free.

BEST MODE FOR CARRYING OUT THE INVENTION

The term “on” means that there is direct contact between elements. The term “directly on” means that there is direct contact between one element and another element without an intervening element.

The term “active side” refers to a side of a die, a module, a package, or an electronic structure having active circuitry fabricated thereon or having elements for connection to the active circuitry within the die, the module, the package, or the electronic structure. The term “processing” as used herein includes deposition of material or photoresist, patterning, exposure, development, etching, cleaning, and/or removal of the material or photoresist as required in forming a described structure.

Referring now toFIG. 1, therein is shown a top view of an integrated circuit packaging system100in an embodiment of the present invention. For example, the integrated circuit packaging system100can be used in applications for quad flat package (QFP) with exposed pad.

The integrated circuit packaging system100can include a lead finger102, such as a lead or a terminal, at a perimeter of an encapsulation104, such as a cover including an encapsulant, an epoxy molding compound (EMC), or a molding material. For example, the encapsulation104can be formed with EMC fillers having sizes in an approximate range from 1 micrometer (um) to 75 micrometers (um).

Referring now toFIG. 2, therein is shown a cross-sectional view of the integrated circuit packaging system100along a section line2-2ofFIG. 1. The integrated circuit packaging system100can include a paddle202, such as a die-attach paddle (DAP), a die-attach pad, or a die pad.

The paddle202can be adjacent to the lead finger102. The paddle202can be surrounded by the lead finger102. The paddle202and the lead finger102can be portions of a leadframe (not shown).

An adhesive204, such as a film, an epoxy, or a conductive adhesive, can be attached to the paddle202and an integrated circuit206, such as an integrated circuit die, a wirebond integrated circuit, or a chip. The adhesive204can conduct heat away from the integrated circuit206to the paddle202.

The integrated circuit206can be mounted over the paddle202. An interconnect208, such as a bond wire, a ribbon bond wire, or a conductive wire, can be connected to the lead finger102and the integrated circuit206.

The encapsulation104can be formed over the lead finger102, the paddle202, the adhesive204, the integrated circuit206, and the interconnect208. The encapsulation104can partially cover the lead finger102and the paddle202.

A portion of the lead finger102can be exposed from the encapsulation104at non-horizontal sides of the encapsulation104to provide connectivity between the integrated circuit206and external systems (not shown). The paddle202can be partially exposed from the encapsulation104.

Referring now toFIG. 3, therein is shown a more detailed view of a portion of the paddle202. The paddle202can have a bottom side302and a top side304opposite to the bottom side302. The bottom side302can be approximately parallel to the top side304.

The paddle202can include an extension306from the top side304over the bottom side302. The extension306can horizontally extend beyond the bottom side302.

The extension306can be formed at a periphery of the paddle202. The extension306can have a shape or a structure that is formed by an indented planar surface308, an outwardly extending planar surface310, and a non-indented planar surface312.

The indented planar surface308can be formed to continue from the bottom side302. The outwardly extending planar surface310can be formed to continue from the indented planar surface308. The non-indented planar surface312can be formed to continue from the outwardly extending planar surface310and between the outwardly extending planar surface310and the top side304.

The outwardly extending planar surface310is between the indented planar surface308and the non-indented planar surface312. The indented planar surface308can be approximately parallel to the non-indented planar surface312.

The extension306can extend between the indented planar surface308and the non-indented planar surface312. The extension306horizontally extends from the indented planar surface308. The outwardly extending planar surface310can be a lower planar surface of the extension306. An upper planar surface of the extension306can be at the top side304.

The indented planar surface308can be a vertical planar surface that is perpendicular to the bottom side302. The indented planar surface308can intersect the outwardly extending planar surface310.

The indented planar surface308can be at an angle314with the outwardly extending planar surface310. The angle314is defined as an angle taken or measured from an exterior of the extension306and between the indented planar surface308and the outwardly extending planar surface310.

The angle314can preferably be of approximately 135 degrees plus 25 degrees or minus 5 degrees. For example, the angle314can be in an approximate range from 130 degrees to 145 degrees. Also for example, the angle314can be in an approximate range from 130 degrees to 140 degrees.

The outwardly extending planar surface310can be a non-vertical planar surface that is non-perpendicular to the indented planar surface308and the non-indented planar surface312. The outwardly extending planar surface310can intersect the non-indented planar surface312.

The non-indented planar surface312can intersect the top side304. For illustrative purposes, the non-indented planar surface312is shown as a vertical planar surface that is perpendicular to the top side304, although the non-indented planar surface312can be a non-vertical planar surface that is non-perpendicular to the top side304.

For example, the paddle202can have a length ratio of a length of the outwardly extending planar surface310over a length of the indented planar surface308in an approximate range from 0.3 to 2.7, based on the angle314of approximately 135 degrees plus 25 degrees or minus 5 degrees. Also for example, the paddle202can have a length ratio of the length of the outwardly extending planar surface310over a length of the non-indented planar surface312in an approximate range from 0.3 to 8.5, based on the angle314of approximately 135 degrees plus 25 degrees or minus 5 degrees.

The outwardly extending planar surface310can extend and intersect the non-indented planar surface312at a horizontal distance316away from the indented planar surface308. The horizontal distance316is defined as a length of the extension306between the indented planar surface308and the non-indented planar surface312.

As the angle314increases, the horizontal distance316can decrease. For example, a length ratio of the horizontal distance316over the length of the indented planar surface308can be in an approximate range from 0.3 to 2.4, based on the angle314of approximately 135 degrees plus 25 degrees or minus 5 degrees.

For illustrative purposes, the angle314is shown as 130 degrees, although the angle314can be different. For example, the angle314can be 135 degrees or 160 degrees as shown by dotted lines.

The paddle202can be formed by stamping or other mechanical processes. For example, the extension306can be formed by stamping the paddle202such that the indented planar surface308is at the angle314with the outwardly extending planar surface310.

The paddle202can be partially exposed from the encapsulation104ofFIG. 1. The bottom side302can be exposed from the encapsulation104. The bottom side302can be coplanar with the encapsulation104.

The bottom side302can be mounted over external systems (not shown). For example, the bottom side302can be attached to an external printed circuit board. Also for example, the bottom side302can be grounded by being connected to ground, an external ground potential, or an electrical reference point that is external to the integrated circuit packaging system100ofFIG. 1.

While other paddles have what appear to be similar angles, the problems that have been discovered have gone undetected and unrecognized. It has been only through a thorough study of the problems that the answer was realized that the angle314was critical to solving the problems.

It has been discovered that the indented planar surface308intersecting the outwardly extending planar surface310at the angle314provides improved reliability. Based on failure analysis, tiny delamination occurs in gaps under stamped areas or half-etched areas of leadframe designs and has more chance to occur due to big epoxy mold compound (EMC) fillers clogging the gaps. With angle314, a gap under the outwardly extending planar surface310has sufficient spacing to fill the encapsulant to allow improved moldability. The improved moldability prevents voids and porosity surfaces that can cause delamination thereby satisfying customer requirements of no delamination allowed at any area, compared to traditional designs that use the same encapsulant.

It has also been discovered that the paddle202having the angle314allows the encapsulation104that is not only void free but also has a mold lock feature that reliably secures the paddle202in the encapsulation104. The angle314has an approximate range. The approximate range is set on one end by the need to hold the encapsulation104and is set on the other end by the need to have the encapsulation104, having approximately 1-75 micrometers (um) size filler, be able to fill the underside of the paddle202(e.g. below the outwardly extending planar surface310). If the angle314is less than 130 degrees, the voids increase. If the angle314is greater than 160 degrees, the horizontal distance316of the extension306is too small for the paddle202to be sufficiently locked in the encapsulation104. With the angle314preferably at 135 degrees, a balance of having the encapsulation104free of the voids and the mold lock feature is achieved. It is therefore critical that the angle314is approximately 135 degrees plus 25 degrees or minus 5 degrees.

It has further been discovered that the paddle202having the angle314allows a more compact footprint of the integrated circuit packaging system100. Based on the angle314, the paddle202has the length ratio of the horizontal distance316over the length of the indented planar surface308in the approximate range from 0.3 to 2.4. As the angle314increases to approximately 160 degrees, not only is the paddle202sufficiently locked in the encapsulation104but the horizontal distance316decreases thereby allowing the footprint to be more compact.

Referring now toFIG. 4, therein is shown a flow chart of a method400of manufacture of the integrated circuit packaging system100in a further embodiment of the present invention. The method400includes: forming a paddle having an indented planar surface intersecting an outwardly extending planar surface at an angle of approximately 135 degrees plus 25 degrees or minus 5 degrees in a block402; mounting an integrated circuit over the paddle in a block404; and forming an encapsulation over the integrated circuit and under the extension void free in a block406.

The resulting method, process, apparatus, device, product, and/or system is straightforward, cost-effective, uncomplicated, highly versatile, accurate, sensitive, and effective, and can be implemented by adapting known components for ready, efficient, and economical manufacturing, application, and utilization.