PATENT COVER GRAPHIC


United States Patent 3,457,636
July 29, 1969

Twin-Film Resistor Adjustment
John W. Ireland
James C. Holloway


Filed November 12, 1964
Image of US PATENT 3,457,636

Abstract of the Disclosure

Method and means for rapid, accurate, alteration of individual thin-film resistors of a multiresistor network to desired resistance values and temperature coefficients of resistance independently. Alteration to desired values, with close tolerances of these resistor parameters, is obtained by heating to stabilization of resistance value, then for a short duration, heating at high temperature. Desired parameter values are obtained by the heating being effected in successive inert and oxidizing atmospheres in combinations predetermined to provide desired characteristics.

A fixture constructed and apertured to hold the network and apparatus incorporating heat applying means and simultaneous resistance measuring circuitry operate together to effect independent heating under required ambient conditions and durations for each of the network resistors to be altered in resistance value and temperature coefficient of resistance as required. The separate applications of heat to individual resistors is obtained without destruction of adjacent elements by employing electrical current, hot prove or hot gas heat applying means so as to avoid excessive heating of the elements
Figure descriptions: cover graphic

  • Figure 1 is a plan view of a simplified multiresistor thin-film network.
  • Figure 2 is a graph showing typical resistance adjustments as a function of adjustment time.
  • Figure 3 is a graph showing resistance adjustment as a function of adjustment time of a specific thin-film resistance material.
  • Figure 4 is a graph showing the change in TCR as a function of resistance adjustment of two specific thin-film resistance material.
  • Figures 5 and 6 are graphs useful in understanding the simultaneous adjustment of resistance and TCR.

 Citations [54]:
  
2,994,847 08/1961 Vodar 3,261,082 07/1966 Maissel 3,108,019 10/1963 Davis 2,818,522 12/1957 Wheeler 3,308,528 03/1967 Bullard 3,056,937 10/1962 Peitikin
National Museum of American History
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