Claims
- 1. In the method of forming an electrically insulative coating having a surface smoothness value of 250 A or less, peak to valley, over a polycrystalline or a microroughened substrate having surface irregularities of as great as 500 A, the steps of:
- Rf bias sputtering a first substantially continuous layer of electrically insulative material over said substrate at a reemission coefficient of about 0.35 or lower; and then
- Rf bias sputtering a second layer of said electrically insulative material over said first layer of electrically insulative material at a reemission coefficient of about 0.6 or greater to provide a surface smoothness of at least about 250 A, peak to valley, or smoother.
- 2. The method of claim 1 wherein said polycrystalline substrate is a ceramic.
- 3. The method of claim 2 wherein said ceramic is ferrite.
- 4. The method of claim 1 wherein said electrically insulative material is amorphous.
- 5. The method of claim 4 wherein said electrically insulative material selected from the group consisting of Al.sub.2 O.sub.3, SiO.sub.2, and Si.sub.3 N.sub.4.
- 6. The method of claim 4 wherein sputtering of said first electrically insulative layer is at a reemission coefficient in the range of about 0.15 to 0.35.
- 7. The method of claim 1 wherein said electrically insulative material is selected from the group consisting of Al.sub.2 O.sub.3, SiO.sub.2, and Si.sub.3 N.sub.4.
- 8. The method of claim 7 wherein said second insulative layer is sputtered at a reemission coefficient in the range of about 0.6 to 0.8.
- 9. The method of claim 1 wherein said first electrically insulative layer is sputtered at a reemission coefficient of about 0.15 to 0.35.
- 10. The method of claim 1 wherein said first insulative layer is sputtered at a reemission coefficient of about 0.25.
- 11. The method of claim 1 wherein said second electrically insulative layer is sputtered at a reemission coefficient in the range of about 0.6 to 0.8.
- 12. The method of claim 1 wherein said insulative layer having a surface smoothness value of about 250 A or less, peak to valley, is partially coated with material in the form of a raised pattern having a thickness of about 500 A.
- 13. The method of claim 12 wherein said material is magnetic.
- 14. The method of claim 13 wherein said magnetic material is permalloy exhibiting an H.sub.ce of about 1.5 oe or less, an H.sub.k within the range of about 2.5 to 5.5 oe, and an H.sub.ch of about 1.5 oe or less, a .beta. of about 5.degree. or less, and an .alpha. of about 10.degree. or less.
- 15. The method of claim 12 wherein said insulative layer having a surface smoothness value of about 250 A or less, peak to valley, is partially coated with metallic magnetic permalloy in the form of a raised line pattern having a thickness of about 500 A and exhibiting an H.sub.ce of about 1.5 oe or less, an H.sub.k within the range of about 2.5 to 5.5 oe, an H.sub.ch of about 1.5 oe or less, a .beta. of about 5.degree. or less, and an .alpha. of about 10.degree. or less.
- 16. In the method of forming an electrically insulative coating having a surface smoothness value of about 250 A or less, peak to valley, over a polycrystalline ferrite substrate, the steps of:
- Rf bias sputtering a first substantially continuous layer of electrically insulative amorphous Al.sub.2 O.sub.3 over said ferrite at a reemission coefficient of about 0.25;
- Rf bias sputtering a second layer of electrically insulative Al.sub.2 O.sub.3 over said first layer of electrically insulative amorphous Al.sub.2 O.sub.3 at a reemission coefficient of about 0.7 to provide a surface smoothness value of about 250 A or less, peak to valley.
- 17. In the method of forming an electrically insulative coating having a surface smoothness value of about 250 A or less, peak to valley, over a substrate having a raised pattern having a thickness of about 500 A, the steps of:
- Rf bias sputtering a first substantially continuous layer of electrically insulative material over said substrate and raised pattern at a reemission coefficient of about 0.35 or lower; and then
- Rf bias sputtering a second layer of said electrically insulative material over said first layer of said electrically insulative material at a reemission coefficient of about 0.6 or greater, to provide a surface smoothness value of about 250 A or less, peak to valley.
- 18. The method of claim 17 wherein the raised pattern includes magnetic material, the first layer of electrically insulative material is sputtered at a reemission coefficient in the range of about 0.15 to 0.35, and is amorphous, and wherein said insulative material is selected from the group consisting of Al.sub.2 O.sub.3, SiO.sub.2, and Si.sub.3 N.sub.4.
- 19. The method of claim 18 wherein said magnetic material is permalloy exhibiting an H.sub.ce of about 1.5 oe or less, an H.sub.k within the range of about 2.5 to 5.5 oe, and an H.sub.ch of about 1.5 oe or less, a .beta. of about 5.degree. or less, and an .alpha. of about 10.degree. or less.
- 20. The method of claim 19 wherein a magnetic head is formed by forming conductive connections to said permalloy, coating said permalloy and conductive connections with insulation, and placing additional ferrite on the insulation to form a magnetic head.
- 21. The method of claim 17 wherein the reemission coefficient for sputtering of the second layer is no greater than 0.8.
- 22. The method of claim 17 wherein the reemission coefficient for sputtering the first layer is at least 0.15.
Parent Case Info
This is a continuation-in-part of copending application Ser. No. 606,692, filed Aug. 21, 1975, now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
3983022 |
Auyang |
Sep 1976 |
|
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
606692 |
Aug 1975 |
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