RU2260872C2 - Semiconductor wafer machine tool - Google Patents

Abstract

FIELD: machining semiconductor wafers.

SUBSTANCE: proposed machine tool designed for circular machining of semiconductor wafers to produce wafers having side surfaces of desired shape with minimal quantity of post-machining circular scratches and to execute great number of process operations without displacing wafers from one position to other has pair of supporting and driving rollers that function as supports for vertically disposed semiconductor wafers and are set in motion by means of drive belt connected to them. Machine tool also has two opposing movable wafer-machining units each incorporating first and second members designed for machining wafers when they are installed in first and second positions. Second design alternate of semiconductor wafer machine tool and self-aligning arbor fastening assembly is also proposed.

EFFECT: enlarged functional capabilities of machine tool, improved quality of post-machining side surfaces of wafers.

22 cl, 17 dwg

Description

BACKGROUND OF THE INVENTION

The present invention relates to the processing of semiconductors, in particular to a machine for processing vertically semiconductor wafers.

In the manufacture of semiconductor devices and devices, it is necessary to perform a large number of various technological operations related, in particular, to the processing of semiconductor wafers. Such operations include the operation of cleaning and polishing / leveling the plane, for example, by the chemical-mechanical method (CMP). One of the known methods of polishing / leveling a plane is based on the use of polishing plates with a planetary drive. One of the disadvantages of this method is the need to perform in a certain order a large number of different operations that require a lot of time and increase the cost of manufacturing semiconductor wafers. Another disadvantage of this method is the relatively high degree of variation in the topography of the processed surfaces of the semiconductor wafers.

Another known method of polishing / leveling the plane of semiconductor wafers is circular polishing. In one of the known circular polishing machines, a vertically mounted semiconductor wafer is driven by special drive rollers. From opposite sides, two cylindrical polishers are pressed against a rotating plate. Polishers are mounted on mandrels rotating in different directions, located on opposite sides of the workpiece. The mandrels overlap the plate in diameter and pass through its center. Rotating mandrels set in motion around the circumference of polishers, whose axes are perpendicular to the diameter of the plate. During processing, a liquid, such as an abrasive slurry, a chemical solution or a washing solution, is sprayed onto opposite sides of a rotating polished plate from special nozzles.

One of the disadvantages of the known machines for circular polishing is that polishing in them occurs only as a result of movement in a circle. In this case, the relative speed between each polishing pad and the plate turns out to be different for different points on the surface of the plate — higher at the edge of the plate and lower at the center of the plate. As a result, circular scratches remain on the sides of the polished plate, and the material is removed unevenly from the surface of the plate, and more material is removed from the central part of the plate, which is polished for a longer time, than from its outer part. Due to the uneven removal of material, the sides of the plate take the form of expanding from the center of the plate to its outer edge of the cone. Given the recent trend in the semiconductor industry, a trend towards miniaturization and a decrease in the size of individual elements of semiconductor devices and devices (chips or crystals) to 0.18 μm or less, such a conical surface shape of the treated semiconductor wafer is unacceptable.

With all of the above, there is a need to develop a method and a machine for circular processing of semiconductor wafers, on which it would be possible to produce plates with the desired shape of the side surfaces with a minimum number of circular scratches remaining on them after processing and performing a large number of technological operations without moving the wafer from one position to another.

SUMMARY OF THE INVENTION

The above problem is solved using the proposed in the present invention machine for processing vertically mounted semiconductor wafers.

In accordance with one aspect of the present invention, there is provided a machine for processing semiconductor wafers. This machine has a pair of support rollers mounted in a certain way, which serve as supports for a vertically located semiconductor wafer. Each support-drive roller is driven into rotation by a drive belt connected to it. The machine also has two opposite movable plate processing units located opposite each other. Each processing unit has two - the first and second - processing elements that process the semiconductor wafer. The movable processing unit can be set in the first position in which the processing of the plate is carried out by its first processing element, and in the second position in which the processing of the plate is carried out by the second processing element of the block.

In accordance with another object of the present invention, it proposes another machine for processing semiconductor wafers. This machine has a first support-drive roller, which can rotate in a support mounted on the first pivot arm, and is designed to drive the rotation of a vertically machined plate. The machine also has a second supporting-drive roller, which can rotate in a support mounted on the second pivot arm, and is designed to drive the rotation of a vertically located plate. Through each rotary lever, the energy necessary for driving the workpiece to rotate the plate being supplied is supplied to the support-drive roller mounted on it, and each lever can be used by turning it in the corresponding support from the first position to the second to change the height of the position vertically mounted on the support drive rollers plate.

Another object of the present invention is a mounting unit for self-centering mandrels with processing elements (tools) of the semiconductor wafer. The self-centering mandrel has an inner sleeve with an element located on its outer surface, forming an articulated fulcrum. An outer cylindrical sleeve (sheath) of the mandrel is fitted on the inner sleeve. The mandrel shell, externally coated with the material used to process the semiconductor wafer, is pivotally connected to the inner sleeve at the support point located on the outer surface of the inner sleeve and, when the processing material contacts the plate, rotates at this support point in a position parallel to the surface of the semiconductor wafer.

It should be noted that in the above summary of the invention and in the detailed description below, it is only an example of a possible implementation of the invention, the scope of which, as follows from the claims, is not limited to this example.

BRIEF DESCRIPTION OF THE DRAWINGS

Below the invention is described in more detail on the example of some variants of its implementation with reference to the accompanying drawings, which show:

figure 1 is a front view of the proposed in one embodiment of the machine for processing semiconductor wafers,

in Fig.2 is a side view of the machine for processing semiconductor wafers shown in Fig.1 with the image of the movable processing unit located in Fig.1 on the right with the mandrels and polishers shown in cross section and dashed lines in two positions mounted on the support drive rollers of the semiconductor plate ,

figure 3 is a front view of the machine shown in figure 1 for processing semiconductor wafers with neutral processing units and not touching the wafer polishers and, if necessary, mounted on the walls of the machine body devices for cleaning polishers,

on figa is a front view of the machine shown in figure 1 for processing semiconductor wafers with the image located not inside the machine body, but outside the swing arms and the drive cylinder of the rotation mechanism of the processing units,

on figb is a more detailed image of the levers and the drive cylinder located in the upper extreme position of the rod shown in figa mechanism of rotation of the processing units,

on figa is a cross section made in accordance with another embodiment of the processing unit with the mounting unit of a self-centering mandrel with a polisher and brush,

on figb is a more detailed image of the middle part shown in figa attachment site of the self-centering mandrel made in the form of a hinge support point relative to which the shell of the mandrel is rotated,

Fig.6 is a graph obtained as a result of four experiments, reflecting the dependence of the amount of material removed from the surface of the plate when processing it in the usual manner of central polishing on the radial distance from the center of the plate,

on figa and 7B - the data obtained as a result of four experiments on the amount of material removed from the semiconductor wafer during its processing by the usual method of central polishing, with the image located on the surface of the wafer measurement points located at different distances from the center of the wafer and distributed around direction

удаления материала с поверхности пластины при ее центральном полировании обычным способом от расстояния от центра пластины,on figa and 8B are graphs reflecting the dependence of speed

removing material from the surface of the plate when it is centrally polished in the usual way from a distance from the center of the plate,

удаления материала с поверхности пластины при ее нецентральном полировании предлагаемым в одном из вариантов способом от расстояния от центра пластины,on figa and 9B are graphs reflecting the dependence of speed

removal of material from the surface of the plate when it is off-center polished by the method proposed in one of the options from the distance from the center of the plate,

figure 10 is an image in a perspective view of a processing unit of semiconductor wafers, made in accordance with one of the options, and

on figa and 11B is a detailed image of the main components and parts of the proposed in accordance with one of the variants of the processing unit of semiconductor wafers.

PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION

Below, with reference to the drawings, several specific examples of a possible embodiment of the invention are described in more detail.

The examples below describe methods and a machine that can be used to process various products. Such products include, for example, semiconductor wafers of any size, including wafers with a diameter of 200 to 300 mm (as well as wafers of smaller and larger diameters). In the description below, in particular, we are talking about a machine on which it is processed precisely such semiconductor wafers. In this regard, it should be noted that the machine proposed in the invention can be used for processing various other parts, for example, hard disks and other similar parts. In the processing of such parts, in particular, finishing operations, chemical-mechanical polishing (CMP), mechanical or liquid cleaning (as is usually the case with semiconductor wafers), etching and washing with liquids, in particular deionized water, are performed. In the examples below, the inventive method and machine are used for highly accurate controlled processing of semiconductor wafers. In the machine according to the invention, it is possible, in particular, to carry out cleaning operations, finishing operations and polishing corresponding sections of the surface of the semiconductor wafers in a controlled manner. When processing various sections of the surface of the plate with different durations, the plate moves in a controlled manner inside the special machine body. For processing semiconductor wafers on the proposed invention, the machine can use various types of processing tools (in particular brushes, polishers, etc.). Therefore, in the description below, it is necessary to take into account the possibility of various designs of the machine proposed in the invention.

Semiconductor wafer processing machine

Figure 1 and 2 shows the proposed in accordance with one of the options for the machine for processing semiconductor wafers, shown in section in front view and side view (right), respectively. The machine 1 shown in these drawings has a housing 2, which, as described in detail below, serves as a supporting structure for various components and parts of the machine. The upright semiconductor wafer W, which is shown in FIG. 1 as a side view and in FIG. 2 as a front view (dashed lines), is supported on supporting-driving rollers 6, 6 ′.

The plate W shown in FIG. 1 is in contact with the upper pair of polishers 8, 8 ', one of which (polisher 8) is located to the right of the plate and touches its right side W1, and the other (polisher 8') is located to the left of the plate and touches it left side of W2. In this case, the lower polishers 12, 12 'are at a certain distance from the plate and do not touch its lateral sides W1 and W2, respectively. The machine 1 intended for processing semiconductor wafers does not have to have a two-sided symmetrical arrangement, however, its multiple nodes and subnodes are preferably made in the form of two identical nodes or subnodes symmetrically to the right and left of the plane of symmetry of the plate W mounted vertically in the housing 2 The terms "right" and "left" in this case refer to the plate W in the plane of the drawing in figure 1. Another arrangement is possible for certain elements of the machine, in particular the two brushes 12b and polishers shown in FIGS. 11A and 11B. In this case, brushes identical to the brushes 12b can be mounted on mandrels or a central roller connected directly to one of the gears 44 or 46.

Shown in figures 1-3, the upper polishers 8, 8 'are located on the outer side of the cylindrical upper mandrels 10, 10', and the lower polishers 12, 12 'are located on the outer side of the cylindrical lower mandrels 14, 14'. The upper and lower mandrels are horizontal, with the upper mandrel 10 and the lower mandrel 14 located to the right of the plate W, and the upper mandrel 10 'and the lower mandrel 14' to the left of the plate W. In the vertical direction, the upper 10, 10 'and lower 14, 14 'mandrels are located at a certain distance from each other. In one embodiment, the distance between the upper and lower mandrels in each pair of mandrels is equal to a certain, preferably from third to fourth, part of the radius of the semiconductor wafer. One of the ends of each upper mandrel 10, 10 'and each lower mandrel 14, 14' is mounted in a bearing in a housing 16, 16 ', inside of which there are rotating gears of the drive mechanism 17 and the turning of the processing elements of the machine. The design of the mechanism 17 of the drive and rotation of the processing elements of the machine is discussed in more detail below in the section "The mechanism of the drive and rotation of the processing elements of the machine". In one embodiment, the mechanism 17 for turning and turning the processing elements of the machine tool consists of a mechanism 13 for driving polishing wheels through which the engine torque is transmitted to the mandrels 10, 10 'and 14, 14', and a mechanism 15 for turning the polishing wheels, which controls the polishing wheels 8 in a controlled manner. 8 'and 12, 12' with respect to the plate W from the inoperative position to the working one and vice versa.

The right and left cases 16, 16 ′ with drive gears shown in FIG. 1 can rotate on axes 18, 18 ′, which are located at a small distance from the plane of the plate W. When the right case 16 is rotated in the corresponding direction, its upper end approaches the plane of the plate W, and the upper polisher 8 mounted on the mandrel 10 is pressed against the right side W1 of the plate, and the lower polisher 12 mounted on the mandrel 14 moves away from it. When the right housing 16 is rotated in a different direction, its lower end approaches the plane of the plate W (see FIG. 3), and the lower polisher 12 is pressed against the right side W1 of the plate, and the upper polisher 8 moves away from it at this time. Obviously, in a similar way, when the left housing 16 'with the drive gears is rotated in the corresponding direction, the left upper and lower polishers 8', 12 'are pressed against the left side W2.

The rotation axes 18, 18 'of the housings with drive gears are so close to the plane of the plate W that it is sufficient to rotate the housings 16, 16' by a small angle A, A 'so that the upper polishers 8, 8' (or when turning in the opposite direction - the lower polishers 12, 12 ′) could be pressed against the opposite sides W1, W2 of the plate and thereby “clamped” it on two sides by opposite polishers. Angle A depends, among other things, on the diameter of the polishers. In one embodiment, angle A is approximately 15 to 25 °. On the other hand, as shown in FIG. 3, the distance from the axes 18, 18 ′ to the plane of the plate W is large enough so that when the housings 16, 16 ′ with drive gears are rotated to a vertical position, both pairs of upper 8, 8 ′ and lower 12, 12 'of the polishing pad occupied a neutral position and did not touch the plate W, being at a sufficiently large distance from it.

The design of the housings 16, 16 'allows the movement of either the upper or lower mandrel of each pair of mandrels in the direction of the plate and pressing the polishing pad mounted on one mandrel to one of the sides of the plate. This design of the machine for polishing semiconductor wafers according to the invention allows two separate polishing operations of the wafer, one of which polishes the wedge “sandwiched” between the upper polishers and the other a wafer “sandwiched” between the lower polishers.

As shown in figures 1-3, proposed in the invention, the machine has a support-drive unit 23, which serves as a support for the plate W and at the same time drives it. In one embodiment, the support-drive unit 23 of the machine is made in the form of a device with which you can adjust the height of the position of the plate driven into rotation by the outer edge of the plate. In figure 2, the plate W is shown (in dashed lines) in the raised and lowered positions Wa and Wb, respectively. As already noted above, the bearings of the plate W are supporting-driving rollers 6, 6 '. In figure 2, these supporting-drive rollers 6, 6 'are shown in the raised position 6a, 6a' (dashed lines) and in the lowered position 6b, 6b '. Support-drive rollers 6, 6 ', on which the plate W is supported by its outer edge Wp, are fixed at the ends of the pivoting levers 20, 20', which are pivotally attached to the corresponding supporting part. This supporting part can be fixed on a suitable base, for example, on the right wall 4 or on the lower wall 5 of the machine body 2.

One of the elements of the support-drive unit 23 is the drive mechanism 21, through which the drive force necessary to bring the plate into rotation is transmitted to the support-drive rollers 6, 6 'from the engine. The support-drive unit 23 also includes a mechanism 27 for changing the height of the position of the plate, made in the form of pivoting levers 20, 20 'with support-drive rollers that can rotate around axes 22, 22'. The levers 20, 20 'with the rollers are connected to each other by a gear transmission and rotate symmetrically relative to each other in different directions. The remaining parts of the support-drive unit 23, including the details of the mechanism 21 of the drive of the support-drive rollers and the mechanism 27 for changing the height of the position of the workpiece, are discussed in detail below in the section "Support-drive unit that allows you to change the height of the position of the plate standing on the edge".

In the upper part of the right side wall 4 of the machine housing, there is a clamping device 26 with a pivoting centering arm 25, on the end of which a centering plate is mounted on top of the roller 24. The centering roller 24 abuts against the upper point of the outer edge Wp of the plate W and forms a lateral support in addition to centering the plate W, the holding plate in place when the polishing pad (8, 8 ', 12, 12') is withdrawn from it to the neutral position. When moving the plate in height from one position (Wa) to another (Wb) (see FIG. 2), the centering roller 24 mounted on the pivot arm 25 remains constantly pressed against the outer edge Wp of the plate. In figure 2, the centering roller in the upper position is indicated by 24, and in the lower (shown by dashed lines) position by 24 '. If necessary, additional rollers located at the outer edge of the plate can be installed on the machine, using them as supports to increase the stability of the plate or as drive or loading / unloading rollers.

The levers 20, 20 'with support-driving rollers 6, 6' in figure 2 are shown in an intermediate position. The possible angle of rotation of the levers 20, 20 'with the supporting-drive rollers is determined by the upper and lower extreme positions of the supporting-driving rollers 6, 6' shown in the drawing. When lifting the levers 20, 20 ', the support-driving rollers 6, 6' rise up and approach one another. The rise of the rollers is accompanied by the rise of the plate W, which rises up not only because the rollers rise up, but also because the distance between them also decreases. Conversely, the rotation of the levers 20, 20 'in the other direction and the lowering of the rollers is accompanied by the lowering of the plate W. When the support-drive rollers move within the angle B, the axis Wo of the plate rises or falls down a certain height within the distance shown in figure 2 arrow C. By adjusting the movement of the supporting-drive rollers 6, 6 ', it is possible to regulate the movement of the semiconductor wafer processed on the machine in the vertical direction. In this case, for example, by shifting and spreading the support-drive rollers, it is possible periodically, with a certain frequency, to raise and lower the plate W relative to the polishing pad (8, 8 'or 12, 12').

As shown in figures 1-3, the plate W during its processing on the machine is essentially in an upright position, and the polishers are located essentially horizontally. Obviously, with the machine according to the invention, it is possible, if necessary, to process the otherwise arranged W plates. It is also obvious that the polishers can be positioned, if necessary, and at a certain angle to the vertical. In this case, the movement of the plate relative to the polishing pad should occur in the direction perpendicular to the axis of the mandrels. However, in any case, the vertical arrangement of the plate W in the machine is more preferable, since the design of various support and drive units is simplified, the problems of draining from the processing zone of the plate used in polishing abrasive slurry, processing and washing solutions are more easily solved.

The mechanism of drive and rotation of the processing elements of the machine

The mechanism 17 for driving and turning the processing elements of the machine is shown in FIG. 2 (in cross section), in FIGS. 4A and 4B (front view on the outer side of the front wall 3) and in FIG. 5 (detailed cross-sectional view of the drive mechanism housing and mandrel shown in figure 2). As shown in figure 2, the housing 16 of the drive mechanism is connected to the team consisting of two shafts coaxial shaft 19, which passes through the front wall 3 and goes out. The internal shaft of the coaxial prefabricated shaft 19 drives the mandrel with the tool to process the plate, and the external shaft is used to control the rotation of the polishing wheels, which are moved when the case is rotated in one direction or another relative to the side surfaces of the plate processed on the machine (pressed or retracted from them). The prefabricated coaxial shaft 19 thus constructed is at the same time one of the elements of the polishing mechanism rotation mechanism 13 and the polishing mechanism rotation mechanism 15 relative to the plate surface being machined. In one embodiment, the mechanism 17 of the drive and the rotation of the processing elements of the machine has separate coaxial shafts 19, 19 'for each of the housings 16, 16' of the drive mechanism. The following description of the design and operation of the right housing 16 of the drive mechanism fully applies to the left housing 16 '.

The coaxial shaft 19 consists of an internal transmission shaft 28 and a hollow outer shaft 30 of the turning mechanism of the processing tools relative to the plate. The transmission shaft 28, through which the drive force necessary for their rotation is supplied to the mandrels (10, 10 ', 14, 14'), rotates in bearings 43a and 43b, which are installed at the ends of the outer hollow shaft 30. The outer hollow shaft 30 is mounted in the bearings 31a and 31b of the support bracket 32 of the machine tool machining tool drive mechanism and is designed (together with another same shaft) to control the rotation of the housing 16, 16 'and to press one of the pairs of polishers (8, 8' or 12, 12 ') to the sides of the polished semiconductor wafer W.

As shown in FIGS. 2 and 4A, the polishing mechanism rotation mechanism 13 consists of left and right drive motors 34, 34 ′, drive pulleys 36, 36 ′, drive belts 38, 38 ′ and pulleys 40, 40 ′ mounted on the rotary shafts. The drive pulleys 36, 36 'are mounted on the ends of the shafts of the engines 34, 34', respectively, located under the bearing bracket 32. The drive belts 38, 38 'are worn on the pulleys 36, 36' and 40, 40 ', which are mounted on the outgoing from the bracket 32 the ends of the transmission shafts 28, 28 ', respectively. As shown in FIGS. 2 and 5, the transmission shaft 28 passes through the front wall 3 and drives the gear gear 42, which is firmly fixed on its inner end. The transmission shaft 28 rotates in a bearing 43a, which is mounted in the housing 16 on its rotation axis 18 . It should be noted that the second transmission shaft 28 '(not shown in FIGS. 2 and 5) is made both according to the connection diagram and the construction of the supports, similar to the transmission shaft 28.

As shown in more detail in FIG. 5A, the transmission shaft 28 and the shaft 30 of the turning mechanism of the processing tools pass through the front wall 3 of the machine body. The gear 42 fixed on the inner end of the transmission shaft is engaged with the upper and lower gears 44 and 46, which are fixed (Figs. 1 and 2) at the ends of the upper and lower mandrels 10 and 14, respectively, and have axes in common with them. It should be noted that the lower mandrel 14 shown in FIGS. 1 and 2 is not shown in FIG. 5, but instead shows the mounting rod 12a provided in another embodiment, described in more detail below, with a brush 12b mounted on it. Through the gear 42 and the gears 44 and 46 of the mandrels, the drive motor rotates the upper and lower mandrels 10 and 14, which simultaneously rotate in the same direction.

Driven by rotation of the gears 44 and 46, the upper and lower mandrels 10 and 14, respectively, can be installed parallel to the side of the plate W in the housing 16 in conventional thrust bearings. In one embodiment, the attachment unit 48 for fixing the self-centering mandrels 10 and 14 allows automatically aligning the position of the processing polishers 8, 12 with respect to the side surface of the plate W, uniformly distributing the pressure with which the polishers are pressed against the plate over the entire surface of the plate. The construction of the self-centering mandrel attachment assembly 48 is described in more detail below in the section "The self-centering mandrel attachment assembly".

As shown in figa, the mechanism 17 of the drive and rotation of the machining elements of the machine has two drive motors 34, 34 ', designed to rotate the mandrels installed in the bodies 16, 16' with processing tools. For the operation of engines 34, 34 ', conventional power supplies and control and regulation elements with feedback sensors (not shown) can be used to ensure that the motors rotate in the opposite direction and rotate in the opposite direction, but with the same speeds of polishers (8, 8' or 12 , 12 '), located on opposite sides of the plate W. The direction of rotation of the polishing pad is preferably chosen so that the friction forces arising when the polishing pad touches the plate are directed downward and they pressed the plate against the drive rollers 6, 6 '. Engines 34, 34 'can be controlled manually or according to an appropriate program using a computer system associated with commonly used controllers (not shown). Obviously, if necessary, to drive all the machining tools of the machine, you can use only one engine with the appropriate transmission (belt or gear), which transfers the drive force from the engine to both cases with mandrels and polishers (or brushes).

The mechanism 15 for turning the polishing wheels relative to the plate is designed to control the rotation of the housings 16, 16 'and pressing either the upper polishers 8, 8' or the lower polishers 12, 12 '(brushes) against the opposite sides of the plate W. As shown in Fig. 4A, the outer shafts 30, 30 'are fixed levers 52, 52', inclined inward in the direction of the plane of symmetry of the plate W. The ends of the levers 52, 52 'are made in the form of gear segments 54, 54' of the same radius, the axes of which coincide with the axes of the outer shafts 30, 30 ', respectively. The gear segments 54, 54 'engage with each other, and therefore the levers 52, 52' and the shafts 30, 30 'connected to them rotate in the opposite direction strictly synchronously.

Under the bracket 32 (see FIGS. 2 and 4A) there is a linear-type vertical actuator 56 (for example, a conventional pneumatic cylinder or other similar device), the end of the rod of which is connected by a hinge 59 to the outer edge of the lever 52 (see FIGS. 4A and 4B) . When the stem 58 is extended, the lever 52 rotates counterclockwise (Fig. 4A), and the gear connected with it by a gear formed by the meshing teeth of the segments 54, 54 ', the lever 52' rotates the same angle clockwise. In such a mechanism for turning the levers 52, 52 ′ from the position shown in FIG. 4A to the position shown in FIG. 4B, the stem 58 must be fully extended from the cylinder. Obviously, when lowering and moving the rod 58 into the cylinder, the levers rotate in the opposite direction and move from the position shown in figv to another position not shown in the drawings. In other words, when lowering and moving the rod 58 into the cylinder, the lever 52 rotates clockwise, and the lever 52 '- counterclockwise.

As shown in FIGS. 2 and 5A, the outer shaft 30 of the turning mechanism of the processing tools is rigidly connected to the housing 16 of this mechanism, and therefore any rotation of the shaft 30 is accompanied by the same rotation of the housing. When the body 16 is rotated, the installed upper and lower mandrels 10 and 14 (or brushes 12a, 12b) respectively move in the corresponding direction and approach or move away from the plane of the plate W. The stroke of the rod 58 is selected and adjusted so that when the shafts 30, 30 'are rotated the upper and lower polishers 8 and 12, respectively, could be pressed against the polished plate W. As already noted above, the angle of rotation of the polishers depends, among other things, on their diameter. The operation of the linear actuator 56 can be controlled manually using appropriate controls from a power source (not shown) or, in another embodiment, according to an appropriate program using a computer system associated with controllers (not shown) commonly used for these purposes. The force generated by the linear actuator 56, and accordingly generated by the drive and rotation mechanism 17, the force and / or pressure of the polishers against the surface of the plate W can be adjusted using the appropriate feedback sensors or force regulators.

Obviously, to drive polishers (brushes) and rotate them relative to the plate to be machined, one can use other schemes for transmitting the drive force from the drive motors to the housings 16, 16 'of the drive mechanism and the rotation of the machining elements of the machine. It is also obvious that the housing 16, 16 ', and the mechanism 17 of the drive and rotation of the processing elements of the machine may have a design different from that described above. So, for example, drive motors can be installed directly on the housings 16, 16 'and not be used to drive the polishers 8, 8' and 12, 12 'of the coaxial shafts described above. In addition, the movement of the housings 16, 16 'of the drive mechanism and the rotation of the polishing pad relative to the plate W can be achieved not by rotation, but by linear movement, for example, by connecting the housings to a linear telescopic actuator located opposite one of the two opposite sides of the plate W processed on the machine .

Support and drive unit. allowing you to change the height position of the plate standing on the edge

One of the elements of the support-drive unit 23, which allows you to change the height position of the plate standing on the edge, is a prefabricated coaxial shaft 61, which is part of the support-roller mechanism 21 to drive the plate into rotation, and the mechanism 27 changes in height of the position of the plate (see Fig. 1 and 2). The drive coils shaft 6, 6 'is driven through the coaxial assembly shaft, which rotates the plate standing on them, and the rotary levers 20, 20' are rotated, with the help of which the position of the plate W can be changed in height with respect to the polishers 8, 8 'and 12, 12 '. The support-drive unit 23 has separate prefabricated coaxial shafts 61, 61 'connected to the front and rear pivoting levers 20, 20' and the support-drive rollers mounted on them. The following description of the construction and principle of operation of the assembled coaxial shaft 61 and the front swing arm 20 with the support-drive roller fully applies to the design and operation principle of the pre-assembled coaxial shaft 61 'and the rear swing arm 20' with the support-drive roller.

As shown in FIG. 1, the assembled coaxial shaft 61 consists of an internal transmission shaft 60 and a rotary support roller of the hollow outer shaft 62. The transmission shaft 60, which is one of the elements of the support-roller mechanism 21 of the plate drive, is rotated through a belt 64 support-drive roller 6. The transmission shaft 60 rotates in bearings 63a and 63b, which are installed inside the hollow shaft 62 of the rotation mechanism of the support-drive roller at each of its ends. The shaft 62 of the rotation mechanism of the support-drive roller is installed in the bearings of the housing, in particular in the bearings 65a and 65b installed in the right wall 4 of the housing. The shaft 62 is designed for the controlled rotation of the lever 20 and the movement of the support-drive roller from the upper / inner position 6a to the lower / outer position 6b and vice versa (see figure 2).

As shown in figures 1 and 2, the supporting-roller mechanism 21 of the drive plate has left and right drive motors 66, 66 ', respectively, which are installed in the lower part of the right wall 4. On the output shafts of the engines 66, 66' are installed drive pulleys 68, 68 ', respectively, on which drive belts 70, 70' are worn. Driven belt pulleys 72, 72 ', on which belts 70, 70' are also worn, are installed at the ends of the transmission shafts 60, 60 ', which exit from the housing through holes made in its right wall 4.

As shown in figure 1, at the inner end of the transmission shaft 60, which passes through the right wall 4, a pulley 74 located inside the housing 76 of the rotary lever is fixed, the axis of which coincides with the axis of rotation of the lever 22. The inner (leading) pulley 74 is connected to the driven belt 64 located inside the housing 76 of the pivot arm with the driven pulley 78. The driven pulley 78 of the belt drive is fixed to the end of the shaft 80, which rotates in bearings located at the outer end of the housing 76 of the pivot arm. The end of the shaft 80 leaves the housing 76 of the pivot arm in the direction of the plane of the plate W, and a support-driving roller 6, adjacent to the housing, is fixed to it, on which the plate rests with its edge.

In one embodiment, the support-drive mechanism 21 of the plate drive has (see FIG. 2) two separate drive motors 66, 66 ', one for each swing arm 20, 20' with a support-drive roller. Engines 66, 66 'can be operated from conventional power supplies using appropriate controls and feedback sensors (not shown) that rotate the drive rollers 6, 6' in the same direction and at substantially the same speed . Engines 66, 66 'can be controlled manually or according to an appropriate program using a computer system associated with commonly used controllers (not shown). In another embodiment of the invention, a single drive engine is used in the plate drive mechanism with a corresponding transmission (belt or gear) transmitting drive force to both support-drive rollers mounted on the swing arms.

Shown in FIGS. 1-3, a plate moving mechanism 27, which in a controlled manner rotates the levers with support-driving rollers 6, 6 ', has left and right shafts 62, 62', respectively, each of which has an end that extends from the housing to the outside at some distance from the right wall 4 (the left shaft 62 'in Fig.1-3 is not shown). The front and rear gears 82, 82 'lying on the same plane are mounted on the outwardly projecting ends of the shafts 62, 62', the diameter of the circumference of which is preferably equal to the distance between the axes 22, 22 'of the rotation of the levers and which therefore engage at a point, which divides this distance into approximately half. The shafts 62, 62 'connected in this way to the gears 82, 82' thus connected are rotated strictly synchronously at the same speed, but in opposite directions. Shafts 62, 62 'of the rotation mechanism are rigidly connected to the housing 76, 76' of the levers, and therefore any rotation of the shafts is accompanied by a rotation of the levers 20, 20 'and the supporting drive rollers 6, 6' mounted on them.

As the linear actuator 84 shown in FIG. 2, a linear type stepper motor or other similar mechanism mounted substantially horizontally on the outside of the lower part of the right wall 4 can be used. At the end of the output rod 86 of this actuator there is a hinge 87 through which it connected to the end of the gear lever 88. The lever 88 is fixed on the side of one of the gears 82, 82 '. When the rod 86 is extended, the lever 88, the gear 82 (or 82 ') and the shaft 62 of the mechanism of rotation of the levers of the support-drive rollers are rotated counterclockwise to the corresponding angle (in the drawing plane of FIG. 2), and the other gear 82 (or 82 ') and the other shaft 62' rotate the same angle clockwise. When the gears and shafts are rotated in this direction, the support-drive rollers 6, 6 'are extended and lowered down to position 6b, 6b'. With the reverse stroke of the rod 86 into the cylinder, the gears, shafts and levers rotate in the other direction, and the support-drive rollers 6, 6 'are shifted and rise upward to the position 6a, 6a'.

The stroke of the rod 86 is selected and adjusted so that the angle of rotation of the shafts 62, 62 'is sufficient to move the plate W at a certain distance indicated by arrow C (see FIG. 2) in the vertical direction. The distance over which the plate should move in the vertical direction is determined by the height position of the sections of the plate processed by the polishers 8, 8 'or 12, 12' fed to them, which is discussed in more detail below). The diameter of the support drive rollers 6, 6 'and the length of the pivoting levers 20, 20' are selected in accordance with a possible variation in the diameters of the plates processed on the machine, i.e. taking into account the possibility of processing plates with a diameter of 200 to 300 mm on a machine. If necessary, the range of diameters of the plates processed on the machine can be expanded by changing the geometry of the support-drive mechanism 21 of the drive plate and replacing the housings 76, 76 'of the swing arms, the drive belts 64, 64' of the support-drive rollers and the support-drive rollers themselves 6, 6 ' taking into account the possibility of their installation in place. For the same purpose, the length of the lever 88 can be changed (by changing the levers themselves or using a lever with mechanically adjustable length), on which, with the same stroke of the linear actuator 84, the angle of rotation of the gears and, accordingly, the height position of the support-drive rollers depend. The operation of the linear actuator 84 can be controlled manually using conventional controls and power sources (not shown) or, in another embodiment, according to an appropriate program using a computer system associated with controllers (not shown) commonly used for these purposes.

It is obvious that for the drive of the support-drive rollers 6, 6 'and their rotation together with the pivoting levers 20, 20', one can also use others in the design of the device for transmitting drive forces from drive motors and actuators. It is also obvious that the whole design of the support-drive unit, designed to drive the plate standing on the edge and change its height position, can to one degree or another differ from the one considered above. This assembly, in particular, can be made in the form of a vertically movable supporting platform with rotating support-drive rollers and drive motors fixedly mounted on it.

Mounting unit for self-centering mandrels

The upper mandrel 10 shown in FIG. 5A with the polishing pad 8 attached thereto is mounted in the attachment unit 48 of the self-centering mandrels. The attachment unit 48 of the self-centering mandrels has a rigid, cylindrical setting roller 90, which is rigidly connected to the housing 16 of the drive mechanism and turning the machining elements of the machine and serves as a cantilever support of the mandrel 10. The setting roller 90 runs parallel to the plane of the plate W and ends at a point located beyond the plane 91 passing through the center of the mandrel. A cogwheel 44 of the upper mandrel drive is put on the mounting roller 90, in the central hole of which there is a bearing 92, which enables independent rotation of the mandrel on the stationary mounting roller (roller 90 is attached to the housing 16). The gear wheel 44 is connected to the inner sleeve 94 of the mandrel and transmits torque to it from the drive motor. The inner mandrel sleeve 94, within which the set roller 90 passes with a clearance, has a bearing 96 located adjacent to the center plane 91 of the mandrel and can rotate the gear 44 relative to the set roller. Outside and inside the hollow hub 98 of the gear 44, corresponding seals 97a and 97b are mounted. These seals 97a and 97b prevent various fluids and / or polishing slurries from entering the housing 16 of the drive mechanism and turning the machining elements of the machine.

On the inner sleeve 94 of the mandrel with a clearance, a mandrel shell 100 is made in the form of a cylindrical sleeve and having a length of at least equal to the length of the polishing pad 8. The mandrel shell 100 is supported by a hinge 102 located at a point lying next to the plane 91 passing through the center of the mandrel . As a hinge 102, which serves as the fulcrum of the mandrel shell, any device located circumferentially on the outer surface of the inner sleeve 94 can be used. In one embodiment, an elastic O-ring mounted in a groove 104 provided on the outer surface of the mandrel inner sleeve 94. The hinge 102 forms a fulcrum located in the central plane of the mandrel shell, with respect to which the mandrel shell and its longitudinal axis can tilt to a small angle to the longitudinal axis of the inner sleeve 94. The gap between the mandrel shell 100 and its inner sleeve 94 allows the shell to tilt to the inner sleeve within given angle. A polishing pad 8 is fixed on the outer surface of the mandrel shell 100. In one embodiment, the polishing pad 8 is made in the form of a tape wound in a spiral around the mandrel shell 100 and is located symmetrically with respect to the central plane 91 of the mandrel.

The torque from the inner sleeve 94 of the mandrel is transmitted to the sheath 100 by the connecting element 106. The connecting element 106 not only transfers torque from the inner sleeve to the sheath of the mandrel, but also fixes the sheath relative to the inner sleeve in the axial direction, while allowing tilt within certain limits of the sheath mandrel relative to its inner sleeve. In one embodiment, the torque-transmitting connecting element 106 is made in the form of a spring-loaded key installed in the holes of the inner sleeve 94 of the mandrel and its sheath 100 located on the same axis. In another embodiment of the invention, this connecting element 106 is made in the form of a leading finger.

When turning the housing 16 of the drive mechanism and turning the machining elements of the machine and pressing the polishing pad 8 to one of the sides of the plate W (not shown in FIG. 5A), the mandrel shell 100, under the influence of pressure arising on the contact line of the polishing pad with the side surface of the plate, is tilted by a certain the angle at which the pressure is equalized along the entire length of the contact line, and the axis of the polisher becomes parallel to the surface of the plate. At the same time, under the influence of the torque transmitted to the mandrel shell 100 by the connecting element 106, the polishing pad 8a mounted on the mandrel shell rotates, which, pressing against the surface of the plate along its entire length, uniformly polishes it.

FIG. 5B shows in more detail the construction of the central portion adjacent to the hinge 102 (the pivot point of the mandrel shell) shown in FIG. 5A of the attachment unit 48 of the self-centering mandrels. As already noted above, the hinge 102, which serves as a support for the shell of the self-centering mandrel, is made in the form of a ring with a circular cross section. This ring has a relatively high hardness of 70 to 80 units on the Shore A hardness scale. The ring is installed in a groove 104, made on the outer surface of the inner sleeve 94 of the mandrel, which can be made of plastic. It is obvious that in FIG. 5B, for simplification, the mounting roller 90 of the attachment point of the self-centering mandrels is not shown. The groove 104 is located in a plane passing through the center of the mandrel sheath 100, which can be made of stainless steel. The connecting element 106, made in the form of a leading finger, is located in the corresponding holes of the mandrel shell 100 and its inner sleeve 94. As shown in FIG. rotate relative to the inner sleeve at a fulcrum made in the form of a ring with a circular cross section. In one embodiment, the ends of the mandrel sheath 100 can move in one direction or another by 0.060 inches. Mounted on the shell of the mandrel polisher 8 is made in the form of a tape wound in a spiral around the shell 100 of the mandrel with a small gap between the turns. With such a winding of the polishing tape on the outer surface of the polishing pad there are almost no gaps that adversely affect the quality of polishing. In one embodiment, a polyurethane foam tape is used to make a polishing pad.

Fluid injection

For injection of process fluids used in the processing of semiconductor wafers on the machine, nozzles 110 are shown in FIG. 1 and are mounted on the walls of the housing 2. The jets of sprayed liquid coming out of the nozzles 110 fall on opposite sides of the plate W processed on the machine or on the outer surface of the polishers 8, 8 'and 12, 12'. As the liquids sprayed by the nozzles 110, which are supplied to them from the collectors 112, polishing suspensions, chemical treatment solutions, emulsions, cleaning liquids, washing liquids, cooling solutions, deionized water and mixtures thereof are used. If necessary, these fluids can be injected simultaneously through different nozzles or in a certain sequence through the same or different nozzles. In the lower inclined wall 5 there is a nozzle 114 through which fluids injected into it are drained from the housing. Additional nozzles can be installed inside the casing, using them to remove after one or several operations on processing the plate, residual slurries or solutions from the elements processing the plate, in particular from polishers and brushes, as well as from other parts, such as mandrels, drive mechanism housings, rollers and levers of rotation of rollers. For the supply of process fluids to the manifolds 112, a conventional system consisting of various pipelines, including those connected to the manifolds, valves, pumps, tanks, filters, and sedimentation tanks (not shown), can be used. It is possible to control the operation of such a system by changing the sequence of injection of fluids and their flow rate manually or alternatively using a computer with the program for controlling valves, pumps and actuators embedded in it.

Devices for cleaning (sharpening) polishers

If necessary, the machine according to the invention can be equipped with sliding devices 116, shown in FIGS. 1 and 3, for cleaning (sharpening) polishers pivotally mounted on the inner walls of the housing 2 next to each polisher. The main element of such a device 116 is a horizontal knife 118, the length of which is essentially equal to the length of the adjacent polishing pad. Each knife 118 is pivotally mounted to a support point 120 located above it, with respect to which it can be rotated in the direction of the adjacent polisher by the actuator 122. The actuator 122 can be made in the form of a conventional electromagnet with a sliding rod 124 connected to the outer side of the knife 118, which rotates the knife in the direction polishing pad at an angle D. To clean the polishing pad, simultaneously turn the housing 16, 16 'at an angle E or E' and press the corresponding polishing pad (8 or 10) to the one extended into the working the position of the knife 116. The angles D and E and the dimensions of the polishing device for polishing are selected so that during the processing of grinding (sharpening) of any polisher 8 and 10, it does not touch the side surface of the wafer W. In other words, so that during of the polishing pad (sharpening) the plate processed on the machine could remain in place, the processed polisher should occupy a "neutral" position. At the end of the operation of cleaning (sharpening) of the polishers, the knives 118 are returned by the actuators 122 by turning in the corresponding direction to the original (inoperative) position.

Figure 10 in axonometric projection shows the node 200 processing semiconductor wafers, made in accordance with one of the options. In this assembly 200, there is a housing 2, within which the plate processing device 210 itself is located. An aperture 204 is made in the upper part of the housing 2, through which, if necessary, the semiconductor wafer lifted up can be transferred to another machine assembly to perform another technological operation. In principle, the housing of the device 210 for processing plates can be made completely closed without any hole in its upper wall. The housing 2 also has a door 202 that provides access to the inside of the housing for servicing the assemblies and parts of the device for processing plates located therein, as well as for replacing brushes or polishers and corresponding mandrels.

During operation, the door 202 is kept closed so that various kinds of particles and dust generated during processing of the plates do not get out of the housing. In a preferred embodiment, a narrow slot 206 is made in the door 202, through which a machined plate W can be inserted inside the body of the plate processing unit 200. Through the same slot 206, the machined plate can be removed from the housing. In another embodiment (not shown in the drawings), the door 202 is proposed to be made with sliding panels that allow the slot 206 to be closed during processing of the plate. As already mentioned above, the processing of the plates in the device 200 for their processing is carried out by polishers 8 mounted on the mandrels 10 and 14. In this case, both groups of mandrels 10 and 14 are equipped with polishers 8, which allows final processing or polishing of the plate (depending on requirements) using lower or upper mandrels. As already noted above, during processing the plate rises and falls down and is ultimately processed with a certain offset from the center. During the processing of the plate, jets of the corresponding liquid are directed from the nozzles 110 onto the polishers 108. Nozzles 110 can be connected to a source of an appropriate liquid, for example deionized water, chemical treatment solutions or suspension, the choice of which depends on the nature of the operation. In the device processing device 110 proposed in this embodiment, there is also a plate alignment device 26 for pressing the upper roller 25 to press against the upper edge of the plate. To move the plate in the vertical direction, determined by the selected processing mode, and remove the corresponding amount of material from different in radial a linear actuator 84 (which is preferably in the form of a linear stepper motor) is intended for the direction of the surface areas of the plate. In more detail, the design of the linear actuator shown in figa. The drawing also shows the mechanism 21 of the drive of all supporting-drive rollers 6.

11A, the design of the plate processing device 210 is shown in more detail. The main elements of the plate processing device 210 are blocks 212 of paired plate processing elements. Each such block 212 consists of two plate-processing elements located on one of the sides of the plate W. In this case, such plate-processing elements are a polisher located on the mandrel 10 and a brush 12b, which are connected to the drive elements located in the housing 16. On the opposite side of the plate is another block 212 with a mandrel 10 with a polishing pad located at the bottom and a brush 12b located at the top.

Based on this drawing, we can conclude that structurally, the device 210 processing plates can be performed in different ways. So, for example, the block 212 of the plate-processing elements may contain the mandrels with polishing pad 8 shown in FIG. 10. In the embodiment shown in FIGS. 11A and 11B, the mandrel 10 is located in the lower part of the block 212 and the brush 12b in the upper part. When using the brush 12b, the mandrel must be replaced with a conventional brush fixing rod connected to the corresponding drive parts located in the housing 16. In one embodiment, brushes made of polyvinyl alcohol-based material are used as brushes. Such material used for the manufacture of brushes should be soft enough to avoid damage to the surface of the plate, which is extremely sensitive to damage, and at the same time should provide good mechanical contact between the brush and the surface of the plate and remove sediment, chemicals and various particles from it. The use of polyvinyl alcohol-based material for the manufacture of brushes in various cleaning systems is described in US Pat. No. 5,875,507, which is incorporated herein by reference. In one embodiment, it is proposed to use the rod 12a, on which the brush is mounted, for supplying various liquids through it to the cleaning zone.

As noted above, in the linear actuator 84 there is a rod 86, which is connected to the actuating lever 88. The linear actuator 84, its rod 86 and the actuating lever 88 are designed to rotate the levers 20 with supporting-drive rollers and move the plate W in the vertical direction , which rises up or falls down, depending on the location (in the center or offset from the center) of the section of the plate to be processed (finishing, polishing or stripping). The rotation of the supporting-drive rollers 6 is carried out by motors 66 connected to them located in the pivoting levers 20 and shown in FIG.

As shown in FIG. 11A, the blocks 212 of the plate processing elements of the machine are rotated and rotated relative to the plate by the drive and rotation mechanism 17 of the processing elements of the machine. In the shown in this drawing, the mechanism 17 of the drive and rotation of the plate-processing elements of the machine has a support bracket 32. The bracket 32 serves as a support for the two outer shafts 30 of the rotation mechanism of the plate-processing elements. Each of these shafts 30 passes through an arm 32 and is connected to a block 212 of the plate processing elements of the machine tool. A transmission shaft 28 extends inside each shaft 30. The rotation of the plate-processing elements is carried out from the drive motors 34 by drive belts 38 mounted on the drive and driven belt pulleys 36 and 40, respectively. The rotating driven belt pulley 40 drives the transmission shaft 28, which is connected to the corresponding plate processing element of the machine through a gear located inside the lever 16. In the presence of such a transmission, the inner transmission shaft 28 drives a pair of corresponding plate processing elements, in this case, mandrels 10 with a polisher and brushes 12b.

The transmission connecting the internal transmission shaft 28 with the mandrel and the brush can be made in the form of several gears located in the housing 16. The rotation of these gears is accompanied by the rotation of the brush 12b and the mandrel 10 with a polishing pad. On figa and 11B shows the blocks 212 processing the plate elements, in which the mandrel 10 with polishing pad pressed against both sides of the plate W, and the brushes 12b are at some distance from the plate. Obviously, by turning the housing 16 in the other direction, brushes 12b can be brought to both sides of the plate. When brushing the sides of the plate with brushes, the mandrels 10 will not touch the plate and will be at a certain distance from it. The rotation mechanism of the bodies 16 is made, as described above in more detail, so that the plates can touch only either the polishing pad of the mandrels 10 or the brush 12b.

Semiconductor wafer processing methods

One of the methods for treating semiconductor wafers of the present invention is an off-center polishing of wafers, which, as compared to the conventional central polishing method, provides generally more uniform radial removal of material from the side surface of the polished wafer. Prior to polishing, the sides of the plate can be leveled using the usual plane alignment method, for example, polishing by the chemical-mechanical method (CMP). In one embodiment, the off-center polishing method according to the invention allows to obtain a polished surface, which in its geometry practically does not differ from the original flat surface. Some examples of central (in diameter) and off-center polishing of the plates are characterized by the data shown in Fig.6-9.

The graphs shown in Fig.6, built on the basis of data obtained as a result of four experiments on polishing a plate, the currently known method of central polishing, shows the amount of material taken at different radially different points on the surface of the plate. The vertical axis in these graphs shows the amount of material removed from the plate, measured in angstroms (10 ^-10 m), and the horizontal axis shows the radius at which the measurement point is located (total measurements were made at 121 points that were uniformly distributed over the diameter of the plate , except for points located within 5 mm from the edge of the plate). The graphs shown in FIG. 6 indicate that with central polishing, when the line of contact of the polisher with the surface of the plate passes through the center of the plate, substantially more material is removed from the central part of the plate than from its sections located at the outer edge.

With circular polishing, the rotation speed of the polishing pad usually exceeds the speed of the polished plate. Polishers are pressed against the sides of the plate, usually with equal force, and rotate in opposite directions with a linear speed directed along the line of contact between the polisher and the plate down or toward the plate as the distance between the outer surface of the polisher and the surface of the plate decreases in the direction of rotation. The absolute amount of material removed during polishing from different points on the surface of the plate depends on a number of factors, including the duration of polishing, the pressure in the contact zone of the polisher with the plate, the material of the polisher, its rotation speed, the rotation speed of the plate and the composition of the polishing slurry. When polishing the wafer with the usual central polishing method, the amount of material removed from the central portion of the wafer is an order of magnitude greater than the amount of material removed from the periphery of the wafer, as indicated by the peaks in the graphs shown in Fig. 6 between points 50 and 70. With this nature of material removal from the surface of the centrally polished plate, its sides will have a profile opposite to the curve shown in Fig.6. In other words, as a result of the removal of a relatively large amount of material from the central part of the plate, its side surfaces after polishing acquire a concave or "plate-like" shape. Thus, for a given mode (parameters) of central polishing, the process of removing material from the side surface of the plate along the length of the line of contact between the polisher and the plate is clearly uneven.

The results of the experiments shown in figa and 7B, indicate that with central polishing the removal of material at points equidistant in the radial direction from the center of the plate is almost uniform with random moderate deviations from the average value. On figa shows 49 points at which during four different experiments measured the amount of material removed from the plate with central polishing. On figb in the form of graphs shows the data obtained during four experiments on the amount of material removed from the plate at different points on its surface (measured in angstroms of the change in the thickness of the plate from its average value). Fig. 7A shows: a point (1) located in the center of the plate, points (2-9) located with equal pitch on a circle whose radius is equal to one third of the radius of the plate, points (10-25) located with equal pitch on a circle whose radius is equal to two-thirds of the radius of the plate, and points (26-49) located at equal intervals on a circle 5 mm apart from the outer edge of the plate. The ordinate scale selected for constructing the graphs shown in FIG. 7B allows you to show the amount of material removed from the polished plates at points 2-49, but the graphs do not show the amount of material removed in the center of the plates (point 1), which as indicated above, an order of magnitude greater than the amount of material removed from most of the surface of the plates. As shown in figb, the amount of material removed from the surface of the plates as a result of polishing can be divided into three distinct zones corresponding to the three concentric rings at which the points at which measurements were made. Deviations within each of these zones from the mean are random and indicate the absence of any pattern in the change in the measurement results in the angular direction.

In the case of off-center polishing proposed in the invention, the absolute amount of material removed from the surface of the plate at each of its points depends, as in central polishing, on many factors listed above when considering the data shown in FIGS. 6, 7A and 7B. However, when off-center polishing is carried out according to the invention, the amount of material removed from the surface of the plate also depends on the movement of the plate relative to the line of contact with the polisher. Proposed in the invention, the machine allows you to control the movement of the plate relative to used for processing elements of the machine, in particular polishers. By controlling the movement of the plate relative to the polishing pad, it is possible to control the process of removing material from various parts of the surface of the plate and to produce plates with a flat or other necessary shape surface.

The mode of controlled movement of the plate can be chosen so that when moving the plate up or down relative to the polishing pad, its side surfaces acquire the necessary shape. To process the entire surface of the plate, the line of contact between the polisher and the plate at some point in time during polishing should pass through the center of the plate, i.e. have in the radial direction a zero offset relative to the center. Obviously, the plate motion mode can be set so that the polishing of the plate begins in the center of the plate at the moment of passing through the center of the line of contact of the plate with the polisher and continues as the polisher approaches the edge of the plate or, conversely, starts from the edge of the plate and continues in the direction its center.

It is also obvious that the necessary amount of material can be removed from the surface of the plate by adjusting separately or jointly other parameters of the polishing mode, for example, the rotation speed of the polisher, the rotation speed of the plate, and the pressure along the line of contact between the polisher and the plate. You can control the movement of the plate relative to the polishing pad, as well as change other parameters of the polishing mode using the program for controlling various means and control devices designed to change the polishing mode, which is embedded in the computer. Using such means and control devices, it is possible, for example, to individually or simultaneously control the operation of a linear actuator 84 for raising or lowering the plate, the operation of drive motors 66, 66 ', which drive the drive rollers, and the operation of the linear actuator 56 designed to rotate the housings 16, 16 'of the drive mechanism and rotate the plate-processing elements of the machine, and the operation of the engines 34, 34', which these elements are driven into rotation.

The off-center polishing method according to the invention makes it possible to compensate for the non-uniform radial removal rate of the material from the surface of the plate by moving the plate relative to the polishing pad and making semiconductor plates with a polished flat surface or a surface of another predetermined shape. Adjusting the speed of movement of the plate relative to the polishing pad (or other parameters of the polishing mode, which have the same effect on the polishing process as the speed of movement of the plate) allows you to remove material from different radius sections of the surface of the plate with the speed necessary to give the surface of the plate the desired shape. If necessary, the parameters of the polishing mode can be adjusted so that the removal rate of the material is the same at all points of the polished surface of the plate. Such adjustment of the polishing mode may be appropriate when polishing plates with surfaces aligned on a plane. In another embodiment, by adjusting the parameters of the polishing mode, it is possible to ensure that the material removal rate is different at different parts of the wafer surface. Such adjustment of the polishing mode may be appropriate when polishing plates with non-planar lateral surfaces, for example concave or convex, and the manufacture of plates with essentially aligned side surfaces.

от радиуса обработки для пластин диаметром 200 мм, отполированных центральным полированием по обычной технологии. Пластины полировали с использованием полировальной суспензии на описанном выше станке при скорости вращения полировальников, равной 200 об/мин. Скорость вращения пластины изменяли с 30 об/мин (фиг.8А) до 50 об/мин (фиг.8Б). Приведенные на фиг.8А и 8Б графики свидетельствуют о существенно нелинейной зависимости скорости удаления материала от радиуса обработки с резким увеличением не показанной на графиках скорости удаления материала в центре пластин (в зоне с радиусом около 5 мм).The rate of removal of material from the plate in a given polishing mode can be determined on the basis of experimental data. So, in particular, on figa and 8B shows the dependence of the rate of removal of material from the surface of the plate (expressed in angstroms per minute or

from the machining radius for plates with a diameter of 200 mm polished by central polishing using conventional technology. The plates were polished using a polishing slurry on the machine described above at a polishing pad rotation speed of 200 rpm. The rotation speed of the plate was changed from 30 rpm (FIG. 8A) to 50 rpm (FIG. 8B). The graphs shown in FIGS. 8A and 8B indicate a substantially non-linear dependence of the material removal rate on the processing radius with a sharp increase in the material removal rate not shown in the graphs in the center of the plates (in an area with a radius of about 5 mm).

On figa and 9B shows the dependence of the rate of removal of material from the surface of the plate (A / m) on the radius of processing for plates with a diameter of 200 mm, polished proposed in the invention method of off-center polishing. The plates were polished in the same mode as with central polishing (Figs. 8A and 8B), except that during polishing the plates moved at a constant speed relative to the polishing pad (except for the area directly adjacent to the center of the plate and the outer edge of the plate ) In addition, in both experiments, the polishers rotated at a speed of 600 rpm, and the plates rotated at a speed of 30 rpm. During polishing, the plates were moved relative to polishers at a speed of 10 inches per minute (inch / min) (Fig. 9A) and 40 inches / min (Fig. 9B).

(фиг.9Б), а при более низкой скорости (10 дюймов/мин) - со скоростью около

(фиг.9А). Иными словами, увеличение скорости перемещения пластины относительно полировальников сопровождается некоторым снижением скорости удаления материала с поверхности пластины. Учитывая, однако, что четырехкратное увеличение скорости перемещения пластины относительно полировальников снижает скорость удаления материала с поверхности пластины всего на 25%, можно сделать вывод о том, что скорость перемещения пластины относительно полировальников не является доминирующим фактором, от которого зависит скорость удаления материала с пластины во время ее полировки. Основным фактором, от которого зависит суммарное количество материала, удаляемого в процессе полировки с любого в радиальном направлении участка поверхности пластины, является общая продолжительность процесса полировки или время обработки пластины.The rate of material removal from the surface of the plate during off-center polishing (the curves shown in FIGS. 9A and 9B) changes in the radial direction much less than during central polishing in the usual way (the curves shown in FIGS. 8A and 8B). The presence of a slight slope of the curves shown in figa and 9B, indicates a slight increase with off-center polishing the rate of removal of material from the surface of the plate as it approaches the edge of the plate. In addition, at a higher speed of movement of the plate relative to the polishing pad (40 inches / min), removal of material from the surface of the plate occurs on average at a speed of about

(figb), and at a lower speed (10 inches / min) - with a speed of about

(figa). In other words, an increase in the speed of movement of the plate relative to the polishing pad is accompanied by some decrease in the rate of removal of material from the surface of the plate. Considering, however, that a fourfold increase in the speed of movement of the plate relative to polishing pad reduces the rate of removal of material from the surface of the plate by only 25%, we can conclude that the speed of movement of the plate relative to polishing pad is not the dominant factor on which the rate of removal of material from the plate during polishing time. The main factor that determines the total amount of material removed during polishing from any radially portion of the plate surface is the total duration of the polishing process or the processing time of the plate.

In one embodiment, a polishing pad is used, which along the entire length overlaps the chord of the plate for all possible positions of the polishing pad during movement of the processed plate relative to it, as a result of which the contact of the polishing pad with the plate is maintained throughout the entire processing time. Moreover, for any specific position of the polisher relative to the movable plate, the part of the surface of the plate external to the contact line will be polished, i.e. located farther from the center than the contact line, part of the surface of the plate. On the other hand, with the same position of the movable plate relative to the polisher, the interior or located closer to the center than the contact line, part of the surface of the plate will not be polished. As shown in Fig.6-8, the removal rate of the material from the surface of the plate does not have to be the same along the entire length of the contact line.

The processing of the plates by off-center polishing can be carried out in a certain mode or according to a certain program of translational movement of the plate in height, in accordance with which, during polishing, the position of the plate changes in time with respect to the polishing pad. In one embodiment, for off-center polishing of the plates, a program of translational movement of the plate is used, in accordance with which the same amount of material is removed from each in the radial direction of the plate section and the thickness of the plate in the radial direction is reduced by the same amount. In another embodiment, for off-center polishing of the plate, another program of translational movement of the plate is used, according to which different amounts of material are removed from different in the radial directions of the surface of the plate and the thickness of the plate in the radial direction is reduced by a different amount.

In one embodiment of the method of non-central polishing of the plates according to the invention, each side of a vertically arranged plate is treated with a cylindrical element processing the plate in a region of substantially linear contact. During rotation of the plate, at least one of the parameters of the processing mode is controlled so that when moving the contact zone from the first position to the second, removal of material from the surface of the plate occurs at different speeds. In one embodiment, the change in the rate of material removal during the translational movement of the plate occurs so that the plate after processing has essentially the same thickness. The adjustable parameter of the plate processing mode can be the pressure with which the processing element is pressed against the plate, the rotation speed of the plate, the rotation speed of the processing elements of the plate and the speed at which the contact zones located on opposite sides of the plate move from the first position to the second.

In one embodiment, in the first position, the contact zone passes through the center of the plate, and in the second position, it passes at a certain distance from the center of the plate, for example, near its edge. The movement of the contact zones from the first position to the second occurs when lowering or raising the plate. In one embodiment, the speed of the translational movement of the plate in the vertical direction and the movement of the contact zones from the first position to the second is controlled so that the plate after processing has the same thickness at all points. Knowing, based on the results of the experiments, the actual change in the radial direction of the material removal speed from the surface of the plate at a certain polishing mode, it is always possible to develop a program for translational movement of the plate, in which the processed plate would have the same thickness at any point. Alternatively, in the manufacture of plates of equal thickness, it is possible to change the height position of the polished plate (raising it up or lowering it down) and at a constant speed, while controlling one or more other parameters of the polishing mode, for example, the pressure of the polishing pad against the plate, the rotation speed of the plate, or the speed rotation of polishers. Thus, the proposed method of off-center polishing of the invention can be used for the manufacture of plates with a slightly concave and convex side surface of the plates with an almost absolutely flat side surface.

The present invention also provides a method for processing a semiconductor wafer, comprising performing two processing operations of a vertically arranged wafer in one housing. For such processing of the plate, two blocks of plate processing elements are used, for example, the blocks 212 shown in FIG. 11A located inside one housing at opposite sides of the plate. Each such block consists of the first and second elements for processing the plate. As such elements, for example, cylindrical polishers and cylindrical brushes can be used. The plate located vertically between the blocks of the processing elements is driven into rotation by the plate drive mechanism available on the machine.

To perform the first plate processing operation, the blocks of the processing elements thereof are oriented so that their first plate processing elements touch the opposite sides of the vertically rotating plate. In one embodiment, to perform the first operation, the blocks of the plate-processing elements are rotated in the first direction until the first plate-processing elements are in contact with opposite sides of the rotating plate. After the first operation, the blocks of the plate-processing elements are oriented in such a way that their second plate-processing elements touch the opposite sides of the vertically rotating plate. In one embodiment, to perform the second operation, the blocks of the plate-processing elements are rotated in a different direction opposite to the first direction until the second plate-processing elements contact the opposite side surfaces of the rotating plate.

The blocks processing the plate elements can be performed in such a way that, using them, it is possible to perform any necessary combination of operations for processing the plate. In one embodiment, when performing the first such operation, the plate is cleaned, and in this case, cylindrical brushes are used as the first elements processing the plate. In this embodiment, during the second operation, the plate is polished, and therefore, cylindrical polishers are used as the second platinum processing elements. If necessary, these operations can be performed in reverse order, i.e. first polish the side surfaces of the plate and then clean them.

In another embodiment, when performing the first and second processing operations of the plate, cleaning is performed. In this case, for example, when performing the first operation of cleaning the plate, relatively large particles are removed from it, and when performing the second operation, relatively small particles are removed. In another embodiment, when performing the first and second operations, the plate is polished. At the same time, for example, in the first polishing operation, the required amount of material is removed from the side surfaces of the plate, and in the second they are final refined.

If necessary, when the plate is off-center, the method of the invention proposes to move the plate in the vertical direction, i.e. raise it or lower it, it is possible in the process of processing the first or second processing elements being in contact with it. To move the plate in the vertical direction, you can use an appropriately designed drive mechanism and rotate it driven into rotation by the outer edge of the plate. In one embodiment, when both operations of the processing of the plate consist in polishing it, the plate progressively moves in the vertical direction during the execution of at least one polishing operation.

The semiconductor wafer processed on the machine according to the invention and / or one of the methods according to the invention can then be subjected to further processing in corresponding well-known technological operations. Such operations include, in particular, deposition or deposition of oxide materials and electrically conductive materials (e.g. aluminum, copper, mixtures of aluminum and copper, etc.) onto the surface of the plate. When processing semiconductor wafers in a manner known as processing the "back side" of the wafer, various etching operations of the wafer surface are also performed. Etching operations are performed in the manufacture of integrated circuits and the creation of interconnects consisting of metallized tracks, through holes and other elements of the circuit topology. In order to increase the efficiency of the entire technological process for manufacturing semiconductor wafers, in the interval between these operations, certain polishing operations are usually performed by the chemical-mechanical method (CMP), which makes it possible to level the plane of the wafer surface. In the manufacture of integrated circuits after each such operation, before moving on to the next operation, the plate must be polished and cleaned. The final processed plate is cut into individual crystals or individual integrated circuits. Such microcircuits are then placed in an appropriate housing and combined with each other in a finally finished device, for example, transmitted to a customer or an electronic device sold for sale.

Thus, the present invention provides a method and machine for polishing, leveling, cleaning and washing semiconductor wafers and other similar products. In the above description, several specific embodiments of the invention are described. Obviously, however, other embodiments of the invention are possible based on the above description. The above options and some features of the invention are only illustrative examples of a possible implementation of the invention, the scope of which is determined only by the claims.

Claims (22)

1. A machine for processing semiconductor wafers, having a pair of support drive rollers that serve as supports for a vertically arranged semiconductor wafer and are driven by a drive belt connected to them, and two opposed movable wafer processing unit blocks, each of which contains a first and the second processing elements that process the semiconductor wafer and which allow their installation in the first position in which the wafer is processed their first processing elements, and in a second position in which the processing of the plate is carried out by their second processing elements. 2. The machine according to claim 1, in which each plate processing unit has a drive mechanism designed to bring the first and second plate processing elements into rotation. 3. The machine according to claim 1, in which the first plate processing elements are located above the second plate processing elements and each first plate processing element is a cylindrical brush. 4. The machine according to claim 3, in which every second plate-processing element is a cylindrical polisher. 5. The machine according to claim 3, in which every second plate-processing element is a cylindrical brush. 6. The machine according to claim 4, in which each cylindrical polisher is mounted on a mandrel. 7. The machine according to claim 1, in which each plate-processing unit contains a rotating rotation shaft, which is designed to rotate the plate-processing unit from a first position to a neutral position and to a second position, and vice versa, while the plate-processing unit is in neutral position, its plate-processing elements are in a position from which they can be pressed against the plate or removed from it. 8. The machine according to claim 1, in which a pair of support-drive rollers and two processing plate blocks are located inside the housing. 9. The machine of claim 8, also having a centering roller that holds a vertically standing plate on the support drive rollers and is mounted to rotate on a rotary centering lever. 10. The machine according to claim 9, in which the centering rotary lever is pivotally connected to the clamping device mounted on the wall of the housing. 11. A machine for processing a semiconductor wafer having a first support drive roller that is rotatable in a support mounted on a first pivot arm and is designed to drive a vertically mounted plate, a second support drive roller that can rotate in a support mounted on the second pivot arm, and is designed to drive a vertically mounted plate, with the first and second pivot arms mounted on a support-drive arm mounted on them iku supplied driving force required for driving in rotation of the plate, and each swivel arm by means allowing its rotation in a suitable support from the first position to the second position to adjust the height mounted on the support-drive rollers plate. 12. The machine according to claim 11, in which the first and second rotary levers with support-driving rollers are connected to a prefabricated coaxial shaft, consisting of an internal transmission shaft and a hollow outer rotary shaft. 13. The machine according to item 12, in which the first and second rotary levers with support-driving rollers rotate when the outer rotary shaft of the first and second prefabricated coaxial shafts rotates. 14. The machine of claim 12, wherein the rotating internal transmission shafts of the first and second prefabricated coaxial shafts rotate the first and second supporting-drive rollers, respectively. 15. A fastening assembly of a self-centering mandrel having an inner cylindrical sleeve with an element located on its outer surface forming a hinge support point, an outer cylindrical shell put on the inner sleeve, which is externally coated with the material used to process the product, and is pivotally connected to the inner sleeve the outer surface of the inner sleeve, the fulcrum, when turning at which this outer cylindrical shell in contact with the processing material with the product p spolagaetsya parallel to the work surface of the product. 16. The attachment site of the self-centering mandrel according to clause 15, in which the fulcrum is made in the form of a ring with a circular cross-section, which is located in a groove made on the outer surface of the cylindrical inner sleeve. 17. The attachment site of the self-centering mandrel according to clause 15, in which the cylindrical inner sleeve has a hole and is connected to a rotating gear wheel, while the outer shell also has a through hole in which there is a connecting element that enters the hole of the inner sleeve for transmission from it on the outer shell of the drive force necessary to bring it into rotation. 18. The attachment site of the self-centering mandrel according to clause 15, in which the support point of the outer shell is located in a plane passing approximately through the center of the shell. 19. The attachment site of the self-centering mandrel according to claim 17, in which the through hole of the outer shell has a first diameter, and the connecting element has a second diameter smaller than the first diameter by an amount sufficient so that the mandrel shell can rotate at a support point by a certain angle. 20. The attachment site of the self-centering mandrel according to clause 15, in which the material by which the product is processed forms a polishing pad. 21. The self-centering mandrel mounting assembly of claim 15, wherein the cylindrical inner sleeve is made of plastic and the outer shell is made of stainless steel. 22. The attachment site of the self-centering mandrel according to clause 15, in which the workpiece is a semiconductor wafer.

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