Methods for making deposited films with improved microstructures
First Claim
1. A line of sight deposition method comprising:
- emitting material from a source spaced apart from a substrate surface;
depositing a first amount of said material on a first region of said surface to form a first deposit having a first deposition characteristic;
simultaneously depositing a second amount of said material, less than said first amount, on a second region of said surface to form a second deposit having a second deposition characteristic including columnar growth defects due to geometric shadowing; and
removing an amount of said deposited material approximately uniformly from said substrate surface including said first and second regions;
the amount removed being less than said first amount, at least as great as said second amount, and sufficient to remove a portion of the deposited material having said second characteristic and to reduce said columnar growth defects.
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Abstract
Methods for improving microstructures of line-of-sight deposited films are described. Columnar growth defects ordinarily produced by geometrical shadowing during deposition of such films are eliminated without resorting to post-deposition thermal or mechanical treatments. The native, as-deposited coating qualities, including homogeneity, fine grain size, and high coating-to-substrate adherence, can thus be retained. The preferred method includes the steps of emitting material from a source toward a substrate to deposit a coating non-uniformly on the substrate surface, removing a portion of the coating uniformly over the surface, again depositing material onto the surface, but from a different direction, and repeating the foregoing steps. The quality of line-of-sight deposited films such as those produced by sputtering, progressively deteriorates as the angle of incidence between the flux and the surface becomes increasingly acute. Depositing non-uniformly, so that the coating becomes progressively thinner as quality deteriorates, followed by uniformly removing some of the coating, such as by resputtering, eliminates the poor quality portions, leaving only high quality portions of the coating. Subsequently sputtering from a different direction applies a high quality coating to other regions of the surface. Such steps can be performed either simultaneously or sequentially to apply coatings of a uniformly high quality, closed microstructure to three-dimensional or larger planar surfaces.
64 Citations
30 Claims
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1. A line of sight deposition method comprising:
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emitting material from a source spaced apart from a substrate surface; depositing a first amount of said material on a first region of said surface to form a first deposit having a first deposition characteristic; simultaneously depositing a second amount of said material, less than said first amount, on a second region of said surface to form a second deposit having a second deposition characteristic including columnar growth defects due to geometric shadowing; and removing an amount of said deposited material approximately uniformly from said substrate surface including said first and second regions; the amount removed being less than said first amount, at least as great as said second amount, and sufficient to remove a portion of the deposited material having said second characteristic and to reduce said columnar growth defects. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A line of sight deposition method comprising:
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emitting material from a source to establish a flux of said material in the direction of a substrate surface; depositing a portion of said material on regions of said surface which are exposed to at least a portion of said source along a line of sight, including; depositing material on a first said region whose surface tangent forms a first angle with the direction of said flux; depositing material on a second said region whose surface tangent forms a second angle with the direction of said flux less than said first angle; the material deposited in the first region having a first deposition characteristic and the material deposited in the second region having a second deposition characteristic including defects due to geometric shadowing; the amount of material deposited per unit area of said surface being greater in the first region than in the second region; and removing deposited material approximately uniformly from said surfce so as to reduce the accumulation of deposited material having said second characteristic and to increase the relative proportion of deposited material having said first characteristic. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A physical vapor deposition method comprising:
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emitting a physical vapor from a source spaced apart from a substrate surface; depositing a portion of said vapor non-uniformly onto said surface to form a solid coating thereon, the coating including a first portion on a first region of said surface having a first thickness and a second portion on a second region having a second thickness less than the first thickness; and removing a thickness of the coating uniformly over said surface; whereby the thickness of the second portion is reduced in proportion to the thickness of the first portion. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification