A solder bump is stenciled onto a substrate, providing bumped substrate at pitches below 400 microns. The solder is applied through stencil/mask and paste method; the mask, however, remains attached to the substrate during reflow. Pitches of greater than 400 microns may also be obtained through the invention. The invention further provides for generation of uniform, controllable volume metal balls.
The purpose of the present invention is to improve releasability from the jig of a method of producing a minute metal ball by heating and melting and then cooling a metal piece of specific dimensions and further, to present a metal ball with very good dimensional accuracy and sphericity, even though diameter is minute. By means of the above-mentioned method, very good releasability between the metal ball and jig after melting and cooling is obtained and long-term use of the tool becomes possible by placing a metal piece on a jig with a layer of fine powder of BN, AlN or C having low wettability with the metal piece in between, or by making a layer of fine powder adhere to the surface of the metal piece and then placing this metal piece on the jig or shaking and arranging individual metal pieces in holes in the same. Moreover, the layer of fine powder on the jig or the surface of the metal piece used in the method of the present invention does not prevent spheroidising of the metal piece under surface tension during melting, and there is no deterioration of surface properties of the metal ball that is obtained and it is thereby possible to markedly improve dimensional accuracy and sphericity of the metal ball.
Pads to be used for flip chip bonding and wire bonding are pattern-formed on a surface of a substrate. The pads to be used for flip chip bonding are shielded. Plating is applied to each of the pads to be used for wire bonding. Bonding pads for wire bonding is shielded by a masking tape. An adhesive layer is applied to the surface of each of pads to be used for flip chip bonding. Solder powder is provided to adhere to the surface of each of pads to be used for flip chip bonding with the adhesive layer. The masking tape is peeled off from the bonding pads for wire bonding. The solder powder is melted by reflowing so that the solder covers the pads to be used for flip chip bonding.
Automatically monitoring pads of material deposited on a surface of a workpiece using an inspection system that senses a deposited pad of material and determines pad height values at a plurality of locations across the pad, and a shape classifier that receives the pad height values as inputs and outputs a plurality of three-dimensional shape attributes related to pad deposit conditions.
Methods and apparatus for forming a plurality of uniformly sized solder balls utilize a stencil having a plurality of holes of uniform volume disposed on a substrate. Solder is disposed in the holes of the stencil on the substrate. Typically, the solder is in the form of solder paste which is distributed into the holes using a squeegee. While within the holes of the stencil on the substrate, the solder is melted to form solder balls. The stencil may then be removed to leave the solder balls on the substrate, or the solder balls may be removed while the stencil remains on the substrate.
Methods and apparatus for forming a plurality of uniformly sized solder balls utilize a stencil having a plurality of holes of uniform volume disposed on a substrate. Solder is disposed in the holes of the stencil on the substrate. Typically, the solder is in the form of solder paste which is distributed into the holes using a squeegee. While within the holes of the stencil on the substrate, the solder is melted to form solder balls. The stencil may then be removed to leave the solder balls on the substrate, or the solder balls may be removed while the stencil remains on the substrate.
