Wafer coating and singulation method

A method for providing an underfill material on an integrated circuit chip, comprising the following steps in the order named:

• a. providing a wafer having a front side and a back side, the wafer containing at least one integrated circuit chip, the integrated circuit chip having a plurality of solder bumps on said front side of the wafer;
• b. cutting said front side of the wafer to form channels that define edges on said at least one integrated circuit chip, the cutting being of a depth which does not cut completely through the wafer;
• c. coating said front side of the wafer with an underfill material so as to leave a portion of each of said solder bumps uncoated;
• d. removing material from the back side of the wafer to reduce the thickness of the wafer sufficiently to cause the channels to extend from the front side to the back side;
• e. singulating the wafer by cutting underfill material in the channels sufficient to singulate the integrated circuit chip from the wafer;
• and
• f. wherein the underfill material coated on the front side remains affixed to the singulated integrated circuit chip.

A wafer level method for providing a layer of underfill adhesive on an integrated circuit having an active surface that includes solder balls on electrically conductive pads, comprising:

• providing a silicon wafer containing one or more of the integrated circuits;
• cutting the active surface of the wafer to form channels that define edges on the integrated circuit, the cutting being of a depth which does not penetrate completely through the wafer;
• forming a layer of underfill adhesive on the active surface of the integrated circuit and in the channels, wherein at least some portion of most of the solder balls remain uncovered;
• partially curing the underfill adhesive;
• removing silicon from the back side of the wafer sufficient to cause the channels to penetrate completely through the wafer;
• and
• cutting the underfill adhesive contained in the channels to singulate at least one integrated circuit chip having an underfill material on its active surface and edges.

A method of providing a layer of underfill adhesive on a wafer having an array of bumped integrated circuits, each circuit having an active surface that includes solder balls on electrically conductive pads, comprising:

• dicing the wafer on the bumped side to form grooves having a predetermined depth that is less than the thickness of the wafer;
• coating the wafer with an underfill material so as to cover the active surface and fill the grooves with the underfill material;
• polishing the side of the wafer opposite the active surface until the diced grooves extend completely through the wafer;
• and
• cutting through the underfill material in the grooves to singulate the array of bumped integrated circuits.