CN111438085A

CN111438085A - Cleaning mechanism

Info

Publication number: CN111438085A
Application number: CN202010030608.4A
Authority: CN
Inventors: 现王园二郎
Original assignee: Disco Corp
Current assignee: Disco Corp
Priority date: 2019-01-17
Filing date: 2020-01-13
Publication date: 2020-07-24
Anticipated expiration: 2040-01-13
Also published as: JP2020115496A; CN111438085B; JP7222721B2

Abstract

A cleaning mechanism is provided for cleaning the lower surface of a plate-shaped workpiece without using a brush to which dust adheres. The cleaning mechanism (8) cleans the lower surface (Wa) of a plate-shaped workpiece (W) held by a holding unit (14), and comprises: a tub (80) formed in a concave shape by a bottom plate (800) and a side plate (801); a supply port (81) formed at the center of the bottom plate for supplying water into the barrel; and a brush (83) which is disposed in the barrel with the center thereof aligned with the center of the bottom plate, wherein the upper surface (83a) of the brush (83) which is the bristle tip is at a position higher than the upper end surface (801a) of the side plate (801) by a predetermined distance, the brush (83) is covered with a water surface which is raised from the upper end surface (801a) of the side plate (801) by the surface tension of water stored in the barrel (80), and the water flows on the upper surface (83a) of the immersed bristle tip which is the brush (83), thereby cleaning the bristle tip of the brush (83).

Description

Cleaning mechanism

Technical Field

The present invention relates to a cleaning mechanism for cleaning a lower surface of a plate-like workpiece.

Background

A grinding apparatus for grinding a plate-like workpiece such as a semiconductor wafer held by a chuck table with a grinding wheel carries the plate-like workpiece out of a cassette in which the plate-like workpiece is stored in a shelf shape, and carries the plate-like workpiece to the chuck table by carrying means such as a suction pad. Here, there are problems as follows: when dust adheres to the lower surface of the plate-like workpiece held by the chuck table, the dust is sandwiched between the lower surface of the plate-like workpiece and the holding surface of the chuck table, and the plate-like workpiece cannot be ground to a uniform thickness.

Therefore, as disclosed in patent document 1, there is a grinding apparatus having a cleaning mechanism for spraying cleaning water to a lower surface of a plate-shaped workpiece and cleaning the lower surface by bringing a brush into contact with the lower surface of the plate-shaped workpiece.

Patent document 1: japanese patent laid-open publication No. 2011-

However, there are problems as follows: the dust of the plate-like workpiece after cleaning adheres to the brush of the cleaning mechanism, and the dust adhering to the brush adheres to the next newly cleaned plate-like workpiece.

Thus, there are the following problems: in a cleaning mechanism for cleaning the lower surface of a plate-shaped workpiece, the lower surface of the plate-shaped workpiece is cleaned without using a brush to which dust is attached.

Disclosure of Invention

The invention provides a cleaning mechanism for cleaning the lower surface of a plate-shaped workpiece.

The present invention for solving the above-described problems is a cleaning mechanism for cleaning a lower surface of a plate-like workpiece held by a holding unit, the cleaning mechanism including: a tub formed in a concave shape by a bottom plate and a side plate; a supply port formed at the center of the bottom plate for supplying water into the tub; and a brush disposed in the tub such that a center thereof coincides with a center of the bottom plate, an upper surface of the brush, which is a bristle tip, is located at a position higher than an upper end surface of the side plate by a predetermined distance, the brush is covered with a water surface rising from the upper end surface of the side plate due to a surface tension of water stored in the tub, and the bristle tip of the brush is washed by water flowing over the immersed upper surface of the brush.

The cleaning mechanism of the invention comprises: a tub formed in a concave shape by a bottom plate and a side plate; a supply port formed at the center of the bottom plate for supplying water into the tub; and a brush arranged in the tub such that a center thereof coincides with a center of the bottom plate, wherein an upper surface of the brush, which is a bristle tip, is located at a position higher than an upper end surface of the side plate by a predetermined distance, so that after cleaning of the plate-shaped workpiece is completed, cleaning water rising above the upper end surface of the side plate due to surface tension of water accumulated in the tub flows over the bristle tip of the brush from the center toward an outer peripheral side of the brush, thereby allowing dust attached to the bristle tip of the brush to be washed away. Therefore, the lower surface of the plate-like workpiece can be prevented from being cleaned by the brush to which dust adheres in the subsequent cleaning of the lower surface of a new plate-like workpiece. In addition, in the washing of the plate-shaped workpiece, the washing water also flows from the center of the brush toward the outer peripheral side at the boundary between the brush and the lower surface of the plate-shaped workpiece, and therefore, it is possible to prevent dust from adhering to the plate-shaped workpiece and the brush.

Drawings

Fig. 1 is a perspective view showing an example of a grinding apparatus having a cleaning mechanism of the present invention.

Fig. 2 is a perspective view showing an example of a tub and a brush of the washing mechanism.

Fig. 3 is a perspective view showing another example of the brush.

Fig. 4 is a cross-sectional view illustrating a state in which cleaning of the lower surface of the plate-like workpiece is to be started.

Fig. 5 is a cross-sectional view illustrating a state where the lower surface of the plate-like workpiece is cleaned.

Fig. 6 is a cross-sectional view illustrating a state where the cleaning of the lower surface of the plate-shaped workpiece is started in parallel with the operation of conveying the plate-shaped workpiece from the temporary placement area to the chuck table.

Fig. 7 is a cross-sectional view illustrating a state where the lower surface of the plate-shaped workpiece is cleaned in parallel with the operation of conveying the plate-shaped workpiece from the temporary placement area to the chuck table.

Description of the reference symbols

W: a plate-like workpiece; wa: a lower surface of the plate-like workpiece; wb: an upper surface of the plate-like workpiece; 1: a grinding device; 10: a base; 12: a column; 150 a: a 1 st box; 151 a: a 2 nd cartridge; 155: a robot; 152: temporarily placing the area; 153: a contraposition unit; 156: a rotary cleaning unit; 14: a holding unit; 140: an arm portion; 141: a suction pad; 141 c: an adsorption surface; 143: a rotation moving unit; 144: a lifting unit; 16: a carry-out unit; 30: a chuck table; 30 a: a holding surface; 2: a grinding feed unit; 20: a ball screw; 22: an electric motor; 4: a grinding unit; 40: a rotating shaft; 42: an electric motor; 44: grinding the grinding wheel; 440: grinding the grinding tool; 8: a cleaning mechanism; 80: a barrel; 800: a bottom; 801: a side plate; 801 a: the upper end surface of the side plate; 81: providing a port; 85: a support column; 850: providing a path; 851: a joint; 89: a water supply source; 890: an opening and closing valve; 893: providing a tube; 83: brushing; 83 a: the upper surface of the brush as the bristle tips; 831: brushing the plate; 830: an opening; 87: brushing; 87 a: the upper surface of the brush as the bristle tips; 871: the plate is brushed.

Detailed Description

A grinding apparatus 1 shown in fig. 1 includes a cleaning mechanism 8 according to the present invention, and the grinding apparatus 1 is an apparatus for grinding a plate-like workpiece W held by a chuck table 30 by a grinding unit 4. The front side (the side in the (-X direction) on the base 10 of the grinding apparatus 1 is a carrying-in/out area a where the plate-shaped workpiece W is carried in/out with respect to the chuck table 30, and the rear side (the side in the (+ X direction) on the base 10 is a machining area B where the plate-shaped workpiece W held on the chuck table 30 is ground by the grinding unit 4.

The grinding apparatus provided with the cleaning mechanism 8 according to the present invention may be configured to have a double shaft including a rough grinding unit and a finish grinding unit as grinding units, and the chuck table 30 may be positioned below each grinding unit by a rotating table. The cleaning mechanism 8 may be disposed in a cutting device, a polishing device, a laser processing device, or the like, in addition to the grinding device.

The plate-like workpiece W shown in fig. 1 is, for example, a circular semiconductor wafer, and a plurality of devices, not shown, are formed on a lower surface Wa thereof. A protective tape, not shown, is attached to the lower surface Wa of the plate-like work W, for example, and the lower surface Wa is protected by the protective tape. The upper surface Wb of the plate-like workpiece W is a surface to be ground, and the plate-like workpiece W is held on the chuck table 30 with the upper surface Wb facing upward.

On the front surface of the base 10 on the-X direction side, for example, a 1 st cassette mounting portion 150 and a 2 nd cassette mounting portion 151 are provided, a 1 st cassette 150a accommodating a plate-shaped workpiece W before machining is mounted on the 1 st cassette mounting portion 150, and a 2 nd cassette 151a accommodating a plate-shaped workpiece W after machining is mounted on the 2 nd cassette mounting portion 151.

A robot 155 for carrying out the plate-like works W before processing from the 1 st cassette 150a and carrying the plate-like works W after processing into the 2 nd cassette 151a is disposed behind the 1 st cassette 150 a. A temporary placement area 152 is provided adjacent to the robot 155, and a positioning unit 153 is disposed in the temporary placement area 152. The alignment unit 153 aligns (centers) the plate-like workpiece W carried out of the 1 st cassette 150a and placed on the temporary placement area 152 at a predetermined position by a plurality of pins having a reduced diameter.

A holding unit 14 that holds the upper surface Wb of the plate-shaped workpiece W before machining and carries it into the chuck table 30 is disposed adjacent to the alignment unit 153. The holding unit 14 has an arm portion 140 extending horizontally and a suction pad 141 fixed to a lower surface side of one end of the arm portion 140. A rotation moving means 143 configured by a rotation shaft or the like and an elevation means 144 configured by a cylinder mechanism or the like are connected to the arm portion 140, the rotation moving means 143 can rotate the arm portion 140 on a horizontal plane (X-axis Y-axis plane), and the elevation means 144 can elevate the arm portion 140 in the vertical direction (Z-axis direction).

The suction pad 141 (see fig. 4) has, for example, a circular outer shape, and the suction pad 141 includes: an adsorption portion 141a which is made of a porous member or the like and adsorbs the plate-like work W; and a frame 141b that supports the adsorption part 141 a. The suction portion 141a communicates with a suction source, not shown, such as a vacuum generator, and a suction force generated by the suction source is transmitted to a flat suction surface 141c, which is an exposed surface of the suction portion 141a, so that the suction pad 141 sucks and holds the plate-shaped workpiece W by the suction surface 141 c.

As shown in fig. 1, a carrying-out unit 16 capable of sucking and holding a processed plate-like workpiece W and capable of rotating is provided near the holding unit 14. The holding unit 14 and the carry-out unit 16 may be edge gripping mechanisms for gripping the outer periphery of the plate-like workpiece W.

A single-wafer type spin cleaning unit 156 is disposed in a position close to the carry-out unit 16, and the spin cleaning unit 156 cleans the processed plate-shaped workpiece W carried from the chuck table 30 by the carry-out unit 16. The plate-like workpiece W cleaned by the spin cleaning unit 156 is carried into the 2 nd cassette 151a by the robot 155.

The chuck table 30, which is disposed on the base 10 of the grinding apparatus 1 and holds the plate-shaped workpiece W, has a circular outer shape, for example, and the chuck table 30 has a holding surface 30a, and the holding surface 30a is communicated with a suction source, not shown, and is formed of a porous member or the like, and sucks and holds the plate-shaped workpiece W. The chuck table 30 is surrounded by the cover 39, and can be reciprocated in the X-axis direction on the base 10 by an X-axis direction feeding unit, not shown, disposed under the cover 39 and a bellows cover 39a coupled to the cover 39. The chuck table 30 is rotatable about an axis in the Z-axis direction.

A post 12 is provided upright behind the machining region B (+ X direction side), and a grinding and feeding unit 2 for grinding and feeding the grinding unit 4 in a Z-axis direction away from or toward the chuck table 30 is provided on a front surface of the post 12 on the-X direction side. The grinding feed unit 2 includes: a ball screw 20 having an axial center in a Z-axis direction (vertical direction); a pair of guide rails 21 arranged in parallel with the ball screw 20; a motor 22 coupled to an upper end of the ball screw 20 to rotate the ball screw 20; a lifting plate 23, the inner nut of which is screwed with the ball screw 20, and the side part of the lifting plate 23 is in sliding contact with the guide rail 21; and a bracket 24 that is coupled to the lift plate 23 and holds the grinding unit 4, and when the ball screw 20 is rotated by the motor 22, the lift plate 23 is guided by the guide rail 21 and reciprocates in the Z-axis direction, and the grinding unit 4 held by the bracket 24 is ground and fed in the Z-axis direction.

The grinding unit 4 for grinding the plate-shaped workpiece W held by the chuck table 30 includes: a rotary shaft 40 having a Z-axis direction as an axial direction; a housing 41 rotatably supporting the rotary shaft 40; a motor 42 that rotationally drives the rotary shaft 40; an annular mounting seat 43 connected to the lower end of the rotary shaft 40; and a grinding wheel 44 detachably connected to the lower surface of the mounting base 43.

The grinding wheel 44 includes a wheel base 441 and a plurality of grinding stones 440 arranged in a ring shape on the bottom surface of the wheel base 441 in a substantially rectangular parallelepiped shape. The grinding wheel 440 is formed by bonding diamond abrasive grains or the like with a resin bond, a ceramic bond, a metal bond or the like, for example. In addition, the grinding stone 440 may be integrally formed in a ring shape.

A flow path (not shown) serving as a passage for the grinding water is formed through the rotary shaft 40 in the axial direction (Z-axis direction) of the rotary shaft 40. The flow path passes through the mounting seat 43 and opens on the bottom surface of the grinding wheel base 441 so that grinding water can be discharged toward the grinding whetstone 440.

As shown in fig. 1, the cleaning mechanism 8 of the present invention is disposed, for example, below the movement path of the suction pad 141 of the holding unit 14 on the base 10.

The cleaning mechanism 8 shown in fig. 1 and 2, which cleans the lower surface Wa of the plate-like workpiece W held by the holding unit 14, includes a tub 80 in the illustrated example, and the tub 80 is configured by a bottom plate 800 circular in plan view and a side plate 801 integrally rising in the + Z direction from the outer periphery of the bottom plate 800.

A supply port 81 for supplying water into the tub 80 is formed, for example, through the center of the bottom plate 800. The supply port 81 communicates with a supply passage 850 (see fig. 4) formed in the support column 85 that supports the tub 80 in the base 10 shown in fig. 1, and one end of a supply pipe 893 such as a metal pipe or a flexible resin pipe communicates with the supply passage 850 via a joint 851 attached to a side surface of the support column 85. The other end of the supply pipe 893 is connected to a water supply source 89, which is configured by a pump or the like and can supply washing water (e.g., pure water), via an opening/closing valve 890.

The cleaning mechanism 8 has a brush 83 disposed in the tub 80 so that the center thereof coincides with the center of the bottom plate 800. The brush 83 is formed by, for example, forming elastic resin fibers (for example, nylon) in a straight hair shape and densely packing the resin fibers, and is planted on the upper surface of the annular flat plate-shaped brush plate 831 so that the upper surface 83a, which is the hair tips of the resin fibers, faces in the + Z direction. The lower surface of the brush plate 831 is adhered or screw-fastened to the bottom plate 800 of the tub 80, and a circular opening 830 at the center of the brush 83 allows washing water supplied from the supply port 81 to the brush 83 to overflow.

For example, the thickness of the resin fibers of the brush 83 is 0.1mm, and the height of the brush 83 (the length of the resin fibers) is 10 mm. As shown in fig. 4, the upper surface 83a of the brush 83 attached to the tub 80, which is a bristle tip, is located at a position higher than the upper end surface 801a of the side plate 801 of the tub 80 by a predetermined distance H. The resin fibers of the brush 83 may have a tapered shape in which the tip gradually decreases in diameter toward the hair tip. The predetermined distance H is set to, for example, 2mm, but is not limited to this value, and may be set to a value such that the upper surface 83a, which is a bristle tip, of the brush 83 can be covered by the water surface rising above the upper end surface 801a of the side plate 801 due to the surface tension of the water (washing water) stored in the tub 80, in consideration of the diameter of the tub 80.

The diameter of the brush 83 is preferably set larger than the diameter of the plate-like workpiece W as in the present embodiment.

The cleaning mechanism 8 may have a brush 87 shown in fig. 3 instead of the brush 83 shown in fig. 1 and 2. The brush 87 is formed by, for example, forming elastic resin fibers (for example, nylon) in a straight hair shape and densely packing the resin fibers, and is planted on the upper surface of the circular plate-shaped brush plate 871 so that the upper surfaces 87a of the hair tips of the resin fibers face in the + Z direction. The lower surface of the brush plate 871 is bonded or screw-fastened to the bottom plate 800 of the tub 80 shown in fig. 2. One or more water spray outlets 874 are formed at the center of the brush plate 871 at a portion that is a gap between the bristles, and the water spray outlets 874 are for the washing water supplied from the supply port 81 of the bottom plate 800 of the tub 80 shown in fig. 2 to the brush 87 to overflow. An upper surface 87a of the brush 87 attached to the tub 80, which is a bristle tip, is located at a position higher than an upper end surface 801a of the side plate 801 of the tub 80 by a predetermined distance (for example, 2 mm).

Next, the operation of the grinding apparatus 1 and the operation of the cleaning mechanism 8 when grinding the upper surface Wb of the plate-shaped workpiece W using the grinding apparatus 1 shown in fig. 1 will be described.

When grinding the upper surface Wb of the plate-like workpiece W, first, the robot 155 pulls out one plate-like workpiece W from the 1 st cassette 150a, and moves the plate-like workpiece W to the temporary storage area 152. Next, the rotary moving means 143 rotates the suction pad 141 in the horizontal direction, and positions the suction pad 141 above the plate-shaped workpiece W such that the upper surface Wb of the plate-shaped workpiece W in the temporary placement area 152 faces the suction surface 141c of the suction pad 141 shown in fig. 4, and the center of the upper surface Wb of the plate-shaped workpiece W substantially coincides with the center of the suction pad 141.

Next, the lifting unit 144 lowers the suction pad 141 to bring the suction surface 141c into contact with the upper surface Wb of the plate-like workpiece W. In this state, a suction source, not shown, generates a suction force, and the suction pad 141 to which the suction force is transmitted sucks and holds the plate-shaped workpiece W by the suction surface 141 c. Next, the suction pad 141 holding the upper surface Wb of the plate-shaped workpiece W is raised by the lifting unit 144, and the plate-shaped workpiece W is carried out of the temporary storage area 152 by the holding unit 14.

The rotary moving means 143 rotates the suction pad 141 holding the plate-like workpiece W in the horizontal direction, and positions the plate-like workpiece W above the cleaning mechanism 8 as shown in fig. 4. This positioning is performed, for example, so that the center of the brush 83 and the center of the plate-like workpiece W substantially overlap.

On the other hand, in the cleaning mechanism 8 shown in fig. 4, the opening/closing valve 890 communicates the supply pipe 893 with the water supply source 89. Washing water (e.g., pure water) is supplied from the water supply source 89 to the supply pipe 893, and flows out from the supply port 81 of the tub 80 onto the brush plate 831 through the inside of the support column 85. When the water level of the washing water in the tub 80 is higher than the upper end surface 801a of the side plate 801, the water level rises above the upper end surface 801a of the side plate 801 due to surface tension, and the washing water flows from the center of the opening 830 of the brush 83 to the outer peripheral side on the water level, and the washing water overflows from the tub 80.

The upper surface 83a, which is the bristle tips of the brushes 83 located higher than the upper end surface 801a of the side plate 801 by a predetermined distance H, is covered with washing water in a state of being raised by surface tension.

Similarly, when the brush 87 shown in fig. 3 is disposed in the tub 80 instead of the brush 83, the washing water ejected from the water ejection port 874 accumulates in the tub 80, and the upper surface 87a, which is the bristle tips of the brush 87 located at a predetermined distance higher than the upper end surface 801a of the side plate 801, is covered with the washing water in a state of being raised by surface tension.

In a state where the upper surface 83a of the brush 83, which is a bristle tip, is covered with washing water that rises by surface tension, as shown in fig. 5, the lifting unit 144 lowers the suction pad 141 holding the plate-shaped workpiece W, and brings the lower surface Wa of the plate-shaped workpiece W into contact with the upper surface 83a of the brush 83. The rotary moving unit 143 reciprocates the suction pad 141 at a predetermined angle in the horizontal direction, and wipes off dust adhering to the lower surface Wa of the plate-like workpiece W by the brush 83. In addition, in the washing of the plate-shaped workpiece W, since the washing water flows from the center of the brush 83 toward the outer peripheral side at the boundary between the upper surface 83a of the brush 83 and the lower surface Wa of the plate-shaped workpiece W, the adhesion of dust to the plate-shaped workpiece W and the brush 83 can be prevented. Further, since the opening 830 in the center of the brush 83 is relatively moved in the horizontal direction with respect to the lower surface Wa of the plate-shaped workpiece W, the bristle tips of the brush 83 come into contact with the entire lower surface Wa of the plate-shaped workpiece W while moving, and therefore the entire lower surface Wa of the plate-shaped workpiece W is cleaned without fail.

In addition, the plate-like works W may not be positioned above the cleaning mechanism 8 so that their centers overlap as shown in fig. 4. That is, as shown in fig. 6, the plate-shaped workpiece W may be positioned above the cleaning mechanism 8 at a position where the center of the brush 83 and the center of the plate-shaped workpiece W are offset, the suction pad 141 may be lowered to a position where the lower surface Wa of the plate-shaped workpiece W is brought into contact with the upper surface 83a of the brush 83, which is a bristle tip, and the plate-shaped workpiece W may be moved in the horizontal direction while keeping the lower surface Wa in contact with the upper surface 83a, and then the plate-shaped workpiece W may be moved upward away from the upper surface 83a to complete cleaning, as shown in fig. 7. That is, the lower surface Wa of the plate-like workpiece W may be cleaned by horizontal movement of the suction pad 141 in one direction, instead of reciprocating the suction pad 141 at a predetermined angle in the horizontal direction as described above. That is, in the operation of moving the plate-shaped workpiece W sucked and held by the suction pad 141 from the temporarily placing region 152 shown in fig. 1 onto the chuck table 30 by the rotary moving unit 143, the lower surface Wa of the plate-shaped workpiece W may be cleaned in parallel, so that the increase in the machining time due to the cleaning of the lower surface Wa of the plate-shaped workpiece W does not occur.

Further, at least one of the brush 83 of the cleaning mechanism 8 and the suction pad 141 of the holding unit 14 may be configured to be rotatable about the axis in the Z-axis direction by a rotation mechanism, and at least one of the brush 83 and the suction pad 141 that sucks and holds the plate-shaped workpiece W may be rotated to clean the lower surface Wa.

The lower surface Wa of the ground plate-shaped workpiece W held by the carry-out unit 16 may be cleaned by the cleaning mechanism 8.

The cleaning and removal of the dust adhering to the lower surface Wa of the plate-like workpiece W are performed substantially in the same manner as in the case of using the brush 87 shown in fig. 3.

When the lower surface Wa of the plate-shaped workpiece W is cleaned by the brush 83 for a predetermined time, the plate-shaped workpiece W is lifted up in the + Z direction by the lifting and lowering unit 144, and the brush 83 is separated from the plate-shaped workpiece W as shown in fig. 4. As a result, even when dust adheres to the upper surface 83a, which is a bristle tip, of the brush 83 due to the cleaning of the lower surface Wa of the plate-shaped workpiece W, the cleaning water in a state of being raised by surface tension overflows from the inside of the tub 80 by the flow of the cleaning water on the water surface of the tub 80 from the center of the opening 830 of the brush 83 toward the outer peripheral side, and the dust on the upper surface 83a of the brush 83 is washed away. Therefore, the lower surface Wa of the plate-shaped workpiece W can be prevented from being cleaned by the brush 83 to which dust adheres in the subsequent cleaning of the lower surface Wa of a new plate-shaped workpiece W.

In addition, in the case of using the brush 87 shown in fig. 3, the washing water in a state of being raised by surface tension overflows from the tub 80 by the flow of the washing water on the water surface of the tub 80 from the center of the brush 87 toward the outer peripheral side, and the dust attached to the upper surface 87a of the brush 87 is washed away.

The holding unit 14 shown in fig. 1 moves the plate-shaped workpiece W whose lower surface Wa has been cleaned onto the chuck table 30, and suctions and holds the plate-shaped workpiece W with the upper surface Wb directed upward by the holding surface 30 a. Next, the chuck table 30 holding the plate-like workpiece W is moved in the + X direction to below the grinding unit 4. The grinding unit 4 is fed in the-Z direction by the grinding feed unit 2, and the grinding whetstone 440 rotated with the rotation of the rotary shaft 40 abuts on the upper surface Wb of the plate-shaped workpiece W to grind. In the grinding, the plate-shaped workpiece W held on the holding surface 30a is also rotated with the rotation of the chuck table 30, and thus the grinding whetstone 440 performs the grinding of the entire upper surface Wb of the plate-shaped workpiece W. Further, grinding water is supplied to the contact portion between the grinding stone 440 and the plate-like workpiece W, and the contact portion is cooled and cleaned. Since the lower surface Wa of the plate-shaped workpiece W is cleaned by the cleaning mechanism 8 to be in a state where no dust adheres thereto, the plate-shaped workpiece W can be ground to a uniform desired thickness without interposing dust between the lower surface Wa of the plate-shaped workpiece W and the holding surface 30a of the chuck table 30.

After the plate-shaped workpiece W is ground to a desired thickness, the grinding unit 4 is lifted by the grinding feed unit 2 to be separated from the plate-shaped workpiece W, and the chuck table 30 is moved in the-X direction to be positioned in the vicinity of the carry-out unit 16. Subsequently, the plate-like workpiece W is conveyed to the spin cleaning unit 156 by the carry-out unit 16. The upper surface Wb of the plate-like workpiece W is cleaned by the spin cleaning unit 156. The plate-like workpiece W whose upper surface Wb has been cleaned is stored in the 2 nd cassette 151a by the robot 155.

The cleaning mechanism 8 of the present invention is not limited to the above-described embodiment, and may be implemented in various different forms within the scope of the technical idea thereof. The structure of the grinding apparatus 1 shown in the drawings is not limited thereto, and may be appropriately modified within a range in which the effects of the present invention can be exhibited.

Claims

1. A cleaning mechanism for cleaning the lower surface of a plate-like workpiece held by a holding unit,

this wiper mechanism has:

a tub formed in a concave shape by a bottom plate and a side plate;

a supply port formed at the center of the bottom plate for supplying water into the tub; and

a brush, which is arranged in the barrel with the center consistent with the center of the bottom plate,

the upper surface of the brush as the hair tip is at a position higher than the upper end surface of the side plate by a prescribed distance,

the brush is covered by a water surface that is raised from the upper end surfaces of the side plates by the surface tension of the water stored in the tub, and the water flows over the immersed upper surface of the brush to clean the bristle tips of the brush.