JP2012146897A - Cutting method for semiconductor wafer and cutting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting method and the like for a semiconductor wafer, which can cut the wafer with small bending stress and provide a beautifully divided surface when the wafer is divided.SOLUTION: In the cutting method for a semiconductor wafer, which cuts the semiconductor wafer along a predetermined cutting line for dividing the wafer into a plurality of semiconductor chips, the method comprises: a step of placing the wafer on a vacuum suction base which has a continuous suction face on a surface, which sucks the whole face of the wafer, and a block on a rare face, which is provided so as to be divided with a space according to a chip size; a step of sucking the whole face of the wafer on the suction face by depressurizing the suction face of the vacuum suction base; and a step of warping the sucked wafer together with the vacuum suction base and uniformly cutting the wafer in the predetermined cutting line.

Description

  The present invention relates to a semiconductor wafer cleaving method and cleaving apparatus, and in particular, a semiconductor wafer in which a division line is provided between each chip by a modified portion or a crack between the chips is divided along the division line, and a plurality of The present invention relates to a cleaving method and a cleaving apparatus for a semiconductor wafer that is divided into semiconductor chips.

  In general, in the field of semiconductor device manufacturing, a semiconductor wafer having a substantially disk shape is divided into a plurality of division lines (also referred to as `` streets '') formed in a lattice shape on the surface of the semiconductor wafer, Each semiconductor chip is manufactured by forming devices such as IC, LSI, etc. in the divided areas, dividing each area where the devices are formed along the planned dividing line, and dividing and separating them. ing. The semiconductor chip thus divided is packaged and widely used in electric devices such as mobile phones and personal computers.

  Conventionally, for example, Patent Documents 1 to 4 are known as processing apparatuses that divide a semiconductor wafer along a division line and divide the semiconductor wafer into individual semiconductor chips.

  The processing apparatus known from Patent Document 1 irradiates a wafer after grinding and polishing with a laser beam, a modified region forming means for forming a modified region inside the wafer, and a dicing tape attached to the back surface of the wafer. A tape mounting means for mounting on the frame and an expanding means for expanding the distance between each chip of the wafer by expanding the dicing tape are provided.

  Here, in general, a wafer having a modified region that becomes a starting point of cutting by a laser beam is cleaved by an expansion of a dicing tape, and at this time, it is a tensile stress that acts as a stress. When an object is cleaved with a tensile stress, a very large stress is usually required for cleaving. In the case of a wafer made of a brittle material such as silicon, the bending stress is smaller than the tensile stress, so that the stress for cracking the wafer can be reduced. Stress is required.

  In addition, when the wafer attached to the expanding dicing film is divided by the tensile stress and each chip is separated, in order for the chips to be separated in the expanding dicing film, the portion that extends in the film and the wafer are bonded. In order to hold in, there is a portion that does not stretch. Since the stretched portion and the stretched portion are not necessarily completely homogeneous throughout the film, the portion that is originally desired to be cleaved cannot be sufficiently stretched, and as a result, it may not be cleaved and remain in a partially stuck state. In particular, when there is a time gap in the crack in the wafer surface, the film is easily stretched at the cracked portion, and the tensile stress applied to the film is consumed at the stretched portion of the film. On the other hand, if the wafer is locally cracked and the film is stretched partially, a sufficient tensile stress is not applied to the portion where the wafer is not yet cracked, and the chip remains stuck.

  Furthermore, such an event does not only occur due to the ease or difficulty of stretching in the film plane. The wafer is fixed with a film, which is fixed by simple adhesion. The part where the wafer is cracked and separated is separated from the wafer due to the film stretching, so this adhesion is peeled off around the chip, but the adhesive that bonds this wafer to the film and its strength are also homogeneous Not exclusively. Since it is a member, it always has a certain variation. At that time, the portion where the wafer and the film are firmly bonded locally is difficult to stretch the film, so the wafer is difficult to cleave and divided into chips, but the weakly bonded portion is stretched and cleaved. It may be easy to be done. However, when it is too weakly bonded, several wafer chips may come together and lift from the film. In such a case, even if only the film is elongated, the elongation of the film is not transmitted as a tensile stress between the wafer chips, and as a result, there still remains a problem that some chips cannot be cleaved.

  Further, when expanding and cracking, since an elastic tape material for expanding is usually used and the material is stretched, it is naturally not a rigid member that firmly fixes the wafer as a member that supports the wafer.

  Therefore, when the wafer is divided by tensile stress on such an elastic material, local vibration is partially generated at the moment when the wafer is broken. The locally generated vibration propagates in the wafer surface, but when viewed microscopically, the wafer often breaks depending on how the local vibration is propagated up to the point where the wafer is not desired to be broken. If the wafer is firmly fixed and stress is concentrated on the original cutting line, then applying this stress will not cause such an incorrect cracking, but when the elastic film is pulled and broken on the elastic film. In this case, the elastic film undulates up and down at the moment when the wafer is broken, and it is accidentally broken.

  Next, the semiconductor wafer division processing method in Patent Document 2 is different from the simple tensile stress as in Patent Document 1, and the semiconductor wafer is roughly divided into a plurality of steps as in the following procedures (1) to (4). It is divided into semiconductor chips.

  (1) First, a semiconductor wafer having a line to be divided on its surface is placed on an expandable elastic protective film that is stretched on the inside of an annular frame, with its back side facing downward, and The semiconductor wafer and the elastic protective film are integrated with each other by affixing to the elastic protective film.

  (2) Next, the annular frame to which the semiconductor wafer and the elastic protective film are attached is set on the frame mounting table of the wafer cleaving apparatus. Thereafter, the pressing member having a spherical pressing surface at the upper end is raised from below, the pressing surface of the pressing member is brought into contact with the lower surface of the elastic protective film, and pushed up to press the elastic protective film. To do. As a result, the stress that stretches the elastic protective film and the load that bends the semiconductor wafer through the elastic protective film act on the back surface of the semiconductor wafer, and this bending load acts on the line to be divided so that the semiconductor wafer is divided. Cleaving at the portion of the planned line and dividing into a plurality of semiconductor chips.

  (3) Further, when the pressing member is further pushed up, the elastic protective film is greatly expanded, and a gap is formed between the semiconductor chips to be separated from each other.

  (4) Thereafter, when the pressing member is lowered, the elastic protective film is held in a state where a gap is provided between the semiconductor chips while being stretched.

  In this case, when a pressing member having a spherical pressing surface is raised from the lower side, a load for bending the wafer acts, and the case of dividing only by the tensile stress in Patent Document 1 means that the bending stress acts somewhat. Different. However, in the method in which the wafer is attached to the film and the wafer attached to the film is divided from the lower side by the spherical pressing surface, the portion that first contacts the spherical pressing surface is the inside of the wafer. So, it breaks from the inside first and then to the outside. However, when the elastic film on the inner side is stretched, resistance to the elongation of the film is impaired, and the film is not effectively stretched on the outer side.

  Also, if the inside of the wafer is cracked first and the already cracked chip is tilted, even if you try to follow the spherical pressing surface at the outer periphery of the wafer, there is a case where the wafer cannot be completely cleaved without partially copying. Exists.

  Furthermore, the film itself is not a completely homogeneous film, and there is anisotropy in the direction of more or less easiness to stretch. For this reason, even if the spherical pressing surface is raised from the lower side, the film is displaced from the spherical pressing surface in a direction in which the film tends to be stretched due to variations in the stretchability of the film itself, and the film in the wafer surface is uniform. And a uniform bending stress at each part of the wafer cannot be applied.

  In the case of a wafer attached to a film, the film is easily stretched, but the wafer hardly stretches. Therefore, while the film has spreadability, the film does not have rigidity enough to maintain a planar posture, and is merely attached to the wafer. The posture of the wafer is determined by the wafer itself.

  Further, the pressing member under the film and the film are not adsorbed, but are simply brought into contact and pushed up. Therefore, there is no correction means for bringing the surfaces into close contact with each other by suction and forcing them to conform to the surface shape of the pressing member. In such a case, in the configuration in which the wafer is made thin and easy to break as disclosed in Patent Document 2, it is possible to divide the wafer sufficiently with this degree, but when the wafer is thick, the material having high wafer rigidity, Or, when the starting point of cutting formed on the wafer is very small, it is not sufficient.

  Further, as shown in FIG. 8A, when the wafer 102 is not in close contact with the rigid base 101, the wafer state immediately before the break is set as the vicinity of the cutting scheduled line 103 (the portion indicated by reference numeral 104 in the figure). ) Rises from the base 101, and the steep bending stress F does not act in the vicinity of the planned cutting line, and the stress F is relieved.

  Furthermore, when the wafer 102 is to be bent uniformly by pressing the pressing member from the back surface of the wafer, a bending stress is applied not only to the cutting scheduled line. When there is a small defect in advance other than the line to be cut, it is also assumed that the part other than the line to be cut is sometimes broken starting from the small defect.

  From the above, ideally, as shown in FIG. 8B, the wafer 102 is in close contact with the base 101, and a local and steep bending stress F acts on the planned cutting line 103. It is desirable that almost no bending stress acts on the portion other than the line to be cut. However, Patent Document 2 does not have such a configuration.

  Next, Patent Document 3 discloses that a wafer cutting planned line portion is sucked locally, bending stress is generated in the cutting planned line portion, and the wafer is cleaved by this bending stress. However, in the cleaving method disclosed in Patent Document 3, when the local stress of vacuum suction is used as the bending stress for cleaving the wafer, when the shock wave when the wafer is partially broken propagates in the wafer surface. However, it does not necessarily pass through the wafer cutting planned line portion. Since the abrupt local stress is applied to the wafer by the vacuum suction, it is assumed that at the moment of cracking, the portion deviated from the planned cutting line by the propagation of the vibration is assumed.

  Further, when the wafer is broken by being vacuumed, the entire surface of the wafer is not supported by suction, but vacuum is used as a means for applying local stress for breaking. Therefore, the very periphery of the wafer cutting line is not supported by suction and is not supported below. That is, the wafer is not in a rigidly fixed state, but a half-floating form. In such a case, the bending stress does not necessarily concentrate on the wafer cleaving line, and the problem that the unexpected part breaks due to the bending stress that propagates in the wafer surface when the wafer is cleaved as described above. There are things to do.

  Further, when the wafer is cracked, the local bending stress may be concentrated on the portion of the planned cutting line. However, in the case where there is no support on the back surface of the wafer, there is no space for the wafer to be bent in the whole without the back surface support. There will be room. In this case, even if it is bent to concentrate the stress on the parting line, the wafer will be bent locally at the part immediately adjacent to the parting line. It becomes impossible to efficiently break with less bending stress.

  In addition, when bending stress is generated by the differential pressure generated in the local space by further drawing a vacuum, when applying the bending stress, the amount of displacement giving the bending displacement and the speed for giving the displacement are strictly determined. It cannot be controlled. In order to concentrate the bending stress on the parting line to be cleaved and to cleave with high precision, excessive displacement and applying the excessive displacement at an abrupt speed make the wafer other than the parting line to be cut brittle. It can also cause cracks to the part. In addition, it is virtually impossible to give a predetermined displacement to the wafer with respect to the breaking of the wafer and to perform temporal control for the displacement.

  Next, in Patent Document 4, similarly, since the wafer is not completely fixed near the planned cutting line of the wafer, a space for bending the wafer near the planned cutting line is created. As a result, the bending stress cannot be concentrated on the parting line, so that it cannot be split efficiently and accurately.

JP 2007-214457 A Japanese Patent No. 4494728. JP 2006-344910 A Japanese Patent No. 3276506

  However, in the above-described conventional method for dividing a semiconductor wafer, the pressing surface of the pressing member is pressed against the lower surface of the elastic protective film, the dividing operation for bending the elastic protective film and the semiconductor wafer, and the elastic protective film is extended. Since the separation work for separating the semiconductor chips is performed at the same time, a large stress is required. For this reason, there existed a problem that an apparatus enlarged.

  Further, when the bending process is performed by the pressing member, the adhesion of the elastic protective film to the upper pressing surface of the pressing member is poor, and the elastic protective film and the semiconductor wafer are separated from the pressing surface of the pressing member, and the semiconductor wafer and the pressing surface are separated. A gap is formed between them, and the bending stress applied from the pressing member to the elastic protective film and the semiconductor wafer is dispersed by the gap. The dispersion of the bending stress adversely affects the cutting of the dividing surface at the planned dividing line, and may cause burrs or the like on the dividing surface. For this reason, the processing work which removes a burr | flash is needed, The work cost was increased, and since the bigger stress was also needed, there existed a problem that an apparatus enlarged.

  Therefore, the present invention has been made in view of such circumstances, and when the chip is efficiently cleaved with a relatively small stress, the variation in elasticity of the dicing film to which the wafer is bonded, or when the expansion is performed. Eliminates chip splitting due to variations in anisotropy and wafer-film adhesion, and gives a constant amount of displacement at a controlled rate to generate bending stress in the wafer when cleaving the wafer. The semiconductor wafer cleaving method enables stable chip cleaving and chip division / separation without applying bending stress in the wafer surface by locally concentrating the stress for cleaving. And the technical subject which should be solved in order to provide a cleaving apparatus arises, and this invention aims at solving this subject.

In order to achieve the above object, according to a first aspect of the present invention, there is provided a semiconductor wafer cleaving method in which a semiconductor wafer is cleaved along a division line and divided into a plurality of semiconductor chips, and the wafer is adsorbed over the entire surface. A process of placing the wafer on a vacuum suction table having a continuous suction surface and a block partitioned at intervals on the back surface according to the chip size, and the suction surface of the vacuum suction table is depressurized. A step of adsorbing the wafer to the entire adsorbing surface; bending the adsorbed wafer together with the vacuum adsorption table; and cleaving the wafer uniformly on the division line. Provide a cleaving method.

  According to this method, the semiconductor wafer provided with the division lines is pasted onto an expandable elastic protective film, for example, and the semiconductor wafer and the elastic protective film are integrated, and this is placed on the vacuum suction table. It arranges and it fixes by adsorbing with this vacuum adsorption stand. Next, when a bending force is applied to the vacuum suction table on which the semiconductor wafer and the elastic protective film are fixed by vacuum suction by a vacuum suction table bending mechanism, the semiconductor wafer and the elastic protective film are partitioned at intervals according to the chip size. The entire suction surface of the vacuum suction table is bent at a portion between the plurality of blocks, and the semiconductor wafer is also bent and bent by this bending, and the semiconductor wafer is cleaved starting from the dividing line.

  Thereby, the chip can be efficiently cleaved with a relatively small bending stress without depending on the tensile stress as in the prior art.

  In addition, since the groove portion provided on the opposite side of the suction plate to the wafer suction surface corresponding to the planned cutting line position is bent, the bending rigidity of the suction plate is increased in the chip surface, and almost in the chip surface. First, the line to be divided between chips is greatly bent. As a result, the stress is locally concentrated only on the division lines, and the wafer can be efficiently cleaved.

  Further, the wafer is adsorbed on the adsorption plate in advance, so that even if the wafer is warped, the plane is corrected on the adsorption plate. Here, since the wafer is in full contact with the suction plate, the deflection of the wafer completely follows the deflection of the suction plate and deforms integrally with the suction plate.

  Conventionally, even if the wafer is pushed up by a convex pressing body, it is not in close contact with the suction table, so when a bending force is applied, the wafer does not follow the shape of the table with a curvature locally. There was a case that the bending stress was locally relieved by the floating, and the bending stress was locally reduced and it was difficult to break. However, in the case of this configuration, the wafer is basically in close contact with the vacuum suction table, so that in the process of bending the wafer together with the vacuum suction table, local lifting of the wafer is suppressed, and the vacuum suction table is bent. Force to follow completely. Therefore, stress concentrates on the wafer division planned line, and the wafer can be cut accurately.

  Further, since the bending stress can be applied to the wafer by the continuous bending of the suction plate, it is possible to apply the bending stress to the wafer surface almost simultaneously even on a large wafer surface.

  In addition, although the chips are cleaved and divided substantially individually, the suction plate is a single continuous plate, so the chips are fixed to another mechanism in the plane, and the relative positions change. There is no room to do it.

  Moreover, there is no element that has spreadability and the mutual positional relationship is crazy like the expanded film. Since the continuous suction plate is bent from the flat state, the relative position between the wafer chips can be cut without moving.

  In addition, due to variations in elasticity of the dicing film to which the wafer is bonded, variations in anisotropy during expansion, and variations in adhesion between the wafer and the film, the chip separation performance does not change, and the wafer does not change. It is possible to give a displacement for generating such bending stress.

  Further, a certain amount of displacement for generating a bending stress applied to the wafer can be simultaneously given by simultaneously bending the surface of the suction table that supports the wafer.

  Further, since the constant displacement amount can be given at a controlled speed, it is possible to divide the stress while concentrating the stress on the planned cutting line.

  Furthermore, since the wafer is adsorbed in vacuum, the wafer is closely supported by a vacuum suction table, which is a rigid body, and the wafer displacement near the cleaving is completely suppressed, so the stress for cleaving is concentrated locally. It will be.

  Also, if you break the wafer and fix it on the adhesion table, it is difficult to peel it off, but after supporting and bending the wafer by vacuum suction, return it to its original horizontal position and turn off the vacuum. By simply releasing the air, there is no need to remove the adhesive or the like, and the broken wafer can be easily removed while being attached to the tape.

  In order to achieve the above object, according to a second aspect of the present invention, there is provided a semiconductor wafer cleaving method for cleaving a semiconductor wafer along a predetermined division line and dividing the semiconductor wafer into a plurality of semiconductor chips. A vacuum suction stand comprising a step of attaching an expandable elastic protective film, and a continuous suction plane for sucking the entire surface of the wafer on the front surface, and a block on the back surface that is partitioned at intervals according to the chip size. A step of placing the wafer on the surface, a step of planarly adsorbing the wafer to which the elastic protective film is attached to the vacuum adsorption table, and bending the adsorbed wafer together with the vacuum adsorption table to form the divided A step of cleaving the wafer uniformly along a predetermined line, and after the cleaving, tension is applied to the elastic protective film to separate the plurality of semiconductor chips. And the extent, to provide a cleaving method of semiconductor wafer made of.

  According to this method, the semiconductor wafer provided with the division lines is pasted onto an expandable elastic protective film, for example, and the semiconductor wafer and the elastic protective film are integrated, and this is placed on the vacuum suction table. It arranges and it fixes by adsorbing with this vacuum adsorption stand. Next, when a bending force is applied to the vacuum suction table in which the semiconductor wafer and the elastic protective film are fixed by vacuum suction by a vacuum suction table bending mechanism, the wafer is formed corresponding to the planned cutting line position of the wafer. The entire suction surface of the vacuum suction table is bent at each groove portion, and the semiconductor wafer is also bent and bent by this bending, and the semiconductor wafer is cleaved starting from the division line. Thereby, the chip can be efficiently cleaved with a relatively small bending stress without depending on the tensile stress as in the prior art.

  Thereby, the chip can be efficiently cleaved with a relatively small bending stress without depending on the tensile stress as in the prior art.

  In addition, since the groove portion provided on the opposite side of the suction plate to the wafer suction surface corresponding to the planned cutting line position is bent, the bending rigidity of the suction plate is increased in the chip surface, and almost in the chip surface. First, the line to be divided between chips is greatly bent. As a result, the stress is locally concentrated only on the division lines, and the wafer can be efficiently cleaved.

  Further, the wafer is adsorbed on the adsorption plate in advance, so that even if the wafer is warped, the plane is corrected on the adsorption plate. Here, since the wafer is in full contact with the suction plate, the deflection of the wafer completely follows the deflection of the suction plate and deforms integrally with the suction plate.

  Conventionally, even if the wafer is pushed up by a convex pressing body, it is not in close contact with the suction table, so when a bending force is applied, the wafer does not follow the shape of the table with a curvature locally. There was a case that the bending stress was locally relieved by the floating, and the bending stress was locally reduced and it was difficult to break. However, in the case of this configuration, the wafer is basically in close contact with the vacuum suction table, so that in the process of bending the wafer together with the vacuum suction table, local lifting of the wafer is suppressed, and the vacuum suction table is bent. Force to follow completely. Therefore, stress concentrates on the wafer division planned line, and the wafer can be cut accurately.

  Further, since the bending stress can be applied to the wafer by the continuous bending of the suction plate, it is possible to apply the bending stress to the wafer surface almost simultaneously even on a large wafer surface.

  In addition, although the chips are cleaved and divided substantially individually, the suction plate is a single continuous plate, so the chips are fixed to another mechanism in the plane, and the relative positions change. There is no room to do it.

  Moreover, there is no element that has spreadability and the mutual positional relationship is crazy like the expanded film. Since the continuous suction plate is bent from the flat state, the relative position between the wafer chips can be cut without moving.

  In addition, due to variations in elasticity of the dicing film to which the wafer is bonded, variations in anisotropy during expansion, and variations in adhesion between the wafer and the film, the chip separation performance does not change, and the wafer does not change. It is possible to give a displacement for generating such bending stress.

  Further, a certain amount of displacement for generating a bending stress applied to the wafer can be simultaneously given by simultaneously bending the surface of the suction table that supports the wafer.

  Further, since the constant displacement amount can be given at a controlled speed, it is possible to divide the stress while concentrating the stress on the planned cutting line.

  Furthermore, since the wafer is adsorbed in a vacuum, the wafer is closely supported by the rigid wafer chuck, and the wafer displacement near the cleaving is completely suppressed, so that the stress for cleaving is concentrated locally. become.

  Also, if you break the wafer and fix it on the adhesion table, it is difficult to peel it off, but after supporting and bending the wafer by vacuum suction, return it to its original horizontal position and turn off the vacuum. By simply releasing the air, there is no need to remove the adhesive or the like, and the broken wafer can be easily removed while being attached to the tape.

  Moreover, in order to achieve the said objective, invention of Claim 3 provides the cleaving method of the semiconductor wafer in which the said elastic protective film is a film which has air permeability.

  According to this method, the elastic protective film vacuum-adsorbed on the vacuum suction table can move somewhat with respect to the vacuum suction table due to its air permeability, and in a state of being in close contact with the elastic protection film without making wrinkles. Adsorbed and held.

  The present invention has been proposed in order to achieve the above object, and the invention according to claim 4 is a semiconductor wafer cleaving apparatus for cleaving a semiconductor wafer along a predetermined division line and dividing it into a plurality of semiconductor chips. A vacuum suction stand comprising: a continuous suction plate that sucks the entire surface of the wafer under reduced pressure; and a plurality of blocks that are provided on the back side of the suction plate and arranged at intervals according to the chip size; There is provided a semiconductor wafer cleaving apparatus comprising: a vacuum suction table bending mechanism that cleaves the wafer by bending the vacuum suction table that holds and holds the wafer.

  According to this configuration, the semiconductor wafer cleaving method according to the first, second, or third aspect can be easily performed.

  In order to achieve the above object, according to a fifth aspect of the present invention, in a semiconductor wafer cleaving apparatus for cleaving a semiconductor wafer along a predetermined division line and dividing the semiconductor wafer into a plurality of semiconductor chips, the wafer is reduced in pressure. While vacuuming the entire surface, a vacuum suction table having a plurality of grooves formed to a predetermined depth corresponding to the cutting line position of the wafer on the back side of the surface holding the wafer, and holding the wafer by suction There is provided a wafer cleaving apparatus comprising: a vacuum adsorption table bending mechanism that cleaves the wafer by bending the vacuum adsorption table.

  According to this configuration, the semiconductor wafer cleaving method according to the first, second, or third aspect can be easily performed.

  In order to achieve the above object, the invention described in claim 6 provides a semiconductor wafer cleaving apparatus, wherein the semiconductor wafer is a wafer to which an expandable elastic protective film is attached.

  According to this configuration, it is possible to handle the semiconductor wafer integrally by pasting with an elastic protective film, and it becomes possible to more easily implement the method for cleaving the semiconductor wafer according to claim 1, 2 or 3. .

  In order to achieve the above object, the invention according to claim 7 provides a semiconductor wafer cleaving apparatus in which the elastic protective film is a film having air permeability.

  According to this configuration, the elastic protective film vacuum-adsorbed on the vacuum suction table can move a little with respect to the vacuum suction table due to its air permeability, and in a state of being in close contact with the elastic protection film without creating wrinkles. Adsorbed and held. Thus, the semiconductor wafer cleaving method according to the first, second or third aspect can be more easily implemented.

  According to the invention, the chip is efficiently cleaved with a relatively small stress, the variation in elasticity of the dicing film to which the wafer is attached, the variation in anisotropy when expanding, and the adhesion between the wafer and the film It is possible to eliminate chip division errors due to variations in characteristics. In addition, when the wafer is cleaved, a constant amount of displacement for generating a bending stress can be given to the wafer at a controlled speed so that the stress for cleaving can be concentrated locally. Cleaving and chip separation / separation can be made possible. Furthermore, it is possible to improve the workability by reducing the size of the apparatus and reducing the deburring work.

The process drawing explaining one Example of the wafer cutting method which concerns on this invention. The perspective view which shows an example of a wafer. The perspective view which shows the state which affixed the wafer on the elastic protective film. The principal part schematic plan view of a wafer cleaving apparatus. FIG. 4 is a cross-sectional view taken along line AA of FIG. 4, (a) is a view showing a state where the protrusion and the rotating body are lowered, (b) is a view showing a state where the protrusion and the rotating body are raised, and (c) is a view showing The figure shown in the state which lowered | hung the protrusion and the rotation body, and raised the semiconductor chip separation member. The top view which shows one modification of a vacuum suction stand. FIG. 7 is an explanatory diagram of the vacuum suction table shown in FIG. 6, (a) and (b) when the cylinder operation is OFF, and (c) when the cylinder operation is ON. The figure explaining the problem of the conventional semiconductor chip separation / separation device.

  In order to achieve the object of obtaining a beautiful dividing surface with a small bending stress and at the time of division, the present invention divides a semiconductor wafer along a division line and divides it into a plurality of semiconductor chips. In a semiconductor wafer cleaving method, a vacuum suction table having a continuous suction surface for sucking the entire wafer on the front surface and a block arranged on the back surface with a space spaced according to the chip size. A step of placing the wafer, a step of depressurizing the suction surface of the vacuum suction table to suck the wafer on the suction surface, and bending the sucked wafer together with the vacuum suction table, And a step of cleaving the wafer uniformly on a predetermined line.

  Hereinafter, a wafer cleaving method according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a dividing process for carrying out the present invention for dividing a silicon wafer as a semiconductor wafer into individual semiconductor chips. In the cleaving method of the present embodiment, a process S1 for attaching an expandable elastic protective film to the back surface of the semiconductor wafer, and a suction plane for adsorbing the entire wafer on the front surface are provided, and the back surface is partitioned according to the chip size. A step S2 of placing the wafer on a vacuum suction table having a formed block; a step S3 of sucking the wafer with the elastic protective film affixed to the vacuum suction table; and the sucked wafer. Step S4 in which the wafer is bent along the dividing line, and the wafer is separated from the plurality of semiconductor chips by applying tension to the elastic protective film after the cutting. Through S5, individual semiconductor chips are formed from the semiconductor wafer.

  Next, each step will be described in detail. First, the semiconductor wafer 10 used in this embodiment has front and back surfaces formed in parallel as shown in FIG. On the surface side of the semiconductor wafer 10, a plurality of division lines 11, 11,... Arranged in a lattice pattern are provided. The dividing line 11 divides the surface side of the semiconductor wafer 10 into a plurality of grid-like regions, and the IC, LSI, etc. for forming the semiconductor chips 12, 12. A functional element is provided. The division line 11 here is a modified portion or a crack formed by laser processing, and is provided so that the semiconductor wafer 10 can be easily cleaved. Sometimes formed.

  Then, the semiconductor wafer 10 on which the division lines 11 are formed is placed on the elastic protective film 13 with its back surface facing downward as shown in FIG. Is fixed on the elastic protective film 13. This sticking and fixing is performed by, for example, pressing and sticking the semiconductor wafer 10 onto the elastic protective film 13 while heating the back surface of the semiconductor wafer 10 and the elastic protective film, or elastically protecting the back surface of the semiconductor wafer 10. Means such as attaching and detaching an adhesive between the films are appropriately employed.

  The elastic protective film 13 is, for example, a sheet-like film having a thickness of about 70 μm, and has a property of being stretchable at room temperature and shrinking by heat at a predetermined temperature (for example, 70 ° C.) or higher. It is a synthetic resin sheet such as (PVC), polypropylene, polyethylene, polyolefin, etc., and has a structure that allows air permeability to be obtained.

  The elastic protective film 13 to which the semiconductor wafer 10 is attached in the step S1 is moved onto the semiconductor wafer cleaving apparatus 14 as shown in FIGS.

  The semiconductor wafer cleaving device 14 is a device for processing the steps S2 to S5, and is anteroposterior (Y-axis direction) and left and right (X Film fixing / holding members 15, 15, 15, 15 disposed in the axial direction), and a vacuum suction table 16 disposed inside a region surrounded by the film fixing / holding members 15, 15, 15, 15. A vacuum suction stand support member 17 that supports the vacuum suction stand 16, a vacuum suction stand bending mechanism 18 that deflects the vacuum suction stand 16, and a plurality of semiconductors that apply tension to the elastic protective film 13. The semiconductor chip separation member 19 is separated from the chip.

  The vacuum suction table 16 has a plate-like continuous suction surface 20a on which the elastic protective film 13 to which the semiconductor wafer 10 is attached is placed, and the semiconductor wafer 10 is sucked through the elastic protective film 13 on the surface side. The suction plate portion 20 is provided. Further, a plurality of grooves 21, 21... Formed to a certain depth corresponding to the position of the division line 11 of the semiconductor wafer 10 are provided on the back surface side of the suction plate portion 20 according to the chip size. A plurality of blocks 22, 22... Partitioned with a predetermined interval are provided integrally with the suction plate portion 19. In FIG. 4, for easy understanding, the grooves 11, 11... And the blocks 22, 22... Are shown by solid lines, but actually, as shown in FIG. It is provided on the side.

  The vacuum suction table 16 is flexible and is normally held in a horizontal plane as shown in FIG. 5 (a). However, the vacuum suction table 16 is bent as shown in FIG. 5 (b). When it is lifted by the mechanism 18, it bends to a state where it bulges upward.

  More specifically, a plurality of intake holes 23, 23... Are provided on the upper surface (hereinafter referred to as “suction surface”) of the suction plate portion 19 corresponding to the blocks 22, 22. Each of the suction holes 23, 23... Is connected to a vacuum suction device via a pipe material (not shown). When the vacuum suction device is operated for suction, air is sucked from the suction holes 23, 23. The suction surface 20a of the suction plate portion 20 is decompressed so that the semiconductor wafer 10 can be sucked and held on the suction surface 20a via the elastic protective film 13. In the present embodiment, the intake holes 23, 23... (Black holes in the figure) provided in places other than the part where the semiconductor wafer 10 is placed are closed.

  The vacuum suction table bending mechanism 18 includes a pressing table 24 having a bowl-like cross section, and a protrusion and rotating body 25 that moves the pressing table 24 up and down and rotates 90 degrees.

  The semiconductor chip separating member 19 is generally lower than the position of the elastic protective film 13 stretched on the film fixing and holding member 15 between the film fixing and holding member 15 and the vacuum suction table supporting member 17. Is arranged. The semiconductor chip separating member 19 can move up and down. When the semiconductor chip separating member 19 is moved upward, a tensile force is applied to the elastic protective film 13 stretched on the film fixing and holding member 15 so that the entire elastic protective film 13 is moved. Can be extended in the XY direction.

  Next, the operation of the semiconductor wafer cleaving apparatus 14 will be described with reference to FIGS. 4 and 5 according to the processing steps S1 to S5 shown in FIG.

  In the semiconductor wafer cleaving apparatus 14, when the cleaving process of the semiconductor wafer 10 is not performed, the evacuation in the suction plate portion 20 is stopped, and the semiconductor chip separating member 19 is moved downward.

  Then, the semiconductor wafer 10 that has been attached with the expandable elastic protective film 13 in the process of the step S1 has four sides of the elastic protective film 13 fixed by the film fixing and holding members 15, 15, 15, 15. As shown in FIG. 5 (a), it is set on the suction plate portion 20 of the vacuum mounting table 16 (step S2).

  Next, evacuation at the suction plate unit 20 is started. When evacuation is started, the pressure on the suction surface 20a is reduced, and the elastic protective film 13 is sucked and held on the entire suction surface 20a as shown in FIG. 5 (a) (step S3). .

  Subsequently, the vacuum suction table bending mechanism 18 is driven in a state where the suction plate 20 is evacuated. Then, the protruding and rotating body 25 protrudes upward together with the pressing base 24. As a result, the pressing base 24 abuts against the lower surface of the block 22 and pushes up. Further, when the entire vacuum mounting table 16 is pushed up from the lower side, the vacuum mounting table 16 protrudes upward together with the elastic protective film 13, and the whole is curved and deformed in a bowl shape. At this time, the semiconductor wafer 10 affixed on the elastic protective film 13 is also protruded upward and curved and deformed in a bowl shape. Due to this curvature, the semiconductor wafer 10 is bent along the x-axis direction (or y-axis) side along the planned division line 11 with the planned division line 11 as a base point. It is cleaved every time. When the cleaving by bending in the x-axis direction (or y-axis direction) is finished, the protruding and rotating body 25 is returned downward together with the pressing table 24. FIG. 5C shows this state.

  Next, the protruding and rotating body 25 is rotated 90 degrees together with the pressing table 24, and then the protruding and rotating body 25 is protruded upward together with the pressing table 24, and the semiconductor wafer 10 is formed into a bowl shape together with the elastic protective film 13. Curve and deform. By this bending, the semiconductor wafer 10 is bent on the y-axis direction (or x-axis direction) side along the planned dividing line 11 with the planned dividing line 11 as a base point, and the side along the y-axis by this bending is the semiconductor chips 12, 12. ... cleaved every time. When the cleaving by bending in the x-axis direction (or y-axis) side is finished, the protruding and rotating body 25 is returned downward together with the pressing table 24. Thereby, the side along the x axis and the side along the y axis are cleaved. That is, the process of the cleaving step S4 is performed.

  In the case where the elastic protective film 13 is absorbed and held on the vacuum mounting table 16 in this manner and bent into a bowl shape and divided, the semiconductor wafer 10 is integrated with the vacuum mounting table 16 and the Since it does not float from the vacuum mounting table 16, the bending stress is concentrated on the portion of each division planned line 11. Therefore, compared with the conventional method of bending and cleaving without adsorbing the elastic protective film 13 to the base, the bending stress for dividing is small, and it is neatly divided without creating burrs or the like on the cut section. Can do.

  Further, when the process of the cleaving step S4 is completed and the protrusion and the rotating body 25 are returned downward together with the pressing table 24, the pressing table 24 is lowered to an initial position away from the vacuum mounting table 16. As shown in FIG. 5C, the vacuum mounting table 16 is also returned to the horizontal state.

  When the semiconductor wafer cleaving process in step S4 is completed, the semiconductor chip separation member 19 is then moved upward, and the semiconductor chip separation is placed below the elastic protective film 13 stretched on the film fixing and holding member 15. The member 19 is abutted against each other to apply a tensile force to the elastic protective film 13, and the entire elastic protective film 13 is extended in the XY direction. As a result, the semiconductor chips 12, 12,... Are largely separated from each other and divided into individual semiconductor chips 12, 12,..., And the semiconductor chip separating member 19 is also returned to a predetermined position below. That is, the process of the separation / separation step S5 ends. After completion of step S5, the elastic protective film 13 is removed from the film fixing and holding member 15 together with the semiconductor chip 12.

  The gap formed between the semiconductor chips 12, 12... By extending the elastic protective film 13 is maintained even after the tension of the elastic protective film 13 is removed. And in the semiconductor wafer 10 divided in this way, since the elastic protective film 13 is spaced between the respective semiconductor chips 12, 12,..., The individual semiconductor chips 12, 12 do not contact each other, and it is possible to prevent the semiconductor chips 12, 12...

  Further, the semiconductor wafer cleaving apparatus 14 uses an air cylinder 26 and an air cylinder 27 as shown in FIG. 6, for example, as shown in FIG. In response to the operation of the air cylinder 26, the vacuum mounting table 16 is bent in the x-axis direction, and the vacuum mounting table 16 is bulged upward along the x-axis, and the operation of the air cylinder 27. The y-axis control member 29 which bends the vacuum mounting table 16 in the y-axis direction and bulges the vacuum mounting table 16 along the y-axis may be provided.

  FIG. 7 is a view for explaining the operation of the vacuum suction stand bending mechanism 18 shown in FIG. That is, in this structure of the vacuum suction table bending mechanism, when the air cylinder 26 (or 27) is not pulled, the vacuum mounting table 16 has a planar shape as shown in FIGS. I am doing. When the air cylinder 26 (or 27) is pulled, a bending force as indicated by the symbol F is generated on the vacuum mounting table 16, and the whole of the vacuum mounting table 16 is bent upward. The elastic protective film 13 is bent together with the semiconductor wafer 10 by this deformation, and the semiconductor wafer 10 is cleaved.

  The air cylinder is provided with only one of the air cylinder 26 and the air cylinder 27, and the elastic protective film 13 and the semiconductor wafer 10 mounted on the vacuum mounting table 16 are rotated by 90 degrees together with the film fixing and holding member 15. Then, the cleaving process may be performed. Further, a positioning tray 30 for positioning and placing the semiconductor wafer 10 on the vacuum mounting table 16 may be provided.

  Furthermore, in the said Example, although the vacuum mounting base 16 disclosed the structure formed by integrally forming the suction plate part 20 and the block 22, the suction plate part 20 and the block 22 were formed separately and integrated. It may be a structure.

  Further, as described above, the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

  As described above, the present invention can be applied to an apparatus for dividing a printed wiring board or the like in addition to dividing a semiconductor wafer.

DESCRIPTION OF SYMBOLS 10 Semiconductor wafer 11 Scheduled division line 12 Semiconductor chip 13 Elastic protective film 14 Semiconductor wafer cleaving device 15 Film fixing holding member 16 Vacuum mounting table 17 Vacuum suction table support member 18 Vacuum suction table bending mechanism 19 Semiconductor chip separation member 20 Suction plate part 20a Suction surface 21 Groove 22 Block 23 Intake hole 24 Press base 25 Protruding and rotating body 26 Air cylinder 27 Air cylinder 28 x-axis control member 29 y-axis control member 30 Positioning pan

Claims (7)

In the method of cleaving a semiconductor wafer that cleaves the semiconductor wafer along the division line and divides it into a plurality of semiconductor chips,
A process of placing the wafer on a vacuum suction table having a continuous suction surface that sucks the entire surface of the wafer on the front surface, and a block partitioned at intervals on the back surface according to the chip size;
Depressurizing the suction surface of the vacuum suction table to suck the entire surface of the wafer onto the suction surface;
Deflecting the adsorbed wafer together with the vacuum adsorption table, and cleaving the wafer uniformly on the division line; and
A method for cleaving a semiconductor wafer comprising: In the method of cleaving a semiconductor wafer that divides the semiconductor wafer along the division line and divides the semiconductor wafer into a plurality of semiconductor chips,
A step of applying an expandable elastic protective film to the back surface of the wafer;
A process of placing the wafer on a vacuum suction table made up of blocks that have a continuous suction plane that sucks the entire surface of the wafer on the front surface and is partitioned on the back surface at intervals according to the chip size;
A step of planarly adsorbing the wafer to which the elastic protective film is attached to the vacuum adsorption table;
Bending the sucked wafer together with the vacuum suction table, and cleaving the wafer uniformly along the division line; and
After cleaving, applying tension to the elastic protective film and separating the plurality of semiconductor chips;
A method for cleaving a semiconductor wafer, comprising:   3. The method for cleaving a semiconductor wafer according to claim 2, wherein the elastic protective film is a film having air permeability. In a semiconductor wafer cleaving apparatus that cleaves a semiconductor wafer along a division line and divides it into a plurality of semiconductor chips,
A vacuum suction stand comprising a continuous suction plate for vacuum-adsorbing the entire surface of the wafer, and a plurality of blocks provided on the back side of the suction plate and spaced at intervals according to the chip size;
A vacuum suction table bending mechanism that cleaves the wafer by bending the vacuum suction table holding and holding the wafer;
A cleaving apparatus for a semiconductor wafer, comprising: In a semiconductor wafer cleaving apparatus that cleaves a semiconductor wafer along a division line and divides it into a plurality of semiconductor chips,
The vacuum suction table having a plurality of grooves formed to a certain depth corresponding to the planned cutting line position of the wafer on the back side of the surface holding the wafer while depressurizing and sucking the entire wafer;
A vacuum suction table bending mechanism that cleaves the wafer by bending the vacuum suction table holding and holding the wafer;
A cleaving apparatus for a semiconductor wafer, comprising:   6. The semiconductor wafer cleaving apparatus according to claim 4, wherein the semiconductor wafer is a wafer to which an expandable elastic protective film is attached.   7. The semiconductor wafer cleaving apparatus according to claim 6, wherein the elastic protective film is a film having air permeability.

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