# US 5,710,683 A · Thin film tape head with substrate for reduced pole-tip recession > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,710,683 A - Document ID: US5710683A - Status: Granted - Kind: A - Application number: 08/634,212 - Filed: 1996-04-18 - Granted: 1998-01-20 - Earliest claimed: 1996-04-18 - Assignees: Storage Technology Corporation - Inventors: Ramesh Sundaram - Web page: https://patentgrep.com/patent/US5710683A ## CPC - G11B 5/31: using thin films {(G11B5/1274, G11B5/1278, G11B5/1874, G11B5/1875, G11B5/33, G11B5/49 take precedence; magnetic thin film structures H01F10/00)} - G11B 5/3106: {where the integrated or assembled structure comprises means for conditioning against physical detrimental influence, e.g. wear, contamination (G11B5/3133 takes precedence)} - G11B 5/313: {Disposition of layers} - G11B 5/29: Structure or manufacture of unitary devices formed of plural heads for more than one track {(G11B5/33, G11B5/49 and subgroups take precedence; in thin film structure G11B5/31)} - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract The present invention provides a tape head with reduced pole-tip recession. A recessed substrate and a closure of the tape head are separated by a plurality of layers, which include, for example, a bottom layer, a recessed bottom pole, a gap layer, a top pole and a top layer. The recessed bottom pole is positioned in the recess of the substrate. By utilizing the recessed substrate and the recessed bottom pole, the thickness of the overcoat layer is reduced, thereby reducing the distance between the substrate and the closure at an air-bearing surface of the recording head. With the present invention, wear is reduced, thereby reducing pole tip recession. ## Claims ### Claim 1 A thin film magnetic tape recording head, comprising: a substrate having a substantially planar side with a substrate recess defining a recessed portion along said side; a closure; and a plurality of layers positioned between said substrate and said closure, said plurality of layers comprising, a recessed bottom pole positioned along said side of said substrate, wherein said recessed bottom pole has a pole recess adjacent to said substrate recess in said side of said substrate whereby said pole recess extends into said substrate beyond said substantially planar side, a coil structure deposited in said pole recess, a gap layer deposited between said recessed bottom pole and said closure, a top pole positioned between said gap layer and said closure, and a top layer positioned between said top pole and said closure and having a substantially uniform thickness, wherein said top layer has a thinness sufficient to reduce a distance between said substrate and said closure at an air bearing surface end of the head; and wherein said top layer exposed at said air bearing surface between said top pole and said closure is sufficiently thin that a distance between said substrate and said closure is defined substantially by said recessed bottom pole and said top pole. ### Claim 2 (depends on 1) A thin film magnetic tape recording head according to claim 1, further comprising a bottom layer positioned between said bottom pole and said substrate. ### Claim 3 (depends on 1) A thin film magnetic tape recording head according to claim 1, wherein said distance between said closure and said substrate is substantially 15 microns and said top layer comprises 2 microns of said distance. ### Claim 4 (depends on 1) A thin film magnetic tape recording head according to claim 1, wherein a portion of said gap layer is deposited between said top pole and said coil. ### Claim 5 (depends on 1) A thin film magnetic tape recording head according to claim 1, wherein said top pole is substantially planar. ### Claim 6 (depends on 1) A thin film magnetic tape recording head according to claim 1, wherein said plurality of layers further comprises: a shared top pole deposited between said top pole and said bottom pole; a first gap layer between said bottom pole and said shared pole; and a second gap layer between said top pole and said shared pole, wherein said second gap layer defines a read gap and said first gap layer defines a write gap. ### Claim 7 (depends on 6) A thin film magnetic tape recording head according to claim 6, wherein said top layer at said air bearing surface is sufficiently thin that a distance between said substrate and said closure is defined substantially by said recessed bottom pole, said first gap layer, said shared pole, said second gap layer and said top pole. ### Claim 8 (depends on 1) A thin film magnetic tape recording head according to claim 1, wherein said plurality of layers further comprises: a recessed shared pole deposited between said top pole and said first recessed bottom pole; a first gap layer between said top pole and said recessed shared pole; and a second gap layer between said recessed bottom pole and said recessed shared pole, wherein said second gap layer defines a read gap and said first gap layer defines a write gap. ### Claim 9 (depends on 1) A thin film magnetic tape recording head according to claim 1, wherein said top layer comprises alumina, and said closure and said substrate comprise aluminum oxide titanium carbide. ### Claim 10 A thin film magnetic tape recording head, comprising: a substrate having a substantially planar side with a substrate recess defining a recessed surface portion along said substantially planar side; a closure; and a plurality of layers positioned between said substrate and said closure, said plurality of layers comprising, a recessed bottom pole positioned along said side of said substrate, wherein said recessed bottom pole has a pole recess adjacent to said substrate recess in said side of said substrate, whereby said pole recess extends into said substrate beyond said substantially planar side, a first gap layer deposited between said recessed bottom pole and said closure, a shared pole deposited between said first gap layer and said closure, a second gap layer deposited between said shared pole and said closure, a top pole positioned between said second gap layer and said closure, and a top layer positioned between said top pole and said closure, wherein said top layer has a substantially uniform thickness and a thinness sufficient to reduce a distance between said substrate and said closure at an air bearing surface end of the head, such that said distance is substantially defined by said bottom pole, said shared pole, and said top pole. ### Claim 11 (depends on 10) A thin film magnetic tape recording head according to claim 10, further comprising: a bottom layer positioned between said bottom pole and said substrate. ### Claim 12 (depends on 10) A thin film magnetic tape recording head according to claim 10, wherein said shared pole is recessed and said first gap layer comprises a read gap layer and said second gap layer comprises a write gap layer. ### Claim 13 (depends on 10) A thin film magnetic tape recording head according to claim 10, wherein said shared pole is substantially planar and said first gap layer comprises a write gap layer and said second gap layer comprises a read gap layer. ### Claim 14 A multi-track thin film magnetic tape head, comprising a plurality of thin film magnetic tape recording heads, wherein each thin film magnetic tape recording head comprises: a substrate having a substantially planar side with a substrate recess defining a recessed surface portion along said substantially planar side; a closure; and a plurality of layers positioned between said substrate and said closure, said plurality of layers comprising, a recessed bottom pole positioned along said side of said substrate, wherein said recessed bottom pole has a pole recess adjacent to said substrate recess in said side of said substrate whereby said pole recess extends into said substrate beyond said substantially planar side, a coil structure including multiple coils deposited along said recess, a gap layer deposited between said recessed bottom pole and said closure, a top pole positioned between said gap layer and said closure, and a top layer positioned between said top pole and said closure and having a substantially uniform thickness, wherein said top layer has a thinness sufficient to reduce a distance between said substrate and said closure at an air bearing surface end of the head.