Abstract: A semiconductor wafer is applied to a support disk via an intervening adhesive layer with the front side of the semiconductor wafer facing the adhesive layer, which is sensitive to a certain exterior factor for reducing its adhesive force; the semiconductor wafer is ground on the rear side; the wafer-and-support combination is applied to a dicing adhesive tape with the so ground rear side facing the dicing adhesive tape, which is surrounded and supported by the circumference by a dicing frame; the certain exterior factor is effected on the intervening adhesive layer to reduce its adhesive force; and the intervening adhesive layer and support disk are removed from the semiconductor wafer or chips without the possibility of damaging the same.

Abstract: A flat-object holder can hold a flat object-and-frame assembly, and the holder has the flat object fixed to the frame with protection tape. The flat-object holder includes at least a flat object supporting area for fixedly holding the flat object via the protection tape by applying a suction force, and a frame fixing area for fastening the frame. The flat-object holder bearing the flat object-and-frame assembly can be fixedly held by a selected chuck table by applying a negative pressure to the flat object supporting area. The flat-object holder can transfer and put the flat object-and-frame assembly in a container. Thus, no matter how thin the flat object may be, it can be handled without the fear of breaking.

Abstract: A semiconductor wafer (W) where circuits are formed in the area formed in the area divided by streets is split into semiconductor chips having an individual circuit. By interposing an adhesive sheet whose adhesive force is lowered by stimulation between the semiconductor wafer (W) and the support plate (13), the front side of the semiconductor wafer (W) is adhered to the support plate (13), exposing the rear face (10) of the semiconductor wafer (W). The rear face (10) of the semiconductor wafer (W) with the support plate (13) is ground. After the grinding is finished, the semiconductor wafer (W) is held with the rear face (10) up is diced into semiconductor chips (C). The adhesive sheet is given stimulus to lower the adhesive force and the semiconductor chips (C) are removed from the support plate (13). The semiconductor wafer and semiconductor chips are always supported by the support plate, avoiding damaging or deforming.

Abstract: In manufacturing thinned semiconductor chips by grinding a semiconductor wafer supported on a rigid support substrate, in order to remove semiconductor wafer or semiconductor chips from the support substrate without damage to the semiconductor wafer or semiconductor chips, a semiconductor wafer at its surface is bonded on a light-transmissive support substrate through an adhesive layer having an adhesion force to reduce upon exposed to light radiation, thereby exposing the back surface of the semiconductor wafer. A tape is bonded to the backside of the semiconductor wafer integrated with the support substrate of after grinding, wherein the tape is supported at the periphery. Before or after bonding of the tape, light radiation is applied to the adhesive layer at a side close to the support substrate to reduce the adhesion force in the adhesion layer.

Abstract: It is an object of the invention to provide a method for manufacturing an IC chip wherein a wafer is prevented from being damaged and the ease of handling thereof is improved so that the wafer can be appropriately processed into IC chips, even if a thickness of the wafer is extremely reduced to approximately 50 &mgr;m.

Abstract: A wafer support plate comprises a support surface on which a semiconductor wafer is supported, and a crystal orientation mark which indicates the crystal orientation of the semiconductor wafer. Even the semiconductor wafer thinned by grinding can be stably held on the support surface, and the crystal orientation can be recognized even when the outer periphery of the semiconductor wafer has chipped.

Abstract: A grinder composed of at least a chuck table (17) having a suction region (1) and a frame (2) and grinding means (30) for grinding a semiconductor wafer (W) held on the chuck table (17) is used. When a semiconductor wafer (W) having an outside diameter Dl smaller than that of the suction region (1) is ground, a semiconductor wafer (W) protective member (3) having an outside diameter D3 larger than the outside diameter Dl of the semiconductor wafer and larger than the diameter D2 of the suction region (1) is stuck on the side not to be ground of the semiconductor wafer (W). The whole surface of the semiconductor wafer (W) is held on the suction region (1), with the semiconductor wafer protective member (3) down. The exposed surface of the held semiconductor wafer (W) is ground by the grinding means (30). Thus the edge of the semiconductor wafer (W) is prevented from breaking, chipping and cracking.

Abstract: A semiconductor wafer is applied to a support disk via an intervening adhesive layer 10 with the front side of the semiconductor wafer facing the adhesive layer, which is sensitive to a certain exterior factor for reducing its adhesive force; the semiconductor wafer is ground on the rear side; the wafer-and-support combination is applied to a dicing adhesive tape with the so ground rear side facing the dicing adhesive tape, which is surrounded and supported by the circumference by a dicing frame; the certain exterior factor is effected on the intervening adhesive layer to reduce its adhesive force; and the intervening adhesive layer and support disk are removed from the semiconductor wafer or chips without the possibility of damaging the same.

Abstract: Disclosed is a flat-object holder for holding a flat object-and-frame assembly, which has the flat object fixed to the frame with a protection tape. The flat-object holder comprises at least a flat object supporting area for fixedly holding the flat object via the protection tape by applying a suction force, and a frame fixing area for fastening the frame. The flat-object holder bearing the flat object-and-frame assembly can be fixedly held by a selected chuck table by applying a negative pressure to the flat object supporting area. The flat-object holder can transfer and put the flat object-and-frame assembly in a container. Thus, no matter how thin the flat object may be, it can be handled without the fear of breaking.

Abstract: An alloy used for the production of a rare-earth magnet alloy, particularly the boundary-phase alloy in the two-alloy method is provided to improve the crushability. The Alloy consists of (a) from 35 to 60% of Nd, Dy and/or Pr, and the balance being Fe, or (b) from 35 to 60% of Nd, Dy and/or Pr, and at least one element selected from the group consisting of 35% by weight or less of Co, 4% by weight or less of Cu, 3% by weight or less of Al and 3% by weight or less of Ga, and the balance being Fe. The volume fraction of R2Fe17 phase (Fe may be replaced with Cu, Co, Al or Ga) is 25% or more in the alloy and the average size of an R2Fe17 phase is 20 &mgr;m or less. The alloy can be produced by a centrifugal casting at an average accumulating rate of melt at 0.1 cm/second or less.

Abstract: An alloy used for the production of a rare-earth magnet alloy, particularly the boundary-phase alloy in the two-alloy method is provided to improve the crushability.The alloy consists of (a) from 35 to 60% of Nd, Dy and/or Pr, 1% or less of B, and the balance being Fe, or (b) from 35 to 60% of Nd, Dy and/or Pr, 1% or less of B, and at least one element selected from the group consisting of 35% by weight or less of Co, 4% by weight or less of Cu, 3% by weight or less of Al and 3% by weight or less of Ga, and the balance being Fe. The total volume fraction of R.sub.2 Fe.sub.17 and R.sub.2 Fe.sub.14 B phases (Fe may be replaced with Cu, Co, Al or Ga) is 25% or more in the alloy. The average size of each of the R.sub.2 Fe.sub.17 and R.sub.2 Fe.sub.14 B phases is 20 .mu.m or less. The alloy can be produced by a centrifugal casting at an average accumulating rate of melt at 0.1 cm/second or less.

Abstract: An alloy used for the production of a rare-earth magnet alloy, particularly the boundary-phase alloy in the two-alloy method is provided to improve the crushability.The Alloy consists of (a) from 35 to 60% of Nd, Dy and/or Pr, and the balance being Fe, or (b) from 35 to 60% of Nd, Dy and/or Pr, and at least one element selected from the group consisting of 35% by weight or less of Co, 4% by weight or less of Cu, 3% by weight or less of Al and 3% by weight or less of Ga, and the balance being Fe. The volume fraction of R.sub.2 Fe.sub.17 phase (Fe may be replaced with Cu, Co, Al or Ga) is 25% or more in the alloy and the average size of an R.sub.2 Fe.sub.17 phase is 20 .mu.m or less. The alloy can be produced by a centrifugal casting at an average accumulating rate of melt at 0.1 cm/second or less.

Abstract: A permanent magnet which contains R, T and B as main ingredients wherein R is Y or a rare earth element and T is Fe or Fe and Co and has a primary phase of R.sub.2 T.sub.14 B is produced by compacting a mixture of 60 to 95 wt % of a primary phase-forming master alloy and a grain boundary phase-forming master alloy both in powder form and sintering the compact. The primary phase-forming master alloy has columnar crystal grains of R.sub.2 T.sub.14 B with a mean grain size of 3-50 .mu.m and grain boundaries of an R rich phase and contains 26-32 wt % of R. The grain boundary phase-forming master alloy is a crystalline alloy consisting essentially of 32-60 wt % of R and the balance of Co or Co and Fe. In anther form, a permanent magnet which contains R, T and B as main ingredients wherein R is yttrium or a rare earth element, T is Fe or Fe+Co/Ni and has a primary phase of R.sub.2 T.sub.

Abstract: A master alloy for magnet production, which contains as main ingredients R representing at least one element selected from rare-earth elements including Y, T representing Fe or Fe and Co, and B, and includes columnar crystal grains substantially made up of R.sub.2 T.sub.14 B, and crystal grain boundaries composed primarily of R-enriched phases having an R content higher than that of R.sub.2 T.sub.14 B, said columnar crystal grains having a mean diameter lying in the range of 3 to 50 .mu.m. The master alloy is formed into a sintered magnet through pulverization, compacting and sintering steps. The dispersion of the R-enriched phases in the master alloy is so well-enough that the R-enriched phases can also be well dispersed in the resulting sintered magnet. In addition, the master alloy is so easily pulverized that the incorporation of oxygen at the time of pulverization can be reduced.

Abstract: The sintered permanent magnet of the invention has a composition of the formula:(R.sub.1-.alpha. Dy.sub..alpha.).sub.a Fe.sub.(100-a-b-c-d-e) B.sub.b Al.sub.c Sn.sub.d M.sub.ewherein R is at least one rare earth element exclusive of Dy, M is at least one element selected from the group consisting of Co, Nb, W, V, Ta, Mo, Ti, Ni, Bi, Cr, Mn, Sb, Ge, Zr, Hf, Si, In, and Pb, and 0.01.ltoreq..alpha.0.5, 8.ltoreq.a.ltoreq.30, 2.ltoreq.b.ltoreq.28, 0.2.ltoreq.c.ltoreq.2, 0.03.ltoreq.d.ltoreq.0.5, and 0.ltoreq.e.ltoreq.3. The sintered permanent magnet of R-Fe-B system has excellent thermal stability and high maximum energy product.

Abstract: A highly corrosion-resistant rare-earth-iron magnet has a paraxylylene polymer film or a chloropara-xylylene polymer film formed thereon. The substrate magnet surface has a roughness Ra of no more than one micron. The magnet has a plasma polymer film formed beforehand or afterwards. The plasma polymer film has a protective film consists of only carbon and hydrogen, with a refractive index decreasing from the boundary surface between the film and the magnet toward the exposed surface. The protective coating has a thickness about three times the surface roughness of the substrate magnet.

Abstract: A permanent magnet having high coercivity and energy product contains rare earth elements, boron, at least one element of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W, and a blance of Fe or Fe and Co, and consists of a primary phase of substantially tetragonal grain structure, or a mixture of such a primary phase and an amorphous or crystalline rare earth element-poor auxiliary phase wherein the volume ratio of auxiliary phase to primary phase is smaller than a specific value.

Abstract: A permanent magnet material having high coercivity and energy product is provided which contains rare earth elements, boron, at least one element of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W, optional nickel, and a balance of Fe or Fe and Co, and consists of a primary phase of substantially tetragonal grain structure, or a mixture of such a primary phase and an amorphous or crystalline rare earth element-poor auxiliary phase wherein the volume ratio of auxiliary phase to primary phase has a specific relationship to other parameters.