JP7320940B2 - Wafer holding device and wafer carrier holding device - Google Patents

Description

The present invention relates to a wafer holding device and a wafer transfer and holding device.

A device provided in a semiconductor product is formed by coating a silicon wafer (hereinafter simply referred to as "wafer") with a photosensitive resin as an etching resist and then etching the silicon wafer. The wafer is ground by a back grinder on the back surface of the pattern surface on which the devices are etched. During this back grinding, a back grind (BG) tape is previously attached to the pattern surface.

Such back-grinded wafers can be transported using a full-surface suction pad (see, for example, Japanese Unexamined Patent Application Publication No. 2002-100000) that suctions the entire back surface of the wafer, or a vacuum that is generated between the wafer and the wafer by discharging an air flow onto the front surface of the wafer. A holding device having a Bernoulli nozzle that holds a wafer with pressure is known (see, for example, Patent Document 2).

JP 2010-50265 A Japanese Patent No. 6254432

However, when an extremely thin wafer is sucked by the full-surface suction pad according to Patent Document 1, there is a risk that the wafer may crack or the device may be contaminated if grinding dust gets caught between the suction pad and the wafer. be.

Further, in the holding device according to Patent Document 2, when a wafer is warped, an appropriate negative pressure cannot be obtained, causing the wafer to fall off. There is a problem that there is a risk of inducing

Therefore, there arises a technical problem to be solved in order to hold the thin wafer without damaging the wafer, and an object of the present invention is to solve this problem.

In order to achieve the above object, a wafer holding device according to the present invention sucks and holds a wafer, and is formed in a ring shape having a diameter larger than a device forming region of the wafer. A suction pad that can abut on a peripheral edge, a frame that embeds the suction pad on the bottom surface, and a vacuum source that is connected to the suction pad and generates a negative pressure between the suction pad and the wafer. .

According to this configuration, the suction pad sucks and holds the outer peripheral edge of the wafer with a negative pressure without contacting the device forming area at the center of the wafer. Wafer damage and device contamination due to biting can be suppressed. In addition, even a warped wafer can be held by suction because the suction pad comes into contact with the outer periphery of the wafer.

Moreover, it is preferable that the wafer holding device according to the present invention further includes an air source connected to the suction pad and supplying compressed air between the suction pad and the wafer.

According to this configuration, the suction can be easily released by supplying compressed air between the suction pad and the wafer held by suction on the suction pad.

Further, in the wafer holding device according to the present invention, the frame is formed in a disk shape, and a communication hole is formed through the frame vertically. A supply air source is preferably connected.

According to this configuration, when the wafer holding device sucks and holds the wafer, the pressure of the compressed air supplied into the frame through the communication hole cancels out various pressures that press the wafer toward the frame. By doing so, cracking of the wafer can be suppressed.

Further, in the wafer holding device according to the present invention, the frame is formed in a disk shape, and a communication hole is formed vertically through the frame. A supply of water supply is preferably connected.

According to this configuration, when the wafer holding device sucks and holds the wafer, the pressure of the moisturizing water supplied into the frame through the communication hole cancels out various pressures that press the wafer toward the frame. By doing so, cracking of the wafer can be suppressed. Moreover, since the wafer surface is maintained in a wet state while the wafer holding device is sucking and holding the wafer, it is possible to suppress adhesion of grinding dust to the wafer surface.

Moreover, it is preferable that a wafer transfer/holding device according to the present invention includes the wafer holding device described above and a transfer mechanism connected to the frame for transferring the wafer holding device.

According to this configuration, the transfer mechanism can move the wafer holding device to an arbitrary location.

According to the present invention, the suction pad sucks and holds the outer peripheral edge of the wafer with a negative pressure without contacting the device forming area at the center of the wafer. It is possible to suppress wafer damage and device contamination caused by In addition, even a warped wafer can be held by suction because the suction pad comes into contact with the outer periphery of the wafer.

FIG. 1 is a schematic diagram showing a wafer transfer system provided with a wafer transfer/holding device according to one embodiment of the present invention; The top view and bottom view which show a flame|frame. Partially cutaway side view showing the frame. Sectional drawing which shows the principal part of an adsorption holding apparatus. FIG. 4 is a schematic diagram showing a procedure for transferring a wafer from a first chuck to a second chuck;

An embodiment of the present invention will be described based on the drawings. In addition, hereinafter, when referring to the number, numerical value, amount, range, etc. of the constituent elements, unless otherwise specified or clearly limited to a specific number in principle, it is limited to the specific number It does not matter if it is more than or less than a certain number.

In addition, when referring to the shape and positional relationship of components, etc., unless otherwise specified or in principle clearly considered otherwise, etc. include.

In addition, the drawings may exaggerate characteristic parts by enlarging them in order to make the characteristics easier to understand. In addition, in cross-sectional views, hatching of some components may be omitted in order to facilitate understanding of the cross-sectional structure of the components.

FIG. 1 is a schematic diagram showing a wafer delivery system 1. As shown in FIG. A wafer transfer system 1 includes a wafer carrier/holding device 2, a first chuck 3, and a second chuck 4 according to one embodiment of the present invention. The wafer transfer system 1 is used together with, for example, a grinding device, a polishing device, a cleaning device, etc., for planarizing the wafer W, and transfers an extremely thin wafer W (for example, a thickness of 25 μm) between devices.

The wafer carrier/holding device 2 transfers the wafer W placed on the first chuck 3 to the second chuck 4 . For example, the first chuck 3 is a wafer chuck that sucks and holds the wafer W in the grinding device, and the second chuck 4 is a wafer chuck that sucks and holds the wafer W in the cleaning device. Since the second chuck 4 has the same configuration as the first chuck 3, the configuration of the first chuck 3 will be described below as an example, and the second chuck 4 is the same as the first chuck 3. Duplicate configurations are denoted by the same reference numerals, and duplicate descriptions are omitted.

The first chuck 3 sucks and holds the wafer W with the planarized surface to be processed facing upward and the device surface on which devices are formed facing downward. The first chuck 3 includes a base 11 made of a dense body such as ceramic, and a disk-shaped adsorbent 12 embedded in the upper surface of the base 11 and made of a porous material such as ceramic. The outer diameter of the base 11 is set to be slightly larger than that of the wafer W. As shown in FIG. The outer diameter of the attracting body 12 is set to be slightly smaller than that of the wafer W. As shown in FIG.

The first chuck 3 has a pipe line (not shown) formed inside the base 11 . The pipeline is connected to a vacuum source, a compressed air source, or a water supply source via a rotary joint (not shown). When the vacuum source is activated, the wafer W placed on the suction body 12 is held by the suction body 12 by suction. Further, when the compressed air source or the water supply source is activated, the adsorption between the wafer W and the adsorption body 12 is released.

The wafer carrier/holding device 2 includes a wafer holding device 5 and a carrier mechanism 6 for carrying the wafer holding device 5 .

The wafer holding device 5 has a suction pad 51 and a frame 52 . 2A and 2B are a plan view and a bottom view of the wafer holding device 5. FIG. FIG. 3 is a partially cutaway cross-sectional view of the wafer holding device 5. As shown in FIG. FIG. 4 is a partially enlarged view showing the outer peripheral edge of the frame 52. As shown in FIG.

The suction pad 51 is formed in a ring shape slightly smaller than the outer diameter of the wafer W. As shown in FIG. In addition, the inner diameter of the suction pad 51 is set larger than the device forming area in which a large number of devices are arranged side by side in the center of the wafer W. As shown in FIG.

The suction pad 51 is made of a porous material such as ceramics or resin. When the suction pad 51 is made of a resin material, the suction pad 51 can be brought into contact with the wafer W flexibly. In addition, the suction pad 51 made of resin can reduce the deflection amount of the wafer W caused by the biting of the grinding dust.

The frame 52 is formed in a substantially disc shape with a slightly thick peripheral edge. The frame 52 is made of a dense body such as ceramic. A suction pad 51 is embedded in an annular groove 53 formed along the periphery of the frame 52 .

Twelve conduits 54 are provided at equal intervals on the periphery of the frame 52 . The conduit 54 penetrates from the upper surface of the frame 52 to the annular groove 53 . The conduit 54 is connected to the vacuum source S1 and the compressed air source S2 via switching valves (not shown). When the vacuum source S1 is activated, the wafer W is held by the suction pad 51 by suction. Further, when the compressed air source S2 is activated, the suction between the wafer W and the suction pad 51 is released.

A communication hole 55 is formed in the frame 52 so as to vertically penetrate the frame 52 . The communication hole 55 is connected to a water supply source S3 that supplies moisturizing water (pure water). A compressed air source for supplying compressed air may be connected to the communication hole 55 instead of the water supply source S3.

The transport mechanism 6 is a well-known transport robot, and is configured such that an extendable arm 61 made up of a plurality of links 62 can extend and retract in the horizontal direction. A frame 52 is fastened to the tip of the transport mechanism 6 with a bolt (not shown). Reference numeral 56 in FIG. 2 denotes bolt holes through which bolts are inserted.

The operation of the wafer transfer system 1 is controlled by control means (not shown). The control means controls each component constituting the wafer delivery system 1 . The control means is, for example, a computer, and is composed of a CPU, a memory, and the like. Note that the function of the control means may be realized by controlling using software, or may be realized by operating using hardware.

Next, the operation of the wafer transfer system 1 will be explained with reference to FIG.
[Wafer receiving process]

First, as shown in FIG. 5A, the frame 52 is moved above the first chuck 3 holding the wafer W by suction. Thereafter, the transport mechanism 6 further lowers the frame 52 so that the suction pads 51 are in close contact with the peripheral edge of the wafer W. As shown in FIG.

Next, as shown in FIG. 5B, compressed air (air) is discharged between the first chuck 3 and the wafer W to release the suction between the first chuck 3 and the wafer W. Next, as shown in FIG. In synchronism with the discharge of the compressed air, a negative pressure is generated between the suction pad 51 and the wafer W to cause the suction pad 51 to suction the wafer W, thereby moving the wafer W from the first chuck 3 to the suction pad. Hand over to 51.

In general, grinding marks tend to remain in the center of the wafer W. and the wafer W can be suppressed from being bitten by grinding dust.

When transferring the wafer W from the first chuck 3 to the frame 52 , moisturizing water is supplied into the closed space R formed by the frame 52 and the wafer W through the communication hole 55 . As a result, the pressure of the compressed air blown out from the device surface side acting on the wafer W and the pressure of the moisturizing water supplied from the side to be ground are offset, and the wafer W becomes thin and large in diameter due to the pressure of the compressed air. It is possible to suppress cracking of the wafer W. For example, when the compressed air blown out from the first chuck 3 is set to 0.2 MPa, the pressure of moisturizing water supplied into the frame 52 through the communication hole 55 is 0.2 MPa or slightly higher. It is set to a pressure (such as 0.3 MPa).

In addition, since the surface to be processed of the wafer W can be maintained in a wet state by supplying the moisturizing water to the wafer W, it is possible to suppress adhesion of grinding dust remaining on the surface to be processed.

After the wafer W is sucked by the suction pad 51, the transfer mechanism 6 raises the frame 52 as shown in FIG. 5(c).
[BG tape washing process]

Next, while the wafer W is being transferred, the cleaning brush 70 arranged below the wafer W cleans the BG tape attached to the device surface side of the wafer W. FIG. Specifically, as shown in FIG. 5(d), a cleaning brush 70 having a known structure is pressed against the wafer W while being rotated about a horizontal axis, thereby removing the grinding debris adhering to the BG tape.

Also, when cleaning the BG tape with the cleaning brush 70 , moisturizing water is supplied into the closed space R formed by the frame 52 and the wafer W through the communication hole 55 . As a result, the pressure acting on the wafer W pressing the cleaning brush 70 from the device surface side and the pressure of the moisturizing water supplied from the surface to be ground side are offset, and the pressing force pressing the cleaning brush 70 against the wafer W It is possible to suppress cracking of the thin and large-diameter wafer W.

In addition, since the surface to be processed can be maintained in a wet state by supplying moisturizing water to the wafer W, it is possible to suppress adhesion of grinding dust remaining on the surface to be processed.
[Wafer delivery process]

First, as shown in FIG. 5E, the frame 52 holding the wafer W by suction is moved above the second chuck 4 . After that, the transport mechanism 6 further lowers the frame 52 to bring the wafer W into close contact with the second chuck 4 .

Next, as shown in FIG. 5F, compressed air is discharged from the pipe line 54 to release the suction between the suction pad 51 and the wafer W. Then, as shown in FIG. Also, in synchronism with the discharge of the compressed air, a negative pressure is generated between the second chuck 4 and the wafer W to cause the second chuck 4 to adsorb the wafer W, thereby pulling the wafer W from the adsorption pad 51. Transfer to second chuck 4 .

When transferring the wafer W from the frame 52 to the second chuck 4 , moisturizing water is supplied into the closed space R formed by the frame 52 and the wafer W through the communication hole 55 . As a result, the moisturizing water diffused in the closed space R suppresses the infiltration of grinding dust and the like into the closed space R.

Moreover, since the surface to be processed can be maintained in a wet state by supplying moisturizing water to the wafer W, adhesion of grinding dust remaining on the surface to be processed can be suppressed.

After the wafer W is sucked by the second chuck 4, the frame 52 is moved away from the second chuck 4 as shown in FIG. 5(g).

In this manner, according to the wafer holding device 5 according to the embodiment of the present invention, the suction pad 51 sucks and holds the outer peripheral edge of the wafer W with negative pressure without contacting the device forming region at the center of the wafer W, Damage to the wafer W and contamination of the devices due to biting of grinding dust can be suppressed compared to the conventional case where the entire surface of the wafer W is sucked. Moreover, since the suction pad 51 contacts the outer peripheral edge of the wafer W, even a warped wafer W can be held by suction.

In addition, the present invention can be modified in various ways without departing from the spirit of the present invention, and it is natural that the present invention extends to such modifications.

REFERENCE SIGNS LIST 1 ... Wafer delivery system 2 ... Wafer carrier and holder 3 ... First chuck 4 ... Second chuck 5 ... Wafer holder 6 ... Transfer mechanism 11 ... Base REFERENCE SIGNS LIST 12: Adsorbent 51: Adsorption pad 52: Frame 53: Annular groove 54: Pipe line 55: Communication hole 56: Bolt hole 61: Telescopic arm 62: Link 70 Washing brush S1 Vacuum source S2 Compressed air source S3 Water source W Wafer

Claims (2)

A holding device for sucking and holding a wafer,
a suction pad formed in a ring shape having a diameter larger than the device forming region of the wafer and capable of coming into contact with an outer peripheral edge of the wafer;
a frame embedding the suction pad on the bottom surface;
a vacuum source connected to the suction pad to create a negative pressure between the suction pad and the wafer;
a water supply source that is connected to a communication hole vertically penetrating the frame and supplies moisturizing water into the frame to press the wafer downward so as to offset the external pressure that presses the wafer toward the frame;
A wafer holding device comprising: A wafer holding device according to claim 1 ;
a transfer mechanism connected to the frame for transferring the wafer holding device;
A wafer carrier and holder, comprising: