公开(公告)号：DE2750659A1

公开(公告)日：1978-06-15

申请号：DE2750659

申请日：1977-11-12

Applicant: IBM

Inventor： BARCLAY DONALD JOHN ,  CHAI BALJIT SINGH ,  KIRKMAN DAVID HORROBIN

IPC: H01L33/00 ,  G02F1/01 ,  G04G17/06 ,  G09F9/30 ,  H05K3/32

公开(公告)号：DE2441422A1

公开(公告)日：1975-03-13

申请号：DE2441422

申请日：1974-08-29

Applicant: IBM

Inventor： BARCLAY DONALD JOHN ,  PROWTING CHRISTOPHER THOMAS ,  CHAMBERS DAVID WALTER

IPC: C25D7/00 ,  C25D3/56 ,  C25D5/00 ,  C25D21/12 ,  H01F41/14

Abstract: 1414353 Controlling electro-plating of magnetic films I B M UNITED KINGDOM Ltd 4 Sept 1973 41475/73 Heading C7B [Also in Division G3] In electro-plating a ferromagnetic alloy film, e.g. of Fe-Ni, the current supply is varied to control the desired alloy composition by magnetizing at least a portion of the film to saturation during plating, and directing a beam of polarized light for reflection off the magnetized area, the reflected beam being intercepted and analyzed for changes in polarization due to the Kerr magnetooptic effect, a signal derived from such detected changes being used to control automatically the plating current. An alternating magnetic field may be used. As described an He-Ne laser directs plane polarized light through a window 71 of glass cell 60, the reflected light being intercepted by an analyzer set 2 degrees off extinction and passed to a photo-multiplier. The resulting signal has A.C. and D.C. components which vary respectively according to the changes in polarization of the light and reflectivity of the plated film. These voltage components are separated and amplified, the D.C. component being divided into the A.C. component to compensate for reflectivity changes. The final signal is applied to a differential amplifier which compares it with a desired fixed or variable signal and the resultant signal is used to control the plating current. The cell used may have a sliding plastics base 65 into which the substrate 68, e.g. a metallized glass slide, is held in a recess. Rod 74 is spring-loaded and provides electrical contact with the substrate. A Pt spiral anode 74 is used. Provision is made for a calomel electrode 76 which samples electrolyte via capillary 77 for calibration purposes, of which details are described. The bath disclosed comprises NiCl 2 , FeSO 4 , H 3 BO 3 and NaSCN in aqueous solution, the latter salt controlling the proportions of Fe and Ni in the alloy deposited.