JP7807249B2 - Method for arranging protective member and method for processing workpiece - Google Patents

Description

The present invention relates to a protective member disposition method for disposing a protective member on a workpiece, and a workpiece processing method for processing a workpiece on which a protective member is disposed.

In the manufacturing process for device chips used in electronic devices such as mobile phones and personal computers, first, multiple intersecting dividing lines (streets) are set on the surface of a wafer made of a semiconductor or other material. Then, devices such as ICs (Integrated Circuits) and LSIs (Large-scale Integration) are formed in each area defined by the dividing lines. The wafer is then divided along the dividing lines to form individual device chips.

Wafer division is performed, for example, using a cutting device equipped with an annular cutting blade (see, for example, Patent Document 1). Alternatively, wafer division is performed using a laser processing device capable of laser processing wafers, or a plasma etching device capable of plasma etching wafers (see, for example, Patent Documents 2 and 3).

In cutting machines, cutting water is supplied to the cutting blade and workpiece to remove generated heat and cutting chips while cutting the workpiece. However, when the cutting water that has absorbed the cutting chips comes into contact with the surface of the workpiece, the cutting chips adhere to the surface of the workpiece, causing the surface to become contaminated. To address this issue, a tape-like protective member is sometimes attached to the surface of the workpiece, and the workpiece is cut together with the protective member. In this case, contamination is prevented because the cutting water does not come into contact with the surface of the workpiece.

Furthermore, when a workpiece is laser-processed using a laser processing device, molten material known as debris is generated and adheres to the surface of the workpiece. Therefore, a water-soluble protective material is first applied to the entire surface of the workpiece before laser processing it. In this case, if the workpiece is subsequently washed, the debris adhered to the protective material can be removed along with the protective material. Furthermore, in a plasma etching device, a protective material (resist film) that exposes the workpiece along the intended dividing line is first applied to the surface of the workpiece, and the exposed portion of the workpiece is then plasma-etched.

Japanese Patent Application Laid-Open No. 2000-87282 Japanese Patent Application Laid-Open No. 2004-188475 Japanese Patent Application Laid-Open No. 2006-108428

However, when a workpiece is cut together with its protective member using a cutting device, the material that made up the protective member adheres to the cutting edge of the cutting blade, causing the cutting blade to become clogged. Eventually, the cutting resistance increases, and the workpiece cannot be cut properly. Furthermore, with laser processing devices, the impact of the laser processing can cause the protective member to peel off near the processing point. Furthermore, plasma etching of the workpiece requires exposure and development processes to form a protective member that precisely exposes a specified area on the workpiece's surface, which requires a lot of effort and expense.

Furthermore, processing equipment is sometimes used to form processing grooves in pipe-shaped workpieces, but it is not easy to process such workpieces precisely. One reason for this is that the workpiece is crushed and deformed when it is processed, causing the processing position to shift. To address this, powdered resin material is filled into the workpiece's communicating holes, which are then melted and a protective member is placed in the communicating holes to resist deformation of the workpiece. However, the longer the workpiece is and the smaller its inner diameter, the more difficult it becomes to pack the powdered resin material.

As such, protective materials that are placed on workpieces for processing can cause various problems when they are placed on the workpiece or when the workpiece is being processed.

The present invention was made in consideration of these problems, and its purpose is to provide a protective member arrangement method that can easily and inexpensively arrange a protective member in a predetermined shape in a predetermined area of a workpiece, and a method for processing the workpiece.

One aspect of the present invention provides a method for disposing a protective member on a surface of a workpiece that is partitioned by a plurality of intersecting planned division lines and has devices formed in each area of the surface, while exposing the workpiece along the planned division lines. The method includes a melting step of melting the resin using an injection tool that has a heater and heats and melts the resin with the heater and injects it; a disposing step of disposing the molten resin injected from the injection tool on the device on the surface of the workpiece; and a solidifying step of solidifying the resin on the surface of the workpiece to dispose the protective member on the surface.

Preferably, in the disposing step, the molten resin is stretched into a thread-like shape and disposed on the surface of the workpiece.

More preferably, the resin is a polyolefin resin or a polyester resin.

According to another aspect of the present invention, there is provided a method for processing a workpiece, the workpiece being partitioned by a plurality of mutually intersecting planned dividing lines and having devices formed in each area of its surface , by exposing the workpiece along the planned dividing lines, disposing a protective member on the surface, and processing the workpiece along the planned dividing lines, the method comprising: a melting step of melting the resin using an injection tool having a heater that heats and melts the resin with the heater and injects it; an disposing step of disposing the molten resin injected from the injection tool on the devices on the surface of the workpiece; a solidifying step of solidifying the resin on the surface of the workpiece to dispose a protective member on the surface; a processing step, after the solidifying step, processing an area of the workpiece where the protective member is not disposed; and a removal step, after the processing step, of attaching a tape to the protective member of the workpiece from above and removing the protective member from the workpiece by lifting the tape from the workpiece.

Preferably, in the disposing step, the molten resin is stretched into a thread-like shape and disposed on the surface of the workpiece.

In one aspect of the present invention, a protective member disposing method and a workpiece processing method use an injection tool that has a heater and that heats and melts resin while injecting it. The resin injected from the injection tool is then disposed on the workpiece and solidified, forming a protective member on the workpiece. This method eliminates the need to remove protective member from unnecessary locations, making it possible, for example, to dispose the protective member only in a specified area on the surface of the workpiece, or to form the protective member into a thread-like shape and dispose it in the through-hole of a pipe-shaped workpiece.

As a result, by not placing a protective member near the cutting blade or laser beam processing point, clogging of the cutting blade caused by cutting the protective member can be prevented, and the protective member can also be prevented from peeling off due to the impact of laser processing. Furthermore, the protective member used as the resist film required for plasma etching can be easily and inexpensively placed without the need for exposure and development processes. Furthermore, a protective member can be formed in a shape that allows it to be easily placed in the communicating holes of a pipe-shaped workpiece.

Therefore, one aspect of the present invention provides a protective member disposition method that easily and inexpensively disposes a protective member in a predetermined shape in a predetermined area of a workpiece, and a method for processing the workpiece.

FIG. 2 is a perspective view schematically showing a workpiece. 1A to 1C are cross-sectional views schematically illustrating a melting step and a disposing step. FIG. 3A is a cross-sectional view schematically showing a workpiece having a protective member disposed on its surface, and FIG. 3B is a cross-sectional view schematically showing an example of a processing step. FIG. 4A is a cross-sectional view schematically showing another example of the processing step, and FIG. 4B is a cross-sectional view schematically showing yet another example of the processing step. FIG. 5(A) is a cross-sectional view schematically showing the first stage of the removal step, FIG. 5(B) is a cross-sectional view schematically showing the protective member with tape attached, and FIG. 5(C) is a cross-sectional view schematically showing the second stage of the removal step. FIG. 6A is a plan view that schematically shows how molten resin is spread, and FIG. 6B is a plan view that schematically shows how thread-like resin is disposed. FIG. 7A is an enlarged cross-sectional view schematically showing a workpiece on which a thread-like protective member is disposed, and FIG. 7B is a cross-sectional view schematically showing a removing step. Figure 8(A) is a perspective view showing a workpiece having a communicating hole, and Figure 8(B) is a perspective view showing a workpiece having a thread-like protective member disposed in the communicating hole. Figure 9(A) is a perspective view that schematically shows how a workpiece having a thread-like protective member disposed in a communicating hole is processed, and Figure 9(B) is a perspective view that schematically shows how the thread-like protective member disposed in the communicating hole is pushed out. FIG. 10(A) is a flowchart showing the flow of each step of a protective member disposing method and processing method according to one example, and FIG. 10(B) is a flowchart showing the flow of each step of a protective member disposing method and processing method according to another example.

An embodiment of the present invention will be described with reference to the accompanying drawings. First, a workpiece on which a protective member is disposed in accordance with the protective member disposing method and workpiece processing method of this embodiment will be described. Figure 1 is a perspective view schematically illustrating an example of a workpiece 1.

The workpiece 1 is, for example, a wafer made of a material such as Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), or other semiconductor. Alternatively, the workpiece 1 is a roughly disk-shaped substrate made of a material such as sapphire, glass, or quartz.

A plurality of mutually intersecting planned division lines 3 are set on the surface 1a of the workpiece 1. Devices 5 such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are formed in each area defined by the planned division lines 3. By dividing the workpiece 1 along the planned division lines 3, individual device chips each equipped with a device 5 can be formed. Cutting the workpiece 1 along the planned division lines 3 is performed using processing equipment such as a cutting device, laser processing equipment, or plasma etching equipment.

The cutting device is equipped with an annular cutting blade with a grinding wheel on its outer periphery. The grinding wheel of the cutting blade contains abrasive grains made of a material such as diamond, and a binder made of a material such as resin or metal that disperses and fixes the abrasive grains. The cutting device cuts the workpiece 1 by cutting the grinding wheel into the workpiece 1 while rotating the cutting blade, forming dividing grooves along the planned dividing lines 3 and dividing the workpiece 1.

In a cutting device, cutting water is supplied to the cutting blade and workpiece 1 when cutting the workpiece 1. The cutting water removes heat generated by cutting and also removes cutting chips generated from the workpiece 1 and cutting blade during cutting. However, if the cutting water containing cutting chips comes into contact with the surface 1a of the workpiece 1, problems arise, such as contamination of the surface 1a of the workpiece 1 or adhesion of cutting chips to the device 5, reducing the quality of the device chip.

Therefore, in the past, a tape-like protective member was applied to the entire surface 1a of the workpiece 1, and the workpiece 1 was cut together with the protective member. In this case, the surface 1a of the workpiece 1 is protected by the protective member, so it is not contaminated by cutting water, etc. However, when the workpiece 1 together with the protective member is cut with a cutting blade, the material that made up the protective member adheres to the grinding wheel portion of the cutting blade, causing the cutting blade to become clogged. A cutting blade in this state experiences high cutting resistance and is unable to cut the workpiece 1 normally.

The laser processing device, which cuts the workpiece 1 by laser processing, has the function of focusing a laser beam of a wavelength absorbed by the workpiece 1 onto the workpiece 1 and ablation-processing the workpiece 1. The laser processing device irradiates the workpiece 1 with a laser beam along the planned division line 3, forming a division groove in the workpiece 1.

At this time, molten material called debris is generated from the workpiece 1 and adheres to the surface 1a of the workpiece 1, so the surface 1a of the workpiece 1 is first covered with a water-soluble protective material before the workpiece 1 is laser processed. The generated debris adheres to the water-soluble protective material, but when the ablation-processed workpiece 1 is washed, the debris is washed away along with the water-soluble protective material, so no debris remains on the workpiece 1.

However, when a laser beam is focused on the workpiece 1 through a water-soluble protective material, the protective material may partially peel off. This is because if the processing point of the workpiece 1 is covered with a protective material, the protective material is subjected to a strong impact that breaks through when the workpiece 1 is partially melted or vaporized by the laser beam and scattered. If the protective material partially peels off and the surface 1a of the workpiece 1 is exposed, debris may adhere to the exposed area.

A plasma etching device capable of plasma etching the workpiece 1 supplies plasma etchant gas to the workpiece 1. The etchant gas then partially removes the workpiece 1, forming division grooves along the planned division lines 3. At this time, a resist film must be applied in advance as a protective member to the surface 1a of the workpiece 1 to prevent the etchant gas from acting on areas other than the planned division lines 3. Here, the resist film must precisely expose a predetermined area of this surface 1a.

To apply a resist film that exposes a predetermined area to the workpiece 1, first, a photosensitive resin material is applied to the entire surface 1a of the workpiece 1, and light is applied along the planned dividing lines 3, or to areas other than the planned dividing lines 3, to partially alter the resin material. A developer is then applied to the resin material, removing the resin material in the areas that overlap with the planned dividing lines 3, thereby exposing the surface 1a of the workpiece 1 along the planned dividing lines 3.

As such, applying a resist film to the workpiece 1 requires a photosensitive resin material, a developer, and a cleaning solution, and the resin material must be precisely exposed to light. Therefore, plasma etching requires a large amount of money and a long processing time. It also requires complex and expensive exposure equipment.

Furthermore, the workpieces processed by the processing device are not limited to plate-shaped objects such as semiconductor wafers. Figure 8(A) and other figures schematically show a pipe-shaped workpiece 15 equipped with a communicating hole 17. The pipe-shaped workpiece 15 processed by the processing device is formed, for example, with an outer diameter of approximately 2 mm and an inner diameter of approximately 1 mm.

The pipe-shaped workpiece 15 is made of a flexible, bendable material such as resin or glass. For example, the workpiece 15 is precisely cut to a predetermined length, or a groove is formed at a specific location. The workpiece 15 can then be incorporated into precision machinery as a fluid flow path or used in medical procedures.

However, it is not easy to precisely machine such a workpiece 15. First, it is difficult to fix the pipe-shaped workpiece 15. Also, when a cutting tool is applied to the workpiece 15, the workpiece 15 may deform and be crushed, resulting in a shift in the machining position. To address this issue, a conventional method has been to fill the communicating holes 17 of the workpiece 15 with a powdered resin material, melt it, and then provide a protective member in the communicating holes 17 to resist deformation. However, the longer the workpiece 15 is, and the smaller the inner diameter of the workpiece 15, the more difficult it becomes to pack the powdered resin material.

As such, various problems can arise when protective members are placed on the workpieces 1, 15 for processing, or when the workpieces 1, 15 are processed. Therefore, in the protective member placement method and workpiece processing method according to this embodiment, protective members of a predetermined shape are placed in predetermined areas on the workpieces 1, 15 to prevent problems caused by the protective members. The protective member placement method and workpiece processing method according to this embodiment are described below.

Figure 10(A) is a flowchart showing the flow of each step in the method for processing a workpiece according to this embodiment. However, it is not necessary to perform all of the steps shown in Figure 10(A). Furthermore, the protective member disposing method according to this embodiment is included in the method for processing a workpiece shown in Figure 10(A). Therefore, the protective member disposing method will be explained in conjunction with the explanation of the method for processing a workpiece below.

First, we will explain an example in which a protective member is placed on the plate-shaped workpiece 1 shown in Figure 1 and then processed. That is, we will explain a case in which a workpiece 1 is partitioned by a plurality of mutually intersecting planned division lines 3, and devices 5 are formed in each region of the surface 1a. The workpiece 1 is exposed along the planned division lines 3, and a protective member is placed on the surface 1a and then processed.

First, a melting step S10 is performed in which the resin is melted using an injection tool that has a heater and injects the resin while heating and melting it, and a disposing step S20 is performed in which the molten resin injected from the injection tool is disposed on a device 5 on the surface 1a of the workpiece 1. Figure 2 is a cross-sectional view that schematically shows the melting step S10 and the disposing step S20.

Here, we will explain the injection tool 2 used in the melting step S10 and the disposing step S20. For example, the injection tool 2 is a glue gun, and has the function of melting and injecting the rod-shaped resin 4. The operator holds the injection tool 2 in their hand. The main body 6 of the injection tool (glue gun) 2 shown in Figure 2 includes a grip portion 8a that the operator holds when holding the main body 6, and a trigger 8b on which the fingers of the hand gripping the grip portion 8a can be hooked. A path is provided inside the upper end of the main body 6 through which the rod-shaped resin 4 is introduced, melted, and injected.

Explaining in more detail, the main body 6 has a support section 10 at its rear end into which rod-shaped resin 4 is introduced and supported. The tip of the rod-shaped resin 4 introduced from the inlet of the support section 10 passes through a feed section 12 provided at the outlet on the tip side of the support section 10, advances through the external space, and then advances again inside the main body 6 from an inlet 14 on the front side of the main body 6.

The feeding part 12 is mechanically connected to the trigger 8b. When the operator pulls the trigger 8b with their fingers, the feeding part 12 moves forward of the main body 6, feeding the resin 4 forward and sending the resin 4 into the inlet 14.

A heater 16 is housed inside the front of the main body 6. The heater 16 is arranged to surround the resin 4 that is introduced through the inlet 14 and flows inside the main body 6. The heater 16 heats and melts the resin 4. A power cable 22 that connects to a power source is provided at the base of the grip portion 8a of the main body 6, and the power cable 22 is connected to the heater 16 inside the main body 6.

The heater 16 is powered by power supplied from the power cable 22. The heater 16 is, for example, a PTC (Positive Temperature Coefficient) heating element, and has the function of heating an object to a predetermined temperature. The heater 16 is configured to heat the resin 4 to a temperature above its melting point or softening point; for example, the heater 16 heats the resin 4 to approximately 165°C.

At the very tip of the main body 6 is an injection section 18 for molten resin 20 formed by heating rod-shaped resin 4 with a heater 16. When the operator pulls the trigger 8b with their finger, the feed section 12 pushes the rod-shaped resin 4 into the main body 6, and the molten resin 20 heated by the heater 16 is extruded from the injection section 18.

A material known as a hot melt adhesive is preferably used as the material for resin 4. Examples of materials that can be used for resin 4 include polyolefin resin, polyester resin, ethylene vinyl acetate resin, and polyamide resin.

In the melting step S10, a rod-shaped resin 4 is introduced into the injection tool 2, and the resin 4 is heated and melted by the heater 16. Then, in the disposing step S20, the injection tool 2 is moved above the device 5 on the surface 1a of the workpiece 1, and the trigger 8b is pulled to inject the molten resin 20 from the injection tool 2, disposing the injected resin 20 on the device 5. The temperature of the molten resin 20 decreases as it spreads from the point of impact on the device 5 to the surrounding area.

Next, a solidification step S30 is performed in which the molten resin 20 is solidified on the surface 1a of the workpiece 1 to form a protective member on the surface 1a. Figure 3(A) includes a cross-sectional view that schematically shows the protective member 9 formed by solidifying the resin 20 on the surface 1a of the workpiece 1. The resin 20 is solidified, for example, by being allowed to cool. This allows the protective member 9 to be formed to protect the device 5 formed on the surface 1a of the workpiece 1.

In the disposing step S20, by not disposing the molten resin 20 in the area along the planned dividing line 3 on the surface 1a of the workpiece 1, a predetermined area on the surface 1a of the workpiece 1 along the planned dividing line 3 can be exposed from the protective member 9. In this case, there is no need to perform a process such as precisely exposing part of the resin 20 to light, nor is there any need to apply a developer to the resin 20.

After the solidification step S30, a processing step S40 is performed to process the area of the workpiece 1 where the protective member 9 is not provided. Figure 3(A) is a cross-sectional view showing a schematic view of the workpiece 1 held on the chuck table 26 of the processing device 24. The chuck table 26 has the function of suction-holding the workpiece 1 to be processed. Tape 7 may be attached to the back surface 1b of the workpiece 1 in advance. The outer periphery of the tape 7 may also be attached to a ring frame (not shown) made of a metal material.

The processing of the workpiece 1 can be, for example, cutting processing in which the workpiece 1 is cut with an annular cutting blade, laser processing in which a laser beam is irradiated onto the workpiece 1, or plasma etching processing in which an etchant gas converted into plasma is applied to the workpiece 1. However, the processing performed in processing step S40 is not limited to these.

Figure 3(B) is a cross-sectional view that schematically illustrates cutting of the workpiece 1 as an example of processing step S40. The cutting of the workpiece 1 is performed by a cutting device 24a. The cutting device 24a has a chuck table 26 that holds the workpiece 1 by suction, and a cutting unit 28 that cuts the workpiece 1 held by the chuck table 26.

The cutting unit 28 has a spindle 30 parallel to the upper surface of the chuck table 26, a rotary drive source (not shown) that rotates the spindle 30, and a cutting blade 32 fixed to the tip of the spindle 30. The cutting blade 32 has an annular grinding wheel portion on its outer periphery that contains countless abrasive grains made of diamond or the like and a binder made of resin or metal material that disperses and fixes the abrasive grains.

When cutting the workpiece 1, the spindle 30 is rotated to rotate the cutting blade 32, and the cutting unit 28 is lowered so that the bottom end of the grinding wheel portion of the cutting blade 32 is lower than the back surface 1b of the workpiece 1. Next, the cutting unit 28 and chuck table 26 are moved relatively in a direction parallel to the top surface of the chuck table 26, and the rotating cutting blade 32 cuts into the workpiece 1 along the intended division line 3. This forms a division groove in the workpiece 1.

After cutting the workpiece 1 along one planned dividing line 3, the workpiece 1 is similarly cut along the other planned dividing lines 3 with the cutting blade 32. When the workpiece 1 has been cut along all planned dividing lines 3, the workpiece 1 is divided into individual chips.

At this time, the protective member 9 exposes the workpiece 1 along the planned dividing line 3, so the cutting blade 32 does not cut into the protective member 9. As a result, clogging of the cutting blade 32 due to cutting the protective member 9 does not occur, and the processing load on the workpiece 1 does not increase.

Figure 4(A) is a cross-sectional view schematically showing laser processing of the workpiece 1 as another example of processing step S40. The laser processing of the workpiece 1 is performed by laser processing device 24b. Laser processing device 24b has a chuck table 26 that holds the workpiece 1 by suction, and a laser processing unit 34 that laser processes the workpiece 1 held by the chuck table 26.

The laser processing unit 34 has the function of focusing a laser beam of a wavelength that can be absorbed by the workpiece 1 onto the workpiece 1. The laser processing unit 34 includes a laser oscillator that can emit a laser beam of a wavelength of, for example, 355 nm, and an optical system that shapes the laser beam into a predetermined shape and irradiates it at a predetermined position, and is equipped with a processing head 36 at the end of the optical system. The laser processing unit 34 has the function of emitting a laser beam 38 from the processing head 36 and focusing it on the workpiece 1.

When laser processing the workpiece 1, a laser beam 38 is emitted from the processing head 36 and focused on the workpiece 1 at a predetermined height while the laser processing unit 34 and chuck table 26 are moved relatively in a direction parallel to the upper surface of the chuck table 26. The workpiece 1 is then laser processed (ablation processed) along the planned division lines 3 to form division grooves in the workpiece 1. When the workpiece 1 has been laser processed along all of the planned division lines 3, the workpiece 1 can be divided into individual chips.

However, there are cases where irradiating the workpiece 1 with the laser beam 38 along each planned division line 3 once is not enough to form high-quality division grooves of sufficient depth. In such cases, the laser beam 38 may be irradiated onto the workpiece 1 multiple times while changing the height of the focal point of the laser beam 38. Then, by repeating the laser processing multiple times, a division groove penetrating the back surface 1b of the workpiece 1 is formed in the workpiece 1.

Here, the protective member 9 exposes the workpiece 1 along the planned dividing line 3, so the processing position is not covered by the protective member 9. As a result, the protective member 9 is not pushed up by the strong impact caused by the irradiation of the laser beam 38, and the protective member 9 is not partially peeled off from the workpiece 1 due to laser processing.

Figure 4(B) is a cross-sectional view schematically showing plasma etching of the workpiece 1 as yet another example of processing step S40. Plasma etching of the workpiece 1 is performed in a plasma etching apparatus 24c. The plasma etching apparatus 24c includes a chuck table 26 that holds the workpiece 1 by suction, and a processing chamber (not shown) that houses the chuck table 26.

For example, inside the processing chamber, a pair of electrodes connected to a high-frequency power source are arranged facing each other in the vertical direction. The lower electrode is housed inside a chuck table 26 that holds the workpiece 1, and a cooling mechanism for cooling the workpiece 1 is provided on the chuck table 26.

When performing plasma etching, the interior of the processing chamber is evacuated, the air inside is then exhausted, etchant gas 40 is introduced into the processing chamber, and a high-frequency voltage is applied to a pair of electrodes. The etchant gas is then converted into plasma near the chuck table 26, and the converted etchant gas 40 acts on the exposed portions of the workpiece 1, etching the workpiece 1 and forming separation grooves.

Note that if the workpiece 1 is significantly thicker than the width of the dividing grooves formed in the workpiece 1, there is a risk that the sidewalls of the areas removed along the intended dividing lines 3 may be significantly damaged by etching while the workpiece 1 is being etched. Therefore, after allowing the etching of the workpiece 1 to proceed to a certain extent, a protective film may be formed to protect the formed wall surfaces, and then etching may be resumed. Then, the etching of the workpiece 1 and the protection of the wall surfaces may be repeated to further excavate the workpiece 1.

For example, sulfur hexafluoride ( _SF6 ) is used as the etchant gas 40. When a protective film is to be formed on the wall surface of the workpiece 1 exposed by etching, a _gas such as _C4F8 is applied to the wall surface to form the protective film.

Here, the protective member 9 exposes the workpiece 1 along the planned dividing line 3, so the processing position is exposed through the protective member 9. In other words, the protective member 9 functions as a resist film. In the workpiece processing method according to this embodiment, the protective member 9 that functions as a resist film can be easily and quickly formed on the workpiece 1 without using a photosensitive resin or performing exposure and development processes.

When processing step S40 is performed using either method, for example, a dividing groove 3a (see Figure 5(A), etc.) is formed in the workpiece 1 along the planned dividing line 3, and the workpiece 1 is divided into individual chips.

In the workpiece processing method according to this embodiment, after processing step S40 is performed, removal step S50 is performed to remove protective member 9 from workpiece 1. Removal step S50 is explained with reference to Figures 5(A), 5(B), and 5(C). In removal step S50, for example, tape 11 is applied from above to protective member 9 of workpiece 1, and tape 11 is then lifted up from workpiece 1 to remove protective member 9 from workpiece 1.

This will be explained in more detail. In the removal step S50, as shown in FIG. 5(A), the tape 11 is positioned above the workpiece 1. Here, the tape 11 includes an adhesive layer exposed downward and a base layer that supports the adhesive layer. Next, the tape 11 is lowered to contact the protective member 9 disposed on the surface 1a side of the workpiece 1. FIG. 5(B) is a cross-sectional view that schematically shows the tape 11 in contact with and adhered to the protective member 9.

The tape 11 is then pulled upward. Figure 5(C) is a cross-sectional view that schematically shows the state in which the tape 11 has been pulled upward. When the tape 11 is pulled upward, the protective members 9 arranged on each device 5 are peeled off together from the surface 1a of the workpiece 1 and removed from the workpiece 1.

As described above, in the protective member disposing method and workpiece processing method according to this embodiment, molten resin 20 can be disposed in a predetermined area of the workpiece 1 using an injection tool 2 capable of injecting molten resin 20. This allows the protective member 9 to be disposed in a predetermined area on the surface 1a of the workpiece 1. According to this method, the protective member 9 can be disposed in the predetermined area easily and inexpensively.

In the disposing step S20, the molten resin 20 injected from the injection tool 2 onto the device 5 on the workpiece 1 flows and spreads in a circular shape over the device 5 until it solidifies in the solidifying step S30. However, the device 5 formed on the surface 1a of the workpiece 1 is often rectangular.

Therefore, to form a protective member 9 that sufficiently covers the entire device 5, the amount of molten resin 20 injected onto each device 5 must be large enough to reach the corners of the device 5. However, in this case, the resin 20 spreads far away from each side of the device 5, resulting in a large amount of resin 20 being used. Also, the area of the workpiece 1 that is not covered by the protective member 9 becomes smaller, making it impossible to expose a sufficiently large area of the surface 1a of the workpiece 1 from the protective member 9.

Therefore, in the disposing step S20, the molten resin 20 may be spread in a desired direction on the surface 1a of the workpiece 1 to form a protective member 9 that sufficiently covers the entire device 5 but does not cover positions far away from the device 5. Figure 6(A) is a plan view that schematically shows how the molten resin 20 is spread on the surface 1a of the workpiece 1. In the example shown in Figure 6(A), the molten resin 20 is stretched using the injection part 18 of the injection tool 2.

More specifically, molten resin 20 is first injected into the center of device 5. Then, while the lower end of injection unit 18 is buried in the molten resin 20, injection unit 18 is moved toward one corner of device 5. This causes the resin 20 to be stretched toward that corner. After that, the injection unit 18 is moved toward another corner of device 5, further stretching the molten resin 20. This process is repeated until the molten resin 20 is stretched over all four corners. In Figure 6, the trajectory 18a of injection unit 18 is shown by a dashed line.

Here, when the injection unit 18 is close to a corner of the device 5, additional resin 20 may be injected from the injection unit 18 as needed. On the other hand, when the injection unit 18 is close to the center of one of the sides of the device 5, no additional molten resin 20 is injected from the injection unit 18. This allows the corner of the device 5 to be sufficiently covered with the resin 20, and prevents the resin 20 from spreading to positions far from the device 5. Then, by performing the solidification step S30, a protective member 9 that covers the device 5 without waste can be formed.

Note that the protective member 9, which fully covers the device 5 without waste, may be disposed on the workpiece 1 using a different procedure. That is, the area where the protective member 9 is disposed may be controlled using a different procedure. Figure 6(B) is a plan view schematically showing a protective member 13 disposed on the surface 1a of the workpiece 1 using a different procedure. The protective member 13 is formed by disposing the resin 20 on the surface 1a of the workpiece 1 while stretching it into a thread-like shape in the disposing step S20, and then solidifying the resin 20 in the solidifying step S30.

The resin 20 stretched into threads can be formed, for example, by slowly injecting the resin 20 from the injection tool 2 in a state where the resin has low fluidity. It can also be formed by grasping two ends of the resin 20 injected from the injection tool 2 and pulling the grasped portions apart. However, the method for forming the resin 20 stretched into threads is not limited to these.

Then, in the disposing step S20, the formed, elongated thread-like resin 20 is disposed on the surface 1a of the workpiece 1. For example, as shown in Figure 6(B), the thread-like resin 20 is deformed into a spiral shape to cover the device 5 without any gaps. After that, when the temperature of the resin 20 is reduced by performing the solidifying step S30, a protective member 13 is formed to cover the device 5. Note that the resin 20 may deform to fill gaps before solidifying. Figure 7(A) is a cross-sectional view schematically showing the workpiece 1 on which the thread-like protective member 13 is disposed.

This method makes it easy to arrange a protective member 13 of a suitable shape on the surface 1a of the workpiece 1, even in areas of the workpiece 1 where processing is not desired or areas requiring protection are not rectangular.

When thread-like protective members 13 are disposed on the surface 1a of the workpiece 1, tape 11 does not need to be used in the removal step S50 to remove the protective members 13, and the thread-like protective members 13 may be pulled up from one end. Figure 7(B) is a cross-sectional view that schematically shows how the thread-like protective members 13 are pulled up from the end.

The protective member 13 can be pulled up, for example, using a tool (not shown) such as tweezers that has a pair of gripping portions and whose tip ends can be adjusted to pick up the protective member 13. Alternatively, the protective member 13 may be pulled up using a single needle-shaped tool that can pierce the protective member 13, by piercing the protective member 13 with the needle-shaped tool. Furthermore, the removal step S50 using the pulling-up technique may be performed on protective members in forms other than thread-like protective members 13.

Here, "molten resin or protective material stretched into a thread-like shape" refers to a state in which the cross-sectional size of the resin or protective material is uniform throughout, and the length is extremely long compared to the cross-sectional diameter. This shape can also be called string-like, rope-like, or long, and there are no particular restrictions on the cross-sectional size or length. The term "thread-like" does not limit the use of the resin or protective material.

In the above description, the resin 4 is melted, the molten resin 20 is injected from the injection tool 2, stretched into a thread, and disposed on the surface 1a of the workpiece 1. The resin 20 is then cooled and solidified on the surface 1a of the workpiece 1, thereby disposing the protective member 13 on the surface 1a of the workpiece 1. However, the timing of solidification of the molten resin 20 is not limited to this. In other words, the molten resin 20 may be stretched into a thread, first cooled and solidified to form the thread-like protective member 13, and then the thread-like protective member 13 may be disposed on the workpiece 1.

Explaining from a different angle, the protective member disposing method and workpiece processing method according to this embodiment have been mainly described up to this point in which the solidifying step S30 is performed after the disposing step S20. However, the solidifying step S30 may be performed before the disposing step S20, or may be performed simultaneously with the disposing step S20. Figure 10 is a flowchart illustrating the flow of each step of the workpiece processing method according to this embodiment in which the solidifying step S30 is performed before the disposing step S20.

In reality, the resin 20 begins to cool when it is injected from the injection tool 2, and it is not apparent at what point the resin 20 solidifies to become the protective members 9, 13. At the very least, when molten resin 20 is injected from the injection tool 2 and the protective members 9, 13 are disposed on the workpiece 1, it can be said that both the disposing step S20 and the solidifying step S30 have been completed.

Fiber-like protective members can be formed by injecting molten resin 20 from the injection tool 2, stretching the resin 20 into a fiber-like shape, and solidifying it. These protective members can be applied to a variety of workpiece shapes for a variety of applications. For example, a fiber-like protective member can be suitably applied to a pipe-shaped workpiece 15 having a communicating hole 17, as shown in Figure 8(A).

Next, we will explain the protective member disposition method and workpiece processing method according to this embodiment, which involves disposing a thread-like protective member on a pipe-shaped workpiece 15. Below, we will explain the flow of each step with reference to the flowchart shown in Figure 10 (B).

First, a melting step S10 is performed in which the resin 4 is melted using the injection tool 2 shown in Figure 2. Next, a solidification step S30 is performed in which the molten resin 20 is injected from the injection tool 2, stretched into a thread-like shape, and solidified to form a thread-like protective member 19 (see Figure 8 (B)).

The thickness of the thread-like protective member 19 is determined by the length of the molten resin 20 before and after it is stretched. More specifically, the rate of change in the cross-sectional area of the resin 20 before and after it is stretched is inversely proportional to the rate of change in the length of the resin 20 before and after it is stretched. For example, if the resin 20 is stretched to twice its original length, the cross-sectional area of the resin 20 will be halved. Therefore, the thickness of the thread-like protective member 19 can be controlled by the length to which the molten resin 20 is stretched.

Then, in the solidification step S30, the thickness (diameter) of the thread-shaped protective member 19 is preferably determined by referring to the thickness (diameter) of the communicating hole 17 of the pipe-shaped workpiece 15. For example, the thickness of the thread-shaped protective member 19 should be equal to or smaller than the thickness of the communicating hole 17. However, if the thread-shaped protective member 19 is too thin, the thread-shaped protective member 19 will not be able to perform the function described below. Therefore, for example, it is preferable that the thickness of the thread-shaped protective member 19 be at least half the thickness of the communicating hole 17. However, the thickness of the thread-shaped protective member 19 is not limited to this.

Next, an arrangement step S20 is performed in which the thread-like protective member 19 is arranged on the workpiece 15. Figure 8(B) is a perspective view that schematically shows the arrangement step S20. For example, in the arrangement step S20, the thread-like protective member 19 is arranged on the workpiece 15 by receiving it in the communication hole 17 of the workpiece 15.

More specifically, one end of the thread-like protective member 19 is inserted into the communication hole 17 of the workpiece 15, and the thread-like protective member 19 is pushed into the communication hole 17. Note that if the thread-like protective member 19 is thicker than the communication hole 17, it will be difficult to insert the thread-like protective member 19 into the communication hole 17.

Furthermore, the length of the protective member 19 does not need to match the length of the workpiece 15. If the protective member 19 is longer than the length of the workpiece 15, one or both ends of the protective member 19 housed in the communicating hole 17 will protrude from the workpiece 15, making it easier to ultimately remove the protective member 19 from the workpiece 15. In other words, the protective member 19 can be removed from the workpiece 15 simply by pinching and pulling out the protruding ends of the protective member 19.

Next, processing step S40 is performed to process the workpiece 15 on which the thread-like protective member 19 is disposed. Figure 9(A) is a schematic perspective view of the workpiece 15 being processed. For example, the workpiece 15 is cut by the cutting blade 32 of the cutting device 24a shown in Figure 3(B), forming a groove in the workpiece 15. When the groove extends from one end of the workpiece 15 to the opposite end, the workpiece 15 is cut.

For example, if a thread-like protective member 19 is not provided in the through-hole 17 of a pipe-shaped workpiece 15, when the cutting blade 32 is brought into contact with the workpiece 15, the workpiece 15 will be pressed by the cutting blade 32, deformed, and crushed. In this case, the processing position will be shifted, and the workpiece 15 will not be processed precisely.

In contrast, if a protective member 19 is provided in the communication hole 17, when the workpiece 15 is pressed against the cutting blade 32, the protective member 19 exerts a force on the workpiece 15 to maintain its shape, resisting the force that would deform the workpiece 15. As a result, the workpiece 15 is less likely to deform during processing, and the processing position is less likely to shift. This makes it possible to achieve precise processing of the workpiece 15.

Instead of using thread-like protective members 19, it is possible to fill the through holes 17 of the workpiece 15 with powdered resin material, heat and melt the powdered resin material inside the workpiece 15, and then place the protective member inside the through holes 17. However, in this case, the workpiece 15 must be able to withstand the temperature at which the resin material melts.

In addition, it is not easy to introduce powdered resin material into every corner of the communicating hole 17. Furthermore, the protective member formed by solidifying the molten powdered resin inside the communicating hole 17 may adhere to the inside of the communicating hole 17 and be difficult to remove. In contrast, this problem does not arise when thread-like protective members 19 are formed and placed in the communicating holes 17 of the workpiece 15.

After the processing of the workpiece 15 is completed, a removal step S50 is performed to remove the thread-like protective member 19 from the workpiece 15. Figure 9(B) is a perspective view schematically showing the removal step S50.

For example, in the removal step S50, the thread-like protective member 19 housed in the communication hole 17 is removed from the workpiece 15 by pushing it out of the workpiece 15. A convex jig 42, for example, may be used to push out the thread-like protective member 19. The convex jig 42 has a convex portion 44 whose thickness (diameter) is smaller than the thickness (diameter) of the communication hole 17.

When the convex portion 44 is inserted into one end of the communicating hole 17 while the convex jig 42 is used to push the thread-like protective member 19, a portion of the thread-like protective member 19 comes out from the opposite end of the communicating hole 17, making it possible to pinch and pull out the exposed portion of the protective member 19. Alternatively, if the length of the convex portion 44 of the convex jig 42 is longer than the workpiece 15, the tip of the convex portion 44 can be inserted into the communicating hole 17 and pushed through it, thereby removing the thread-like protective member 19 from the workpiece 15.

Furthermore, if at least one end of the thread-shaped protective member 19 is exposed from the communication hole 17 of the workpiece 15, the thread-shaped protective member 19 can be pulled out from the workpiece 15 without using the convex jig 42. In other words, the convex jig 42 does not necessarily have to be used in the removal step S50.

As described above, in the protective member disposing method and workpiece processing method according to this embodiment, the resin 20 injected from the injection tool 2 is disposed on the workpiece 1 and solidified, thereby disposing the protective members 9, 13 on the workpiece 1. This method makes it possible to easily and inexpensively dispose the protective members 9, 13 on the surface 1a of the workpiece 1 without performing a process to remove the protective members 9, 13 from unnecessary locations.

Furthermore, with the protective member disposing method and workpiece processing method according to this embodiment, the protective member 19 can be disposed relatively easily in the communication hole 17 even for a pipe-shaped workpiece 15. Furthermore, the protective member 19 can also be removed relatively easily from the communication hole 17 of the workpiece 15.

The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the above embodiment describes a case in which a protective member 19 is placed in the through-hole 17 of a pipe-shaped workpiece 15, and then the workpiece 15 is machined. However, one aspect of the present invention is not limited to this.

To secure the protective member 19 to the workpiece 15, the protective member 19 may be heated and melted before the workpiece 15 is processed. In this case, the protective member 19 adheres to the workpiece 15 as it cools and solidifies. This makes it difficult for the protective member 19 to move while the workpiece 15 is being processed.

Furthermore, when processing a workpiece 1 that is partitioned by a plurality of mutually intersecting planned division lines 3 and has devices 5 formed in each region of its surface 1a, and a thread-like protective member 13 is disposed on the workpiece 1, the protective member 13 may be heated and melted. In this case, too, the molten protective member 13 adheres to the surface 1a of the workpiece 1 as it cools and solidifies. Therefore, the protective member 13 can adequately protect the regions of the surface 1a that require protection while the workpiece 1 is being processed.

In the above embodiment, the case was described in which the operator holds the grip portion 8a of the injection tool 2 having the heater 16 in his or her hand and pulls the trigger 8b with his or her finger to inject molten resin 20 from the injection tool 2, but this aspect of the present invention is not limited to this. In other words, in one aspect of the present invention, the operator does not need to handle the injection tool 2 by hand, and an injection device equipped with another type of injection tool may be used to inject molten resin 20 into the workpiece 1.

For example, the injection device includes an injection tool that has a heater that can heat the resin and can inject molten resin, a support table that can support the workpiece 1 on its upper surface, and a movement unit that can move the injection tool and support table relatively in a direction parallel to the upper surface of the support table. The injection device then injects molten resin from the injection tool into a predetermined position on the workpiece 1 while controlling the relative positions of the injection tool and support table.

In addition, the structures, methods, etc. related to the above embodiments can be modified as appropriate without departing from the scope of the present invention.

REFERENCE SIGNS LIST 1, 15 Workpiece 1a Front surface 1b Back surface 3 Planned division line 3a Division groove 5 Device 9, 13, 19 Protective member 7, 11 Tape 17 Communication hole 2 Injection tool 4 Resin 6 Main body 8a Grip portion 8b Trigger 10 Support portion 12 Feed-out portion 14 Inlet 16 Heater 18 Injection portion 18a Trajectory 20 Molten resin 22 Power cable 24 Processing device 24a Cutting device 24b Laser processing device 24c Plasma etching device 26 Chuck table 28 Cutting unit 30 Spindle 32 Cutting blade 34 Laser processing unit 36 Processing head 38 Laser beam 40 Etchant gas 42 Convex jig 44 Convex portion

Claims (5)

1. A protective member disposing method for a workpiece, the workpiece having devices formed in each region of the surface thereof, partitioned by a plurality of mutually intersecting planned dividing lines, and disposing a protective member on the surface while exposing the workpiece along the planned dividing lines, the method comprising:
a melting step of melting the resin using an injection tool having a heater and injecting the resin while heating and melting the resin with the heater;
a disposing step of disposing the molten resin injected from the injection tool onto the device on the surface of the workpiece;
and a solidification step of solidifying the resin on the surface of the workpiece to thereby dispose the protective member on the surface. The protective member disposing method according to claim 1, characterized in that, in the disposing step, the molten resin is stretched into a thread-like shape and disposed on the surface of the workpiece. The protective member disposing method according to claim 1 or 2, characterized in that the resin is a polyolefin-based resin or a polyester-based resin. A method for processing a workpiece, the method comprising: exposing a workpiece along the planned dividing lines, the workpiece being partitioned by a plurality of planned dividing lines that intersect with each other and having devices formed in each area of the surface; disposing a protective member on the surface of the workpiece; and processing the workpiece along the planned dividing lines,
a melting step of melting the resin using an injection tool having a heater and injecting the resin while heating and melting the resin with the heater;
a disposing step of disposing the molten resin injected from the injection tool onto the device on the surface of the workpiece;
a solidification step of solidifying the resin on the surface of the workpiece to provide a protective member on the surface;
a processing step of processing an area of the workpiece where the protective member is not provided after the solidifying step;
a removing step, after the processing step, of attaching tape to the protective member of the workpiece from above and removing the protective member from the workpiece by lifting the tape from the workpiece. The method for processing a workpiece according to claim 4, characterized in that, in the disposing step, the molten resin is stretched into a thread-like shape and disposed on the surface of the workpiece.