Thin-film magnetic recording head manufacture
View Patent ↗This invention relates to a multi-layer lithographically fabricated device used to produce improved thin-film recording heads. It further relates to a focused particle beam system for milling a recording head pole-tip assembly without irradiating a sensitive structure, e.g. a read head, of the recording head. The invention precisely forms a pole-tip assembly by milling a second structural element without irradiating a first structural element. The invention avoids irradiating the first structural element by placing a first marker element, which can be imaged and/or damaged, in the same layer of a multi-layer lithographically fabricated device as the first structural element. The marker element has a fixed spatial relationship to the first structural element. Thus, by imaging the first marker element and the second structural element, and knowing the separation between the first structural element and the first marker element, a focused particle beam system can determine the relative location of the first and second structural elements. Consequently, the focused particle beam system can determine, without irradiating the sensitive first structural element, which portions of the second structural element require milling. In this manner, the focused particle beam system mills the second structural element to produce a desired pole-tip configuration. By producing a desired pole-tip configuration, these methods and apparatus produce an improved recording head capable of higher storage density than prior art techniques.
1. A process for locating a second structural element with respect to a first structural element in a multi-layer lithographically fabricated device, comprising the steps of
a) imaging, with a focused particle beam, a first marker element and at least one of said second structural element and a second marker element on said device,
said first structural element being in a first layer, and said first marker element being in said first layer at a known distance and direction from said first structural element,
said second structural element being in a second layer, and said second marker element being in said second layer, said structural elements and
said marker elements intersecting a geometrical surface that extends transversely to said first and second layers, and
b) determining, responsive to said imaging step, the location of said second structural element relative to the location of said first structural element.
2. The process of claim 1 , wherein said step of determining the location of said second structural element relative to the location of said first structural element includes the step of processing information regarding the location of said marker elements derived from imaging said first marker element and at least one of said second structural element and said second marker element.
3. The process of claim 1 , wherein said second structural element and said second marker element are the same element.
4. The process of claim 1 , wherein said second marker element is located at a known distance and direction relative to said second structural element, and
wherein said imaging step images said first and second marker elements and does not image said second structural element.