Automatic analyzing/controlling device for electroless composite plating solution

Abstract

An automatic analysis and control system for electroless composite plating solution for automatically analyzing an electroless composite plating solution and performing such a control as to obtain an appropriate bath composition and/or use conditions, wherein, as a technique for measuring the concentration of a metallic component in the plating solution by absorptiometry, the system includes a mechanism for measuring transmissivity or absorbance at least two or more different wavelengths after the plating solution is automatically introduced into an analytical cell, and a mechanism for calculating the objective concentration from the measured values and displaying the calculation results.

1 . An automatic analysis and control system for electroless composite plating solution for automatically analyzing an electroless composite plating solution and performing such a control as to obtain an appropriate bath composition and/or use conditions, wherein, as a technique for measuring the concentration of a metallic component in said plating solution by absorptiometry, said system comprises a mechanism for measuring transmissivity or absorbance at least two or more different wavelengths after said plating solution is automatically introduced into an analytical cell, and a mechanism for calculating the objective concentration from the measured values and displaying the calculation results.  
     
     
         2 . An automatic analysis and control system according to  claim 1 , wherein at least one of said measurement wavelengths is spectrometrically conditioned so that the half-width is 1 to not more than 100 nm.  
     
     
         3 . An automatic analysis and control system according to  claim 1  or  2 , wherein the combination of the measurement wavelengths is obtained by selecting at least one measurement wavelength in a wavelength range of 250 to 350 nm or 450 to 550 nm, and selecting at least one other measurement wavelength not overlapping with said at least one measurement wavelength in a wavelength range of 350 to 450 nm or 550 to 880 nm.  
     
     
         4 . An automatic analysis and control system according to any one of  claims 1  to  3 , wherein a measuring time table is so set that a standing time of not less than 15 sec is secured after the automatic introduction of said plating solution into said analytical cell and before the start of measurement of the transmissivity or absorbance.  
     
     
         5 . An automatic analysis and control system according to any one of  claims 1  to  4 , wherein a function of periodically introducing pure water into said analytical cell to wash said analytical cell and measuring the transmissivity or absorbance at a set measurement wavelength in the condition where said cell is filled with pure water is provided, and the thus measured value is used as a reference value of 100% transmissivity or absorbance zero relative to measured value of transmissivity or absorbance of said plating solution measured in the period before the next similar measurement for pure water.  
     
     
         6 . An automatic analysis and control system according to any one of  claims 1  to  5 , wherein a vertically elongate plating solution dwell portion having a cross sectional area of not less than two times of the cross sectional area of a sampling pipe is provided in the course of a sampling passage for introducing said plating solution into said analytical cell, an inlet to said plating solution dwell portion is provided at an upper portion, and an outlet from said plating solution dwell portion is provided at a lower portion, whereby a trap mechanism for preventing fine bubbles in said plating solution from being fed into said analytical cell is provided.  
     
     
         7 . An automatic analysis and control system according to any one of  claims 1  to  6 , wherein said electroless composite plating solution is an electroless composite nickel plating solution, and the nickel component in said plating solution is measured.