Abstract:
A semiconductor device manufacturing apparatus includes a damage forming equipment, dividing equipment and removing equipment. The damage forming equipment forms damage layers used as starting points to divide a semiconductor wafer into discrete semiconductor chips on a rear surface side of the semiconductor wafer which is opposite to an element forming surface. The dividing equipment divides the semiconductor wafer into discrete semiconductor chips with the damage layers used as the starting points. The removing equipment removes a rear surface portion of the semiconductor wafer to at least a depth where the damage layers are no more present.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2003-004767, filed Jan. 10, 2003, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a semiconductor device manufacturing method and apparatus to discretely divide a semiconductor wafer into semiconductor chips (semiconductor elements) after elements are formed in the semiconductor wafer and more particularly to a technique for discretely dividing the semiconductor wafer. 
     2. Description of the Related Art 
     Conventionally, when a semiconductor wafer on which elements have been formed is discretely divided to form semiconductor chips, mechanical cutting (dividing by cutting using a diamond blade or grindstone), dividing by forming cut grooves and breaking, dividing by breaking with distortions and scratches used as starting points by use of a scriber (refer to Jpn. Pat. Appln. KOKOKU Publication No. H05-54262, for example), cutting by application of a laser beam, dividing by use of a combination of application of a laser beam and distortion (refer to Jpn. Pat. Appln. KOKAI Publication No. P2002-192367, for example) and the like are used. 
     FIGS. 1A and 1B show an extracted part of the conventional semiconductor device manufacturing process described above, FIG. 1A being a perspective view showing a step of forming cut grooves in a semiconductor wafer by use of a diamond blade and FIG. 1B being a cross sectional view showing a back-side grinding step. First, as shown in FIG. 1A, grooves  13 - 1 ,  13 - 2 ,  13 - 3 , . . . for dividing are formed (half-cut) along dicing lines or chip dividing lines on an element forming surface  11 A side of a semiconductor wafer  11  on which elements have been formed. After this, a protection film  14  is affixed to the element forming surface  11 A of the semiconductor wafer  11  and then, as shown in FIG. 1B, a rear surface portion  11 B of the semiconductor wafer  11  is ground to at least a depth Δ0 which reaches the grooves  13 - 1 ,  13 - 2 ,  13 - 3 , . . . to divide the semiconductor wafer  11  into discrete semiconductor chips  11 - 1 ,  11 - 2 ,  11 - 3 , . . . . 
     Alternatively, a dicing tape is affixed to the rear surface  11 B of the semiconductor wafer  11  which is opposite to the element forming surface  11 A and the semiconductor wafer is cut (full cut) along the dicing lines or chip dividing lines by use of the diamond blade  12  in some cases. 
     However, in the mechanical cutting process such as the blade dicing process, cutting streaks (scratches or distortions) may occur on the side surface of the semiconductor chip as shown in FIG.  2 A. Further, chippings may occur on the element forming surface (also on the rear surface in the case of full cut) as shown in FIG.  2 B. 
     This applies to a case wherein scratches or distortions are formed by use of a scriber and the semiconductor wafer is divided by breaking and, as shown in FIG. 3A, scratches (less than 5 μm) or distortions (approximately several μm) may occur on the side surface of the semiconductor chip. Further, as shown in FIG. 3B, chippings may occur on the element forming surface. 
     In the cutting process by application of a laser beam, occurrence of cutting streaks and chippings by mechanical cutting can be prevented, but distortions (damages) occur on the side surface of the semiconductor chip as shown in FIG.  4 A. Further, as shown in FIG. 4B, the side surface of the semiconductor chip becomes uneven and the mechanical strength is lowered. In addition, melted Si is re-crystallized so that adjacent elements will tend to interfere with each other, thereby causing chippings to occur. Further, there occurs a problem that the element characteristic is deteriorated (for example, the pause characteristic of a DRAM is degraded) or a melted portion is attached to the wiring surface by heat generated at the time of laser application. 
     Thus, in the conventional semiconductor device manufacturing method and apparatus, when the semiconductor wafer is cut and divided into discrete semiconductor chips, cutting streaks (scratches or distortions) may occur on the side surface of the semiconductor chip, damages by heat may occur, the characteristic of the semiconductor chip may be deteriorated, faults may occur and the resistance to bending or breaking may be lowered. Further, even if the semiconductor chip does not become faulty, cutting streaks and uneven portions caused by application of the laser beam will remain on the peripheral portion of the semiconductor chip and the shape and quality thereof are poor. 
     BRIEF SUMMARY OF THE INVENTION 
     A semiconductor device manufacturing apparatus according to an aspect of the invention comprises a damage forming equipment which forms damage layers used as starting points to divide a semiconductor wafer into discrete semiconductor chips on a rear surface side of the semiconductor wafer which is opposite to an element forming surface, a dividing equipment which divides the semiconductor wafer into discrete semiconductor chips with the damage layers used as the starting points, and a removing equipment which removes a rear surface portion of the semiconductor wafer to at least a depth where the damage layers are no more present. 
     A semiconductor device manufacturing method according to another aspect of the invention comprises forming a damage layer used as starting points to divide a semiconductor wafer into discrete semiconductor chips on a rear surface side of the semiconductor wafer which is opposite to an element forming surface, dividing the semiconductor wafer into discrete semiconductor chips with the damage layer used as the starting points, and removing a rear surface portion of the semiconductor wafer to at least a depth where the damage layer is no more present. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     FIG. 1A is a perspective view showing a step of forming cut grooves in a semiconductor wafer by use of a diamond blade and showing an extracted part of a conventional semiconductor device manufacturing process; 
     FIG. 1B is a cross sectional view showing a back-side grinding step and showing an extracted part of a conventional semiconductor device manufacturing process; 
     FIG. 2A is a microphotograph of the side surface of a semiconductor chip when a semiconductor wafer is divided by blade dicing; 
     FIG. 2B is a microphotograph of the element forming surface side when a semiconductor wafer is divided by blade dicing; 
     FIG. 3A is a microphotograph of the side surface of a semiconductor chip when a semiconductor wafer is divided by use of a scriber; 
     FIG. 3B is a microphotograph of the element forming surface side when a semiconductor wafer is divided by use of a scriber; 
     FIG. 4A is a microphotograph of the side surface of a semiconductor chip when a semiconductor wafer is divided by application of a laser beam; 
     FIG. 4B is a microphotograph of the element forming surface side when a semiconductor wafer is divided by application of a laser beam; 
     FIG. 5 is a perspective view showing a dicing tape affixing step, for illustrating a semiconductor device manufacturing method and apparatus according to a first embodiment of the present invention; 
     FIG. 6 is a perspective view showing a step of forming cut grooves used as division starting points, for illustrating the semiconductor device manufacturing method and apparatus according to the first embodiment of the present invention; 
     FIG. 7 is a perspective view showing a wafer dividing step, for illustrating the semiconductor device manufacturing method and apparatus according to the first embodiment of the present invention; 
     FIG. 8 is a cross sectional view showing a back-side grinding step, for illustrating the semiconductor device manufacturing method and apparatus according to the first embodiment of the present invention; 
     FIG. 9 is a perspective view showing a pickup tape affixing step, for illustrating the semiconductor device manufacturing method and apparatus according to the first embodiment of the present invention; 
     FIG. 10A is a microphotograph of the element forming surface side of a mirror-finished portion of a semiconductor chip formed by the semiconductor device manufacturing method and apparatus according to the first embodiment of the present invention; 
     FIG. 10B is a microphotograph of the side surface of a semiconductor chip formed by the semiconductor device manufacturing method and apparatus according to the first embodiment of the present invention; 
     FIG. 11 is a perspective view showing a dicing tape affixing step, for illustrating a semiconductor device manufacturing method and apparatus according to a second embodiment of the present invention; 
     FIG. 12 is a perspective view showing a step of forming scratches or distortions used as division starting points, for illustrating the semiconductor device manufacturing method and apparatus according to the second embodiment of the present invention; 
     FIG. 13 is a perspective view showing a wafer dividing step, for illustrating the semiconductor device manufacturing method and apparatus according to the second embodiment of the present invention; 
     FIG. 14 is a cross sectional view showing a back-side grinding step, for illustrating the semiconductor device manufacturing method and apparatus according to the second embodiment of the present invention; 
     FIG. 15 is a perspective view showing a pickup tape affixing step, for illustrating the semiconductor device manufacturing method and apparatus according to the second embodiment of the present invention; 
     FIG. 16 is a perspective view showing a dicing tape affixing step, for illustrating a semiconductor device manufacturing method and apparatus according to a third embodiment of the present invention; 
     FIG. 17 is a perspective view showing a step of forming re-crystallization layers used as division starting points, for illustrating the semiconductor device manufacturing method and apparatus according to the third embodiment of the present invention; 
     FIG. 18 is a perspective view showing a wafer dividing step, for illustrating the semiconductor device manufacturing method and apparatus according to the third embodiment of the present invention; 
     FIG. 19 is a cross sectional view showing a back-side grinding step, for illustrating the semiconductor device manufacturing method and apparatus according to the third embodiment of the present invention; 
     FIG. 20 is a perspective view showing a pickup tape affixing step, for illustrating the semiconductor device manufacturing method and apparatus according to the third embodiment of the present invention; 
     FIG. 21 is a perspective view showing a step of forming re-crystallization layers used as division starting points, for illustrating a semiconductor device manufacturing method and apparatus according to a fourth embodiment of the present invention; 
     FIG. 22 is a cross sectional view showing a back-side grinding step, for illustrating the semiconductor device manufacturing method and apparatus according to the fourth embodiment of the present invention; 
     FIG. 23 is a schematic view showing an ice chuck, for illustrating a semiconductor device manufacturing method and apparatus according to a fifth embodiment of the present invention; 
     FIG. 24 is a schematic view showing another example of the ice chuck, for illustrating the semiconductor device manufacturing method and apparatus according to the fifth embodiment of the present invention; 
     FIG. 25 is a perspective view showing part of a manufacturing process and a manufacturing apparatus, for illustrating a semiconductor device manufacturing method and apparatus according to a sixth embodiment of the present invention; and 
     FIG. 26 is a perspective view showing part of a manufacturing process, for illustrating a semiconductor device manufacturing method and apparatus according to a seventh embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Embodiment 
     FIGS. 5 to  9  sequentially show parts of a manufacturing process and parts of a manufacturing apparatus, for illustrating a semiconductor device manufacturing method and apparatus according to a first embodiment of the present invention. 
     First, as shown in FIG. 5, a dicing tape (protection member, protection tape or holding tape)  22  is affixed to an element forming surface  21 A side of a semiconductor wafer  21  on which elements have been formed. 
     Next, as shown in FIG. 6, grooves (damage layers)  24 - 1 ,  24 - 2 ,  24 - 3 , . . . used as starting points to divide the semiconductor wafer into discrete semiconductor chips are formed on a rear surface  21 B side of the semiconductor wafer  21  which is opposite to the element forming surface  21 A by use of a diamond blade  23 . The grooves  24 - 1 ,  24 - 2 ,  24 - 3 , . . . are formed shallower than the thickness of the semiconductor chip obtained at the time of completion. Further, it is preferable to form the grooves  24 - 1 ,  24 - 2 ,  24 - 3 , . . . in a direction corresponding to the crystallization direction of the semiconductor wafer (for example, Si) since the grooves are used as the starting points of cleavage. 
     Next, as shown in FIG. 7, a breaking process is performed to cleave the semiconductor wafer  21  by using the grooves  24 - 1 ,  24 - 2 ,  24 - 3 , . . . as the starting points to form discrete semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . . 
     After this, as shown in FIG. 8, a portion on the rear surface  21 B side of the discretely divided semiconductor wafer  21  is ground and removed until the semiconductor wafer comes to have preset thickness. If the depth of the grooves  24 - 1 ,  24 - 2 ,  24 - 3 , . . . is Δ1 and the grinding amount is Δ2, then damage layers such as scratches or distortions formed on the side surfaces of the semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . by forming the grooves  24 - 1 ,  24 - 2 ,  24 - 3 , . . . can be removed by setting up the relation of Δ1&lt;Δ2. For example, since the wafer thickness is 725 μm in the case of an 8-inch semiconductor wafer, Δ2 becomes equal to 695 to 275 μm if the final thickness Δ3 of the semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . is 30 to 450 μm and therefore the depth Δ1 of the grooves  24 - 1 ,  24 - 2 ,  24 - 3 , . . . can be freely and selectively set in a range shallower than 695 to 275 μm. 
     Next, as shown in FIG. 9, after a pickup tape  26  mounted on a wafer ring  25  is affixed to the rear surface of the semiconductor wafer  21 , the protection tape  22  on the element forming surface  21 A side is peeled. 
     Then, the semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . picked up by use of a picker are mounted on lead frames or TAB tapes and sealed into resin or ceramic packages, respectively, to complete semiconductor devices. 
     According to the manufacturing method and the apparatus with the above configuration, since the grooves  24 - 1 ,  24 - 2 ,  24 - 3 , . . . are formed in a region (discarding portion) which is to be removed in the back-side grinding process, the damage layers are not left behind on the semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . obtained after the back-side grinding process and occurrence of distortion of Si and minute cracks of the separation surface and edge portion can be prevented. Further, since the side surface of the semiconductor chip sealed into the package is a cleavage plane, uneven portions and scratches are not formed on the element forming surface and side surface of the semiconductor chip and the quality and shape thereof are good as shown in FIGS. 10A and 10B. 
     Therefore, a deterioration in the characteristic of the semiconductor chip, occurrence of faults and a lowering in the resistance to bending or breaking can be suppressed. 
     Second Embodiment 
     FIGS. 11 to  15  sequentially show parts of a manufacturing process and parts of a manufacturing apparatus, for illustrating a semiconductor device manufacturing method and apparatus according to a second embodiment of the present invention. 
     First, as shown in FIG. 11, a dicing tape (protection member, protection tape or holding tape)  22  is affixed to an element forming surface  21 A side of a semiconductor wafer  21  on which elements have been formed. 
     Next, as shown in FIG. 12, scratches or distortions (damage layers)  28 - 1 ,  28 - 2 ,  28 - 3 , . . . used as starting points to divide the semiconductor wafer into discrete semiconductor chips are formed on a rear surface  21 B side of the semiconductor wafer  21  which is opposite to the element forming surface  21 A by use of a diamond scriber  27 . The scratches or distortions  28 - 1 ,  28 - 2 ,  28 - 3 , . . . are formed shallower than the thickness of the semiconductor chip obtained at the time of completion. Further, it is preferable to form the scratches or distortions  28 - 1 ,  28 - 2 ,  28 - 3 , . . . in a direction corresponding to the crystallization direction of the semiconductor wafer (for example, Si) since the scratches or distortions are used as the starting points of cleavage. 
     Next, as shown in FIG. 13, a breaking process is performed to cleave the semiconductor wafer  21  by using the scratches or distortions  28 - 1 ,  28 - 2 ,  28 - 3 , . . . as the starting points to form discrete semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . . 
     After this, as shown in FIG. 14, a portion on the rear surface  21 B side of the discretely divided semiconductor wafer  21  is ground and removed until the semiconductor wafer comes to have preset thickness. If the depth of the scratches or distortions  28 - 1 ,  28 - 2 ,  28 - 3 , . . . is Δ 4  and the grinding amount is Δ 2 , then damage layers such as scratches or distortions formed on the side surfaces of the semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . can be removed by setting up the relation of Δ 4 &lt;Δ 2 . Since the wafer thickness is 725 μm in the case of an 8-inch semiconductor wafer, for example, Δ 2  becomes equal to 695 to 275 μm if the final thickness Δ 3  of the semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . is 30 to 450 μm and therefore the depth Δ 4  of the scratches or distortions  28 - 1 ,  28 - 2 ,  28 - 3 , . . . can be freely and selectively set in a range shallower than 695 to 275 μm. 
     Next, as shown in FIG. 15, after a pickup tape  26  mounted on a wafer ring  25  is affixed to the rear surface of the semiconductor wafer  21 , the protection tape  22  on the element forming surface  21 A side is peeled. 
     Then, the semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . picked up by use of a picker are mounted on lead frames or TAB tapes and sealed into resin or ceramic packages, respectively, to complete semiconductor devices. 
     According to the apparatus with the above configuration and the manufacturing method, since the scratches or distortions  28 - 1 ,  28 - 2 ,  28 - 3 , . . . are formed in a region (discarding portion) which is to be removed in the back-side grinding process, damage layers are not left behind after the back-side grinding process and occurrence of distortion of Si and minute cracks of the separation surface and edge portion can be prevented. Further, since the side surface of the semiconductor chip sealed into the package is a cleavage plane, uneven portions and scratches are not formed on the element forming surface and side surface of the semiconductor chip and the quality and shape thereof are good. 
     Therefore, a deterioration in the characteristic of the semiconductor chip, occurrence of faults and a lowering in the resistance to bending or breaking can be suppressed. 
     Third Embodiment 
     FIGS. 16 to  20  sequentially show parts of a manufacturing process and parts of a manufacturing apparatus, for illustrating a semiconductor device manufacturing method and apparatus according to a third embodiment of the present invention. 
     First, as shown in FIG. 16, a dicing tape (protection member, protection tape or holding tape)  22  is affixed to an element forming surface  21 A side of a semiconductor wafer  21  on which elements have been formed. 
     Next, as shown in FIG. 17, Si re-crystallization layers (damage layers)  30 - 1 ,  30 - 2 ,  30 - 3 , . . . used as starting points to divide the semiconductor wafer into discrete semiconductor chips are formed on a rear surface  21 B side of the semiconductor wafer  21  which is opposite to the element forming surface  21 A by irradiating a laser beam from a laser irradiation device  29 . The re-crystallization layers  30 - 1 ,  30 - 2 ,  30 - 3 , . . . are formed shallower than the thickness of the semiconductor chip obtained at the time of completion. Further, it is preferable to form the re-crystallization layers  30 - 1 ,  30 - 2 ,  30 - 3 , . . . in a direction corresponding to the crystallization direction of the semiconductor wafer (for example, Si) since the re-crystallization layers are used as the starting points of cleavage. 
     Next, as shown in FIG. 18, a breaking process is performed to cleave the semiconductor wafer  21  by using the re-crystallization layers  30 - 1 ,  30 - 2 ,  30 - 3 , . . . as the starting points to form discrete semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . . 
     After this, as shown in FIG. 19, a portion on the rear surface  21 B side of the discretely divided semiconductor wafer  21  is ground and removed until the semiconductor wafer comes to have preset thickness. If the depth of the re-crystallization.layers  30 - 1 ,  30 - 2 ,  30 - 3 , . . . is Δ 5  and the grinding amount is Δ 2 , then damage layers formed on the side surfaces of the semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . by forming the re-crystallization layers  30 - 1 ,  30 - 2 ,  30 - 3 , . . . can be removed by setting up the relation of Δ 5 &lt;Δ 2 . Since the wafer thickness is 725 μm in the case of an 8-inch semiconductor wafer, for example, Δ 2  becomes equal to 695 to 275 μm if the final thickness Δ 3  of the semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . is 30 to 450 μm and therefore the depth Δ 5  of the re-crystallization layers  30 - 1 ,  30 - 2 ,  30 - 3 , . . . can be freely and selectively set in a range shallower than 695 to 275 μm. 
     Next, as shown in FIG. 20, after a pickup tape  26  mounted on a wafer ring  25  is affixed to the rear surface of the semiconductor wafer  21 , the protection tape  22  on the element forming surface  21 A side is peeled. 
     Then, the semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . picked up by use of a picker are mounted on lead frames or TAB tapes and sealed into resin or ceramic packages, respectively, to complete semiconductor devices. 
     According to the apparatus with the above configuration and the manufacturing method, since the Si re-crystallization layers  30 - 1 ,  30 - 2 ,  30 - 3 , . . . are formed in a region (discarding portion) which is to be removed in the back-side grinding process, damage layers are not left behind after the back-side grinding process and occurrence of distortion of Si and minute cracks of the separation surface and edge portion can be prevented. Further, since the side surface of the semiconductor chip sealed into the package is a cleavage plane, uneven portions and scratches are not formed on the element forming surface and side surface of the semiconductor chip and the quality and shape thereof are good. 
     Therefore, a deterioration in the characteristic of the semiconductor chip, occurrence of faults and a lowering in the resistance to bending or breaking can be suppressed. 
     Fourth Embodiment 
     FIGS. 21 and 22 sequentially show parts of a manufacturing process and parts of a manufacturing apparatus, for illustrating a semiconductor device manufacturing method and apparatus according to a fourth embodiment of the present invention. 
     In the fourth embodiment, silicon re-crystallization regions  30 A- 1 ,  30 A- 2 ,  30 A- 3 , . . . are formed in a semiconductor wafer  21  by focusing a laser beam on the internal portion of the semiconductor wafer  21  and adjusting laser beam power when the laser beam is applied. 
     Thus, in a case where the silicon re-crystallization regions are formed in the semiconductor wafer, damage layers can be removed by setting up the relation of Δ 6 &lt;Δ 2  when the depth of the re-crystallization regions  30 A- 1 ,  30 A- 2 ,  30 A- 3 , . . . is Δ 6  and the grinding amount is Δ 2 . 
     Therefore, the same operation and effect as those of the firs to third embodiments can be attained. 
     Fifth Embodiment 
     FIGS. 23 and 24 sequentially show parts of a manufacturing apparatus, for illustrating a semiconductor device manufacturing method and apparatus according to a fifth embodiment of the present invention. 
     In the third and fourth embodiments, the silicon re-crystallization layers  30 - 1 ,  30 - 2 ,  30 - 3 , . . . or  30 A- 1 ,  30 A- 2 ,  30 A- 3 , . . . are formed in the semiconductor wafer  21  by irradiating the laser beam. However, there occurs a possibility that laser processing gives a bad influence on the semiconductor chip by generation of heat. 
     Therefore, in the fifth embodiment, the semiconductor wafer  21  is held by use of an ice chuck shown in FIG. 23 and a laser beam is applied to the semiconductor wafer  21  while it is set in a cooled state. 
     The ice chuck shown in FIG. 23 includes a cooling bath  31 , controller  32  and ice plate  33 . A refrigerant is supplied from the cooling bath  32  to the ice plate  33  to cool the same. The semiconductor wafer  21  is held on the ice plate  33  and cooled. The temperature of the ice plate  33  is controlled in a temperature range of approximately −40° C. to 5° C. by the controller  32 . 
     According to the manufacturing method and the apparatus with the above configuration, an influence of heat given to the semiconductor chip at the time of laser processing can be significantly reduced and occurrence of an operation failure of the semiconductor chip, for example, a degraded pause characteristic of a DRAM can be suppressed. 
     The ice chuck is not limited to the configuration containing the cooling bath  31  as shown in FIG.  23  and can be provided with a thermoelectric cooling unit using a Peltier element as shown in FIG.  24 . The Peltier element includes a P-type element  34 , N-type element  35  and metal electrode  36 . Voltage is applied to the Peltier element from a power supply  37  to generate or absorb heat by causing a current to flow across the contact surface between the different types of metals. 
     The ice chuck using the Peltier element makes it easy to control temperatures and cool an object to a set temperature in a short period of time. 
     Sixth Embodiment 
     FIG. 25 is a perspective view showing part of a manufacturing process and a manufacturing apparatus, for illustrating a semiconductor device manufacturing method and apparatus according to a sixth embodiment of the present invention. 
     In the first to third embodiments, the semiconductor wafer is divided by cleavage and breaking. In the sixth embodiment, a dicing tape  22  is stretched in directions indicated by arrows in the drawing by use of stretching jigs  38 - 1 ,  38 - 2 ,  38 - 3 , . . . to divide the semiconductor wafer by using grooves  24 - 1 ,  24 - 2 ,  24 - 3 , . . . , scratches or distortions  28 - 1 ,  28 - 2 ,  28 - 3 , . . . , re-crystallization layers  30 - 1 ,  30 - 2 ,  30 - 3 , . . . , or re-crystallization layers  30 A- 1 ,  30 A- 2 ,  30 A- 3 , . . . as starting points. 
     Thus, the semiconductor wafer  21  can be divided into discrete semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . by stretching the dicing tape  22 . 
     Seventh Embodiment 
     FIG. 26 is a perspective view showing part of a manufacturing process, for illustrating a semiconductor device manufacturing method and apparatus according to a seventh embodiment of the present invention. 
     In each of the above embodiments, a case where the wafer ring  25  is used when the pickup tape  26  is affixed is explained as an example. However, as shown in FIG. 26, a pickup tape  26  can be affixed and used instead of the dicing tape  22  without using a wafer ring  25 . 
     This invention is not limited to the first to seventh embodiments and can be variously modified without departing from the technical scope thereof. 
     Various modifications are explained in detail below. 
     [Modification 1] 
     In the first to third embodiments, only the dicing tape  22  is affixed to the element forming surface  21 A of the semiconductor wafer  21 , but it is possible to affix a dicing tape  22  mounted on a wafer ring. 
     The wafer ring can be used depending on the configuration of the manufacturing apparatus or the like. 
     [Modification 2] 
     In the first to third embodiments, since scratches or chippings which may occur at the time of back-side grinding of the semiconductor chip can be removed with higher precision if the grinding surface is etched (for example, by dry etching, wet etching, gas etching, CMP) after back-side grinding, the resistance to bending or breaking at the time of picking-up of the semiconductor chip can be enhanced. 
     [Modification 3] 
     In the first to third embodiments, the rear surface portion of the semiconductor wafer can be removed only by etching if the amount of grinding of the rear surface portion is small. 
     [Modification 4] 
     The dividing direction of the semiconductor wafer can be set in a direction perpendicular to the rear surface of the wafer or in the same direction as the Si crystallization direction. 
     [Modification 5] 
     The damage layers such as the grooves  24 - 1 ,  24 - 2 ,  24 - 3 , . . . scratches or distortions  28 - 1 ,  28 - 2 ,  28 - 3 , . . . , re-crystallization layers  30 - 1 ,  30 - 2 ,  30 - 3 , . . . , or re-crystallization layers  30 A- 1 ,  30 A- 2 ,  30 A- 3 , . . . are formed while the dicing tape is kept affixed to the element forming surface side of the semiconductor wafer. However, the damage layers can be formed without using the dicing tape, a protection tape  22  is affixed to the element forming surface  21 A before the semiconductor wafer  21  is divided, and then the semiconductor wafer  21  can be divided by breaking and cleaving or by stretching the protection tape  22 . 
     [Modification 6] 
     A case wherein the protection tape  22  is affixed to the element forming surface  21 A side of the semiconductor wafer  21  is explained as an example, but it is possible to affix a protection member other than the tape. For example, adhesive resin is coated on the element forming surface  21 A side and a protection plate or holding plate can be affixed to the resin. 
     [Modification 7] 
     A case wherein the pickup tape  26  is affixed and used instead of the dicing tape  22 , and the discrete semiconductor chips  21 - 1 ,  21 - 2 ,  21 - 3 , . . . are picked up is explained as an example. However, it is also possible to directly separate the semiconductor chips from the dicing tape  22  and pick up the semiconductor chips. 
     With the method and the apparatus of the configuration described in the first to seventh modifications, basically the same operation and effect can be attained as those of the first to seventh embodiments. 
     As described above, according to one aspect of this invention, it is possible to provide a semiconductor device manufacturing method and apparatus with which damages caused by heat or cutting streaks formed on the side surface of the semiconductor chip can be reduced, and a deterioration in the characteristic of the semiconductor chip, occurrence of faults and a lowering in the resistance to bending or breaking can be suppressed. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.