Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
172 words
A method of fabricating a generally planar, sheet-like, device having a first, robust, area and, contiguous therewith, a second, fragile, area to be constructed by removal of some of the material of which the device consists, in which method: a) starting with a corresponding generally planar, sheet-like blank, in which both first and second areas are robust, some of the material to be removed from the blank to make the second, fragile, area is so removed from one major face of the blank, to form a recess in the blank; b) the thus-formed recess is filled with a fixing material, so as to support and fix in place the thin area of blank material constituting the base of the recess; and thereafter c) the remainder of the material to be removed from the blank to make the second, fragile, area is so removed from the other major face of the blank, so forming the required second, fragile, area supported and fixed by the fixing material and contiguous with the first, robust, area.
Claim 2
Independent Claim
172 words
A method of fabricating a generally planar, sheet-like, device having a first, robust, area and, contiguous therewith, a second, fragile, area to be constructed by removal of some of the material of which the device consists, in which method: a) starting with a corresponding generally planar, sheet-like blank, in which both first and second areas are robust, some of the material to be removed from the blank to make the second, fragile, area is so removed from one major face of the blank, to form a recess in the blank; b) the thus-formed recess is filled with a fixing material, so as to support and fix in place the thin area of blank material constituting the base of the recess; and thereafter c) the remainder of the material to be removed from the blank to make the second, fragile, area is so removed from the other major face of the blank, so forming the required second, fragile, area supported and fixed by the fixing material and contiguous with the first, robust, area.
Claim 3
Independent Claim
14 words
A method as claimed in Claim l, applied in the fabrication of a lead-frame.
Claim 4
Independent Claim
36 words
A method as claimed in either of the preceding Claims, in which, where the device is a lead-frame, the material of which the blank is constituted is a nickel-iron alloy, or copper or a copper-based alloy.
Claim 5
Independent Claim
52 words
A method as claimed in any of the preceding Claims, in which, where the device is a lead-frame, the "robust" area ends up as the "legs" of the final package, tough enough to withstand handling, while the "fragile" area ends up as extremely fine conductors a hundred or so microns in width.
Claim 6
Independent Claim
116 words
A method as claimed in any of the preceding Claims, in which, where the device is a lead-frame, material is removed both simply to "thin" the sheet over the whole of the defined, second area, so that it becomes more suitable for forming into the inner leads of the lead-frame, and from between those portions that are to be the leads, so separating each lead from its neighbours; in the first stage the blank is thinned, from one of its major faces, to roughly half its original thickness, while in the second stage the remaining between-lead blank material is removed from the other major face, so leaving the formed leads flush with this other major face.
Claim 7
Independent Claim
26 words
A method as claimed in any of the preceding Claims, in which the removal of material from the blank is accomplished by a chemical etching technique.
Claim 8
Independent Claim
67 words
A method as claimed in any of the preceding Claims, in which, in the first stage, material is removed both from all over the whole of the second area of the blank (that area destined to become the fragile area of the device), so thinning that area, and at the same time from the first area (the area destined to become the robust area of the device).
Claim 9
Dependent Claim
43 words
A method as claimed in Claim 7, in which, where the device is a lead-frame, the robust area material between those portions destined to be the outer part of the leads is removed at the same time as the second area is thinned.
Claim 10
Independent Claim
30 words
A method as claimed in any of the preceding Claims, in which, where the device is a lead-frame, the fixing material is a silica-filled epoxy or a glass or glass-ceramic.
Claim 11
Dependent Claim
44 words
l0. A method as claimed in any of the preceding Claims, wherein, where the device is a lead-frame, a central area of the recess, big enough to take the chip to which the lead-frame will be connected, is left completely free of fixing material.
Claim 12
Independent Claim
52 words
A method as claimed in any of the preceding Claims, in which, where the device is a lead-frame, the material removed from the other major face is both that material lying between the portions defining the inner leads and the remainder of the thickness of first area material in the between-leg portions.
Claim 13
Dependent Claim
15 words
A lead-frame wherever fabricated by a method as claimed in any of the preceding claims.