JP2008270627A - Dicing apparatus and dicing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dicing apparatus and a dicing method for securing satisfactory cutting property even in the case of using a thin semiconductor wafer as an object. <P>SOLUTION: In a dicing device for cutting a semiconductor wafer 6 by a revolving blade 13, and for dividing the semiconductor wafer into semiconductor chips 6a as individual pieces, an ice blast nozzle 15 for injecting a wash medium 20 including freezing particles 20a of wash water and drops 20b in a super-cooling state to the blade 13 by using a rubber nozzle is arranged, and configured to inject the wash medium to the cutting sites of the semiconductor wafer 6 by the blade 13 or the side faces of the blade 13. Thus, it is possible to secure satisfactory cutting property even in the case of using a thin semiconductor wafer as an object by improving cooling effects, and preventing blocking due to the adhesion of fine organic foreign matters to the blade 13. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dicing apparatus and a dicing method for dividing a semiconductor wafer into individual semiconductor chips.

A semiconductor element used for an electronic device is manufactured through a dicing process in which a plurality of functional circuits are collectively formed on a disk-shaped semiconductor wafer and then the semiconductor wafer is divided into individual pieces. The dicing process is performed by cutting a semiconductor wafer along a scribe line, which is a dividing line for each element, using a dicing blade that is generally rotated at a high speed. In the dicing apparatus used in this process, the grinding fluid is supplied to the cutting part by the dicing blade, whereby the cutting waste is discharged from the processing part and the dicing blade and the wafer sheet are overheated by the heat generated by the cutting. Cutting failure is prevented (see Patent Document 1). In the prior art shown in this patent document example, the grinding water is cooled to a low temperature by using a cooling gas generator that separates compressed air into cold air and hot air.
JP 2005-20984 A

  In recent years, semiconductor devices have been made thinner, and ultrathin semiconductor devices of about several tens of μm have been used. For this reason, also in the dicing process, it is required to perform dicing on a semiconductor wafer having the same thickness. However, when cutting such an ultrathin semiconductor wafer adhered to an adhesive sheet using a dicing blade, there are the following problems.

  When the semiconductor wafer to be cut is thin, the residual degree of the resin component of the adhesive sheet that adheres to the dicing blade during the cutting process increases. That is, when the thickness of the semiconductor wafer is large, the resin component adhering to the dicing blade in the cutting process is largely removed by friction with the semiconductor wafer itself, whereas when the semiconductor wafer is thin, it adheres. The resin component remains without being removed by friction with the semiconductor wafer. As a result, clogging of the dicing blade is likely to proceed, and the machinability is significantly reduced such as frequent chipping at the cutting site. As described above, the conventional dicing apparatus has a problem that it is difficult to ensure good cutting properties when a thin semiconductor wafer is used.

  Accordingly, an object of the present invention is to provide a dicing apparatus and a dicing method that can ensure good cutting properties even when a thin semiconductor wafer is targeted.

  The dicing apparatus of the present invention is a dicing apparatus that divides the semiconductor wafer into individual semiconductor chips by cutting the semiconductor wafer along a scribe line with a blade that rotates, and is attached to a wafer sheet. A wafer table for holding the semiconductor wafer; a dicing head on which the blade is mounted; moving means for moving the wafer table relative to the dicing head; frozen particles of cleaning liquid and / or supercooling with respect to the blade Freeze cleaning medium spraying means for spraying a cleaning medium containing droplets in a state, the frozen cleaning medium spraying means atomizing the cleaning liquid by using a Laval nozzle and freezing the cleaning liquid by a rapid cooling effect by adiabatic expansion. Solid-liquid two-phase spray containing particles and supercooled droplets Injecting forming a transducer group.

  The dicing method of the present invention is a dicing method for dividing the semiconductor wafer into individual semiconductor chips by cutting the semiconductor wafer along a scribe line with a rotating blade, which is in a state of being attached to a wafer sheet. A wafer holding step of holding the semiconductor wafer by a wafer table, a cutting step of cutting the semiconductor wafer by the blade rotating by moving the wafer table relative to a dicing head on which the blade is mounted, And a frozen cleaning medium spraying step of spraying a cleaning medium containing frozen particles of cleaning liquid and / or supercooled droplets onto the blade, and in the frozen cleaning medium spraying process, the cleaning liquid is atomized by using a Laval nozzle For rapid cooling effect due to adiabatic expansion Ri solid-liquid to form a two-phase spray particles of injecting comprising frozen particles and droplets of supercooled state of the cleaning solution.

  According to the present invention, the cleaning liquid is atomized by using a Laval nozzle, and a solid-liquid two-phase spray particle group including frozen particles of the cleaning liquid and supercooled droplets is formed on the blade by a rapid cooling effect by adiabatic expansion. By spraying, the clogging due to the cooling effect and the adhesion of fine organic foreign matter to the blade can be prevented, and good machinability can be ensured even when a thin semiconductor wafer is targeted.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a dicing apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory view of a cleaning medium injection state by a Laval nozzle used in the dicing apparatus according to an embodiment of the present invention, and FIG. FIG. 4 is a structural explanatory diagram of a Laval nozzle used in the dicing apparatus according to an embodiment of the present invention, and FIG. 5 is an embodiment of the present invention. FIG. 6 and FIG. 7 are explanatory views of the arrangement state of the Laval nozzle in the dicing apparatus according to the embodiment of the present invention. FIG. 8 is a dicing method according to the embodiment of the present invention. It is explanatory drawing of blade adhesion foreign material removal in.

  First, the configuration of the dicing apparatus 1 will be described with reference to FIG. The dicing apparatus 1 has a function of dividing a semiconductor wafer into individual semiconductor chips by cutting a semiconductor wafer in which a plurality of semiconductor chips are formed with a dicing blade that rotates at high speed. In FIG. 1, the wafer mounting unit 2 has a configuration in which a wafer table 3 is held by a table moving mechanism 4 so as to be movable in the XYZΘ direction. A wafer chuck mechanism 3 a for holding a workpiece to be cut is provided on the upper surface of the wafer table 3.

  In the present embodiment, the wafer jig 5 that holds the semiconductor wafer 6 on the resin wafer sheet 7 and stretches the wafer sheet 7 on the annular wafer ring 8 is used as a workpiece to be cut. The wafer chuck mechanism 3a holds the wafer. That is, the wafer table 3 holds the semiconductor wafer 6 that is stuck to the wafer sheet 7. Here, the semiconductor wafer 6 is a thin semiconductor wafer having a thickness of 100 μm or less.

  The position where the wafer table 3 is moved in the Y direction by the table moving mechanism 4 is a dicing work position by the dicing mechanism 10. The dicing mechanism 10 is configured by providing a dicing head 12 at the end of a spindle portion 11 having a built-in rotation drive mechanism. A dicing blade 13 (hereinafter simply referred to as a blade 13), which is a thin grindstone for cutting the semiconductor wafer 6, is mounted on the dicing head 12 while being sandwiched between mounting flanges 14.

  With the wafer jig 5 held by the wafer chuck mechanism 3a, the table moving mechanism 4 is driven to move the wafer table 3 in the Y direction, whereby the semiconductor wafer 6 adhered to the wafer sheet 7 is dicing head 12. Is positioned at the dicing work position. That is, the table moving mechanism 4 is a moving means for moving the wafer table 3 relative to the dicing head 12. As the moving means, a configuration in which the wafer table 3 is fixedly arranged and the dicing head 12 is moved with respect to the wafer table 3 together with the spindle portion 11 may be used.

  The dicing mechanism 10 is provided with an ice blast nozzle 15 and a working fluid supply unit 16 for supplying a working fluid to the ice blast nozzle 15. The ice blast nozzle 15 injects a cleaning medium onto the blade 13. By doing this, the cutting part is cooled, and the cutting waste generated by cutting and the foreign matter adhering to the blade 13 are removed to improve the machinability.

  In the dicing process of dividing the semiconductor wafer 6 into individual pieces, as shown in FIG. 2A, the blade 13 is rotated in the direction of arrow a at a high speed, and the scribe lines that are the division lines of the individual pieces set on the semiconductor wafer 6 are obtained. The semiconductor wafer 6 is moved relative to the blade 13 in the direction of the arrow b while cutting along the line 6b. Thereby, along the scribe line 6b in the semiconductor wafer 6, the dicing groove 6c penetrating the semiconductor wafer 6 in the thickness direction is formed by the blade 13 having a thickness of about several tens of μm. Divided into chips 6a.

  As described above, the target semiconductor wafer 6 is a thin wafer, and the thickness t1 is smaller than the thickness t2 of the wafer sheet 7 holding the semiconductor wafer 6. In the cutting of the semiconductor wafer 6 by the blade 13, as shown in FIG. 2B, the tip of the blade 13 penetrates the semiconductor wafer 6 in the thickness direction and is cut in a form partially cut into the wafer sheet 7. Is done. For this reason, in the dicing process, foreign matter such as cutting waste obtained by cutting silicon as a component of the semiconductor wafer 6 or organic foreign matter generated by partially cutting the wafer sheet 7 is generated along the scribe line 6b. And is discharged from the dicing groove 6c. Some of these foreign substances adhere to the surface of the semiconductor wafer 6 and some also adhere to the tip of the blade 13. Since such organic foreign matters attached to the semiconductor wafer 6 impair the product quality, and those attached to the blade 13 cause clogging and reduce machinability, all of them are removed during the dicing process. There is a need.

  However, among these foreign substances, the organic foreign substances are softened by the heat generated during cutting of the resin that is the main component of the wafer sheet 7 and the adhesive material for adhering the semiconductor wafer 6 and the wafer sheet 7. If they adhere to the surface of the semiconductor wafer 6 or the blade 13, it is not easy to peel them off. In particular, when a thin semiconductor wafer 6 is the target, the effect of the organic foreign matter adhering to the surface is small because the action of polishing and removing the organic foreign matter by the high-hardness semiconductor wafer 6 is small. Therefore, in the dicing apparatus 1 shown in the present embodiment, a good foreign matter removal result is obtained by applying cleaning by the ice blast nozzle 15 for organic foreign matters having a high degree of difficulty of removal. .

  That is, as shown in FIG. 2B, the cleaning medium 20 including the frozen particles 20a of the cleaning liquid (in this case, the cleaning water) and / or the supercooled liquid droplets 20b is removed from the blade by the ice blast nozzle 15. In FIG. 13, spraying is performed on a cutting portion to be cut in contact with the semiconductor wafer 6. As a result, the cutting portion is cooled together with the wafer sheet 7, and the cutting waste and organic foreign matters generated on the scribe line 6b are removed. Details such as the incident angle of the cleaning wafer 20 on the semiconductor wafer 6 and the distance from the semiconductor wafer 6 are set based on trial results of actual dicing tests on individual semiconductor wafers 6.

  Next, the configuration of the piping system of the working fluid supply unit 16 will be described with reference to FIG. In FIG. 3, the working fluid supply unit 16 is supplied with water used as a cleaning liquid and compressed air used as an ejection medium from a cleaning water supply source 22 and an air supply source 21, respectively. A piping system for supplying cleaning water and compressed air to the ice blast nozzle 15 will be described. The air supply pipe 21 a connected to the air supply source 21 is connected to the ice blast nozzle 15 via a regulator 23, a filter 24, a refrigeration air dryer 25, and an opening / closing valve 27. By controlling the opening / closing valve 27 to open / close, the compressed air supplied to the ice blast nozzle 15 is on / off controlled.

  The regulator 23 adjusts the pressure of the compressed air supplied to the air supply pipe 21a, and the filter 24 filters and removes foreign substances in the compressed air supplied together. The refrigeration air dryer 25 freezes and removes moisture by cooling the compressed air. The temperature sensor 26 connected to the air supply pipe 21a detects the temperature of the supplied compressed air. By operating the regulator 23, the pressure supplied to the ice blast nozzle 15 can be set to a predetermined pressure.

  The cleaning water supply pipe 22a connected to the cleaning water supply source 22 is connected to a fixed discharge pump 28, and the pump 28 discharges the supplied cleaning water quantitatively. The discharged cleaning water is supplied to the cooling unit 32 through the discharge water pipe 28a. A flow rate sensor 29, a check valve 30, and a filter 31 are interposed in the discharge water pipe 28a. The flow sensor 29 detects the flow rate of the cleaning liquid flowing through the discharge water pipe 28a. The check valve 30 prevents the backflow of the cleaning liquid, and the filter 31 filters and removes foreign matters in the cleaning liquid.

  Refrigerant such as antifreeze liquid cooled by the refrigerant circulation unit 33 circulates in the cooling unit 32, and the cleaning liquid supplied from the discharge water pipe 28 a passes through the cooling unit 32 to have a predetermined set temperature (main temperature). In the embodiment, it is cooled to about 5 ° C.) and is supplied to the ice blast nozzle 15 through the cold water supply pipe 32a in this state. At this time, by controlling the driving of the pump 28 by a control unit (not shown) based on the detection result of the flow sensor 29, the ice blast nozzle 15 is always supplied with cold water having a preset predetermined flow rate.

  Next, with reference to FIG. 4, the structure of the ice blast nozzle 15 and the manner of spraying the cleaning medium 20 by the ice blast nozzle 15 will be described. As shown in FIG. 4A, the ice blast nozzle 15 is mainly composed of a cylindrical nozzle body 15a, and an internal flow path hole 17 is formed through the nozzle body 15a in the longitudinal direction. . The upstream side of the internal flow path hole 17 is an introduction portion 17a to which the compressed air (arrow c) is introduced by connecting the air supply pipe 21a. On the downstream side of the introduction part 17a, the reduced diameter part 17b in which the flow path diameter of the internal flow path hole 17 is reduced along the flow direction, the throat part 17c in which the flow path diameter is reduced to the smallest, and the enlarged diameter in which the flow path diameter increases. The part 17d and the acceleration cooling part 17e whose flow path diameter gradually increases are sequentially provided in the flow direction of the compressed air.

  That is, the ice blast nozzle 15 configured as described above forms a Laval nozzle having a reduced diameter portion 17b, a throat portion 17c, and an enlarged diameter portion 17d. The shapes of the reduced diameter portion 17b, the throat portion 17c, and the enlarged diameter portion 17d are set such that the supplied compressed air is cooled to a low temperature by adiabatic expansion. On the upstream side of the throat portion 17c, a droplet supply pipe 18 for introducing the cleaning liquid in the same direction as the flow of compressed air is provided, and the liquid is supplied in a predetermined amount from the cold water supply pipe 32a and cooled. The washing water is discharged downstream from the tip of the droplet supply pipe 18 in the form of fine droplets 19.

  The flow of compressed air supplied to the introduction portion 17a at a pressure of about 0.2 MPa to 1 MPa is accelerated by the reduced diameter portion 17b (arrow d), and passes through the throat portion 17c at a flow velocity of about the speed of sound. Then, the pressure decreases and further accelerates (arrow e) by passing through the enlarged diameter portion 17d and moving into the enlarged diameter portion 17d, and the temperature is reduced to about -110 ° C by adiabatic expansion. Then, the droplet 19 that flows out from the tip of the droplet supply pipe 18 and is atomized by the flow of compressed air is rapidly cooled by the compressed air whose temperature has decreased, and the frozen particles 20a and droplets in which the droplet 19 is frozen. Either or either one of the droplets 20b existing in the state of droplets while 19 is supercooled is generated. Here, a solid-liquid two-phase spray particle group including the frozen particles 20a and the droplets 20b is formed. The cleaning medium 20 that is a flow of compressed air containing such a solid-liquid two-phase spray particle group flows at a high speed to the downstream side while being accelerated in the accelerating cooling section 17e that gradually increases in diameter (arrow f). Injected from the tip of the ice blast nozzle 15.

  In the above-described configuration, the ice blast nozzle 15, the air supply source 21 that supplies the cleaning water and compressed air to the ice blast nozzle 15, and the pump 28 use the cleaning medium containing the frozen particles 20 a of the cleaning liquid and the supercooled droplets 20 b as the semiconductor wafer. The frozen cleaning medium spraying means is configured to spray through the ice blast nozzle 15 to the cutting part by the six blades 13. In the example shown in FIG. 6, the frozen washing medium ejecting means atomizes the washing water by using a Laval nozzle, and at the same time, the washing water frozen particles 20 a and the supercooled droplets 20 b are brought about by a rapid cooling effect due to adiabatic expansion. A solid-liquid two-phase atomized particle group containing is formed. Such an ice blast nozzle 15 is already known, and its configuration is described in detail in Japanese Patent Application Laid-Open No. 2007-73615.

  In addition to the configuration example shown in FIG. 4A, the configuration example shown in FIG. 4B can also be used as the configuration of the frozen cleaning medium injection means using the Laval nozzle (Japanese Patent Laid-Open No. 10-101). No. 223587). That is, the ice blast nozzle 115 shown in FIG. 4B has a configuration in which the internal flow passage hole 117 is formed by penetrating the nozzle body 115a in the longitudinal direction. The upstream side of the internal flow path hole 117 is an introduction part 117a to which the compressed air (arrow g) is introduced by connecting the air supply pipe 33b. On the downstream side of the introduction part 117a, the reduced diameter part 117b in which the flow path diameter of the internal flow path hole 117 is reduced along the flow direction, the throat part 117c in which the flow path diameter is reduced to the smallest, and the diameter expansion in which the flow path diameter increases. The part 117d and the acceleration cooling part 117e whose flow path diameter gradually increases are sequentially provided in the flow direction of the compressed air. The shapes of the reduced diameter portion 117b, the throat portion 117c, and the enlarged diameter portion 117d are set so that the supplied compressed air is cooled to a low temperature by adiabatic expansion, as in the case of the ice blast nozzle 15.

  That is, the flow of the compressed air supplied to the introduction part 117a is accelerated by the reduced diameter part 117b (arrow h), and passes through the throat part 117c at a flow velocity about the speed of sound. Then, the pressure is lowered and further accelerated by moving through the enlarged diameter portion 117d and into the enlarged diameter portion 24d (arrow i), and the temperature is lowered to about -110 ° C. by adiabatic expansion. On the upstream side of the throat 117c, an opening 118a having a droplet supply path 118 through which cleaning liquid is introduced in the same direction as the flow of compressed air is provided on the inner surface of the reduced diameter portion 117b, and a cold water supply pipe 32a is provided. The cleaning liquid supplied from is discharged in the form of fine droplets 19 from the opening 118a.

  The droplets 19 atomized by the flow of compressed air are rapidly cooled by the compressed air whose temperature has decreased, and, like the ice blast nozzle 15, a solid-liquid two-phase containing frozen particles 20 a and supercooled droplets 20 b. A group of spray particles is formed. The cleaning medium 20, which is a flow of compressed air containing such spray particles, flows at a high speed to the downstream side (arrow j) while being accelerated in the accelerating cooling unit 117 e that gradually increases in diameter (arrow j), and the tip of the ice blast nozzle 115. It is injected from the part.

  Next, the function of the ice blast nozzle 15 in the dicing process of cutting the semiconductor wafer 6 with the blade 13 will be described with reference to FIG. FIG. 5A schematically shows a foreign matter generation state in a cutting portion 40 where the semiconductor wafer 6 is cut by the blade 13. That is, when the semiconductor wafer 6 is cut by the blade 13, as shown in FIG. 5A, a dicing groove 6c that penetrates the semiconductor wafer 6 in the thickness direction is formed along the scribe line 6b. The front end portion of the wafer enters the inside of the wafer sheet 7.

  At the time of forming the groove, in addition to the cutting waste from which the semiconductor wafer 6 has been cut, organic components such as the resin component of the wafer sheet 7 and the adhesive layer formed on the surface of the wafer sheet 7 are softened by heat during cutting. The organic foreign matter 7 a that has become a fine piece is generated along the scribe line 6 b and adheres to the surface of the semiconductor wafer 6. At the same time, the organic foreign matter 7b adheres to the side surface of the tip of the blade 13, and clogging that causes the cutting performance of the blade 13 to deteriorate occurs.

  FIG. 5B shows a state in which the cleaning medium 20 is sprayed by the ice blast nozzle 15 onto the cutting portion 40 in a state where the organic foreign matter 7 a is attached to the surface of the semiconductor wafer 6 in this way. By spraying the cleaning medium 20, the semiconductor wafer 6 and the wafer sheet 7 in the cutting portion 40 are cooled by the frozen particles 20a and the droplets 20b, and the cutting performance by the blade 13 is improved. Along with this cooling effect, cutting scraps generated by cutting the components of the semiconductor wafer 6 by cutting, and organic foreign matter 7a having a small adhesive force to the semiconductor wafer 6 are impacted by a jet of compressed air or frozen particles 20a. Removed by force.

  The droplets 20b act on the organic foreign matter 7a that is not removed by these and is attached to the surface of the semiconductor wafer 6. That is, since the droplet 20b is in a supercooled state, it rapidly freezes and solidifies when it contacts the fine organic foreign matter 7a. The plurality of droplets 20b adhere to and accumulate on the organic foreign matter 7a, so that the organic foreign matter 7a is enveloped by the frozen body 20c in which the droplet 20b is frozen and solidified, and a solid matter 34 is generated. Since such a solid 34 has a remarkably large and large pressure receiving area as compared with the size of the organic foreign matter 7a itself, as shown in FIG. Then, the organic foreign matter 7 a is removed from the semiconductor wafer 6 by peeling off from the surface of the semiconductor wafer 6 at the cutting portion 40. That is, in the example shown here, the freeze cleaning medium spraying means sprays the cleaning medium 20 onto the cutting part 40 that is cut in contact with the semiconductor wafer 6 with the blade 13, thereby cutting the cutting part 40 into the wafer sheet. 7 is cooled, and foreign matters such as cutting dust and organic foreign matter 7a generated on the scribe line 6b are removed.

  In the example shown in FIGS. 1 and 2, an example in which the cleaning medium 20 is sprayed onto the cutting portion 40 by only one ice blast nozzle 15 is shown. However, as shown in FIG. The nozzle 15 may be arranged. That is, in the example shown in FIG. 6, the ice blast nozzle 15 is disposed at a position where the cutting portion 40 where the semiconductor wafer 6 is cut by the blade 13 is aimed from both sides of the blade 13. As a result, the cleaning medium 20 can be sprayed onto the cutting portion 40 from the direction optimal for foreign matter removal, and the foreign matter removal performance is improved.

  Further, in addition to the cutting part 40 being the object to be cleaned by the ice blast nozzle 15, the blade 13 itself may be the object to be cleaned as shown in FIG. Here, in order to remove the organic foreign matter 7b shown in FIG. 5A from the surface of the blade 13 and prevent clogging, the cleaning medium 20 is sprayed. That is, as shown in FIG. 7A, the blade is disposed downstream of the cutting portion 40 in the rotation direction of the blade 13 (here, a position rotated approximately 45 to 60 degrees clockwise from the cutting portion 40). A blade cleaning portion 41 for cleaning the outer peripheral end portion of 13 is set, and the ice blast nozzle 15 is arranged with the blade cleaning portion 41 as a spray target position. Here, since the side surface of the blade 13 is a foreign matter removal target, it is desirable to arrange the two ice blast nozzles 15 at positions aimed from both sides of the blade 13.

  Further, in the present embodiment, the frozen foreign matter peeling portion 42 is disposed at a position substantially opposite to the blade cleaning portion 41 in the blade 13. As shown in FIG. 7B, the frozen foreign matter peeling portion 42 includes a peeling member 43 provided with a peeling groove 43a through which the cleaning target range on the outer peripheral side of the blade 13 can pass, and the inner surface of the peeling groove 43a. A fine wire brush 44 that is in sliding contact with the side surface of the blade 13 is implanted. By rotating the blade 13 with the peeling member 43 mounted, the foreign matter adhering to the side surface of the blade 13 is scraped off by the tip of the wire brush 44 and removed.

  FIG. 8 schematically shows blade attached foreign matter removal by the ice blast nozzle 15. As described above, in FIG. 8A, the organic foreign matter 7b (see FIG. 5A) generated in the cutting portion 40 and attached to the surface of the blade 13 is transferred to the blade cleaning portion 41 by the rotation of the blade 13. It shows the reached state. Then, as shown in FIG. 8B, the cleaning medium 20 is sprayed by the ice blast nozzle 15 onto the surface of the blade 13 in such a state. As a result, the frozen particles 20a and the droplets 20b contained in the sprayed cleaning medium 20 collide with the side surfaces of the blade 13, and the organic foreign matter 7b attached to the blade 13 is compressed. It is removed by the impact force of air or frozen particles 20a.

  The droplets 20b act on the organic foreign matter 7b that is not removed by these and adheres to fine irregularities on the surface of the blade 13 to cause a clogged state. That is, since the droplet 20b is in a supercooled state, it rapidly freezes and solidifies when it contacts the fine organic foreign matter 7b. The plurality of droplets 20b adhere to and accumulate on the organic foreign matter 7b, so that the organic foreign matter 7b is enveloped by the frozen body 20c in which the droplet 20b is frozen and solidified, and a solid matter 34 is generated.

  Then, when the solid matter 34 generated in this way reaches the frozen foreign matter peeling part 24, the solid matter 34 attached to the surface of the blade 13 is removed from the peeling member 43 as shown in FIG. 8C. The wire brush 44 planted on the surface is scraped off by being brought into sliding contact with the surface of the blade 13. That is, even if the fine organic foreign matter 7b is difficult to be scraped off by the wire brush 44 when it is attached alone, it is easily scraped off by the wire brush 44 by being encapsulated by the frozen body 20c to form the solid matter 34. Can do.

  That is, in the example shown here, the cleaning medium spraying means sprays the cleaning medium 20 onto the blade cleaning part 41 set in a part other than the cutting part 40 in the blade 12, so that the fine particles attached to the blade 13 are sprayed. The organic foreign matter 7b which is a foreign matter is removed. The frozen foreign matter peeling unit 24 peels off the solid matter 34 generated by freezing and solidifying the supercooled droplets 20b enclosing the organic foreign matter 7b from the blade 13 in removing the organic foreign matter 7b attached to the blade 13. It is a means.

  In addition to the peeling member 25 in which the wire brush 44 is implanted, as a peeling means, a configuration in which a peeling member such as a scraper is brought into contact with the side surface of the blade 13, or high-pressure air is inclined with respect to the side surface of the blade 13 by an air knife. It is also possible to use a method of spraying from the direction. Even in the case of using such a method, it is possible to easily peel and remove organic foreign matters that are difficult to remove by a normal method by enclosing the fine organic foreign matters 7b with the frozen bodies 20c to form the solid matter 34. .

  The dicing apparatus 1 of the present invention has the above-described configuration, and the dicing method of the semiconductor wafer 6 using the dicing apparatus 1, that is, the semiconductor wafer 6 is cut along the scribe line 6b by the blade 13 that rotates at high speed. Thus, the dicing method for dividing the semiconductor wafer 6 into individual semiconductor chips 6a includes the following steps.

  That is, first, the semiconductor wafer 6 adhered to the wafer sheet 7 is held by the wafer table 3 shown in FIG. 1 (wafer holding step). Next, the table moving mechanism 4 is driven to move the wafer table 3 to a dicing work position by the dicing mechanism 10. Here, the wafer moving table 4 is moved along a predetermined alignment path by the table moving mechanism 4, and the semiconductor wafer 6 is relatively moved with respect to the dicing head 12 on which the blade 13 is mounted, whereby the semiconductor wafer 6 is rotated at a high speed. Cutting along the scribe line 6b by the blade 13 (cutting process).

  In this cutting process, as shown in FIG. 2, the cleaning medium 20 containing the frozen particles 20a of the cleaning water and / or the supercooled droplets 20b is sprayed onto the blade 13 by the ice blast nozzle 15 (cleaning medium injection). Process). In this cleaning medium jetting step, the cleaning water is atomized by the ice blast nozzle 15 using a Laval nozzle, and the solid liquid 2 containing the frozen particles 20a of the cleaning water and the supercooled droplets 20b by the rapid cooling effect by adiabatic expansion. Phase spray particles are formed and jetted. Thus, by using the Laval nozzle, it is possible to form a solid-liquid two-phase spray particle group with a simple configuration and use it as a cleaning medium.

  In the cleaning medium spraying step, the cleaning medium 20 is sprayed onto the cutting part 40 that contacts the semiconductor wafer 6 with the blade 13 and cuts, thereby cooling the cutting part 40 together with the wafer sheet 7 and scribing. Foreign matter such as cutting waste and organic foreign matter generated in the line 6b is removed. More desirably, in this cleaning medium spraying step, the cleaning medium 20 is sprayed onto the blade cleaning part 41 set at a part other than the cutting part 40, thereby fine organic foreign matter 7 b or the like adhering to the blade 13. Remove foreign material.

  In the present embodiment, in the removal of the fine foreign matter, a configuration in which the solid matter 34 generated by freezing and solidifying the supercooled droplet 20b enclosing the foreign matter is peeled off from the blade 13 by the frozen foreign matter peeling portion 24 is used. Adopted. By adopting such a configuration, it is possible to efficiently remove the fine organic foreign matter 7b that has been difficult to remove from the blade 13 in the past.

  Therefore, even when a thin semiconductor wafer 6 in which clogging of the blade is likely to progress due to the remaining fine organic foreign matter adhering in the cutting process is targeted, the organic foreign matter once attached is efficiently removed. In addition, it is possible to prevent deterioration of machinability due to clogging and prevent defects such as chipping at the cutting site.

  The present invention has an effect that good cutting performance can be ensured even when a thin semiconductor wafer is targeted, and can be used in a dicing process of dividing a semiconductor wafer into individual semiconductor chips.

The perspective view of the dicing apparatus of one embodiment of the present invention Explanatory drawing of the injection state of the washing | cleaning medium by the Laval nozzle used for the dicing apparatus of one embodiment of this invention Piping system diagram of working fluid supply unit in dicing apparatus of one embodiment of the present invention Structure explanatory drawing of the Laval nozzle used for the dicing device of one embodiment of the present invention Explanatory drawing of cutting foreign material cleaning in the dicing method of one embodiment of the present invention Explanatory drawing of the arrangement state of the Laval nozzle in the dicing apparatus of one embodiment of this invention Explanatory drawing of the arrangement state of the Laval nozzle in the dicing apparatus of one embodiment of this invention Explanatory drawing of the foreign material removal by a blade in the dicing method of one embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dicing apparatus 3 Wafer table 6 Semiconductor wafer 6a Semiconductor chip 6b Scribe line 6c Dicing groove 7 Wafer sheet 7a, 7b Organic foreign substance 10 Dicing mechanism 12 Dicing head 13 Blade 15 Ice blast nozzle 16 Working fluid supply part 20 Cleaning medium 20a Frozen particle 20b Droplet 21 Air supply source 22 Washing water supply source 34 Solid matter 40 Cutting part 41 Blade washing part 42 Freezing foreign matter peeling part

Claims (8)

A dicing apparatus that divides the semiconductor wafer into individual semiconductor chips by cutting the semiconductor wafer along a scribe line with a rotating blade,
A wafer table for holding the semiconductor wafer attached to a wafer sheet, a dicing head to which the blade is mounted, a moving means for moving the wafer table relative to the dicing head, and And a frozen cleaning medium ejecting means for ejecting a cleaning medium containing frozen particles of cleaning liquid and / or supercooled droplets,
The freeze cleaning medium injection means atomizes the cleaning liquid by using a Laval nozzle and forms a solid-liquid two-phase spray particle group including frozen particles of the cleaning liquid and supercooled droplets by a rapid cooling effect by adiabatic expansion. And a dicing apparatus characterized by jetting.   The freeze cleaning medium spraying means cools the cutting portion together with the wafer sheet by cutting the cleaning medium onto the cutting portion that is cut in contact with the semiconductor wafer in the blade, and the cutting is performed by cutting. The dicing apparatus according to claim 1, wherein foreign matter generated on the scribe line is removed.   The freeze cleaning medium spraying means removes fine foreign matter adhering to the blade by spraying the cleaning medium to a portion other than a cutting portion to be cut in contact with the semiconductor wafer in the blade. The dicing apparatus according to claim 1.   2. The method according to claim 1, further comprising: a peeling unit that peels off the solid matter generated by freezing and solidifying the supercooled liquid droplets enclosing the foreign matter in removing the fine foreign matter attached to the blade. 4. The dicing apparatus according to 3. A dicing method for dividing a semiconductor wafer into individual semiconductor chips by cutting the semiconductor wafer along a scribe line with a rotating blade,
A wafer holding step of holding the semiconductor wafer adhered to a wafer sheet by a wafer table; and rotating the semiconductor wafer by moving the wafer table relative to a dicing head on which the blade is mounted. A cutting step of cutting with a blade, and a frozen cleaning medium spraying step of spraying a cleaning medium containing frozen particles of cleaning liquid and / or supercooled droplets onto the blade,
In the freeze cleaning medium injection step, the cleaning liquid is atomized by using a Laval nozzle, and a solid-liquid two-phase spray particle group including frozen particles of the cleaning liquid and supercooled droplets is formed by a rapid cooling effect by adiabatic expansion. And dicing.   In the freeze cleaning medium spraying step, the cleaning medium is sprayed onto a cutting part to be cut in contact with the semiconductor wafer by the blade, thereby cooling the cutting part together with the wafer sheet and cutting the part. 6. The dicing method according to claim 5, wherein foreign matter generated on the scribe line is removed.   In the freeze cleaning medium spraying step, the cleaning medium is sprayed onto a part other than a cutting part to be cut in contact with the semiconductor wafer in the blade, thereby removing fine foreign matters attached to the blade. The dicing method according to claim 5.   8. The dicing according to claim 7, wherein, in removing fine foreign matter attached to the blade, the solid matter generated by the solidification of the supercooled liquid droplets enclosing the foreign matter frozen and solidified is peeled off from the blade. Method.

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