Method for measuring a thickness of a printed circuit board
AssigneeMicron Technology, Inc.
InventorDonald W. Miller
Life of this patent
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Abstract
The invention relates to a method for measuring a thickness of a printed circuit board having a plating portion provided on a core portion. The method includes directing a laser beam to the core portion of the printed circuit board, whereby the laser beam at least partially reflects from the core portion. The reflected laser beam is monitored and a thickness of the core portion is determined based upon the reflected laser beam. The plating portion of the printed circuit board is then heated by transferring a selected amount of energy thereto. The thermal characteristics of the heated plating are monitored and a thickness of the plating portion is determined based upon these thermal characteristics.
Claims27
A method for measuring a thickness of a printed circuit board having a plating portion of a first material provided on a core portion of a second material, the printed circuit board having a total thickness, the method comprising the steps of:
- directing a laser beam to the core portion of the printed circuit board, the laser beam at least partially reflecting from the core portion;
- monitoring the laser beam reflected from the core portion;
- deriving a thickness of the core portion based upon the monitoring of the laser beam reflected from the core portion to measure a first partial thickness of the total printed circuit board thickness;
- heating the plating portion of the printed circuit board by transferring a selected amount of energy to the plating portion;
- monitoring thermal characteristics of the plating portion upon transfer of the selected around of energy to the plating portion;
- and
- deriving a thickness of the plating portion of the printed circuit board independent of the core portion based upon the thermal characteristics to measure a second partial thickness of the total printed circuit board thickness, the second partial thickness being separated from the first partial thickness.
A method for measuring a thickness of a printed circuit board having a plating portion of a first material provided on a core portion of a second material, the printed circuit board having a total thickness, the method comprising the steps of:
- moving the printed circuit board to a core thickness measuring station;
- directing a laser beam to the core portion of the printed circuit board, the laser beam at least partially reflecting from the core portion;
- monitoring the laser beam reflected from the core portion;
- deriving a thickness of the core portion based upon the monitoring of the laser beam reflected from the core portion to measure a first partial thickness of the total printed circuit board thickness;
- moving the printed circuit board from the core thickness measuring station to a plating thickness measuring station;
- heating the plating portion of the printed circuit board by transferring a selected amount of energy to the plating portion;
- monitoring thermal characteristics of the plating portion upon transfer of the selected amount of energy to the plating portion;
- deriving a thickness of the plating portion of the printed circuit board independent of the core portion based upon the thermal characteristics to measure a second partial thickness of the total printed circuit board thickness, the second partial thickness being separate from the first partial thickness;
- and
- determining the total thickness of the printed circuit board based upon the thicknesses of the core portion and the plating portion.
A method for measuring a thickness of a printed circuit board having a plating portion of a first material provided on two sides of a core portion of a second material, the printed circuit board having a total thickness, the method comprising the steps of:
- directing a laser beam to the core portion of the printed circuit board, the laser beam at least partially reflecting from the core portion;
- monitoring the laser beam reflected from the core portion;
- deriving a thickness of the core portion based upon the monitoring of the laser beam reflected from the core portion to measure a first partial thickness of the total printed circuit board thickness;
- heating a first plating portion on a first side of the printed circuit board by transferring a first selected amount of energy to the first plating portion;
- monitoring thermal characteristics of the first plating portion on the first side of the printed circuit board upon transfer of the first selected amount of energy to the first plating portion;
- heating a second plating portion on a second side of the printed circuit board by transferring a second selected amount of energy to the second plating portion;
- monitoring thermal characteristics of the second plating portion on the second side of the printed circuit board upon transfer of the second selected amount of energy to the second plating portion;
- and
- deriving a combined thickness of the first and second plating portions independent of the core portion based upon the thermal characteristics of the plating portions on the first and second sides of the printed circuit board to measure a second partial thickness of the total printed circuit board thickness, the second partial thickness being separate from the first partial thickness.
Dependencies are inferred from the claim text.