Semiconductor pick-and-place machine automatic calibration apparatus
AssigneeMicron Technology, Inc.
InventorDavid A. Howell
Life of this patent
Estimating the term…
Abstract
An apparatus and method of automatically performing a calibration of the accuracy of placement of semiconductor chips or devices by a pick-and-place machine. The parts are placed on an adhesive-backed glass plate that has calibrated black marks whose dimensions match those of a specific part lead footprint. A gray scale camera mounted on the machine above the inverted glass plate records and sends a signal to a machine computer identifying the coordinates of exposed part silver lead area. The computer calculates part placement error and sends error data to a CRT or camera screen and alarm to alert an operator.
Claims14
In a semiconductor chip manufacturing process, an apparatus that automatically monitors a pick-and-place machine part placement accuracy comprising:
- a. a movable downward scanning gray scale camera mounted above a movable "Y" table section of the machine;
- b. a glass plate having dimensions the same as a plurality of PC boards in an inverted position above the table;
- c. a plurality of black calibration marks on the glass plate that match a part lead footprint;
- d. an adhesive layer above the glass plate affixing a plurality of parts to a top of the plate;
- e. a signal output from the gray scale camera to a machine computer;
- and
- f. an output from the computer to a readout device wherein a misplaced part below the inverted glass plate exposes a silver chip lead and the camera senses a white area and sends a signal to the computer and readout device indicating part placement error.
In a semiconductor chip manufacturing process, an apparatus that automatically monitors a pick-and-place machine part placement accuracy comprising:
- a. a movable downward scanning gray scale camera mounted to a pick-and-place head above "Y" table section of the machine;
- b. a glass plate having dimensions the same as a plurality of PC boards in an inverted position above the "Y" table section;
- c. a plurality of black calibration marks on the glass plate that match a part lead footprint;
- d. an adhesive layer above the glass plate affixing a plurality of parts to a top of the plate;
- e. a signal output from the gray scale camera to a machine computer;
- and
- f. an output from the computer to a CRT and a camera screen wherein a misplaced part below the inverted glass plate exposes a silver part lead and the camera senses a white area and sends a signal to the computer and to the CRT and the camera screen indicating a part placement error.
A method of monitoring and indicating the accuracy of part placement of a semiconductor pick-and-place machine comprising the steps of:
- a. placing a calibrated glass plate having black marks and an adhesive on a top surface of the glass plate, on a machine PCB in-conveyor;
- b. conveying the glass plate to a "Y" table;
- c. placing a plurality of parts on the adhesive on the glass plate by a place head;
- d. conveying the glass plate and parts to a PCA out-conveyor;
- e. removing the glass plate from the out-conveyor and inverting the glass plate;
- f. conveying the inverted glass plate to the "Y" table;
- g. moving the place head and an attached gray scale camera over the inverted glass plate;
- h. sensing a white area adjacent the glass plate black marks by the camera;
- i. transmitting a signal to a machine computer to indicate coordinates of the white area sensed;
- and
- j. indicating on a readout device a magnitude of a part placement error.
Dependencies are inferred from the claim text.