TW201903877A - Manufacturing method of device chips capable of preventing film from peeling off from chips, chip spraying or damages caused by contacts among chips - Google Patents

Abstract

[Problem] In the case of manufacturing a device wafer in which a device is formed on a front surface and a film is formed on a rear surface, it is formed to prevent the film from being peeled from the wafer, the wafer flying, or damage caused by contact between the wafers. [Solution] A method for manufacturing a device wafer, which is a method for manufacturing a device wafer having a device formed on a front surface and a metal film formed on a back surface. The method includes a wafer preparation step, preparing to cut a plurality of crosses on the front surface. Wafers with devices are formed in each area demarcated by the dossier; a slicing step, which divides the wafer into individual device wafers along the dicing path; and a metal film forming step, where the device wafers have been divided into individual device wafers. A metal film is formed on the back of the wafer.

Description

Device wafer manufacturing method

FIELD OF THE INVENTION The present invention relates to a method for manufacturing a device wafer in which a device is formed on a front surface and a film is formed on a back surface.

BACKGROUND OF THE INVENTION Currently, there are a device wafer having a metal layer serving as an electrode on the back surface, a device wafer having a resin layer formed on the back surface to improve the strength of the wafer, or a resin film attached to the back surface as a die attach. ) Device wafers for bonding materials. In manufacturing these device wafers, a metal film or a resin film is formed on the back surface or a resin film is attached in a wafer state, and then the wafer on which the film is formed on the back surface is divided. However, it is difficult to disconnect wafers with different materials laminated. If a wafer with a particularly ductile film such as resin is cut with a dicing blade, the dicing blade will cause blockage caused by the film, and the film will be blocked. There will be burrs on it.

In recent years, in order to improve productivity at the time of wafer division by miniaturization of a device wafer, plasma dicing using a plasma etching apparatus (for example, refer to Patent Document 1) has been adopted. However, plasma cutting with an etching gas cannot cut the various films described above. Then, for example, dry ice is sprayed after the wafer is divided to disconnect the film, and the corresponding processing is performed (for example, refer to Patent Document 2). Prior Art Literature Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2015-037110 Patent Document 2: Japanese Patent Application Publication No. 2016-096266

SUMMARY OF THE INVENTION Problems to be Solved by the Invention However, it is difficult to completely disconnect the film by spraying with dry ice in the manner described in the above-mentioned Patent Document 2, and there is also a concern that an undivided area is generated in the film. Although it is possible to suppress the generation of undivided areas by increasing the spray pressure of dry ice, high-pressure spray of dry ice may cause the film to peel off from the wafer, wafer flying, and damage caused by adjacent wafers contacting each other due to wafer movement doubt.

Accordingly, when forming a device wafer with a device formed on the front side and a film formed on the back side, there is a problem that it is prevented from causing peeling of the film from the wafer, spraying of the wafer, or contact between the wafers. Damage. Means to solve the problem

The present invention for solving the above-mentioned problems is a method for manufacturing a device wafer having a device formed on a front surface and a metal film formed on a back surface, which includes: a wafer preparation step, preparing to intersect a plurality of scribe lines on the front surface; Wafers with devices formed in each of the divided areas; a singulation step, which divides the wafer into individual device wafers along the scribe line; and a metal film formation step, where the devices have been divided into individual ones The metal film is formed on the back of the wafer.

Preferably, in the dividing step, the wafer is thinned to a predetermined thickness from the back surface side, and the thinned wafer is divided into individual device wafers along the dicing path.

Preferably, in the aforementioned dividing step, a groove is formed from the front side of the wafer along the dicing path to a depth of a predetermined finished product thickness, and a protective member is disposed on the front side of the wafer on which the groove is formed. In the state where the protective member side is held by the holding mechanism, the wafer is thinned from the back side to the thickness of the finished product, thereby dividing the wafer into the aforementioned device wafers.

Preferably, in the aforesaid dividing step, the focusing point of the laser beam having a wavelength penetrating to the wafer is positioned inside the wafer, and the irradiation is performed along the cutting path. The laser beam forms a modified layer along the dicing path, and the wafer on which the modified layer is formed is ground from the back side to be thinned, thereby dividing the wafer into individual ones. The aforementioned device wafer. Invention effect

The manufacturing method of the device wafer of the present invention is performed by dividing the wafer into individual device wafers along the scribe lines, and thereafter forming a metal on the back surface of the wafer that has been divided into individual device wafers. A metal film forming step of the film, so that a device having a device formed on the front side and a film formed on the back side can be manufactured without peeling the film from the wafer, spraying the wafer away, or damage caused by the wafers contacting each other. Wafer.

In the singulation step, because the wafer can be thinned from the back side to a predetermined thickness, the thinned wafer is divided into individual device wafers along the dicing path, thereby reducing the number of tape transfers of the wafer. Wait, or implement a series of processes without tape transfer of wafers, so the operation efficiency can be improved.

In the slicing step, a groove is formed from the front side of the wafer along the scribe line to a predetermined thickness, and a protective member is disposed on the front side of the grooved wafer, and the protective member is held by the holding mechanism. In the state of side, the wafer is thinned from the back side to the thickness of the finished product, thereby dividing the wafer into individual device wafers. Therefore, the risk of transporting thinned wafers during a series of steps can be eliminated.

In the dividing step, the laser beam can be irradiated along the dicing path in a state where the focusing point of the laser beam having a wavelength penetrating to the wafer is positioned inside the wafer, thereby forming The modified layer of the dicing path, and the wafer formed with the modified layer is ground from the back side to be thinned, so as to divide the wafer into individual device wafers. Under the circumstances, a series of processes are implemented, so the operation efficiency can be improved.

Embodiments for Carrying Out the Invention (Embodiment 1) Hereinafter, each step in the case of implementing the method for manufacturing a device wafer of the present invention will be described.

(1) Wafer preparation step First, a wafer W shown in FIG. 1 is prepared. The wafer W having a circular plate shape is, for example, a silicon wafer. On its front surface Wa, ICs, LSIs, and the like are formed in a plurality of grid-like regions defined by a plurality of scribe lines S that cross perpendicularly to each other. Device D.

The wafer W is formed in a state supported by a ring frame F as shown in FIG. 2 in order to facilitate the operation process after the wafer W is divided into wafers having the device D. That is, first, the protective tape T1 is attached to the front surface Wa of the wafer W shown in FIG. 2. The protective tape T1 is a disc-shaped tape having an outer diameter larger than the outer diameter of the wafer W, and has, for example, a moderate stretchability against a mechanical external force. The ring frame F is positioned with respect to the wafer W so that the center of the wafer W placed on the sticking table (not shown) and the center of the opening of the ring frame F substantially coincide. Then, the protective tape T1 is pressed and adhered to the front surface Wa of the wafer W by a pressure roller or the like on the sticking table. At the same time, the outer peripheral portion of the adhesive surface of the protective tape T1 is also attached to the ring frame F, whereby the wafer W in a state where the back surface Wb is exposed can be processed through the ring frame F.

(2) Dividing step Next, the wafer W is transferred to the grinding apparatus 1 shown in FIG. 3, for example. The grinding apparatus 1 shown in FIG. 3 grinds the wafer W held on the holding mechanism 10 by the grinding mechanism 11. The holding mechanism 10 includes a circular holding surface 100 which is formed of a porous member or the like and sucks and holds the wafer W, and a suction source (not shown) is connected to the holding surface 100. The holding mechanism 10 is rotatable around an axis in the Z-axis direction, and is capable of reciprocating in the Y-axis direction.

The grinding mechanism 11 includes a main shaft 110 whose axis direction is the Z-axis direction, a motor (not shown) that rotates and drives the main shaft 110, a mounting base 111 connected to the lower end side of the main shaft 110, and a removably mountable mounting base 111 Lower surface of the grinding wheel 112. The grinding wheel 112 includes a ring-shaped wheel base 112b, and a plurality of substantially rectangular parallelepiped-shaped grinding stones 112a arranged annularly on the lower surface of the wheel base 112b.

First, the wafer W is placed on the holding surface 100 of the holding mechanism 10 with the back surface Wb side up, and is sucked and held by the holding mechanism 10. Next, the holding mechanism 10 moves below the grinding mechanism 11 in the Y-axis direction. For example, the rotation center of the grinding wheel 112 deviates from the rotation center of the wafer W by a predetermined distance in the + Y direction to make grinding The rotation track of the grindstone 112a is positioned at a predetermined position by the rotation center of the wafer W.

The grinding wheel 112 is rotated as the main shaft 110 is rotationally driven. In addition, the grinding mechanism 11 is fed in the -Z direction, and the rotating grinding stone 112a is brought into contact with the back surface Wb of the wafer W, thereby performing grinding processing. During the grinding, as the holding mechanism 10 rotates, the wafer W held on the holding surface 100 also rotates. Therefore, the grinding stone 112 a can perform the grinding process on the entire surface of the back surface Wb of the wafer W. In the grinding process, the contact portion between the grinding stone 112a and the wafer W is supplied with grinding water to cool and clean the contact portion. Then, the wafer W is ground to a desired thickness, that is, the grinding process of the wafer W is ended.

The wafer W thinned to a desired thickness is transferred to the laser processing apparatus 2 shown in FIG. 4. The laser processing apparatus 2 includes at least a holding table 20 that attracts and holds the wafer W, and a laser beam irradiating mechanism 21 that irradiates the wafer W held by the holding table 20 with a laser beam having a penetrating wavelength.

The holding table 20 has, for example, a circular outer shape, and sucks and holds the wafer W on a horizontal holding surface 20a made of a porous member or the like. The holding table 20 is formed so as to be rotatable around an axis in the Z-axis direction, and is reciprocated in the X-axis direction by a processing feed mechanism (not shown), and an indexing feed mechanism (not shown) Move back and forth in the Y-axis direction. For example, four (only two are shown in the illustrated example) fixing jigs 200 are arranged on the outer peripheral portion of the holding table 20 equally.

The laser beam irradiating mechanism 21 is a laser beam that is oscillated by the laser beam oscillator 219 and has a wavelength penetrating to the wafer W. The laser beam irradiating mechanism 21 enters the condenser 211 through an optical transmission system such as an optical fiber. The optical lens 211 a can condense and irradiate the laser beam to a predetermined height position of the wafer W held by the stage 20. In addition, the position of the light-condensing spot of the laser beam condensed by the condenser 211 is made perpendicular to the holding surface 20a of the holding table 20 by a light-condensing point position adjusting mechanism (not shown). In the direction (Z-axis direction).

First, the ground wafer W supported by the ring frame F is sucked and held by the holding table 20 with the back surface Wb facing upward. The ring frame F is fixed by each fixing jig 200. Next, the wafer W held on the holding table 20 is fed in the −X direction (direction), and the position of one scribe line S serving as a reference for irradiating the laser beam with the laser beam is detected.

The position detection of the cutting path S is performed by a calibration mechanism (not shown) arranged near the laser beam irradiation mechanism 21. The calibration mechanism includes an infrared irradiation mechanism for irradiating infrared rays, and an infrared camera composed of an infrared CCD and the like, and can perform pattern matching based on an image captured by the infrared camera penetrating the wafer W from the back Wb side. Wait for image processing to detect the position in the Y-axis direction of the scribe line S of the front surface Wa of the wafer W.

As the cutting path S is detected, the holding table 20 is fed in increments in the Y-axis direction to perform the cutting path S as a reference for irradiating the laser beam and the Y-axis of the condenser 211 of the laser beam irradiation mechanism 21 Alignment in direction. Next, the position of the light-condensing point of the laser beam condensed by the condenser lens 211 a is positioned at a predetermined height position inside the wafer W. Then, the laser beam oscillator 219 oscillates to generate a laser beam having a wavelength penetrating to the wafer W, and condenses and irradiates the laser beam to the inside of the wafer W held by the stage 20. The laser beam is irradiated onto the wafer W along the dicing path S, and the wafer W is processed and fed in the −X direction at a predetermined processing feed rate to form the wafer W as shown in FIG. 4. Modified layer M.

If the wafer W is moved in the -X direction along a dicing path S to a predetermined position in the X-axis direction where the laser beam is irradiated, the processing of the wafer W in the -X direction can be stopped and the laser can be stopped. The irradiation of the beam is stopped together. Next, the holding table 20 is fed in steps in the Y-axis direction, and a machining feed in the -X direction is performed. The adjacent cutting track S and the focusing track S, which are positioned as the reference when the laser beam is irradiated, are collected. Registration in the Y-axis direction of the device 211. After the alignment has been performed, the wafer W is processed and fed in the + X direction (return direction), and the laser beam is irradiated along a dicing path S in the same manner as the laser beam in the forward direction. A modified layer M is formed inside the wafer W. By sequentially irradiating the same laser beam, the laser beam is irradiated into the wafer W along all the scribe lines S extending in the X-axis direction, and a modified layer M is formed along each scribe line S. . In addition, when the holding table 20 is rotated by 90 degrees and the wafer W is irradiated with the same laser beam, a modified layer M can be formed inside the wafer W along all the vertical and horizontal scribe lines S.

As shown in FIG. 5, the wafer W on which the modified layer M is formed is transferred to the expansion device 5. The expansion device 5 includes, for example, an annular stage 50 having a larger diameter than the outer diameter of the protective tape T1, and the diameter of the opening 50c of the annular stage 50 is made smaller than the outer diameter of the protective tape T1. On the outer peripheral portion of the ring-shaped stage 50, four (only two are shown in the illustrated example) fixing jigs 52 are equally arranged. The fixing jig 52 can be rotated around the rotating shaft 52 c by a spring or the like not shown, and the ring frame F can be sandwiched between the holding surface 50 a of the ring stand 50 and the lower surface of the fixing jig 52.

In the opening 50 c of the ring-shaped stage 50, the cylindrical expansion drum 53 is arranged at a fixed height position, and the center of the ring-shaped stage 50 and the center of the expansion drum 53 are set to substantially coincide with each other. The outer diameter of the expansion roller 53 is smaller than the outer diameter of the protective tape T1 and larger than the outer diameter of the wafer W. The ring-shaped table 50 is movable up and down by a ring-shaped table lifting mechanism 55 formed of, for example, a cylinder or the like.

First, the ring-shaped frame F is placed on the holding surface 50 a of the ring-shaped table 50 that has been positioned at the reference height position. Next, the fixing jig 52 is rotated, and the ring frame F is clamped and fixed between the fixing jig 52 and the holding surface 50 a of the ring-shaped stage 50. In this state, the holding surface 50a of the ring-shaped stage 50 and the ring-shaped upper end surface of the expansion roller 53 are at the same height position, and the upper end surface of the expansion roller 53 is from the substrate surface side of the protective tape T1 (in FIG. 5). The lower surface side of the wafer) comes into contact with the area between the inner peripheral edge of the ring frame F of the protective tape T1 and the outer peripheral edge of the wafer W.

As shown in FIG. 6, the ring-shaped table 50 is lowered in the -Z direction by the ring-shaped table lifting mechanism 55 to position the holding surface 50 a of the ring-shaped table 50 to the tape expansion position lower than the upper end surface of the expansion roller 53. . As a result, the expansion roller 53 rises relatively with respect to the fixing jig 52, and the protective tape T1 is pushed up by the upper end surface of the expansion roller 53 and is expanded outward in the radial direction. In addition, by applying an external force (expansion force) to the wafer W through the protective tape T1, the crack is extended toward the front surface Wa and the back surface Wb of the wafer W with the modified layer M formed along the scribe line S as a starting point. The wafer W is divided into rectangular device wafers C. In addition, in the dividing step, in addition to dividing the wafer W into the device wafer C in the above-mentioned manner, it may be provided by cutting with a dicing blade, plasma cutting using a plasma etching device, or using A laser full cut of the laser processing apparatus 2 is performed to divide the wafer W into the device wafer C.

Next, the wafer W is transferred to, for example, the sputtering apparatus 8 shown in FIG. 7. Inside the chamber 81 of the sputtering apparatus 8, an electrostatic work bench 80 is arranged. The electrostatic work clamp 80 includes, for example, a base shaft portion 800 rotatably inserted through a lower portion of the chamber 81 through a bearing (not shown), and a disk-shaped table body 801 integrally formed with the base shaft portion 800. The upper surface of the table body 801 is formed of a ceramic such as alumina or a dielectric such as titanium oxide, and becomes a holding surface 801 a that holds the wafer W.

A sputtering source 84 made of a predetermined metal is disposed at a position facing the electrostatic work clamp 80 above the chamber 81, and the sputtering source 84 is arranged in a state supported by the excitation member 83. Assume. A high-frequency power source 85 is connected to the sputtering source 84. An introduction port 810 for introducing a sputtering gas such as argon gas is provided on one side portion of the chamber 81, and a pressure reduction port 811 connected to a pressure reduction source is provided on the other side portion.

In the metal film forming step, first, the wafer W is held by the electrostatic work clamp 80 of the sputtering apparatus 8 with the protective tape T1 facing downward. Then, a pressure reducing source (not shown) is operated, and the pressure in the chamber 81 is reduced to about 10 ^-2 Pa to 10 ^-4 Pa through the pressure reducing port 811. In addition, high-frequency power of about 40 kHz is applied from the high-frequency power source 85 to the sputtering source 84 magnetized by the excitation member 83, and argon gas is introduced from the introduction port 810, thereby generating electricity in the chamber 81 Pulp.

Argon atoms in the plasma collide with the sputtering source 84 to cause the sputtering source 84 to sputter metal particles, and the metal particles travel toward the wafer W formed in a state where the back surface Wb and the sputtering source 84 face each other. Then, the metal particles are deposited on the back surface Wb of the wafer W, and as shown in FIG. 8, the back surface Wb is covered with a metal film J having a substantially uniform and predetermined thickness (for example, about 0.5 μm to 30 μm). The metal film J is disconnected for each device wafer C. In addition, the metal film forming step may be performed by CVD, wet coating, or the like, instead of sputtering as described above.

In the method for manufacturing a device wafer of the present invention, the dividing step of dividing the wafer W into individual device wafers along the scribe line S is performed, and thereafter, the wafer W of the device wafer C that has been divided into individual device wafers C is implemented. The metal film forming step of forming the metal film J on the back surface Wb allows the device to be formed on the front surface Wa without causing the metal film J to be peeled from the wafer, the wafer flying, or damage caused by the wafers contacting each other. D and a device wafer C having a metal film J formed on the back surface Wb.

Furthermore, in this embodiment, in the dividing step, the wafer W is thinned to a predetermined thickness from the back surface Wb side, and the thinned wafer W is divided into individual pieces along the dicing path S. The device wafer C, that is, after the modified layer M formed by the laser beam has been formed, it is divided by a tape extension method, so that a series of processes can be performed even if the tape W of the wafer W is not transferred. Therefore, the operation efficiency can be improved.

(Embodiment 2) Hereinafter, each step in the case where the manufacturing method of the device wafer of this invention is implemented is demonstrated.

(1) Wafer preparation step First, as shown in FIG. 9, a wafer W is prepared, and a protective tape T2 having the same diameter as the wafer W is attached to the front surface Wa. The wafer W is the same wafer as the wafer W shown in FIG. 1.

(2) Dividing step The wafer W is transferred to the grinding apparatus 1 shown in FIG. 9. As shown in FIG. 9, the wafer W is placed on the holding surface 100 with the back surface Wb side facing upward, and is sucked and held by the holding mechanism 10. Next, the holding mechanism 10 holding the wafer W is moved below the grinding mechanism 11 in the Y-axis direction, and is positioned so that the rotation track of the grinding stone 112 a passes through the rotation center of the wafer W.

The grinding wheel 112 is rotated as the main shaft 110 is rotationally driven. Then, the rotating grinding stone 112 a is fed in the −Z direction to abut against the back surface Wb of the wafer W, and a grinding process is performed. Since the wafer W also rotates in accordance with the rotation of the holding mechanism 10, the grinding stone 112 a can perform the grinding process on the entire surface of the back surface Wb of the wafer W. In addition, grinding water is supplied to a contact portion between the grinding stone 112a and the wafer W. After the wafer W is ground to a predetermined thickness, the grinding process of the wafer W is ended.

Next, the wafer W is fully cut along the dicing path S from the front surface Wa of the wafer W by the dicing mechanism 31 shown in FIG. 10. The cutting mechanism 31 includes a main shaft 311 whose axis direction is a direction (Y-axis direction) orthogonal to the movement direction (X-axis direction) of the wafer W in the horizontal direction, and a ring-shaped shape is fixed to the tip of the main shaft 311. Cutting blade 310.

When dicing is performed, for example, a dicing tape T3 having a diameter larger than that of the wafer W is pressed and attached to the back surface Wb of the wafer W. At the same time, the outer peripheral portion of the adhesive surface of the dicing tape T3 is also attached to the ring frame F, so that the wafer W in a state where the front surface Wa is exposed can be processed through the ring frame F. Thereafter, the protective tape T2 shown in FIG. 9 is peeled from the front surface Wa of the wafer W.

The wafer W is attracted and held by a work clamp table (not shown) in a state where the front surface Wa faces upward, and the ring frame F is fixed by a clamping jig or the like of the work clamp table. Thereafter, the wafer W is fed in and out in the −X direction side, and the coordinate position in the Y-axis direction of the scribe line S in which the dicing blade 310 is cut is detected by the wafer W. Along with the detection of the cutting path S, the cutting mechanism 31 is indexed in the Y-axis direction to perform alignment between the cutting path S for cutting and the Y-axis direction of the cutting blade 310.

With the rotation of the main spindle 311, the cutting blade 310 is rotated clockwise when viewed from the -Y direction side. In addition, the cutting mechanism 31 is cut into the feed in the -Z direction, and the cutting mechanism 31 is positioned at the lowermost end of the cutting blade 310 to a predetermined height position where the wafer W is completely cut and cut into the dicing tape T3.

The work table holding the wafer W is fed in and out at a predetermined cutting feed speed toward the −X direction side, thereby cutting the rotating cutting blade 310 along the cutting path S from the front Wa side of the wafer W, and The wafer W is fully cut. When the wafer W is fed to a predetermined position in the -X direction in which the dicing blade 310 cuts one dicing path S, the dicing feed of the wafer W is stopped, and the dicing blade 310 is away from the wafer W. Then, the wafer W moves in the + X direction and returns to the original position. Then, while sequentially cutting the cutting blade 310 in the + Y direction at intervals of adjacent cutting paths S, the same cutting is performed sequentially, thereby cutting along all the cutting paths S in the X-axis direction. Wafer W. In addition, after the wafer W is rotated by 90 degrees, the same dicing process is performed, whereby the wafer W can be cut along all the scribe lines S, and the wafer W can be divided into individual wafers including the device D. Furthermore, in the dividing step, the wafer W may be divided into device wafers by plasma cutting, laser cutting, or tape expansion after a modified layer formed by a laser beam. C.

For example, the wafer W that has been divided into wafers is transported to a spin coater (not shown), etc., and a water-soluble liquid resin (for example, polyvinylpyrrolidone or polymer) is applied from the front Wa side of the wafer W. (Vinyl alcohol), and as shown in FIG. 11, the wafer C is filled with a water-soluble resin H. Then, this water-soluble resin H is dried and hardened, for example.

(3) In the metal film forming step, the wafer W in which the water-soluble resin H is filled between the wafers C is, for example, as shown in FIG. 12, a protective tape T4 is attached to the front Wa, and the dicing tape T3 is peeled from the back Wb. After that, it is transferred to the sputtering apparatus 8 shown in FIG. 7. In addition, the wafer W may be such that the protective tape T4 is not attached to the front surface Wa. In addition, as in the case of the metal film forming step of the first embodiment, a metal film J having a substantially uniform and predetermined thickness (for example, about 0.5 μm to 30 μm) is formed on the back surface Wb. Furthermore, in the formation of the metal film J, a plate-shaped mask (not shown) in which rectangular slits corresponding to the wafer C are formed is preferably used, for example. That is, a mask is covered on the back surface Wb of the wafer W, and sputtering is performed while only the back surface of the wafer C among the back surface Wb of the wafer W is exposed from the rectangular slit of the mask. As a result, the metal film J can be formed only in a region corresponding to the back surface of the wafer C. In the metal film forming step in the second embodiment, the wafer W is in a state in which the water-soluble resin H is filled between the wafers C, so that the side of each wafer C is not covered by the metal film J. Concerns of Coverage.

The wafer W having the metal film J formed on the back surface Wb is, for example, a protective member T5 shown in FIG. 13 is attached to the exposed surface of the metal film J, and the protective tape T4 is peeled off from the front surface Wa, and is transported to FIG. The water-soluble resin removal device shown. For example, in a water-soluble resin removal device, washing water may be sprayed toward the front surface Wa of the wafer W, and the water-soluble resin H may be dissolved by the washing water. As shown in FIG. 13, the water-soluble resin H may be removed from the wafer. C is removed.

The manufacturing method of the device wafer of the present invention is carried out, for example, by performing a dicing step of dividing the wafer W into individual device wafers along the scribe line S by dicing with a blade, and thereafter performing the device wafers that have been divided into individual device wafers. Since the metal film J is formed on the back surface Wb of the wafer W, the metal film J can be manufactured without peeling the metal film J from the wafer, spraying the wafer, or causing damage caused by the wafers contacting each other. A device wafer C having a device D formed on the front surface Wa and a metal film J formed on the back surface Wb.

(Embodiment 3) Hereinafter, each step in the case where the manufacturing method of the device wafer of this invention is implemented is demonstrated.

(1) Wafer preparation step First, a wafer W shown in FIG. 14 is prepared. The back surface Wb of the wafer W is protected by, for example, a dicing tape (not shown). The wafer W is the same wafer as the wafer W shown in FIG. 1.

(2) Dividing step Next, the wafer W is formed from the front surface Wa side of the wafer W along the dicing path S by the cutting mechanism 31 shown in FIG. 14 to form a groove having a depth reaching a predetermined finished product thickness. First, the wafer W is attracted and held in a state where the front surface Wa faces upward by a work clamp (not shown). Thereafter, the wafer W is fed in and out in the −X direction side, and the coordinate position in the Y-axis direction of the scribe line S in which the dicing blade 310 is cut is detected by the wafer W. Next, the cutting mechanism 31 may be fed in the direction of the Y-axis, and the cutting path S for cutting and the Y-axis direction of the cutting blade 310 may be aligned.

The cutting blade 310 is rotated clockwise when viewed from the -Y direction side. Further, the dicing mechanism 31 is cut into the feed in the -Z direction, and the dicing blade 310 is positioned at a predetermined height position where the wafer W is not completely cut. The predetermined height position is a position where the distance from the front surface Wa of the wafer W to the bottom surface of the groove to be formed is the finished thickness of the wafer W.

The wafer W is further fed to the −X direction side at a predetermined cutting feed rate, so that the dicing blade 310 is cut along the dicing path S from the front Wa side of the wafer W to form a depth reaching the thickness of the finished product. Ditch G. The grooves G are formed by sequentially cutting the cutting blades 310 in the + Y direction while advancing the cutting blades 310 in the + Y direction one by one at intervals of adjacent cutting lines S. On wafer W. In addition, the groove G can be formed along all the scribe lines S by performing the same dicing process after rotating the wafer W by 90 degrees.

As shown in FIG. 15, the wafer W having the grooves G is attached with a protective member T6 on the front surface Wa, and a dicing tape (not shown) is peeled off from the back surface Wb. The protective member T6 is a disk-shaped tape having a diameter equal to that of the wafer W.

Then, the wafer W is transferred to the grinding apparatus 1 shown in FIG. 15 and sucked and held by the holding mechanism 10 with the back surface Wb side facing upward. Next, the holding mechanism 10 holding the wafer W is moved below the grinding mechanism 11 in the Y-axis direction.

Then, the grinding wheel 112 is fed in the -Z direction, and the rotating grinding stone 112a grinds the back surface Wb of the wafer W. During the grinding, the wafer W rotates with the rotation of the holding mechanism 10. Therefore, the grinding stone 112 a can perform the grinding process on the entire surface of the back surface Wb of the wafer W. In addition, by grinding the back surface Wb until the bottom of the groove G is exposed on the back surface Wb side of the wafer W, as shown in FIG. 15, the wafer W thinned to the thickness of the finished product can be divided into a plurality of devices. D of the wafer C.

(3) Metal film forming step The wafer W that has been divided into wafers C is transferred to a sputtering apparatus 8 shown in FIG. 7. In addition, as in the case of the metal film forming step of Embodiment 1, as shown in FIG. 16, a substantially uniform predetermined thickness (for example, about 0.5 μm to 30 μm) can be formed for each device wafer C on the back surface Wb. Open the metal film J.

The method for manufacturing a device wafer according to the present invention is performed by dividing the wafer W into individual device wafers along the scribe line S, and thereafter on the back surface of the wafer W that has been divided into individual device wafers. The metal film forming step of forming the metal film J by Wb, so that the device D can be formed on the front surface Wa without causing the metal film J to be peeled from the wafer, the wafer flying, or damage caused by the wafers contacting each other. A device wafer C with a metal film J is formed on the back surface Wb.

In the dividing step, a groove G is formed from the front surface Wa of the wafer W to a predetermined thickness along the scribe line S, and the protective member T6 is disposed on the front surface Wa of the wafer W on which the groove G is formed. With the holding mechanism 10 holding the protection member T6 side, the wafer W is thinned from the back surface Wb side to the thickness of the finished product, thereby dividing the wafer W into individual device wafers C, so it can be implemented in A series of steps eliminates the risk of transporting the thinned wafer W.

(Embodiment 4) Hereinafter, each step in the case of implementing the method for manufacturing a device wafer of the present invention will be described.

(1) Wafer preparation step First, as shown in FIG. 17, a wafer W is prepared, and, for example, a protective tape T7 having the same diameter as the wafer W is attached to the front surface Wa. The wafer W is the same wafer as the wafer W shown in FIG. 1, and may be supported by a ring frame, for example.

(2) Dividing step The wafer W is transferred to the laser processing apparatus 2 and is held by the holding table 20 with the back surface Wb facing upward. Next, the wafer W held on the holding table 20 is fed in the −X direction (direction), and the position of one scribe line S serving as a reference for irradiating the laser beam with the laser beam is detected.

The holding table 20 is fed in the Y-axis direction, and the cutting track S and the Y-axis direction of the condenser 211 of the laser beam irradiation mechanism 21 are aligned. In addition, the position of the light-condensing point of the laser beam condensed by the condenser lens 211a is positioned at a predetermined height position inside the wafer W. Then, the laser beam oscillator 219 oscillates to generate a laser beam having a wavelength penetrating to the wafer W, and condenses and irradiates the laser beam to the inside of the wafer W held by the stage 20. The output of the laser beam is adjusted to, for example, an output in which a crack is extended from a modified layer K described later.

While the laser beam is irradiated onto the wafer W along the dicing path S, the wafer W is processed and fed in the −X direction at a predetermined processing feed rate, and is formed inside the wafer W as shown in FIG. 17. Modified layer K. In addition, a large number of fine cracks are formed that extend from the modified layer K and reach the front surface Wa of the wafer W. The crack also extends toward the back surface Wb of the wafer W.

If the wafer W is moved in the -X direction along a dicing path S to a predetermined position in the X-axis direction where the laser beam is irradiated, the processing of the wafer W in the -X direction can be stopped and the laser can be stopped. The irradiation of the beam is stopped together. Next, the holding table 20 is fed in steps in the Y-axis direction, and a machining feed in the -X direction is performed. The adjacent cutting track S and the focusing track S, which are positioned as the reference when the laser beam is irradiated, are collected. Registration in the Y-axis direction of the device 211. After the alignment has been performed, the wafer W is processed and fed in the + X direction (return direction), and the laser beam is irradiated along a dicing path S in the same manner as the laser beam in the forward direction. A modified layer M and a crack are formed inside the wafer W. By sequentially irradiating the same laser beam sequentially, a modified layer M and a fissure are formed along all the cutting tracks S extending in the X-axis direction. In addition, when the holding table 20 is rotated 90 degrees and the same laser beam is irradiated to the wafer W, a modified layer M and a crack can be formed inside the wafer W along all the vertical and horizontal scribe lines S. . Furthermore, in the wafer preparation step, a protective tape T7 may be attached to the back surface Wb of the wafer W, and in this division step, a laser beam is irradiated onto the wafer W from the front surface Wa side.

Next, the wafer W is transferred to the grinding apparatus 1 shown in FIG. 18 and sucked and held by the holding mechanism 10 with the back surface Wb side facing upward. The holding mechanism 10 holding the wafer W is moved below the grinding mechanism 11 in the Y-axis direction, and the grinding wheel 112 is further fed in the -Z direction, and the rotating grinding stone 112a is used to grind the wafer W. The back of Wb. During the grinding, the wafer W rotates with the rotation of the holding mechanism 10. Therefore, the grinding stone 112 a can perform the grinding process on the entire surface of the back surface Wb of the wafer W. In addition, the modified layer M can be removed by grinding, and the grinding pressure can be applied to the cracks along the scribe line S to divide the wafer W into individual device wafers C.

(3) Metal film forming step The wafer W that has been divided into wafers C is transferred to a sputtering apparatus 8 shown in FIG. 7. In addition, as in the case of the metal film forming step of the first embodiment, as shown in FIG. 19, a substantially uniform predetermined thickness (for example, about 0.5 μm to 30 μm) can be formed for each device wafer C on the back surface Wb. Open the metal film J.

The manufacturing method of the device wafer of the present invention is carried out, for example, by performing a dividing step of dividing the wafer W into individual device wafers along the scribe line S, and thereafter performing the step of dividing the wafer W into the individual device wafers. The metal film forming step of forming the metal film J on the back surface Wb allows the device to be formed on the front surface Wa without causing the metal film J to be peeled from the wafer, the wafer flying, or damage caused by the wafers contacting each other. D and a device wafer C having a metal film J formed on the back surface Wb.

In the dividing step, the laser beam is irradiated along the dicing path S in a state where the condensing point of the laser beam having a wavelength penetrating to the wafer W is positioned inside the wafer W, whereby The modified layer K is formed along the scribe line S, and the wafer W on which the modified layer K is formed is ground from the back surface Wb side to be thinned, thereby dividing the wafer W into individual device wafers C. Therefore, since a series of processes can be performed without the tape transfer of the wafer W, the operation efficiency can be improved.

C‧‧‧Chip (device chip)

D‧‧‧device

F‧‧‧ ring frame

G‧‧‧ trench

H‧‧‧ water-soluble resin

J‧‧‧Metal film

K, M‧‧‧ Modified layer

S‧‧‧ Cutting Road

T1, T2, T4, T7‧‧‧ protection tape

T3‧‧‧Cutting Tape

T5, T6‧‧‧Protection members

W‧‧‧ Wafer

Wa‧‧‧ wafer front

Wb‧‧‧ the back of the wafer

X, + X, -X, + Y, -Y, + Z, -Z‧‧‧ directions

1‧‧‧Grinding device

10‧‧‧ holding agency

100, 20a, 801a‧‧‧

11‧‧‧Grinding mechanism

110‧‧‧ Spindle

111‧‧‧Mount

112‧‧‧Grinding Wheel

112a‧‧‧grinding stone

112b‧‧‧ round abutment

2‧‧‧laser processing equipment

20‧‧‧holding table

200, 52‧‧‧Fixed fixture

21‧‧‧laser beam irradiation mechanism

211‧‧‧Condenser

211a‧‧‧ condenser lens

219‧‧‧laser beam oscillator

31‧‧‧cutting mechanism

310‧‧‧ cutting blade

311‧‧‧ spindle

5‧‧‧Expansion device

50‧‧‧ ring stand

50a‧‧‧ retaining surface

50c‧‧‧Opening of ring stand

52c‧‧‧rotation axis

53‧‧‧Expansion roller

55‧‧‧Circular platform lifting mechanism

8‧‧‧Sputtering device

80‧‧‧Static work clamp

800‧‧‧base shaft

801‧‧‧Workbench body

81‧‧‧ chamber

810‧‧‧Inlet

811‧‧‧Reducing port

83‧‧‧Excitation member

84‧‧‧Sputter source

85‧‧‧High-frequency power

FIG. 1 is a perspective view showing an example of a prepared wafer. FIG. 2 is a perspective view showing a wafer in a state of being supported through a frame. FIG. 3 is a perspective view showing a state where the wafer is ground from the back side to be thinned to a predetermined thickness. FIG. 4 is a cross-sectional view showing a state in which a laser beam is irradiated from the back side along the dicing path to the ground wafer to form a modified layer inside the wafer. 5 is a cross-sectional view showing a state where a wafer attached to a protective tape and supported by a ring frame is set to an expansion device. FIG. 6 is a cross-sectional view showing a state in which a protective tape is expanded by an expansion device to divide a wafer along a reforming layer. FIG. 7 is a cross-sectional view schematically showing an example of a sputtering apparatus. 8 is a cross-sectional view partially showing a wafer that is divided into device wafers and a metal film is formed on a back surface. FIG. 9 is a perspective view showing a state where a wafer is thinned from a back surface side to a predetermined thickness. FIG. 10 is a perspective view showing a state in which a wafer thinned to a predetermined thickness is subjected to a full cut along a dicing path from a front side of the wafer by a dicing mechanism. 11 is a cross-sectional view partially showing a wafer in which a water-soluble resin is filled between device wafers. 12 is a cross-sectional view partially showing a state where a metal film is formed on a wafer in which a water-soluble resin is filled between device wafers. 13 is a cross-sectional view partially showing a wafer divided into device wafers, a metal film formed on a back surface thereof, and a water-soluble resin removed; 14 is a perspective view showing a state where a wafer is cut along a dicing path from a front side by a dicing mechanism to form a groove. FIG. 15 is a perspective view showing a state in which a groove-formed wafer is thinned from a back surface side to a predetermined thickness and divided. 16 is a cross-sectional view partially showing a wafer that is divided into device wafers and a metal film is formed on a back surface. FIG. 17 is a cross-sectional view showing a state where a laser beam is irradiated from the back side along the dicing path, and a modified layer and a crack are formed inside the wafer. FIG. 18 is a perspective view showing a state in which a wafer on which a modified layer and a crack are formed is thinned from a back surface side to a predetermined thickness and divided. 19 is a cross-sectional view partially showing a wafer that is divided into device wafers and a metal film is formed on a back surface.

Claims (4)

A method for manufacturing a device wafer is a method for manufacturing a device wafer having a device formed on a front surface and a metal film formed on a back surface, comprising: a wafer preparation step, preparing to be divided on the front surface by a plurality of crossed cutting paths; A wafer having a device formed in each of the regions; a dividing step of dividing the wafer into individual device wafers along the dicing path; and a metal film forming step of dividing the wafer of the device wafer into individual ones. The metal film is formed on the back surface of the wafer. The method for manufacturing a device wafer according to claim 1, wherein in the aforementioned dividing step, the wafer is thinned from the back side to a predetermined thickness, and the thinned wafer is divided into individual pieces along the dicing path. Device wafer. The method for manufacturing a device wafer according to claim 1, wherein in the aforementioned dividing step, a groove having a depth reaching a predetermined thickness of the finished product is formed along the aforementioned scribe line from the front side of the wafer, and a protective member is disposed on the surface where the protective member is formed. The front side of the grooved wafer is thinned from the back side to the thickness of the finished product while the protection member side is held by the holding mechanism, thereby dividing the wafer into the aforementioned device wafers. The method for manufacturing a device wafer as claimed in claim 1, wherein in the aforementioned dividing step, a focusing point of a laser beam having a wavelength penetrating to the aforementioned wafer is positioned inside the wafer. Irradiating the laser beam along the dicing path to form a modified layer along the dicing path, and grinding the wafer on which the modified layer is formed from the back side to thin it, thereby The wafer is divided into the aforementioned device wafers.