JPH10277931A - Manufacture of hard substrate and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacture of a hard substrate and its device, which can obtain both the advantages of contact polishing with polishing cloth and float polishing in contact with polishing liquids, and thereby improve surface defects to a great extent. SOLUTION: Polishing is performed while load is being applied to a work 10 by a holder part 6. Just before contact polishing is over, a discharge valve 5 is closed. A liquid sump of polishing liquids 71 is formed over the upper surface of polishing cloth 2. Load applied by the holder 6 is removed, and the work 10 is gradually released from the polishing cloth 2. The work 10 is so held as to be stopped at a position where a suitable water film is formed between the work 10 and the polishing cloth 2. The work 10 is released from the polishing cloth 2 so as to allow float polishing to be performed. Oscillation in the horizontal direction is given over to the outer circumferential direction from the center of a level block 1. Rinse water 72 is fed over to the polishing cloth 2 in place of polishing liquids 71.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a manufacturing method and a manufacturing apparatus for processing a work which is a hard substrate such as a semiconductor wafer, a magnetic disk, and an optical lens.

[0002]

2. Description of the Related Art When manufacturing a hard substrate, for example, a semiconductor wafer, it is obtained by holding a semiconductor wafer by any method, applying a polishing load, and polishing the polishing surface by bringing the polishing surface into contact with a polishing cloth. In the polishing with the polishing cloth, a polishing liquid such as an alkaline silica solution is supplied to the polishing cloth surface, and friction between the polishing cloth and the semiconductor wafer, polishing with abrasive grains in the polishing liquid, and chemical polishing with the polishing liquid are performed. So-called mechanochemical polishing is performed, in which polishing is performed by three comprehensive polishing actions.

However, when the hard substrate is polished in such a state that it is in contact with the polishing cloth, the surface shape of the polishing cloth is transferred to the polishing surface or surface defects such as scratches are generated. For example, Japanese Patent Application Laid-Open Nos. 5-177533 and 5-177533
There is a polishing method disclosed in Japanese Unexamined Patent Publication (Kokai) No. These all control the polishing load during polishing, change the combination of high load and low load, and thereby improve surface defects.

[0004] A number of so-called float polishing applications have been filed in which a work to be polished is suspended in a polishing liquid without using a polishing cloth.
No. 50, JP-A-7-124861, etc.), which are polished only by contact between a work and a polishing liquid.
Irregularities are provided on the upper surface of the turntable on which the liquid reservoir can be formed to form a flow of the polishing liquid, and thereby the flatness of the polishing surface is enhanced.

[0005]

However, the method of polishing by changing the load described above is only contact polishing with a polishing cloth, and it is difficult to completely remove surface defects due to the influence of this contact. There is a problem. That is, there is a limit to the surface roughness in the finish in the contact polishing with the polishing cloth. In addition, in the above-mentioned float polishing, a sufficient flow velocity must be given to the polishing liquid in order to obtain effective polishing, and the thickness due to the wavy shape and the outward deflection of the polishing liquid due to the effect of the high flow rate. There is a problem that surface defects such as unevenness are likely to remain. Furthermore, in most of the float polishing, the holding of the work uses the floating by the flow velocity, but the work is unstable in this floating, and there is a danger such as uneven thickness and re-contact after stopping. There is a problem. The present invention has been made in view of the above problems, and can obtain both advantages of contact polishing with a polishing cloth and float polishing by contact with a polishing liquid, thereby greatly improving surface defects. It is an object of the present invention to provide a method of manufacturing a hard substrate and a manufacturing apparatus thereof.

[0006]

According to the present invention, there is provided a method of manufacturing a hard substrate, which comprises applying a polishing load to a hard substrate, bringing the hard substrate into contact with a polishing cloth, and polishing the hard substrate. And a liquid reservoir having a depth sufficient to form a water film between the hard substrate and the hard substrate, by removing the polishing load, separating the hard substrate from contact with the polishing cloth, The front (hail) surface is processed with a processing liquid.

Further, in a method of manufacturing a hard substrate in which a back surface of a hard substrate is held and a front surface of the hard substrate is processed with a polishing cloth and a working liquid thereon, the hard substrate is pressed against the polishing cloth. After polishing, the front surface of the hard substrate is processed in a state where the front surface does not contact the polishing cloth and does not separate from the working liquid.

Further, an apparatus for manufacturing a hard substrate is provided with a surface plate on which a polishing cloth is laid on a surface, and a standing plate is provided along the outer periphery of the surface plate so that a liquid reservoir can be formed on the upper surface of the polishing cloth. And a holding head provided so as to be able to ascend and descend above the polishing cloth, and provided on its bottom surface to hold a hard substrate.

A top ring provided to hold one side of the hard substrate and rotating the hard substrate in a horizontal direction; an elevating mechanism for elevating the top ring; a polishing cloth for polishing the hard substrate; A turntable for rotating the polishing cloth, supply means for supplying a processing liquid to the upper surface of the polishing cloth, and an outer peripheral wall provided on an outer peripheral portion of the turntable and capable of damping the supplied processing liquid, And a discharge valve for controlling the discharge of the processing liquid supplied to the upper surface of the polishing cloth.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, contact polishing is performed by pressing against a polishing cloth as in the prior art, and processing is performed in a non-contact state with the polishing cloth for the purpose of eliminating transfer of the surface shape of the polishing cloth. The polishing pad formed a reservoir of a processing liquid such as a polishing liquid or an etching liquid on the polishing cloth, and raised the polished surface of the hard substrate so as to separate from the polishing cloth, and the polishing surface was immersed in the liquid pool of the processing liquid. In this state, the polishing surface is maintained in a state where it does not come into contact with the outside air, and mechanochemical float polishing with a polishing liquid or etching with an etching liquid is performed.

Further, after the machining with the machining fluid, the machining fluid is exchanged for rinsing water, thereby washing the machining surface and terminating the process, thereby simplifying the subsequent steps and greatly improving the working efficiency. Can be improved.

In carrying out this manufacturing method, an outer peripheral wall is formed so that a liquid reservoir can be formed on an outer peripheral surface of a surface plate on which a conventional polishing cloth is laid, and a polishing liquid is supplied to the surface of the polishing cloth. Thus, processing is performed by a manufacturing apparatus capable of forming a liquid reservoir having an appropriate depth.

Further, a discharge valve is provided, and in the same contact polishing as in the prior art, this discharge valve is opened to discharge the polishing liquid. When performing the above-described processing using only the processing liquid, the discharge valve is closed to close the liquid. A reservoir can be formed. The exchange of the above-mentioned polishing liquid for rinsing water or etching liquid is also performed by opening and closing the discharge valve.

The major differences between the conventional float polishing and the float polishing of the present invention reside in the flow rate of the polishing liquid and the method of holding the work. In other words, by reducing the flow rate of the polishing liquid as much as possible to eliminate the effects of the high flow rate, and by forcibly holding the work rather than floating,
This is an improvement in defects such as uneven thickness.

As the contact polishing with the polishing cloth in the present invention, rough polishing or finish polishing similar to the conventional one is performed, followed by non-contact float polishing. Therefore, in the direct transition from the rough polishing to the float polishing, the float polishing also serving as the final polishing can be performed, and in the transition from the final polishing, the polishing with further improved surface roughness can be performed.

Also, from contact polishing or float polishing,
By exchanging the processing liquid with an etching liquid containing no abrasive grains, it is possible to remove the processing distortion generated in polishing by etching.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a manufacturing apparatus according to the present invention, FIG. 2 is a schematic diagram illustrating a manufacturing method according to the present invention, and FIG. 3 is a graph comparing the surface roughness of each finished product of the present embodiment.

As shown in FIG. 1, a manufacturing apparatus according to the present embodiment includes a surface plate 1 which rotates in a horizontal direction, a polishing cloth 2 laid on the upper surface of the surface plate 1, and a polishing liquid on the upper surface of the polishing cloth 2. ,
A processing liquid supply port 3 for supplying a processing liquid 7 such as a processing liquid such as an etching liquid or rinsing water;
An outer peripheral wall 4 provided around an outer peripheral portion of the surface plate 1 so that the processing liquid 7 can be damped;
And a holding unit 6 that holds the work 10 to be processed, rotates in the horizontal direction, and is capable of ascending and descending above the surface plate 1.
Consists of

The elevating and lowering of the holding unit 6 is controlled, for example, by an elevating mechanism (not shown) using an electropneumatic regulator. When the work 10 is detached from the polishing cloth 2, the polishing surface of the processing liquid 7 is stored. It is provided so that it can be stopped at a height that does not come out of the liquid level.

Next, the polishing method of this embodiment will be described. As shown in FIG. 2A, in the contact polishing, the work 10 is polished by applying a load to the work 10 by the holding unit 6. This contact polishing is the same as the conventional polishing. The workpiece 10 is brought into contact with the polishing cloth 2 while rotating the work 10 in the horizontal direction by the holding unit 6, and the polishing cloth 2 is similarly horizontally rotated to perform polishing.

As shown in FIG. 2B, when the contact polishing is completed, the discharge valve 5 is closed to form a reservoir of the polishing liquid 71 on the upper surface of the polishing cloth 2. The depth of the liquid reservoir is such that when the workpiece 10 is raised, a water film is formed between the polishing cloth 2 and the workpiece 10 in a state where the polishing cloth 2 is rotated, and the polished surface of the workpiece 10 is not exposed to the outside air. The depth is preferably, for example, about 0.5 to 5.0 mm.

When a sufficient liquid reservoir is formed, the holding portion 6
The work 10 is gradually removed from the polishing cloth 2. The detachment of the work 10 from the polishing cloth 2 is different from the conventional floatation,
The polishing cloth 2 is held at a position where an appropriate water film is formed between the polishing cloth 2 and the polishing cloth 2.

At this time, due to the rotation of the platen 1 and the frictional force between the polishing cloth 2 and the polishing liquid 71, a water flow in the polishing liquid 71 has already been generated in the same direction as the rotation. Polishing liquid 71
The flow velocity is desirably a velocity at which no surface defects occur due to the influence of the high flow velocity or outward deflection which occur in the prior art, and the flow velocity is preferably about 0 to 30 rpm.

In addition, since the polishing liquid 71 does not flow, that is, at a flow rate of 0 rpm, the abrasive liquid 71 stagnates and the polishing efficiency is rather poor, so that the surface plate 1 is more preferably rotated to about 5 to 20 rpm. Let it.

A depth and a flow rate sufficient for storing the abrasive liquid 71 are obtained, and the float polishing is performed by separating the work 10 from the polishing cloth 2. At this time, in order to make the polishing finish more uniform, horizontal oscillation is given from the center of the platen 1 to the outer peripheral direction.

Around the time when the float polishing is substantially completed, the process shifts to rinsing. This rinsing is performed by supplying the rinse water 72 instead of the previously supplied polishing liquid 71 and discharging the polishing liquid 71 from the discharge valve 5 as shown in FIG. Is controlled to be equal to each other so that the depth of the liquid reservoir does not change.

As shown in FIG. 3, the surface roughness obtained by the conventional rough polishing and the finish polishing are respectively RMS 10
Å13 ° and RMS 3〜4 ° are further improved by the polishing method of the present invention to about RMS 2Å.

Further, according to the polishing method of the present invention, unlike the conventional polishing method using a dedicated device for float polishing,
Since the normal polishing and the float polishing are performed continuously, the intermediate cleaning and the loss time required when they are put into different apparatuses do not occur, and it can be said that the polishing is very efficient.

Further, ordinary contact polishing, float polishing,
By performing the rinsing continuously, it is possible to prevent defects and scratches caused by re-etching which have conventionally been caused by abrasive grains or polishing debris penetrating the polishing cloth. In addition, processing strain generated by contact polishing can be removed.

Here, the processing strain on the surface is compared. For example, Japanese Patent Application No. 8-299 discloses two groups of semiconductor wafers.
When the depth was measured by the "method for measuring the depth of a strained layer of a semiconductor wafer" described in Japanese Patent No. 199, the semiconductor wafer obtained by finish polishing by conventional contact polishing was:
By setting the etching (SC-1 solution) removal allowance to 10 nm or more, the non-defective rate became a constant value of 90%. On the other hand, regarding the semiconductor wafer obtained by the float polishing in the manufacturing method of the present invention, the non-defective rate before etching was 90%, and the non-defective rate was 100% by setting it to 1 nm or more.
Therefore, the depth of the processed strain layer by the conventional finish polishing is 10 nm or less, and the depth of the processed strain layer is 1 nm or less in the case of the float polishing of the present invention, and the depth of the processed strain layer is greatly reduced, and the yield rate is also improved. You can see that there is.

When processing with an alkaline or acidic etchant containing no abrasive grains after the above-mentioned float polishing or instead of the float polishing, supply of a polishing solution for the float polishing after the float polishing is performed. Instead, an etchant may be supplied. In particular, by performing the etching subsequent to the float polishing, the processing strain remaining in the float polishing can be almost completely removed.

[0032]

According to the present invention, the configuration is as described above.
The advantages of both contact polishing with a polishing cloth and float polishing or etching in a non-contact state can be obtained,
Thereby, there is an excellent effect that surface defects in polishing can be greatly improved. Further, the processing in the present invention has an excellent effect that the working efficiency is very good because the contact polishing and the non-contact polishing are performed continuously unlike the conventional processing using the float polishing equipment. Further, there is an excellent effect that etching defects and scratches can be prevented by polishing debris generated in the contact polishing, and processing strain due to the contact polishing can be removed.

[Brief description of the drawings]

FIG. 1 is a schematic view of a polishing apparatus according to the present invention.

FIG. 2 is a schematic view showing a polishing method according to the present invention.

FIG. 3 is a graph comparing the surface roughness in the finished state of each polishing in this example.

[Explanation of symbols]

 1 {Surface plate 2} Polishing cloth 3} Processing liquid supply port 4} Outer peripheral wall 5} Drain valve 6} Holding part 7} Processing liquid 71} Polishing liquid 72 ‥‥ Rinse water 10 ‥‥ work

Claims (5)

[Claims] 1. A method for applying a polishing load to a hard substrate and bringing the hard substrate into contact with a polishing cloth to polish the hard substrate, and then a depth sufficient to form a water film between the polishing cloth and the hard substrate on the polishing cloth surface. Forming a liquid reservoir and removing the polishing load to separate the hard substrate from contact with a polishing cloth, and processing the front (hail) surface of the hard substrate with a processing liquid. Substrate manufacturing method. 2. A method of manufacturing a hard substrate in which a back surface of a hard substrate is held and a front surface of the hard substrate is processed with a polishing cloth and a working liquid thereon, the hard substrate is pressed against the polishing cloth. And polishing the front surface of the hard substrate without bringing the front surface of the hard substrate into contact with the polishing cloth and separating from the working liquid. 3. A surface plate on which a polishing cloth is laid on a surface, an outer peripheral wall erected along an outer peripheral portion of the surface plate and provided so as to form a liquid reservoir on an upper surface of the polishing cloth, An apparatus for manufacturing a hard substrate, comprising: a holding head provided so as to be able to ascend and descend above a polishing cloth, and provided on a bottom surface thereof to hold the hard substrate. 4. A top ring provided to hold one surface of the hard substrate and rotating the hard substrate in a horizontal direction, an elevating mechanism for elevating the top ring, a polishing cloth for polishing the hard substrate, A turntable for rotating the polishing cloth, supply means for supplying a processing liquid to the upper surface of the polishing cloth, and an outer peripheral wall provided on an outer peripheral portion of the turntable and capable of damping the supplied processing liquid, An apparatus for manufacturing a hard substrate, comprising: a discharge valve for controlling discharge of a processing liquid supplied to an upper surface of the polishing cloth. 5. An outer peripheral wall provided on an outer peripheral portion of the turntable is detachably provided.
Or a polishing apparatus for a hard substrate according to item 4.