PATENT COVER GRAPHIC


United States Patent 3,498,833
March 3, 1970

Double Masking Technique For Integrated Circuit
William I. Lehrer

Filed July 8, 1966
Image of US PATENT 3,498,833

Abstract of the Disclosure

A deposited pattern is sharply defined on a surface by use of a two-step lifting process. To do this, a first layer of liftable material is deposited on the surface in the shape of the desired pattern. Then a second layer of lifting material is deposited over the exposed surface and the first layer of liftable material. The first layer of liftable material is removed, leaving the second layer of lifting material to sharply define the desired pattern on the exposed surface. Metal or other permanent material is then deposited on both the exposed surface and the second layer of lifting material. Removal of this second layer of lifting material leaves on the surface the sharply defined metal pattern. Precise control of the substrate temperature as a function of the thickness of the deposited material controls the depth of the alloy formed between the deposited material and the surface.
Figure descriptions: cover graphic

  • Figure 1 is a plan view of a portion of a hybrid circuit.
  • Figure 2 is a sectional elevation view taken along the line 2-2 of Figure 1.
  • Figure 3 is a plan view of that circuit portion shown in Figure 1 at a subsequent stage of fabrication.
  • Figure 4 is a sectional elevation view taken along the line 4-4 of Figure 3.
  • Figures 5-8 are sectional elevation views of the circuit portion in succeeding stages of fabrication.
  • Figure 9 is a schematic diagram of the completed electrical circuit shown by the illustrated circuit portions.

 Citations [54]:
  
2,995,461 08/1961 Bolcey 2,923,624 02/1960 Hensler 2,748,031 05/1956 Kafig 3,379,568 04/1968 Holmes
National Museum of American History
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