TWI785231B - Wafer Processing Method - Google Patents

Abstract

[Problem] According to the present invention, it is possible to provide a wafer processing method that does not cause quality degradation of components even when a wafer is divided into individual components by positioning a push blade on a planned dividing line and applying an external force. [Solution] The wafer processing method of the present invention is composed of at least the following steps: a polyolefin sheet laying step, positioning the wafer in the opening of the frame having an opening for accommodating the wafer, and placing the polyolefin sheet The sheet is laid on the back of the wafer and the outer periphery of the frame; the integration step is to heat and thermocompress the polyolefin sheet to integrate the wafer and the frame through the polyolefin sheet; The focused point of the beam is positioned on the first planned line for division and the second planned line for division and irradiated to form a division starting point; in the first division step, the pushing knife is positioned on the first planned line for division and an external force is applied to divide the second division line. A planned dividing line; and, the second dividing step, positioning the pushing knife on the second planned dividing line and applying external force to divide the second planned dividing line; and by the first dividing step and the second dividing step The wafer is divided into individual components.

Description

Wafer Processing Method

The invention relates to a wafer processing method, which divides the wafer into individual components.

A wafer with multiple components such as ICs, LSIs, LEDs, etc. formed on the front side by dividing lines, is divided into individual components by a dicing device, a laser processing device, etc., and used in mobile phones, personal computers and other electronic devices. in the device.

There is a type of laser processing device in which the focused point of a laser beam having a penetrating wavelength to the wafer is positioned inside the planned division line and irradiated to form a modified layer as the starting point for division (for example, refer to Patent Document 1), and a type in which a laser beam having an absorptive wavelength to the wafer is positioned on the upper surface of the planned division line and irradiated to form a groove on the front surface by ablation as a division starting point ( For example, refer to Patent Document 2).

After the wafer is divided into individual elements by applying an external force or the like after forming a dividing starting point along the planned dividing line by the above-mentioned laser processing device. After the wafer that has passed the dividing step is divided into individual components, it is held on the dicing film and transported to the pick-up step while maintaining the form of the wafer, so the wafer put into the laser processing device is positioned. On the opening of the frame having an opening for accommodating the wafer, and by adhering the back side of the wafer and the frame to the adhesive layer side of the dicing adhesive film formed with an adhesive layer such as coating an adhesive, it becomes a dicing adhesive The state in which the membrane is integrated with the frame. Thereby, the wafer that has passed through the dividing step can be transported to the pick-up step while maintaining the form of the wafer without the individual divided elements detaching from the dicing film. [Prior art literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 3408805 [Patent Document 2] Japanese Patent Application Laid-Open No. 10-305420

[Problems to be Solved by the Invention] After positioning and sticking the back side of the wafer and the frame on the adhesive layer side of the dicing film, and applying an external force by positioning the push knife on the planned dividing line where the starting point of the dividing is formed, it will be supported on the dicing film through the dicing film. In the case of dividing the wafer on the frame, after dividing the first planned dividing line formed in the first direction by positioning the push knife and applying an external force, the second direction formed in the second direction intersecting the first direction is divided. Position the push knife on the predetermined line for two divisions and apply external force for division. In this case, the first planned dividing line that was divided earlier can be completely divided. However, when dividing along the dividing starting point of the first planned dividing line to form the dividing line, for example, the adhesive layer enters the dividing line, causing the undivided second planned dividing line to meander slightly, and it becomes difficult to press the edge of the knife precisely. Positioning along the second planned dividing line, if the pushing blade is positioned in this way and an external force is applied to divide the second planned dividing line, there is a problem that chipping of the component occurs and the quality deteriorates. In recent years, the small size of components (less than 2mm square) has been demanded, especially 0.5mm square, 0.25mm square, 0.15mm square, etc. The smaller the size of the component, the slightly meandering influence of the second dividing line will be become more pronounced.

The present invention was developed in view of the above facts, and its main technical task is to provide a wafer processing method that does not cause the wafer to be divided into individual components even if the push knife is positioned on the dividing line and an external force is applied. The quality of components will be reduced.

[Technical means to solve the problem] In order to solve the above-mentioned main technical problems, according to the present invention, a wafer processing method is provided, which divides a wafer with a plurality of elements formed on the front side into individual elements, and the plurality of elements are formed by the first direction in the first direction. It is divided by a planned dividing line and a second planned dividing line formed in a second direction intersecting with the first direction; the wafer processing method is composed of at least the following steps: a polyolefin sheet laying step, positioning the wafer In the opening of the frame having an opening for accommodating the wafer, a polyolefin sheet is laid on the back of the wafer and the outer periphery of the frame; in the integration step, the polyolefin sheet is heated and bonded by thermocompression to bond the wafer The circle and the frame are integrated by a polyolefin sheet; the step of forming the starting point of division is to position the converging point of the laser beam on the first planned dividing line and the second planned dividing line and irradiate to form the starting point of dividing; the first dividing step , positioning the pushing knife on the first planned dividing line and applying an external force to divide the first planned dividing line; and, the second dividing step, positioning the pushing knife on the second planned dividing line and applying an external force to divide the second Separating the predetermined line; and dividing the wafer into individual elements by the first dividing step and the second dividing step.

making the wavelength of the laser beam irradiated in the division starting point forming step have penetrability to the wafer, and the focusing point of the laser beam can be positioned inside the first division line and the second division line, To form a modified layer as the starting point of division. In addition, it is also possible to make the wavelength of the laser beam irradiated in the division starting point forming step absorb to the wafer, and to position the converging point of the laser beam between the first planned division line and the second planned division line. On the upper surface, a groove as a starting point for division is formed by ablation.

Preferably, the polyolefin sheet is selected from any one of polyethylene sheet, polypropylene sheet and polystyrene sheet. In addition, the wafer may be composed of any one of a silicon substrate, a sapphire substrate, a silicon carbide substrate, and a glass substrate.

[Efficacy of the invention] In the wafer processing method of the present invention, a wafer having a plurality of elements formed on the front surface is divided into individual elements. Divided by the second predetermined dividing line in the second direction where the direction intersects; the wafer processing method is at least composed of the following steps: a polyolefin sheet laying step, positioning the wafer on the frame with an opening for accommodating the wafer In the opening, the polyolefin sheet is laid on the back of the wafer and the outer periphery of the frame; in the integration step, the polyolefin sheet is heated and bonded by thermocompression to integrate the wafer and the frame through the polyolefin sheet ; Segmentation starting point forming step, positioning the laser beam's focus point on the first planned division line and the second planned division line and irradiating to form the division starting point; the first division step, positioning the pushing knife on the first division division line line and apply external force to divide the first planned dividing line; and, the second dividing step, position the pushing knife on the second planned dividing line and apply external force to divide the second planned dividing line; and by the first dividing step and the second dividing step divide the wafer into individual elements, so it will not be like the case of using a dicing adhesive film with an adhesive layer to stick the wafer, and a part of the adhesive layer enters the area of the first divided line In order to induce deviation, after the first planned dividing line is divided, the pressing knife can be precisely positioned on the second planned dividing line, and the problem of lowering the quality of the component can be solved.

In the following, each step of the wafer processing method based on the present invention will be described in sequence.

(Polyolefin sheet laying procedure) Referring to FIG. 1 and FIG. 2 , the steps of laying polyolefin sheets will be described at the same time. In Fig. 1, there is shown a perspective view showing an embodiment of the step of laying a polyolefin sheet. When carrying out the step of laying polyolefin sheets, first, as shown in FIG. Step 20 of the chuck table. The wafer 10 is made of, for example, a silicon (Si) substrate, and the elements 14 are formed on the front surface 10a divided by the first planned dividing line 12A and the second planned dividing line 12B, wherein the first planned dividing line 12A is formed on In the first direction indicated by the arrow X, the second planned division line 12B is formed in the second direction indicated by the arrow Y perpendicular to the first direction.

The chuck table 20 is made up of a disk-shaped adsorption chuck 21 made of porous ceramics with air permeability and a circular frame portion 22 surrounding the outer periphery of the adsorption chuck 21. The chuck table 20 is connected to a not-shown The wafer 10 mounted on the upper surface (holding surface) of the suction chuck 21 can be sucked and held by the suction means.

After the wafer 10, frame F and chuck table 20 are prepared, as shown in the figure, with respect to the holding surface of the suction chuck 21, the front side 10a side of the wafer 10 is placed downward on the suction chuck 21. center of. After the wafer 10 is placed on the suction chuck 21 , the frame F is placed on the suction chuck 21 while the wafer 10 is positioned at the center of the opening Fa. As can be understood from the figure, the size of the opening Fa of the frame F is formed larger than the wafer 10 to accommodate the wafer 10, and further, the size of the holding surface of the suction chuck 21 is formed slightly larger than that of the frame F. and set to a size that the holding surface of the suction chuck 21 on the outside of the frame F will be exposed.

As shown in FIG. 2, a circular polyolefin sheet, such as a polyethylene (PE) sheet 30, for covering the back surface 10b of the wafer 10, the frame F, and the adsorption chuck 21 is prepared, and placed on the adsorption chuck. 21 on. The polyolefin sheet is preferably formed with a thickness of 20 to 100 μm. As can be understood from FIG. 2 , the polyethylene sheet 30 of this embodiment is at least larger than the diameter of the suction chuck 21, preferably only slightly smaller than the wheel of the circular frame portion 22 of the chuck table 20. formed by the diameter. Thus, the entire holding surface of the suction chuck 21 is covered with the polyethylene sheet 30 . In addition, no adhesive layer such as an adhesive is formed on the mounting surface side of the polyethylene sheet 30 which is mounted on the wafer 10 and the frame F. As shown in FIG.

After the wafer 10, the frame F, and the polyethylene sheet 30 are placed on the suction chuck 21 of the chuck table 20, suction means (not shown) including a suction pump are operated, and the suction force Vm is applied to the suction. The chuck 21 is used to attract the wafer 10 , the frame F and the polyethylene sheet 30 . As mentioned above, since the polyethylene sheet 30 covers the entire upper surface (holding surface) of the suction chuck 21, the attractive force Vm acts on the wafer 10, the frame F, and the polyethylene sheet 30 as a whole. While sucking and holding on the suction chuck 21 , the air remaining between the wafer 10 , the frame F and the polyethylene sheet 30 is sucked and brought into close contact. Based on the above, the polyolefin-based sheet laying step is completed.

(integration step) After carrying out the above-mentioned polyolefin-based sheet laying step, then, carrying out the integration step. The integration steps will be described while referring to FIG. 3 .

In Fig. 3(a), a first embodiment for carrying out the integration step is shown. When carrying out the integration step, as shown in the figure, a hot air blowing means 40 (only a part shown) for heating the polyethylene sheet 30 is positioned above the chuck table 20, wherein the chuck table 20 is under the force of the suction force Vm In a state where the wafer 10 , the frame F and the polyethylene sheet 30 are sucked and held. Although the details are omitted, the hot air blowing means 40 is configured such that a heating part equipped with a temperature adjusting means such as a thermostat (Thermostat) is arranged on the exit side (lower side in the figure) facing the chuck table 20 side, and will A fan unit driven by a motor or the like is arranged on the opposite side (upper side in the figure), and the heating unit and the fan unit are driven to blow hot air L toward the chuck table 20 . When the hot air blowing means 40 is positioned above the chuck table 20, the hot air L is blown at least to the entire area of the wafer 10 covered by the polyethylene sheet 30 and the frame F by the hot air blowing means 40. The sheet 30 is heated at 120 to 140° C. near the melting point, or within a range from a temperature near the melting point to a temperature about 50° C. lower than the temperature near the melting point. By this heating, the polyethylene sheet 30 is softened, and the polyethylene sheet 30 is heat-compression bonded to the back surface 10b of the wafer 10 and the frame F in a tight state, so that the wafer 10, the frame F, and the polyethylene sheet 30 are integrated. change. In addition, the means for performing the integration step of heating the polyethylene sheet 30 and thermocompression bonding with the wafer 10 is not limited to the hot air blowing means 40 shown in FIG. 3( a ), and other means may be selected. Another means (second embodiment) will be described with reference to FIG. 3( b ).

As another means for implementing the above-mentioned integration step, the heating roller means 50 shown in FIG. 3( b ) may also be selected (only a part is shown). More specifically, the heating roller means 50 for heating and pressing the polyethylene sheet 30 is positioned above the chuck table 20 where the suction force Vm is applied to the wafer 10, the frame F, and the polymer. The vinyl sheet 30 acts to attract and hold the state. Although details are omitted, the heating roller means 50 includes a heating roller 52 incorporating a heater (not shown) and a rotating shaft (not shown) for rotating the heating roller 52 , and fluororesin is applied to the surface of the heating roller 52 . processing. When the heating roller 52 is positioned above the chuck table 20, the heater built in the heating roller 52 is operated to push the back surface 10b of the wafer 10 covered by the polyethylene sheet 30 and the entire frame F side, and The heat roller 52 is moved in the direction of the arrow X while rotating in the direction indicated by the arrow R1. The heater built into the heating roller 52 is adjusted so that the polyethylene sheet 30 becomes 120 to 140° C. near the melting point, or from a temperature near the melting point to a temperature 50° C. lower than the melting point. In the range of about temperature. By this heating and pressing, similar to the above-mentioned hot air blowing means 40, the polyethylene sheet 30 can be thermocompression bonded to the back surface 10b of the wafer 10 and the frame F in a state of close contact, and the wafer 10, the frame F and the frame F can be bonded together. The polyethylene sheet 30 is integrated. Furthermore, as a modification example of the heating roller means 50 implementing the integration step, instead of the above-mentioned heating roller 52, a flat plate-shaped pressing member equipped with a heater can also be used to heat and press the polyethylene sheet 30, and the polyethylene sheet 30 can be heated and pressed. The sheet 30 is bonded to the wafer 10 and the frame F by thermocompression. In addition, the thermocompression bonding means is not limited to the above-mentioned means, for example, the polyethylene sheet 30 may be heated by irradiating infrared rays, and the wafer 10 and the frame F may be thermocompression bonded.

In this embodiment, following the above-mentioned integration step, a cutting step of cutting the polyethylene sheet 30 along the frame F is carried out in consideration of subsequent steps. In addition, this cutting step is not an absolutely necessary step, but if implemented, it is easier to handle the wafer 10 and the frame F integrated with the polyethylene sheet 30, which is beneficial to the subsequent steps. Hereinafter, the cutting procedure will be described while referring to FIG. 4 .

(cutting step) As shown in FIG. 4 , the cutting means 60 (only a part is shown) is positioned on the chuck table 20 that attracts and holds the wafer 10 , the frame F and the polyethylene sheet 30 integrated by the integration step. The cutting means 60 is equipped with a disc-shaped blade cutter 62 (shown by a chain line with two dots) for cutting the polyethylene sheet 30, and a tool for rotating the blade cutter 62 in the direction shown by the arrow R2. A motor (not shown) positions the blade edge of the blade cutter 62 substantially at the center in the width direction on the frame F. As shown in FIG. When the blade cutter 62 is positioned on the frame F, the blade cutter 62 is cut into only the thickness of the feed polyethylene sheet 30, and the chuck table 20 is rotated in the direction indicated by the arrow R2. Thereby, the polyethylene sheet 30 can be cut along the cutting line C along the frame F, and the outer periphery of the polyethylene sheet 30 beyond the range of the cutting line C can be cut. Furthermore, the polyethylene sheet 30 has been bonded to the back surface 10b of the wafer 10 and the frame F by thermocompression, and the integrated state of the wafer 10, the frame F, and the polyethylene sheet 30 is maintained. Based on the above, the cutting step is completed.

(Split start point formation step) When the outer periphery of the polyethylene sheet 30 is cut in this cutting step, a division starting point forming step is performed using a laser processing device. As a laser processing method for implementing the step of forming the starting point of division, for example, a method can be selected to set the wavelength of the laser beam to a wavelength that is penetrating to the wafer, and position the laser beam's converging point at the first division. The inside of the predetermined line 12A and the second predetermined line 12B is used to form a modified layer as the starting point of the division. Alternatively, in one method, the wavelength of the laser beam is set to an absorbing wavelength for the wafer, and the focusing of the laser beam The light spot is positioned on the upper surface of the first planned dividing line 12A and the second planned dividing line 12B, and a groove as a starting point of dividing is formed by ablation.

Referring to FIG. 5 , an embodiment of laser processing for forming a modified layer serving as a starting point for division inside the first planned division line 12A and the second planned division line 12B of the wafer 10 will be described.

When forming the modified layer as the origin of division inside the first planned division line 12A and the second planned division line 12B, the laser beam is irradiated from the back surface 10 b of the wafer 10 . Then, as shown in FIG. 5(a), the back surface 10b of the wafer 10 integrated with the frame F in the above-mentioned integration step is directed upward so that the polyethylene sheet 30 side is upward, and transported to FIG. 5(b). ) shows the laser processing device 70 (only a part is shown).

The laser processing device 70 shown in FIG. 5( b ) is a known laser processing device, and its details are omitted, but includes a chuck table not shown, laser beam irradiation means including a condenser 72 , and the like. The wafer 10 transferred to the laser processing apparatus 70 is placed and held on the chuck table with the polyethylene sheet 30 on top. Next, the irradiation position of the laser beam LB from the concentrator 72 of the laser beam irradiation means and the processing position of the wafer 10 are performed by an alignment means provided with an infrared imaging means not shown, that is, the first Alignment between a planned dividing line 12A and a second planned dividing line 12B (alignment step). After this alignment step is completed, as shown in FIG. 5(b), the focusing point of the laser beam LB is positioned inside the wafer 10, and the focusing point 72 is opposite to the wafer 10 in the direction indicated by the arrow X. irradiated across the polyethylene sheet 30 to form the modified layer 100 as the starting point of division along the first planned division line 12A. By appropriately moving the chuck table, after forming the modified layer 100 along all the first planned dividing lines 12A, the chuck table is rotated 90 degrees, and the same as the first planned dividing line 12A, along the first planned dividing line 12A. The modified layer 100 is formed inside the wafer 10 by the planned dividing line 12B. By implementing the above laser processing, the step of forming the origin of division is completed.

In addition, the laser processing conditions of the laser processing apparatus 70 for forming the modified layer 100 as the starting point of division are set as follows, for example. Laser beam wavelength: 1064nm Repetition frequency: 80kHz Average output: 0.5W Processing feed speed: 800mm/s

The division starting point forming step of the present invention is not limited to the above means, and may be implemented using, for example, a laser processing device 70' shown in FIG. 6 . Hereinafter, with reference to FIG. 6 , another embodiment regarding the use of the laser processing device 70' to implement the step of forming the origin of division will be described.

When forming a groove as a starting point for dividing on the front surface 10a of the wafer 10 along the first planned dividing line 12A and the second planned dividing line 12B, as shown in FIG. The F-integrated wafer 10 is transported to the laser processing apparatus 70 ′ shown in FIG. 6( b ) with the front 10 a side facing upward (only a part thereof is shown).

The laser processing device 70' is a known laser processing device, and details are omitted, but it is equipped with a chuck table not shown, a laser beam irradiation means including a condenser 72', etc., and is transported to the laser processing device. The wafer 10 of the apparatus 70' is placed on the chuck table with the front surface 10a of the wafer 10 facing upward, and is attracted and held. Next, the irradiation position of the concentrator 72' of the laser beam irradiation means and the processing position of the wafer 10, that is, the alignment between the first planned dividing line 12A and Alignment between the second planned division lines 12B (alignment step). After the alignment step is finished, as shown in FIG. 6(b), the laser beam LB' is positioned on the front side 10a of the wafer 10, so that the light collector 72' is aligned with the wafer 10 as indicated by the arrow X. The directions shown are relatively moved while irradiating the laser beam LB' to perform ablation processing. By appropriately moving the chuck table, the groove 110 serving as a starting point for dividing is formed along the first planned dividing line 12A and the second planned dividing line 12B. Through the above laser processing, the step of forming the starting point of division is completed.

In addition, the laser processing conditions of the above-mentioned laser processing device 70' for forming the groove 110 as the starting point of division are set as follows, for example. Laser beam wavelength: 355nm Repetition frequency: 80kHz Average output: 2.5W Processing feed speed: 800mm/s

The division starting point forming step of the present invention is not limited to implementing the above-mentioned laser processing method, and other means can also be selected. For example, it is also possible to position and irradiate the laser beam having a penetrating wavelength inside the wafer 10 from the back surface 10b side of the wafer 10, along the first planned dividing line 12A and the second planned dividing line. 12B forms a shield channel composed of pores and amorphous surrounding pores as the starting point of division.

(split step) As mentioned above, after performing the dividing origin forming step, the dividing step is performed. In addition, the dividing step described below is to describe the formation of the modified layer as the starting point of dividing in the inside of the wafer 10 along the first planned dividing line 12A and the second planned dividing line 12B by implementing the above-mentioned dividing starting point forming step. Implementer after 100.

The dividing step of this embodiment includes at least a first dividing step of applying an external force to the first planned dividing line 12A and dividing the first planned dividing line, and a step of applying an external force to the second planned dividing line 12B and dividing the second planned dividing line 12B. The second segmentation step constitutes. Referring to FIG. 7 , a description will be given of the division steps performed using the division device 80 .

The dividing device 80 shown in FIG. 7 includes at least a pressing knife 82, a pair of support parts 83, and an imaging means not shown. When performing the first dividing step, the wafer 10 is placed on the pair of support parts 83 with the front surface 10 a of the wafer 10 facing downward. This imaging means is configured to photograph the wafer 10 from the front side 10a side of the wafer 10 placed on the pair of support parts 83, that is, from the lower side. The planned line 12A correctly positions the first planned dividing line 12A formed by the modified layer 100 between the pair of supporting parts 83 and directly below the pressing blade 82 . The pair of support portions 83 extend in one direction (the Y direction perpendicular to the paper surface in FIG. 7 ), and are positioned so as to sandwich the first planned dividing line 12A as if positioned along the one direction in plan view. The pressing blade 82 positioned above the pair of support portions 83 also extends in the same direction as the pair of support portions 83, and moves in the vertical direction indicated by the arrow Z by an unillustrated pressing mechanism.

As shown in FIG. 7 , by lowering the push knife 82 toward the wafer 10 side along the arrow Z, the modified layer 100 is used as a starting point for splitting, and the wafer 10 is split along the first planned splitting line 12A to form a splitting line. 130. Subsequently, by moving the push blade 82 in the direction indicated by the arrow X relative to the pair of supports 83 and the wafer 10 to process feed, the undivided first planned division line 12A is moved to the push blade. 82 and between the pair of supporting parts 83 , the same dividing process is repeated, and the pressing blade 82 is pressed and external force is applied to all the first planned dividing lines 12A to form the dividing lines 130 . Then, the wafer 10 is rotated by 90 degrees, and the second planned dividing line 12B on which the modified layer 100 is formed is accurately positioned between the pair of supporting parts 83 directly below the pressing blade 82 using the imaging means. The dividing line 130 is formed by dividing by the same procedure as dividing the above-mentioned first planned dividing line 12A. According to the above, the wafer 10 is divided into individual elements 14, and the dividing step is completed. In addition, although the above-mentioned dividing step has been described as being performed after forming the modified layer 100 as a starting point for dividing inside the wafer 10 along the first planned dividing line 12A and the second planned dividing line 12B, in the dividing starting point forming step When the groove 110 as the starting point of division is formed by ablation on the surface 10a of the first planned division line 12A and the second planned division line 12B, division can also be performed by the same means as above.

When the dividing step is completed, it is transferred to the picking step together with the frame F holding the wafer 10, and each component 14 is picked up from the polyethylene sheet 30, and is transferred to the bonding step, or accommodated in a storage box, etc., to Move to next step.

According to the above-mentioned wafer processing method of this embodiment, the wafer 10, the frame F and the polyolefin sheet (polyethylene sheet 30) are not bonded by an adhesive layer formed by coating the surface of the polyolefin sheet with an adhesive or the like. Instead, at least a polyolefin sheet is heated and thermocompression-bonded to integrate the wafer 10 with the frame F. Thereby, there will be no problems such as inducing a deviation due to a part of the adhesive layer entering the divided region (dividing line) as in the case of a dicing film having an adhesive layer, and after dividing the first planned dividing line 12A, it is possible to Precisely positioning the pressing blade 82 on the second planned dividing line 12B does not degrade the quality of the component.

In addition, according to this invention, it is not limited to the above-mentioned embodiment, and various modification examples are provided. In the above-described embodiments, the polyethylene sheet 30 was selected as the polyolefin sheet, but the present invention is not limited thereto, and it can be appropriately selected from polyolefin sheets. As another polyolefin sheet, for example, either a polypropylene (PP) sheet or a polystyrene (PS) sheet may be used.

In the above-mentioned embodiment, in the integration step, the heating temperature is set in the range of 120-140°C near the melting point or from a temperature near the melting point to a temperature about 50°C lower than the temperature near the melting point, The present invention is not limited thereto, and it is preferable to set the heating temperature according to the type of the selected polyolefin sheet. For example, when a polypropylene sheet is selected as the polyolefin sheet, it is preferable to set the heating temperature at 160 to 180°C near the melting point or from a temperature near the melting point to a temperature 50°C lower than the temperature near the melting point. The range up to the temperature of about ℃. In addition, when a polystyrene sheet is selected as the polyolefin sheet, it is preferable to set the heating temperature at 220 to 240° C. near the melting point or from a temperature near the melting point to a temperature lower than the melting point. The range up to the temperature around 50°C.

In the above-mentioned embodiments, although the wafer to be processed is a silicon (Si) substrate, the present invention is not limited thereto, and may be made of other materials, for example, a sapphire (Al ₂ O ₂ ) substrate. , silicon carbide (SiC) substrate, and glass (SiO ₂ ) substrate.

10‧‧‧Wafer 12A‧‧‧The first division schedule 12B‧‧‧The second division schedule 14‧‧‧Components 20‧‧‧Chuck table 21‧‧‧Adsorption Chuck 30‧‧‧polyethylene sheet 40‧‧‧Hot air blowing means 50‧‧‧Heating roller means 52‧‧‧Heating roller 60‧‧‧cutting means 62‧‧‧Blade Knives 70, 70’‧‧‧Laser processing device 72‧‧‧Concentrator 80‧‧‧Splitting device 82‧‧‧Push knife 83‧‧‧A pair of support parts 100‧‧‧modified layer 110‧‧‧groove 130‧‧‧Separation line

Fig. 1 is a perspective view showing the implementation of the step of laying polyolefin sheets in this embodiment. Fig. 2 is a perspective view showing a state in which a polyolefin sheet is placed on a chuck table in the polyolefin sheet laying step shown in Fig. 1 . Fig. 3 is a perspective view showing an implementation state of the integration step of the present embodiment. Fig. 4 is a perspective view showing an implementation state of the cutting step of the present embodiment. Fig. 5 is a perspective view showing an embodiment of the step of forming a division starting point in this embodiment. Fig. 6 is a perspective view showing another embodiment of the step of forming the origin of division in this embodiment. Fig. 7 is a side view showing an implementation mode of the division step of this embodiment.

10‧‧‧Wafer

20‧‧‧Chuck table

21‧‧‧Adsorption Chuck

22‧‧‧round frame

30‧‧‧polyethylene sheet

40‧‧‧Hot air blowing means

50‧‧‧Heating roller means

52‧‧‧Heating roller

F‧‧‧Framework

L‧‧‧hot air

Vm‧‧‧attraction

Claims (5)

A wafer processing method, which divides a wafer with a plurality of elements formed on the front surface into individual elements, and the plurality of elements are formed by a first dividing line formed in a first direction and formed in a direction crossing the first direction. Divided by the second predetermined dividing line in the second direction; the wafer processing method is at least composed of the following steps: a polyolefin sheet laying step, positioning the wafer in the opening of the frame having an opening for receiving the wafer , and the polyolefin sheet that does not have an adhesive layer on the mounting surface side of the bonded wafer and is not divided when the wafer is divided into individual components is directly laid on the back of the wafer and the outer periphery of the frame; integrated In the step, the polyolefin sheet is heated and thermocompressed to form a state where the wafer, the frame and the polyolefin sheet are in close contact, so that the wafer and the frame are integrated through the polyolefin sheet; in the step of forming the starting point of division, the laser The focal point of the light beam is positioned on the first planned line for dividing and the second planned line for dividing and irradiated to form a starting point for dividing; the first dividing step is to position the pushing knife on the first planned line for dividing and apply an external force to divide the first and, the second dividing step, positioning the pushing knife on the second dividing line and applying external force to divide the second dividing line; and dividing the crystal by the first dividing step and the second dividing step The circle is divided into individual elements. The wafer processing method described in claim 1 of the scope of the patent application, wherein the wavelength of the laser beam irradiated in the step of forming the division starting point has penetrability to the wafer, and the focusing point of the laser beam is positioned Inside the first planned dividing line and the second planned dividing line, a modified layer serving as a starting point for dividing is formed. The wafer processing method described in claim 1, wherein the wavelength of the laser beam irradiated in the step of forming the division starting point has absorption properties for the wafer, and the focusing point of the laser beam is positioned at The upper surfaces of the first planned dividing line and the second planned dividing line are used to form a groove as a starting point of dividing by ablation. As for the wafer processing method described in any one of items 1 to 3 of the scope of application, the polyolefin sheet is selected from any one of polyethylene sheets, polypropylene sheets, and polystyrene sheets. As for the wafer processing method described in any one of items 1 to 3 of the scope of application, the wafer is composed of any one of a silicon substrate, a sapphire substrate, a silicon carbide substrate, and a glass substrate.

Images