JP2539753B2 - Mirror polishing machine for semiconductor substrates - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention is applied to a work surface plate below.
A plurality of suction chucks are rotatably mounted and the upper polishing cloth
The surface plate and the work surface plate face each other with a slight eccentric rotation axis.
Place the semiconductor substrate on the chuck and hold it in vacuum.
Revolution of surface plate, rotation of suction chuck, rotation of polishing cloth surface plate
Rotation, eccentricity of the rotating shaft of the upper and lower surface plate
One-time polishing by giving mechanochemical polishing
Can be used to polish multiple semiconductor substrates under the same conditions.
With obtaining improved relates to the mirror-polishing apparatus for a semiconductor substrate capable of mirror polishing extremely high precision without processing strain.

[0002]

2. Description of the Related Art At present, the most common mirror polishing of a semiconductor substrate made of silicon or the like is so-called single-side polishing in which only one side is polished. To explain a general mirror polishing apparatus, a polishing platen on which a plurality of semiconductor substrates are attached is pressed against a polishing cloth made of polyurethane resin or the like adhered to a rotary table with a predetermined pressure, and a particle size of about 5 to 300 nm, for example. the SiO ₂ abrasive grains with caustic soda, and about pH9~12 are suspended in an alkaline solution such as ammonia and ethanolamine, using a polishing solution comprising a so-called colloidal silica, it is relatively rotated, the machine according to the abrasive grains Polishing by a mechanochemical polishing method utilizing both the chemical action and the chemical action by etching of an alkaline solution.

There are various methods for fixing a semiconductor substrate to a polishing platen, and a wax mount method of attaching with a wax or the like is disclosed in JP-A-1-210.
No. 259, Japanese Unexamined Patent Publication No. 1-289657, etc., there are mirror polishing apparatuses, and as a waxless mount type adsorbing to a polishing platen, Japanese Patent Application Laid-Open Nos. 64-2858 and 64-45567. There is a mirror polishing device shown.

[0004]

The mirror surface polishing apparatus is required to remove not only high flatness but also micro scratches and haze to obtain a high quality polished surface free from processing distortion. Contrary to this, improvement of polishing efficiency is also required. In order to improve the polishing efficiency, a waxless mount is advantageous because it makes it easier to attach the wafer to the wafer surface plate and to clean the wafer after polishing. Wax mounts are currently the mainstream because of problems with quality such as stains.

The present invention relates to a mirror surface polishing apparatus for a semiconductor substrate which simultaneously polishes a plurality of substrates by a mechanochemical polishing method, which improves polishing efficiency and is capable of extremely highly accurate mirror surface polishing. It is intended to be provided.

[0006]

SUMMARY OF THE INVENTION The present invention is a mechanical mechanism
Polish multiple substrates at the same time using the Cull Polishing method
In mirror-polishing apparatus for semiconductor substrate, and high quality to obtain a polished surface having no work strain, with the purpose to FIG Rukoto improvement conflicting polishing efficiency to this, during polishing, given to the plurality of semiconductor substrates
As a result of various studies with the optimization of obtaining the rotation action, a plurality of suction chuck rotatably mounted to the work surface plate disposed below the rotating shaft and a polishing cloth surface plate and the workpiece surface plate disposed above By slightly eccentricity and facing each other, the semiconductor substrate vacuum-adsorbed on the upper surface of the suction chuck revolves the work surface plate, the suction chuck rotates, the polishing cloth surface plate rotates, and the upper and lower surface plate rotates. can be polished giving four rotating action of the eccentric of the shaft, a plurality of half in a single polishing
It was found that the conductor substrate can be polished under the same conditions, and an extremely high quality polished surface can be obtained while improving the polishing efficiency.
Completed this invention.

That is, according to the present invention, a polishing cloth surface plate having a polishing cloth adhered to the surface thereof and a work surface plate having a plurality of rotatably mounted substrate holding chucks for holding or supporting a plurality of suctions are vertically opposed to each other. The polishing table is eccentric to the rotation axis of the surface plate, and the semiconductor substrate surface held on the substrate holding chuck is supplied with a supply means for supplying a polishing liquid in which abrasive grains are suspended in a solution and a pressure means for polishing. An apparatus for mirror-polishing a semiconductor substrate, comprising: a rotation driving means that brings a cloth into contact with a semiconductor substrate to allow relative rotation of an upper and lower surface plate and a substrate holding chuck.

Further, according to the present invention, an upper polishing platen having a polishing cloth attached to its surface and supported so as to be movable up and down, and a lower work platen having a plurality of suction chucks rotatably mounted thereon It has a configuration in which the rotation axis of
A supply means for supplying a polishing liquid in which abrasive grains are suspended in a solution to the surface of the semiconductor substrate adsorbed by the suction means on the suction chuck, and a polishing cloth surface plate is brought into contact with the semiconductor substrate by the pressurizing means to move up and down. In a mirror polishing apparatus for a semiconductor substrate, which has a rotation driving means that allows relative rotation between a surface plate and a suction chuck, the suction force of the suction chuck is -250 to -650 mmH.
Vacuum polishing pressure of g for controlling semiconductor substrate mirror polishing device, polishing cloth surface plate held so as to be movable horizontally, semiconductor substrate mirror surface polishing device, work surface plate suction A mirror polishing apparatus for a semiconductor substrate, characterized in that a polishing liquid receiving plate which is arranged between chucks and receives a polishing liquid supplied from a nozzle provided at the center of a polishing cloth surface plate to prevent the liquid from falling is disposed. We also propose.

In the present invention, either the work surface plate or the polishing cloth surface plate may be an upper surface plate or a lower surface plate, and the substrate holding chuck may be either a suction type or a template type, and the number of chucks is arbitrary. However, 3 or more is preferable. The work surface plate has a structure in which a plurality of suction chucks are rotatably placed on the upper surface of the work surface plate and is rotated. As in the embodiment, the work surface plate serving as the lower surface plate is rotatably supported by the suction chucks. In addition to adopting a rotation drive means that interlocks with the rotation of the work surface plate by engaging the sun gear provided on the rotation shaft of the surface plate with the drive shaft penetrating downward and engaging the planetary gear at the end of the drive shaft, Various drive methods such as known gear drive can be appropriately selected such that the rotation is controlled separately from the work surface plate. A suction-type substrate holding chuck (hereinafter referred to as a suction chuck) is for vacuum-sucking and fixing a semiconductor substrate. The shape and material of the suction plate provided on the upper surface of the chuck are not particularly limited, but known acrylic materials, ceramic materials, etc. may be used. It is possible to apply a configuration in which grooves and holes are used as appropriate. Further, a decompression pump or the like can be used as the suction means, but since the suction chuck and the work surface plate rotate, it is necessary to arrange a rotary joint or the like in a pipe or the like connected to the pump. The suction force of the suction chuck that has been subjected to the groove or hole processing can be processed with high accuracy by controlling the vacuum pressure to be -250 to -650 mmHg. That is, if the suction force is less than -250 mmHg, the semiconductor substrate is likely to fly or crack, and if it exceeds -650 mmHg, minute waviness or the like occurs on the substrate and a highly accurate mirror surface cannot be obtained.

In the present invention, the polishing cloth surface plate has a structure in which a predetermined polishing cloth is adhered to the lower surface of the polishing cloth to bring it into contact with the semiconductor substrate on the suction chuck or to be capable of moving up and down to a predetermined position when the substrate is attached and detached. If so, the lift mechanism can employ any of the known structures in addition to the lever type of the embodiment. As the rotation driving means, known gear driving can be adopted in addition to the belt driving of the embodiment. The mirror polishing apparatus of the present invention is characterized in that the rotating shafts of the upper and lower surface plates are eccentrically opposed to each other, and fixed shafts are arranged so that the amount of eccentricity is constant. By holding the surface plate so that it can move in the horizontal direction, the polishing cloth surface plate can be eccentrically arranged with respect to the work surface plate, and by further moving the polishing cloth surface plate by the radius of the work surface plate, for example, the suction chuck It is possible to adopt a configuration that facilitates pull-out inspection and the like. When the polishing cloth surface plate is brought into contact with the semiconductor substrate on the substrate holding chuck to perform polishing, the pressure is set to a predetermined pressure. As used, it is appropriately selected according to the support and lifting mechanism of the polishing cloth surface plate adopted, and the pressing force is selected according to the type of polishing cloth and polishing liquid.

In the present invention, any known polishing suspension such as colloidal silica can be applied to the polishing liquid, and the capacity of the discharge pump can be changed depending on the shape and position of the polishing liquid nozzle, the concentration and supply amount of the polishing liquid, and the like. Is selected. Further, in order to prevent the liquid from falling by receiving the polishing liquid supplied from the nozzle provided at the center of the polishing cloth surface plate, by disposing the polishing liquid receiving plate between each suction chuck of the work surface plate, The polishing liquid flows from the center of the surface plate to the outer peripheral side between the polishing cloth and the polishing liquid receiving plate, and the polishing liquid can be supplied to the entire surface of the polishing cloth without dropping downward.

[0012]

The present invention will be explained with reference to an example in which the polishing cloth surface plate is arranged on the upper side and the work surface plate is arranged on the lower side, and the suction chuck is used.
Multiple suction chucks are rotatably attached to the work surface plate,
By arranging the polishing cloth surface plate and the work surface plate so as to be opposed to each other with the rotation axis slightly eccentric, the rotation of the work surface plate, the rotation of the suction chuck, and the polishing cloth can be performed on the semiconductor substrate vacuum-adsorbed on the upper surface of the suction chuck. The mechanochemical polishing can be performed by giving four rotational actions of the rotation of the surface plate and the eccentricity of the rotating shafts of the upper and lower surface plates to obtain a polishing surface without processing distortion and to improve the polishing efficiency and to achieve extremely high quality. A polished surface is obtained.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partially broken perspective view showing the structure of a mirror polishing apparatus according to the present invention, and FIG. 2 is a perspective view showing the rotation of a polishing cloth surface plate, a work surface plate and a suction chuck. 3 is a schematic longitudinal explanatory view of a mirror-polishing device, which schematically shows the flow of a polishing liquid. A work surface plate 10 in which a rotating shaft 11 is vertically supported in a base 1 has a surface plate exposed on the base 1, and a polishing liquid scattering prevention cover 2 is arranged around the surface of the work surface 10. A polishing liquid recovery tray (not shown) is provided between the outer peripheral portion of the board 10 and the scattering prevention cover 2. A drive gear (not shown) is provided below the rotary shaft 11 of the work surface plate 10 so as to mesh with a gear of a reduction gear of a motor, and a sun gear 12 is provided around the rotary shaft 11 so as to surround the work gear. Further, on the work surface plate 10, five suction chucks 20 are arranged at equal intervals and are rotatably supported by the rotary shaft 2.
1 is a planetary gear 2 that is provided at the tip of the work surface plate 10
2 meshes with the sun gear 12 described above. Work surface plate 1
A suction pipe that connects to the suction chuck 20 is provided in 0, and is connected to an external decompression pump via a rotary joint in the rotary shaft 11. The suction plate of the suction chuck 20 is an acrylic plate having a large number of circumferential grooves.

Polishing cloth surface plate 30 facing the work surface plate 10
The rotary shaft 31 is rotatably held by a bearing on a surface plate support 32 and hung down by a balancer mechanism to be described later. The surface plate support 32 slides on a horizontal table 3 arranged on both sides of the base 1. The eccentric amount of the rotation center of the polishing pad surface plate 30 with respect to the rotation center of the work surface plate 10 is movably mounted on the rail 4 via the slider 33 by the horizontal holding mechanism of the surface plate support base 32. Although it can be set arbitrarily, it is configured to be positioned by a lock mechanism (not shown) so that the eccentricity amount is set in advance. Further, by making the polishing cloth surface plate 30 movable about the radius of the work surface plate 10 by the horizontal holding mechanism, the suction chuck 20 can be pulled out and inspected. Although not shown, the balancer mechanism that hangs the polishing cloth surface plate 30 to set a predetermined pressure is not shown.
(1) A balancer arm, which constitutes a lever having its upper end arranged in the surface plate support 32, is axially supported by a bearing slidably provided on one end, and the other end of the lever is provided with a high pressure cylinder for lifting and a low pressure cylinder for pressurizing. It consists of a piston rod connected. Further, a pulley is provided on the rotary shaft 31 of the polishing cloth surface plate 30 and the driving force of the motor is transmitted by a belt via a reduction gear. A dresser is placed on the base 1 to dress the polishing cloth adhered to the lower surface of the polishing cloth surface plate 30.

The polishing agent is pumped from a tank (not shown) by a pump to enter from the upper end of a pipe 50 penetratingly arranged in the rotary shaft 31 of the polishing cloth surface plate 30, and from the center of the polishing cloth surface plate 30 to the work surface plate 10. Is ejected in the outer peripheral direction from the nozzle 51 arranged opposite to the nozzle. The semiconductor substrate 60 is conveyed by a belt conveyor (not shown) arranged on the base 1 and stopped at a predetermined position, raised and lowered by a mounting table, centered by a pair of arms, and further attracted by a suction plate at the arm tip of the handler. Work surface plate 10 by sucking a semiconductor substrate and rotating an arm
Is transferred onto the suction chuck 20 of FIG. At this time, the polishing cloth surface plate 30 is raised by the high pressure cylinder, and the work surface plate 1
In 0, the rotation indexing control is performed so that the suction chuck 20 stops at a predetermined position below the tip of the arm of the handler that has swung.

When the semiconductor substrate 5 is placed on each suction chuck 20 of the work surface plate 10 and the suction is completed, the polishing cloth surface plate 3
0 descends by the high pressure cylinder and contacts the semiconductor substrate 5,
After the pressure is set to a predetermined value with the low pressure cylinder, the nozzle 5
1, the abrasive is sprayed, the polishing cloth surface plate 30 and the work surface plate 10 are rotationally driven, and the suction chuck 20 is also interlocked,
For example, as shown in FIG. 2, all are rotated in the same rotational direction at preset rotational speeds, and polishing is started together with these relative rotational movements. Further, by disposing the polishing liquid receiving plate 13 between the respective suction chucks 20 of the work surface plate 10, the polishing liquid is moved between the polishing cloth on the surface of the polishing cloth surface plate 30 and the polishing liquid receiving plate 13 from the surface plate center. The polishing liquid flows to the outer peripheral side and the polishing liquid does not drop downward, and the projection 14 provided on the outer peripheral portion of the polishing liquid receiving plate 13 forms a liquid reservoir between the polishing cloth and the polishing liquid receiving plate 13. As a result, the polishing liquid is supplied to the entire surface of the polishing cloth, and the mechanochemical polishing acts on the semiconductor substrate 5 during the relative rotational movement of the surface plate or the like, so that predetermined mirror surface polishing proceeds. When the predetermined polishing is completed, the supply of the polishing liquid, the rotation of the work surface plate 10 and the polishing cloth surface plate 30 are stopped, and the polishing cloth surface plate 30 is raised by the high-pressure cylinder, and is rotated to the predetermined position contrary to the above. Indexed suction chuck 2
0, the arm of the handler swivels, and the semiconductor substrate 5
After being adsorbed, it is transferred to a mounting table, and then transported by a belt conveyor to a required next step.

[0017]

According to the mirror surface polishing apparatus of the present invention, a plurality of suction chucks are arranged on a work surface plate, and the semiconductor substrate vacuum-adsorbed on the upper surface of each suction chuck is revolved around the work surface plate, the suction chuck is rotated, and the polishing cloth is fixed. The mechanochemical polishing can be performed by giving four rotational actions of the rotation of the plate and the eccentricity of the rotating shaft of the upper and lower surface plates, and it is possible to polish multiple semiconductor substrates under the same condition with one polishing. While improving efficiency, a polished surface with no processing distortion can be obtained with extremely high quality.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing the structure of a mirror polishing device according to the present invention.

FIG. 2 is a perspective explanatory view showing the rotation of the polishing cloth surface plate, the work surface plate and the suction chuck of the mirror surface polishing apparatus according to the present invention.

FIG. 3 is a schematic vertical cross-sectional explanatory view of a mirror-polishing device that schematically shows the flow of a polishing liquid of the mirror-polishing device according to the present invention.

[Explanation of symbols]

 1 Base 2 Scatter Prevention Cover 3 Horizontal Platform 4 Slide Rail 5 Semiconductor Substrate 10 Work Surface Plate 11 Rotation Axis 12 Sun Gear 13 Polishing Liquid Receiving Plate 14 Protrusion 20 Suction Chuck 21 Rotation Axis 22 Planetary Gear 30 Polishing Cloth Surface Plate 31 Rotation Axis 32 surface plate support 50 piping 51 nozzle

Claims (4)

(57) [Claims] 1. A polishing plate having a polishing cloth adhered to the surface thereof and a work plate having a plurality of rotatably mounted a plurality of substrate holding chucks for holding and supporting a plurality of suction plates are vertically opposed to each other. The eccentric rotation axis of the semiconductor substrate is used for supplying a polishing liquid in which abrasive particles are suspended in a solution to the surface of the semiconductor substrate held on the substrate holding chuck, and a polishing cloth is applied to the semiconductor substrate by the pressure means. 1. A mirror polishing apparatus for a semiconductor substrate, comprising: a rotation driving means which is brought into contact with the upper and lower surface plates and a substrate holding chuck to relatively rotate. 2. The mirror polishing apparatus for a semiconductor substrate according to claim 1, wherein the substrate holding chuck is a suction type, and the suction force is controlled to a vacuum pressure of −250 to −650 mmHg. 3. The mirror polishing apparatus for a semiconductor substrate according to claim 1, wherein a polishing cloth surface plate arranged above is held so as to be movable in a horizontal direction. 4. A polishing liquid receiving plate which is arranged between respective suction chucks of a work surface plate arranged below and which receives a polishing liquid supplied from a nozzle provided at the center of the polishing cloth surface plate and prevents the liquid from falling. The semiconductor substrate mirror polishing apparatus according to claim 1, 2 or 3, wherein the mirror polishing apparatus is provided.