JP2001198810A - Polishing method for substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the time and trouble to mold a surface plate surface into a curved one because it is not required, and to speedily carry out the sucking work of a substrate onto a suction jig. SOLUTION: A circular suction jig 1 rotating on its own axis with a substrate 2 stuck to a suction surface 1a by suction is disposed on a rotating surface plate, and the lower surface of the substrate is polished by bringing it into sliding contact with the surface plate surface 5a. Plural kinds of suction jigs 1 having the suction surfaces 1a molded into differently curved recessed surfaces or projecting surfaces are prepared, and they are properly selected and used in accordance with the purpose of polishing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for polishing a substrate which can be used for lapping and the like when forming a multilayer device on the substrate.

[0002]

2. Description of the Related Art In a multilayer film element such as a thin film magnetic head or a thin film integrated circuit, an insulating interlayer film such as alumina or silica is laminated on a substrate, and a circuit element is formed in the interlayer film by a photolithography process. I have. For example, in the case of manufacturing a thin film magnetic head, after forming a separation layer such as a Cu material over the entire surface of a ceramic substrate such as AlTiC, a yoke of a NiFe material, a coil or a lead of a Cu material are formed in a number of shot areas on the substrate. Device portions constituting lines, wiring connection pads of Au material and the like are sequentially formed by a photolithography process by step-and-repeat exposure, and the device portions are laminated while being appropriately insulated from each other by an insulating interlayer film of alumina. . Then, lapping polishing is performed to flatten the interlayer film and the metal layer during the lamination.

[0003] By the way, the lapping platen is usually water-cooled, so that there is almost no temperature rise due to heat generated during polishing. On the other hand, as shown in FIG. Through the suction groove 1 on the suction surface 1a.
The suction jig 1 is not water-cooled because it is difficult to connect a water-cooling pipe in addition to the suction pipe 13 communicating with the suction jig 1. Such a suction jig 1
When the substrate 2 is sucked and held on the suction surface 1a in which a large number of suction grooves 12 are formed and is brought into sliding contact with the platen surface 5a, and a device layer (not shown) on the lower surface of the substrate 2 is polished, heat is dissipated as polishing proceeds. The inner peripheral portion of the suction jig 1, which is difficult to thermally expand, deforms the suction surface 1a into a convex surface (FIG. 8). If polishing is continued in this state, as shown in FIG. 9, the interlayer film of the device layer on the lower surface of the substrate 2 becomes thinner in the inner peripheral portion. It should be noted that the drawing is conceptually drawn for easy understanding, and the thickness difference between the thinned inner peripheral portion and the thinned outer peripheral portion is actually about 0.5 μm (the prior art 1).

As shown in a conceptual cross section in FIG. 10, a large number of alumina layers 31A to 31C projecting in a mountain shape near a surface of a device layer 3 on a substrate in a portion to be a contact pad of a thin film magnetic head. A yoke layer 32 made of a NiFe material is laminated on the surface thereof so as to cross the surface thereof, and these are further covered with an insulating film 33 made of alumina. As shown in FIG. 11, the insulating film 33 is polished until the top of the yoke layer 32 is removed and both ends are exposed as magnetic poles.
Since the width of the top of ~ 31C is thicker at the center than at the outer periphery, the amount of polishing at the center is reduced in order to make the facing distances d of the magnetic poles all the same as shown in FIG.
It is necessary to increase the polishing amount of the outer peripheral portion (the above is the related art 2).

Further, as shown in FIG. 12, when a separation layer 21 of Cu material or the like is formed, the center of the substrate 2 is
To be convex with respect to the suction surface 1a of
It is difficult to adsorb the substrate 2 so that dust and oil are not entrained, and work time is required in order to repeat the adsorption and to take care of the adsorption operation (the above-mentioned conventional technology 3).

[0006]

Therefore, in the above prior art 1, as shown in FIG. 13, the platen surface 5a is formed into a concave surface in accordance with the deformation of the suction jig 1 so that the interlayer film of the device layer has an inner peripheral surface. The section was prevented from becoming thin. Also, in the above-mentioned prior art 2, the surface of the surface plate is formed into a concave surface so that the polishing amount of the outer peripheral portion of the substrate is larger than the inner peripheral portion of the substrate.
However, forming the surface of the surface plate into a desired curved surface requires processing,
Since it is necessary to repeat procedures such as cleaning and measurement,
There was a problem that a lot of trouble was required. Also, with regard to the prior art 3, it has been desired to speed up the suction operation.

Accordingly, the present invention is to solve such a problem, and it is not necessary to form the surface of the base plate with a curved surface, so that the work is reduced and the work of sucking the substrate to the suction jig is performed quickly. It is an object of the present invention to provide a method of polishing a substrate, which can perform the polishing.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a circular suction jig (1) that rotates by suctioning a substrate (2) on a suction surface (1a) is rotated. In a polishing method in which the lower surface of the substrate (2) is slid on the surface of the surface plate (5a) and polished, the suction surface (1a) is formed into a concave or convex surface having different curvatures. A jig (1) is prepared, and the above-mentioned plurality of kinds of suction jigs are appropriately selected and used according to the polishing purpose.

In the first aspect of the present invention, the suction surface of the suction jig is formed into a concave surface or a convex surface, and the substrate is sucked and held on the surface, and is polished by slidingly contacting the surface of the platen. Then, various types of polishing can be performed even when a flat surface plate is used, since suction jigs having suction surfaces with different curvatures are appropriately selected and used according to the polishing purpose. As described above, since it is not necessary to form the surface of the base plate with a curved surface, the labor of molding is reduced, and the work of sucking the substrate to the suction surface can be performed quickly because of having an appropriate curvature.

In the second invention, the suction surface (1a) is a concave surface, and the suction surface (1a) is corrected to a flat surface by expansion deformation of the inner peripheral portion of the suction jig (1) due to polishing heat. A suction jig having a curvature of the concave surface (1a) is selectively used.

In the second aspect of the invention, when the inner peripheral portion of the suction jig expands and deforms due to the polishing heat, the suction surface previously formed into a concave surface is corrected to a flat surface by the deformation. Thus, the polished surface of the substrate can be polished flat even if the surface of the platen is kept flat.

In the third aspect of the present invention, the suction surface (1a) is a concave surface, and the curvature of the concave surface such that the polishing amount of the outer peripheral portion of the substrate (2) becomes larger than the inner peripheral portion by a predetermined amount is set. Select the suction jig (1) to use.

According to a third aspect of the present invention, in the process of manufacturing a thin-film magnetic head, a large number of contact pads formed on the device layer (3) on the surface of the substrate (2) are formed on a flat surface (5a). The present invention can be suitably applied to applications in which the opposing interval (d) of the magnetic pole formed by exposing and removing the yoke layer (32) is substantially the same between the inner peripheral portion and the outer peripheral portion.

In the fourth aspect of the present invention, the suction surface (1a) is a convex surface, and the curvature of the convex surface such that the polishing amount of the inner peripheral portion of the substrate (2) is larger than the outer peripheral portion by a predetermined amount is set. Select the suction jig (1) to use.

According to a fourth aspect of the present invention, in the process of manufacturing a thin-film magnetic head, a large number of contact pads formed on the device layer (3) on the surface of the substrate (2) are formed with a flat surface plate (5a). The present invention can be suitably applied to applications in which the opposing interval (d) of the magnetic pole formed by exposing and removing the yoke layer (32) is substantially the same between the inner peripheral portion and the outer peripheral portion.

The reference numerals in the parentheses indicate the correspondence with specific means described in the embodiments described later.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) In FIG.
A vacuum hose 13 is connected to the center of the upper surface of the suction jig 1 via the rotary joint 11 as described in the related art, and a suction groove 12 formed on the suction surface 1a of the suction jig 1 has an interior (not shown). The above-mentioned vacuum hose 13
Is in communication with The suction surface 1a is, for example, a concave surface in which the inner peripheral portion is recessed by about 0.5 μm from the outer peripheral portion.
A substrate 2 having a device layer (not shown) formed on the lower surface is suction-fixed in a curved state following the suction surface 1a.
In the following drawings including FIG. 1, the ratio of the thickness of the suction jig to the substrate is drawn differently from the actual one for easy understanding, and the degree of the concave surface and the convex surface is larger than the actual one. It is painted.

When the substrate 2 sucked and held by the suction jig 1 is brought into contact with the platen surface 5a, which has been flattened by a facing device, and polishing of the substrate 2 is started while the suction jig 1 is rotated, the polishing at the time of polishing is started. Suction jig 1 that is not easily dissipated by heat
The inner peripheral portion of the suction jig 1 thermally expands. However, since the inner peripheral portion of the suction jig 1 is appropriately depressed at room temperature as described above, as shown in FIG. By expansion, it is corrected to a plane that is substantially parallel to the platen surface 5a. Thus, the interlayer film of the device layer and the like formed on the lower surface of the substrate 2 can be polished flat without forming the platen surface 5a as a concave surface unlike the related art. In this case, a plurality of kinds of suction jigs having concave concave suction surfaces having different curvatures are prepared, and one having the best flatness during thermal expansion is selected and used.

By the way, as described in the prior art, C
When the separation layer 21 (FIG. 3) of u material or the like is formed, the substrate 2 is curved so that the center thereof is convex with respect to the suction surface 1a of the suction jig 1, but in the present embodiment, the suction is performed as described above. Face 1
Since a is formed in a concave surface at normal temperature (that is, before the start of polishing), it is relatively easy to adsorb the substrate 2 so that dust and oil are not involved. In particular, as shown in FIG. 3, when the curvature of the substrate 2 is larger than the curvature of the suction surface 1a,
A handle 41 is formed on the upper surface of the central portion, and a rubber plate 4 is formed on the lower surface of the outer peripheral portion.
When the outer peripheral portion of the substrate 2 is pressed using the circular pressing jig 4 to which the substrate 2 is joined, the suction of the substrate 2 can be performed more easily.

(Second Embodiment) FIG. 4 shows a conceptual cross section of the device layer 3 on the lower surface of the substrate 2 sucked and held on the suction surface 1a of the suction jig 1 having a concave surface (see FIG. 1). In a portion to be a contact pad of the thin-film magnetic head, a yoke layer 32 made of a NiFe material is laminated on the surfaces of the alumina layers 31A to 31C projecting in a mountain-shape so as to cross over the alumina layers 31A to 31C. I have. The alumina layers 31A to 31C, the yoke layer 32, and the insulating film 33 are
The suction jig 1 is concavely curved following the curvature of the suction surface 1a. Note that the width of the tops of the mountain-shaped alumina layers 31A to 31C is larger at the center than at the outer periphery, as described in the related art. In this case, the degree of curvature of the attraction surface 1a is, for example, such that the inner periphery is depressed by about 1 μm with respect to the outer periphery, and is larger than that in the first embodiment.

The insulating film 33 of the device layer 3 is
When the polishing is performed on the surface of the platen surface 5a which has been flattened by the facing device, as shown by the dashed line in FIG. 4, the polishing amount decreases in the central portion and the polishing amount in the outer peripheral portion increases, and the top portions of the mountain-shaped alumina layers 31C to 31A As the polishing amount increases in this order, the facing distance d between the magnetic poles at both ends of the yoke layer 32 that is removed and exposed becomes substantially the same between the inner peripheral portion and the outer peripheral portion. In this manner, the distance d between the magnetic poles of each contact pad of the device layer 3 formed on the lower surface of the substrate 2 can be made substantially the same without forming the platen surface 5a as a concave surface as in the related art. In this case, the concave suction surface 1a is used.
A plurality of types of suction jigs 1 having different curvatures (see FIG. 1) are prepared, and a jig having the smallest variation in the magnetic pole interval d of the contact pads is selected and used.

(Third Embodiment) In the second embodiment,
The angled alumina layers 31A to 31 are formed on the device layer 3 on the substrate 2.
After the formation of C, the substrate 2 is placed on the concave suction surface 1 of the suction jig 1.
a, and is polished on a flat platen surface 5a. Instead, as shown in FIG. 5, the adsorption surface 1a of the adsorption jig 1 is made to be a convex surface, and 3
The substrate 2 on which the device layers 3 before forming 1A to 31C are stacked is held by suction. As shown in FIG. 5, the substrate 2 on which most of the device layers 3 have been formed has an inner peripheral portion depressed by about 3 μm with respect to the outer peripheral portion and is largely concavely curved toward the suction jig 1. 1 μm of inner circumference to outer circumference
When the suction jig 1 swelling about m is used, the substrate 2 can be satisfactorily sucked and held without involving dust or oil. In this case, a plurality of types of suction jigs 1 having different curvatures of the convex suction surface 1a are prepared, and the most appropriate one is selected and used.

When the device layer 3 formed on the substrate 2 is polished on a flat platen surface using such an adsorption jig 1, the interlayer film on the outermost surface of the device layer 3 becomes thinner at the inner peripheral portion. Polished. The polished interlayer film (second
The substrate 2 on which the angled alumina layers 31A to 31C, the yoke layer 32, and the insulating film 33 are formed on the substrate 2 is flat or slightly concave at normal temperature as described in the first embodiment. Suction surface 1a of suction jig 1 curved
When the film is sucked and held, the interlayer film 34 having the thinner inner peripheral portion has a cross-sectional shape in which the lower surface is concavely curved downward as shown in FIG. 4 of the second embodiment. When the insulating film 33 of the device layer 3 is polished on the platen surface 5a which has been flattened by a facing device, the top of the yoke layer 32 is removed and exposed similarly to the second embodiment (chain line in FIG. 4). The opposed distance d between the magnetic poles can be made substantially the same between the inner peripheral portion and the outer peripheral portion.

(Other Embodiments) When a film forming apparatus having no self-orbiting function is used, the film thickness distribution of the device layer 3 is decentered as shown by an isometric line diagram in FIG. Therefore, in such a case, it is preferable that an eccentric load is provided on the suction jig 1 having the above-mentioned concave or convex suction surface 1a to polish a large portion of the film thickness.

[0025]

As described above, according to the method for polishing a substrate of the present invention, since it is not necessary to form the surface of the base plate into a curved surface, the labor can be reduced, and the work of sucking the substrate to the suction jig can be performed quickly. Can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a suction jig that suctions and holds a substrate according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a suction jig holding a substrate by suction according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view when a suction jig suctions and holds a substrate according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a device layer according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view when a suction jig sucks and holds a substrate according to a third embodiment of the present invention.

FIG. 6 is an isometric view of a substrate according to another embodiment of the present invention.

FIG. 7 is a cross-sectional view of a suction jig that sucks and holds a substrate in a conventional example.

FIG. 8 is a cross-sectional view of a suction jig that sucks and holds a substrate in a conventional example.

FIG. 9 is a cross-sectional view of a suction jig that sucks and holds a substrate in a conventional example.

FIG. 10 is a sectional view of a device layer in a conventional example.

FIG. 11 is a cross-sectional view of a device layer in a conventional example.

FIG. 12 is a cross-sectional view of a suction jig in a conventional example, showing a state immediately before sucking a substrate.

FIG. 13 is a cross-sectional view of a suction jig that sucks and holds a substrate in a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Suction jig, 1a ... Suction surface, 2 ... Substrate, 3 ... Device layer, 31A-31C ... Angled alumina layer, 32 ... Yoke layer, 33 ... Insulating film, 4 ... Pressing jig, 5a ... Surface plate surface.

Claims (4)

[Claims] 1. A polishing method in which a circular suction jig for rotating a substrate by sucking a substrate on a suction surface is disposed on a rotating surface plate and polishing the lower surface of the substrate by sliding the lower surface of the substrate against the surface surface. A substrate polishing method in which a plurality of types of suction jigs whose surfaces are formed into concave or convex surfaces having different curvatures are prepared, and the plurality of types of suction jigs are appropriately selected and used according to a polishing purpose. 2. A suction jig having a concave curvature, wherein the suction surface is concave, and the suction surface is corrected to a flat surface by expansion deformation of an inner peripheral portion of the suction jig due to polishing heat. The method for polishing a substrate according to claim 1. 3. A suction jig having a concave curvature, wherein the suction surface is a concave surface, and a polishing amount of an outer peripheral portion of the substrate is larger by a predetermined amount than an inner peripheral portion. 2. The method for polishing a substrate according to item 1. 4. A suction jig having a curvature of the convex surface such that the suction surface is a convex surface, and a polishing amount of an inner peripheral portion of the substrate is larger by a predetermined amount than an outer peripheral portion thereof. 2. The method for polishing a substrate according to item 1.