Patent Publication Number: US-6909194-B2

Title: Electronic assembly having semiconductor component with polymer support member and method of fabrication

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of Ser. No. 09/653,366 filed Sep. 1, 2000 now U.S. Pat. No. 6,756,253, which is a division of Ser. No. 09/440,380 filed Nov. 15, 1999, U.S. Pat. No. 6,180,504 B1, which is a division of Ser. No. 09/384,783 filed Aug. 27, 1999, U.S. Pat. No. 6,118,179. 

   FIELD OF THE INVENTION 
   This invention relates generally to semiconductor manufacture, and more particularly to an improved semiconductor component, and to a method for fabricating the component. 
   BACKGROUND OF THE INVENTION 
   Semiconductor components, such as packages, dice and wafers can include external contacts in the form of solder contact balls. The contact balls are in electrical communication with integrated circuits, and other electrical elements, contained on the components. For some components, such as chip scale packages and BGA packages, the contact balls can be arranged in a dense grid array, such as a ball grid array (BGA), or a fine ball grid array (FBGA). The contact balls provide a high input/output capability for a component, and permit the component to be surface mounted to a supporting substrate, such as a printed circuit board (PCB). 
     FIG. 1A  illustrates a contact ball  10 A bonded to a bonding pad  12 A on a semiconductor component  14 A. In this example, the component  14 A comprises a semiconductor package, such as a chip scale package, or a BGA package. The bonding pad  12 A comprises a BGA pad formed on a backside of the component  14 A out of a solderable metal such as molybdenum or copper. 
   One conventional method for attaching the contact ball  10 A to the component  14 A uses a solder reflow bonding process. With this method the contact ball  10 A is formed separately out of a non-eutectic solder alloy such as 95% Pb/5% Sn, 60% Pb/40% Sn, 63% Sn/37% Pb, or 62% Pb/36% Sn/2% Ag. Typically, the contact ball  10 A has the shape of a sphere, or a truncated sphere. 
   Initially, a layer of eutectic solder can be deposited on the bonding pad  12 A using a suitable deposition process such as screen printing to form a eutectic solder fillet  16 A. Typically, the eutectic solder is in the form of a paste. A platen can be used to hold the component  14 A, while the eutectic solder is deposited on the bonding pad  12 A. 
   Alternately, a flux (not shown) can be applied to the bonding pad  12 A. The flux chemically attacks surface oxides, such that the molten solder can wet the surfaces to be bonded. The flux also performs a tacking function prior to solder reflow. Following application of the flux, the contact ball  10 A can be placed on the bonding pad  12 A in physical contact with the eutectic solder and flux. A fixture can be used to center and maintain the contact ball  10 A on the eutectic solder paste and bonding pad  12 A. 
   Following placement of the contact ball  10 A on the bonding pad  12 A, the component  14 A can be placed in a furnace at a temperature sufficient to reflow the eutectic solder and form the fillet  16 A. The eutectic solder fillet  16 A metallurgically bonds the contact ball  10 A to the bonding pad  12 A. The component  14 A can then be removed from the furnace and cooled. In addition, the excess flux can be removed from the exposed surfaces of the component  14 A and the contact ball  10 A, using a suitable cleaning agent. 
   Suitable furnaces for performing the reflow process include convection ovens and infrared ovens. Rather than an oven, the bonding process can be performed using a pulse-thermode, a hot-air thermode, or a laser. A solder ball bumper, for example, uses a laser to form the eutectic solder fillet  16 A, and bond the contact ball  10 A to the bonding pad  12 A. Alternately, the contact ball  10 A can be bonded to the bonding pad  12 A by brazing, by welding, or by application of a conductive adhesive. 
   Following the bonding process, the component  14 A can be surface mounted to a supporting substrate  24 A, such as a printed circuit board (PCB), to form an electronic assembly  22 A. For attaching the component  12 A to the substrate  24 A, a second eutectic solder fillet  26 A bonds the contact ball  10 A to an contact pad  28 A on the supporting substrate  24 A. A solder reflow process, as previously described, can be used to form the eutectic solder fillet  26 A, and to bond the contact ball  10 A to the contact pad  28 A. 
   One factor that can adversely affect the reliability of the assembly  22 A during operation in different customer environments is fatigue failure of the contact ball  10 A, particularly at the interface of the contact ball  10 A with the bonding pad  12 A. Typically, fatigue failures are induced by thermal expansion mismatches between the component  14 A and the supporting substrate  24 A. For example, if the component  14 A comprises a first material, such as ceramic having a first CTE, and the supporting substrate  24 A comprises a second material, such as FR- 4  having a second CTE, cyclic loads can be placed on the contact ball  10 A as the assembly  22 A is thermally cycled during normal operation. 
   The forces acting on the contact ball  10 A include tensile forces  30 , moment forces  32 ,  34  and shear forces  36 . If these forces are large enough, the contact ball  10 A can separate from the bonding pad  12 A on the component  14 A. This separation can form an electrical open in the electrical path between the contact ball  10 A and the bonding pad  12 A on the component  14 A. This separation also compromises the physical bond between the component  14 A and the supporting substrate  24 A. This problem is compounded because the area of interface between the contact ball  10 A and the bonding pad  12 A is relatively small. The forces are thus concentrated over a relatively small area. 
     FIGS. 1B-1F  illustrate other types of components in which separation can occur between an external contact and a bonding pad on the component. In  FIG. 1B , a component  14 B includes a bonding pad  12 B and a contact bump  10 B formed on the bonding pad  12 B. In addition, the contact bump  10 B is bonded directly to an contact pad  28 B on a supporting substrate  24 B. In this example, the contact bump  10 B can be formed on the bonding pad  12 B using a deposition process, such as evaporation of a ball limiting metallurgy (BLM) and solder material through openings in a metal mask. In addition to the contact bump  10 B, the ball limiting metallurgy (BLM) can include a multi layered stack (not shown) such as an adherence layer (e.g., Cr), a solderable layer (e.g., Cu) and a flash layer (e.g., Au). This process is also known as C4 technology, and is typically used to deposit contact bumps  10 B directly onto aluminum bond pads on a semiconductor wafer or die. Alternately, other deposition processes, such as electroless deposition, or electrolytic deposition can be used to form the contact bump  10 B. The contact bumps  10 B can also comprise a pre-formed eutectic ball, which is placed on the contact pad  28 B and reflowed, substantially as previously described for the non-eutectic contact ball  10 A. In this case flux can be employed or reflow can be performed in an inert atmosphere. 
   In  FIG. 1C , a component  14 C includes a bonding pad  12 C and a solder contact column  10 C bonded to the bonding pad  12 C using a eutectic solder fillet  16 C. This type of component  14 C is sometimes referred to as a ceramic column grid array (CCGA). The contact column  10 C comprises an elongated member configured for bonding to an contact pad  28 C on a supporting substrate  24 C using a eutectic solder fillet  26 C. 
   In  FIG. 1D , a component  14 D includes a TAB contact bump  10 D bonded to a multi layered tape  38 , that is similar to TAB tape. This type of component  14 D is sometimes referred to as a TAB ball grid array (TBGA). For surface mounting the component  14 D, the TAB contact bump  10 D is configured for bonding to an contact pad  28 D on a supporting substrate  24 D using a eutectic solder fillet  26 D. 
   In  FIG. 1E , a component  14 E includes a solder mask  40  having an opening  42  in which a solder mask contact ball  10 E is formed. The opening  42  in the solder mask  40  facilitates alignment and bonding of the contact ball  10 E to a bonding pad  12 E on the component  14 E. In addition in the completed assembly, the solder mask  40  insulates the contact ball  10 E from adjacent contact balls  10 E and other electrical elements on the component  14 E, such as conductive traces. For surface mounting the component  14 E, the contact ball  10 E is configured for bonding to an contact pad  28 E on a supporting substrate  24 E using a solder fillet  26 E. 
   In  FIG. 1F , a component  14 F includes a polymer tape  44  having a double sided stud contact bump  10 F which comprises plated studs and a metal filled via in the polymer tape  44 . The stud contact bump  10 F is bonded to a bonding pad  12 F on the component  14 F using a eutectic solder fillet  16 F. In addition, the stud contact bump  10 F is bonded to a contact pad  28 F on a supporting substrate  24 F. 
   The present invention is directed to an improved semiconductor package in which external contacts on the component are rigidified by a separate polymer support member. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention, an improved semiconductor component, and a method for fabricating the component are provided. The semiconductor component can comprise a package, a die, or a wafer configured for surface mounting to a supporting substrate, such as a printed circuit board, to form an electronic assembly. 
   The component includes a substrate, and external contacts on a surface of the substrate in electrical communication with integrated circuits, or other electrical elements on the component. The external contacts can comprise contact balls, contact bumps, contact columns, TAB contact balls, or stud contact bumps. The external contacts include base portions bonded to bonding pads on the substrate, and tip portions configured for bonding to contact pads on the supporting substrate. 
   The component also includes a polymer support member on the substrate configured to rigidify, and absorb forces acting on the external contacts in the electronic assembly. In a first embodiment the polymer support member comprises a single polymer layer on the surface of the substrate that encompasses the base portions of the external contacts. The polymer layer can comprise a resilient, curable material that adheres to the base portions. In addition, the polymer layer can be formed with a thickness approximately equal to one fourth to one half the height of the external contacts, such that forces are transmitted away from the bonded connections with the bonding pads on the substrate, and redistributed across the bulk volume of the external contacts. 
   In a second embodiment the polymer support member comprises a plurality of separate polymer support rings. Each polymer support ring surrounds a base portion of an external contact, and has a thickness approximately equal to one fourth to one half the height of the external contact. Preferably, the polymer support rings are formed of a photoimageable material, such as a thick film resist, such that a photo patterning process can be used to form the polymer support rings. In this embodiment the polymer support rings absorb and redistribute forces exerted on the external contacts, particularly forces occurring at the bonded connections with the substrate. 
   A method for fabricating the first embodiment polymer support member includes the steps of blanket depositing a polymer layer on the surface of the substrate to a thickness approximately equal to one half the height of the external contacts, and then curing the polymer layer. 
   A method for fabricating the second embodiment polymer support member includes the steps of: providing a component substrate having a plurality of contact balls, blanket depositing a photoimageable material on the surface of the substrate and the contact balls, directing an exposure energy towards the photoimageable material and the contact balls, and then developing the photoimageable material to form polymer support rings circumjacent to base portions of the contact balls. During the exposure step the photoimageable material in spaces between the contact balls and the substrate is protected by the contact balls and remains unexposed for defining the polymer support rings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is an enlarged schematic cross sectional view of a prior art contact ball on a semiconductor component bonded to a supporting substrate in an electronic assembly; 
       FIG. 1B  is an enlarged schematic cross sectional view equivalent to  FIG. 1A  of a prior art contact bump; 
       FIG. 1C  is an enlarged schematic cross sectional view equivalent to  FIG. 1A  of a prior art contact column; 
       FIG. 1D  is an enlarged schematic cross sectional view equivalent to  FIG. 1A  of a prior art TAB contact bump; 
       FIG. 1E  is an enlarged schematic cross sectional view equivalent to  FIG. 1A  of a prior art solder mask contact ball; 
       FIG. 1F  is an enlarged schematic cross sectional view equivalent to  FIG. 1A  of a prior art stud contact bump on a polymer tape; 
       FIG. 2A  is a side elevation view of a semiconductor component constructed in accordance with the invention; 
       FIG. 2B  is a bottom view of the component taken along line  2 B— 2 B of  FIG. 2A ; 
       FIG. 3A  is an enlarged cross sectional view taken along section line  3 A— 3 A of  FIG. 2A  illustrating a contact ball on the component reinforced with a polymer layer; 
       FIG. 3B  is an enlarged cross sectional view taken along section line  3 B— 3 B of  FIG. 2A  illustrating an alternate embodiment contact bump on the component reinforced with a polymer layer; 
       FIG. 3C  is an enlarged cross sectional view taken along section line  3 C— 3 C of  FIG. 2A  illustrating an alternate embodiment contact column on the component reinforced with a polymer layer; 
       FIG. 3D  is an enlarged cross sectional view taken along section line  3 D— 3 D of  FIG. 2A  illustrating an alternate embodiment TAB contact ball on the component reinforced with a polymer layer; 
       FIG. 3E  is an enlarged cross sectional view taken along section line  3 E— 3 E of  FIG. 2A  illustrating an alternate embodiment solder mask contact ball on the component reinforced with a polymer layer; 
       FIG. 3F  is an enlarged cross sectional view taken along section line  3 F— 3 F of  FIG. 2A  illustrating an alternate embodiment stud contact bump on the component reinforced with a polymer layer; 
       FIG. 4  is a schematic side elevation view of an electronic assembly assembled using a component constructed in accordance with the invention; 
       FIG. 5A  is an enlarged cross sectional view equivalent to  FIG. 3A  of an alternate embodiment polymer support ring reinforcing a contact ball on a semiconductor component; 
       FIG. 5B  is a cross sectional view of the polymer support ring taken along section line  5 B— 5 B of FIG.  5 A: 
       FIGS. 6A-6B  are schematic cross sectional views illustrating steps in a method for fabricating the semiconductor component with a polymer layer as in  FIG. 2A ; and 
       FIGS. 7A-7C  are schematic cross sectional views illustrating steps in a method for fabricating the semiconductor component with polymer rings as in FIG.  5 A. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 2A and 2B , a semiconductor component  46  constructed in accordance with the invention is illustrated. As used herein the term “semiconductor component” refers to an element, or an assembly, that includes a semiconductor die. By way of example, the semiconductor component  46  can comprise a chip scale package, a BGA device, a bare semiconductor die, a semiconductor wafer containing semiconductor dice, or a panel or wafer containing semiconductor packages. 
   The component  46  includes a substrate  50 , and a plurality of bonding pads  12  and external contacts  10  formed on a surface  52  of the substrate  50 . Representative materials for the component substrate  50  include ceramic, silicon, and glass filled plastics such as FR-4. Representative materials for the bonding pads  12  include molybdenum, copper and nickel. As will be further explained, the external contacts  10  can comprise any of the embodiments shown in  FIGS. 1A-1F . The external contacts  10  are in electrical communication with integrated circuits, and other electrical elements, contained on the component  46 . 
   In addition, the external contacts  10  can be arranged in a dense grid array, such as a ball grid array (BGA), or a fine ball grid array (FBGA). For illustrative purposes the external contacts are shown in array of four rows and nine columns. However, the array can include as many, or as few, rows and columns of external contacts  10  as required, and can include from several to hundreds, or more, external contacts  10 . In addition, a pitch of the external contacts  10  can be selected as required. For example, for fine ball grid array (FGBA) components, the external contacts  10  can have a center to center pitch as small as about 0.004-in (0.100 mm) or smaller. 
   The component  46  also includes a polymer support member in the form of a polymer layer  48  formed on the surface  52  of the substrate  50 . The polymer layer  48  is configured to support the external contacts  10 , and to rigidify and strengthen the bonding of the external contacts  10  to the bonding pads  12  on the component  46 . In an electronic assembly  22  ( FIG. 4 ) constructed using the component  46 , the polymer layer  48  absorbs forces acting on the external contacts  10 . In addition, the polymer layer  48  transfers forces occurring at the interfaces of the external contacts  10  with the bonding pads  12  and redistributes the forces into the center, or full volume, of the external contacts  10 . 
   Referring to  FIGS. 3A-3F , several different embodiments for the component  46  and external contacts  10  are illustrated. In  FIG. 3A , a component  46 A includes a substrate  50 A, bonding pads  12 A on the substrate  50 A, and contact balls  10 A bonded to the bonding pads  12 A using eutectic solder fillets  16 A. The contact balls  10 A can comprise solder balls constructed and bonded to the bonding pads  12 A on the substrate  50 A, substantially as previously described and shown in FIG.  1 A. 
   As also shown in  FIG. 3A , the component  46 A includes a polymer layer  48 A configured to strengthen and rigidify the contact balls  46 A. The polymer layer  48 A has a thickness T that is less than a height H of the contact balls  10 A. This permits tip portions  64 A of the contact balls  10 A to be bonded to mating contact pads  28  ( FIG. 4 ) on a supporting substrate  24  (FIG.  4 ). In addition, with the thickness T less than the height H, an underfill layer  56  ( FIG. 4 ) can be placed between the component  46 A and the supporting substrate  24  (FIG.  4 ), if desired. 
   In the illustrative embodiment, the thickness T of the polymer layer  48 A is approximately one half the height H of the contact balls  10 A (T=½*H). With this thickness, the surface of the polymer layer  48 A will be coincident to a plane through the diameters and centers of the contact balls  10 A. However, the thickness T can also be less than one half the height H, with one fourth to one half being preferred. A representative range for the height “H” of the contact balls  10 A can be from about 0.004-in (0.100 mm) to 0.030-in (0.762 mm). A representative range for the thickness T of the polymer layer  48 A can be from about 0.002-in (0.050 mm) to 0.025-in (0.635 mm). 
   Preferably, the polymer layer  48 A comprises a resilient material that adheres to, and encompasses base portions  66 A of the contact balls  10 A, such that forces can be efficiently absorbed by the polymer layer  48 A, and transmitted away from the interface of the contact balls  10 A with the bonding pads  12 A. As used herein the term “base portions” refers to portions of the contact balls  10 A configured for bonding to the bonding pads  12 A. The term “tip portions” refers to exposed portions of the contact balls  10 A configured for bonding to contact pads  28  ( FIG. 4 ) on a supporting substrate  24  (FIG.  4 ). 
   Preferably, the polymer layer  48 A comprises a curable material, such as polyimide, that can be deposited in viscous form, and then cured to harden. As will be further explained, the polymer layer  48 A can also comprise a photoimageable material, such as a thick film resist, to permit blanket deposition, and then removal from selected portions of the surface  52 A of the component substrate  50 A by development of the material. 
   Referring to  FIG. 3B , an alternate embodiment component  46 B includes contact bumps  10 B formed on bonding pads  12 B on a component substrate  50 B, substantially as previously described, and shown in FIG.  1 B. In addition, the component  46 B includes a polymer layer  48 B that adheres to and encompasses base portions  66 B of the contact bumps  10 B. The polymer layer  48 B has a thickness T 1  that is less than a height H 1  of the contact bumps  10 B such that tip portions of the contact bumps  10 B are left exposed for bonding. In the illustrative embodiment the thickness T 1  is about one half the height H 1  such that a surface of the polymer layer  48 B is coincident to a plane through the centers of the contact bumps  10 B. However, the thickness T 1  can be less than one half the height with from one fourth to one half being preferred. 
   Referring to  FIG. 3C , an alternate embodiment component  46 C includes contact columns  10 C formed on bonding pads  12 C on a component substrate  50 C, substantially as previously described, and shown in FIG.  1 C. In addition, the component  46 C includes a polymer layer  48 C that adheres to and encompasses base portions  66 C of the contact columns  10 C. The polymer layer  48 C has a thickness T 2  that is less that a height H 2  of the contact columns  10 C such that tip portions  64 C of the contact columns  10 C are exposed for bonding. In  FIG. 3C , the thickness T 2  is about one half the height H 2 . However, as the contact columns  10 C are elongated structures with heights of greater than 0.060-in (1.524 mm), the thickness T 2  can be substantially less than one half the height H 2  (e.g., one fourth the height H 2  or less) and still perform adequately. 
   Referring to  FIG. 3D , an alternate embodiment component  46 D includes TAB contact bumps  10 D formed on multi layered TAB tape  38 , substantially as previously described and shown in FIG.  1 D. In addition, the component  46 D includes a polymer layer  48 D that adheres to the TAB tape  38  and encompasses base portions  66 D of the contact bumps  10 D on the polymer tape  38 . The polymer layer  48 D has a thickness T 3  that is less than a height H 3  of the contact bumps  10 D such that tip portions  64 D of the contact bumps  10 D are exposed for bonding. Preferably the thickness T 3  is about one fourth to one half the height H 3  or less. 
   Referring to  FIG. 3E , an alternate embodiment component  46 E includes contact balls  10 E formed on bonding pads  12 E in openings in a solder mask  40  on a component substrate  50 E, substantially as previously described, and shown in FIG.  1 E. In addition, the component  46 E includes a polymer layer  48 E bonded to the solder mask  40  and encompassing base portions  66 E of the contact balls  10 E. The polymer layer  48 E has a thickness T 4  that is less than a height H 4  of the contact balls  10 E such that tip portions  64 E of the contact balls  10 E are exposed for bonding. Preferably the thickness T 4  is about one fourth to one half the height H 4 . 
   Referring to  FIG. 3F , an alternate embodiment component  46 F includes stud contact bumps  10 F formed on polymer film  44  on a component substrate  50 F, substantially as previously described, and shown in FIG.  1 F. In addition, the component  46 F includes a polymer layer  48 F that adheres to the component substrate  50 F and encompasses base portions  66 F of the stud contact bumps  10 F. The polymer layer  48 F has a thickness T 5  that is less than a height H 5  of the stud contact bumps  10 F such that tip portions  64 F of the stud contact bumps  10 F are exposed for bonding. Preferably the thickness T 5  is about one fourth to one half the height H 5 . 
   Referring to  FIG. 4 , the component  46  is shown surface mounted to a supporting substrate  24  to form an electronic assembly  22 . In the assembly  22 , the external contacts  10  on the component  46  are bonded to contact pads  28  on the supporting substrate  24  substantially as previously described. In addition, an underfill layer  56  optionally fills the gap between the component  46  and the supporting substrate  24 . Also in the assembly, the polymer layer  48  strengthens and rigidifies the bonding of the external contacts  10 , to the bonding pads  16  on the component substrate  50 . Further, the polymer layer  48  absorbs and resists forces acting on the external contacts  10 , such that separation from the bonding pads  16  is less likely to occur. 
   Referring to  FIG. 5A , an alternate embodiment semiconductor component  46 G includes a substrate  50 G, and a plurality of bonding pads  12 G on the substrate  50 G. In addition, the component  46 F includes a plurality of contact balls  10 G bonded to the bonding pads  12 G. The component  46 G also includes a polymer support member in the form of a plurality of polymer rings  54  configured to support and rigidify the contact balls  10 G. 
   In the component  46 G, the contact balls  10 G are initially attached to the bonding pads  12 G such that spaces  62  are present between base portions  66 G of the contact balls  10 G and the bonding pads  12 G. This configuration can be achieved by bonding the contact balls  10 G to the bonding pads  12 G using a eutectic solder fillet  16 G. This configuration can also be achieved by forming the contact balls  10 G directly on the bonding pads  12 G using a deposition process such as electroless or electrodeposition, or by using pre-formed eutectic balls substantially as previously described. 
   The polymer rings  54  substantially fill the spaces  62  between the contact balls  10 G and bonding pads  12 G. In addition, the polymer rings function substantially as previously described for polymer layer  48  to strengthen and rigidify the bonds to the contact balls  10 G. In this embodiment a thickness T 6  of the polymer rings  54  is approximately equal to one half a height H 6  of the contact balls  10 G such that tip portions  64 G of the contact balls  10 G remain exposed for bonding. Preferably the thickness T 6  of the polymer rings  54  is from one fourth to one half the height H 6  of the contact balls  10 G. The polymer rings  54  can be formed with this thickness using a photoimageable polymer, and a developing process to be hereinafter described. 
   Referring to  FIGS. 6A and 6B , a method for fabricating the semiconductor component  46  with the polymer layer  48  is illustrated. Initially, as shown in  FIG. 6A , the component substrate  50  can be provided with the external contacts  10  bonded to the bonding pads  16 . The external contacts  10  on the component substrate  50  can be in one of the configurations shown in  FIGS. 3A-3F , or any other conventional configuration. In addition, any conventional bonding process such as solder reflow, laser reflow, welding, brazing, or conductive adhesive bonding, can be used to bond the external contacts  10  to the bonding pads  16 . 
   Preferably the component substrate  50  is provided as a wafer, a panel, a strip, or a leadframe, containing multiple substrates  50 . Following the fabrication process, the component  46  can be singulated using a suitable process such as cutting, shearing or etching. 
   As also shown in  FIG. 6A , the polymer layer  48  can be blanket deposited on the component substrate  50  in a viscous state. Suitable materials for the polymer layer  48  include curable polymers such as polyimide, silicone, epoxy, and thick film resists. A thickness of the polymer layer  48  can be selected substantially as previously described. This thickness can be controlled by dispensing a required volume of material onto the substrate  50 , and then spinning if required, using a suitable apparatus, such as a spin coater or meniscus coater. In addition, the deposition process can be controlled such that the polymer layer  48  adheres to the base portions  66  of the external contacts  10 , but does not completely cover the tip portions  64 , substantially as previously described. 
   As shown in  FIG. 6B , following deposition of the viscous material a curing step can be performed to cure the polymer layer  48 . Depending on the polymer, the curing step can be performed by heating the polymer layer  48  to a required temperature for a required time period. For some materials, such as epoxies, the curing process can be performed by outgassing of a solvent. As also shown in  FIG. 6B , the polymer layer  48  can cure with a curved, or meniscus shape, during adherence to the base portions  66  of the external contacts  10 . 
   Referring to  FIGS. 7A-7C , steps in a method for fabricating the component  46 G with polymer rings  54  are illustrated. Initially, as shown in  FIG. 7A , the component substrate  50 G can be provided. As with the prior process, this fabrication process is preferably performed on multiple substrates  50 G contained on a wafer, a panel, a strip or a leadframe. In this embodiment the external contacts comprise contact balls  10 G that are bonded to the bonding pads  12 G, such that spaces  62  are present between the curved base portions  66 G of the contact balls  10 G, and the bonding pads  12 G. Such a configuration can be achieved by bonding the contact balls  10 G using eutectic solder fillets  16 G (FIG.  5 A). Such a configuration can also be achieved by forming the contact balls  10 G directly on the bonding pads  12 G using a deposition process such as electroless or electrodeposition through openings in a mask, or by using eutectic solder balls substantially as previously described. 
   As also shown in  FIG. 7A , a thick film resist  58  can be blanket deposited on the component substrate  50 G, on the contact balls  10 G and in the spaces between the contact balls  10 G. One suitable thick film resist is a negative tone resist sold by Shell Chemical under the trademark “EPON RESIN SU-8”. The resist can be deposited in layers to a thickness of from about 3-50 mils. The resist also includes an organic solvent (e.g., gamma-butyloracton), and a photoinitiator. A conventional resist coating apparatus, such as a spin coater, or a meniscus coater, can be used to deposit the resist in viscous form onto the substrate  50 G. The deposited resist can then be partially hardened by heating to about 95° C. for about 15 minutes or longer. 
   Next, as shown in  FIG. 7B , the resist  58  can be exposed using an exposure energy  60 . Exposure of the resist  58  can be performed with a conventional UV mask writer using a suitable UV dose. A representative UV dose for the previously described resist formulation is about 165 mJ/cm 2 . During the exposure process the resist present in the spaces  62  is “shadowed” or “protected” by the contact balls  10 G such that this material remains unexposed. 
   Next, as shown in  FIG. 7C , the resist  58  can be developed using a suitable developer. One suitable developer for developing the previously described resist formulation is a solution of PGMEA (propyleneglycol-monomethylether-acetate). Developing of the resist  58  forms the support rings  54  leaving the tip portions  64 G exposed for bonding. Following development, the support rings  54  can be fully hardened. A “full cure” can be performed with a hard bake at about 200° C. for about 30 minutes. 
   Thus the invention provides an improved semiconductor component and method of fabrication. The component includes external contacts and a polymer support member designed to strengthen and rigidify the external contacts. 
   While the invention has been described with reference to certain preferred embodiments, as will be apparent to those skilled in the art, certain changes and modifications can be made without departing from the scope of the invention as defined by the following claims.