Method for defect reduction in magnetic write head fabrication

• US 8,828,248 B2
• Filed: 02/01/2013
• Issued: 09/09/2014
• Est. Priority Date: 02/01/2013
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: HGST Netherlands B.V. (Western Digital Corporation)
• Inventors: Mao, Guomin, Myneni, Satyanarayana, Pentek, Aron, Zhao, Xiaoye
• Primary Examiner(s): Vinh, Lan
• Application Number:
  US13/756,888
• Publication Number:
  US 20140217060A1
• Time in Patent Office: 585 Days
• Field of Search: 216/22, 216/41, 216/49, 216/59, 216/63, 216/67, 216/75, 216/81, 216/72, 438/706, 438/710, 438/714, 438/720
• US Class Current: 216/22
• CPC Class Codes: G11B 5/1278 specially adapted for magnetisations perpendicular to the surface of the record carrier
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
• CPC Class Codes: G11B 5/84 Processes or apparatus specially adapted for manufacturing record carriers

Abstract

Write heads may be formed by reactive ion etching (RIE) a dielectric mask and then reactive ion etching a polymeric underlayer. The first RIE affects the second RIE. The first portion of the first RIE process is performed with a ratio of CF₄ to CHF₃ between about 1.3 to 2, a gas flow ratio of CF₄ to He between 2.2 and about 3, and a ratio of RF source power to RF bias power between about 10 and about 16. The second portion of the first RIE process is performed with a ratio of CF₄ to CHF₃ between about 0.3 to 0.8, a gas flow ratio of CF₄ to He between about 1.2 and about 1.8, and a ratio of RF source power to RF bias between about 22 to 28. With the above parameters, the dielectric mask can be formed with minimized damage on the underlayer.

Claims

1. A method of making a write pole for a perpendicular magnetic recording write head, comprising:

forming a photoresist mask over a dielectric hard mask layer of a stack such that the photoresist mask covers a first portion of the dielectric hard mask layer and leaves a second portion exposed, wherein the stack comprises;

a layer of magnetic material formed over a substrate;

a layer of non-magnetic material formed over the layer of magnetic material;

a polymeric underlayer formed over the layer of non-magnetic material; and

the dielectric hard mask layer formed over the polymeric underlayer;

performing a first reactive ion etch process to remove the exposed second portion of the dielectric hard mask layer such that a portion of the polymeric underlayer is exposed and a dielectric hard mask is formed, wherein a first portion of the first reactive ion etch process comprises exposing the second portion of the dielectric hard mask layer to an etching gas comprising CF₄ and CHF₃, wherein a ratio of CF₄ to CHF₃ in the first portion is between about 1.3 and about 2, wherein a second portion of the first reactive ion etch process uses an etching gas comprising CF₄, and CHF₃, and wherein a gas flow ratio of CF₄ to CHF₃ in the second portion is between about 0.3 to 0.8; and

performing a second reactive ion etch process to remove the exposed polymeric underlayer to expose the layer of non-magnetic material.

2. The method of claim 1, wherein the etching gas used in the first portion of the first reactive ion etch process additionally comprises helium, and a ratio of CF₄ to He is between about 2.2 and about 3.

3. The method of claim 1, wherein the first portion of the first reactive ion etch process further comprises applying a source power to the RIE chamber and a RF bias to an electrode wherein the ratio of the source power to the bias power is between about 10 and about 16.

4. The method of claim 1, wherein the second reactive ion etch process forms a polymeric underlayer mask that is tapered from the dielectric hard mask to the layer of non-magnetic material.

5. The method of claim 4, further comprising:

removing the exposed portions of the layer of non-magnetic material to expose the layer of magnetic material; and

removing exposed portions of the layer of magnetic material to form a write pole that is tapered from the polymeric underlayer mask to the substrate.

6. The method of claim 5, wherein the second reactive ion etch process is performed utilizing an oxygen based chemistry.

7. The method of claim 6, wherein the oxygen based chemistry utilizes CO₂ and N₂ gases.

8. The method of claim 7, wherein removing exposed portions of the layer of non-magnetic material and removing the exposed portions of the layer of magnetic material comprises ion milling.

9. The method of claim 8, wherein the ion milling is performed with argon ions.

10. The method of claim 9, wherein the polymeric underlayer mask that is tapered from the dielectric hard mask to the layer of non-magnetic material at an angle of between about 0.5 degrees to about 1.0 degrees.

11. A method of making a write pole for a perpendicular magnetic recording write head, comprising:

forming a photoresist mask over a dielectric hard mask layer of a stack such that the photoresist mask covers a first portion of the dielectric hard mask layer and leaves a second portion exposed, wherein the stack comprises;

a layer of magnetic material formed over a substrate;

a layer of non-magnetic material formed over the layer of magnetic material;

a polymeric underlayer formed over the layer of non-magnetic material; and

the dielectric hard mask layer formed over the polymeric underlayer;

performing a first reactive ion etch process to remove the exposed second portion of the dielectric hard mask layer such that a portion of the polymeric underlayer is exposed and a dielectric hard mask is formed, wherein a first portion the first reactive ion etch process further comprises applying a source power to the RIE chamber and a RF bias to an electrode wherein the ratio of the source power to the bias power in the first portion is greater than 10 and up to about 16, and wherein a second portion of the first reactive ion etch process also applies a source power to the RIE chamber and a RF bias to an electrode wherein the ratio of the source power to the bias power in the second portion is between about 22 and about 28; and

performing a second reactive ion etch process to remove the exposed polymeric underlayer to expose the layer of non-magnetic material.

12. The method of claim 11, wherein the etching gas used in the first portion of the first reactive ion etch process additionally comprises helium, and a ratio of CF₄ to He is between about 2.2 and about 3.

13. The method of claim 12, wherein the first portion of the first reactive ion etch process comprises exposing the second portion of the dielectric hard mask layer to an etching gas comprising CF₄ and CHF₃, wherein a ratio of CF₄ to CHF₃ is between about 1.3 to about 2.

14. The method of claim 13, wherein the second reactive ion etch process is performed utilizing an oxygen based chemistry.

15. The method of claim 14, wherein the oxygen based chemistry utilizes CO₂ and N₂ gases.

16. The method of claim 15, further comprising:

removing the exposed portions of the layer of non-magnetic material to expose the layer of magnetic material; and

removing exposed portions of the layer of magnetic material to form a write pole that is tapered from the polymeric underlayer mask to the substrate.

17. The method of claim 16, wherein removing exposed portions of the layer of non-magnetic material and removing the exposed portions of the layer of magnetic material comprises ion milling.

18. The method of claim 17, wherein the ion milling is performed with argon ions.

19. The method of claim 18, wherein the polymeric underlayer mask that is tapered from the dielectric hard mask to the layer of non-magnetic material at an angle of between about 0.5 degrees to about 1.0 degrees.

20. A method of making a write pole for a perpendicular magnetic recording write head, comprising:

forming a photoresist mask over a dielectric hard mask layer of a stack such that the photoresist mask covers a first portion of the dielectric hard mask layer and leaves a second portion exposed, wherein the stack comprises;

a layer of magnetic material formed over a substrate;

a layer of non-magnetic material formed over the layer of magnetic material;

a polymeric underlayer formed over the layer of non-magnetic material; and

the dielectric hard mask layer formed over the polymeric underlayer;

performing a first reactive ion etch process to remove the exposed second portion of the dielectric hard mask layer such that a portion of the polymeric underlayer is exposed and a dielectric hard mask is formed, wherein the first reactive ion etch process further comprises a first portion of the first reactive ion etch process and a second portion of the first reactive ion etch process to remove the exposed second portion of the dielectric hard mask layer such that a portion of the polymeric underlayer is exposed and a dielectric hard mask is formed, wherein the first portion of the first reactive ion etch process further comprises introducing an etching gas comprising CF₄ and CHF₃ and He, wherein a gas flow ratio of CF₄ to CHF₃ is between about 1.3 to 2, a gas flow ratio of CF₄ to He is between 2.2 and about 3, and a ratio of RF source power to RF bias power is between about 10 and about 16, wherein the second portion of the first reactive ion etch process also uses gas comprising of CF₄, CHF₃ and He, wherein a gas flow ratio of CF₄ to CHF₃ is between about 0.3 to 0.8, a gas flow ratio of CF₄ to He is between about 1.2 and about 1.8, and a power ratio of the RF source power to RF bias is between about 22 to 28;

performing a second reactive ion etch process to remove the exposed polymeric underlayer to expose the layer of non-magnetic material using oxygen based chemistry comprising of CO₂ and N₂ gases;

ion milling the exposed portions of the layer of non-magnetic material to expose the layer of magnetic material using an Ar ion beam; and

ion milling exposed portions of the layer of magnetic material to form a write pole that is tapered from the polymeric underlayer mask to the substrate using an Ar ion beam.