JP3515917B2 - Method for manufacturing semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the production how the semiconductor device to achieve further thinning of the semiconductor device substrate, in particular, semiconductor completing the semiconductor half processes in order to perform the thin mounting of the semiconductor device substrate grinding the back surface of the device substrate relates to the production how a semiconductor device achieving thinning by.

[0002]

2. Description of the Related Art Semiconductor device substrates are used for oxidation, diffusion, cleaning,
An integrated circuit is formed on the surface by being manufactured by using a semiconductor (first half) process such as a photo-etching technique.

In order to prevent damage during handling of the semiconductor device substrate during the semiconductor process, the semiconductor device substrate is finished to have an appropriate thickness by its diameter. For example, in the case of a silicon substrate having a diameter of 150 mm to 200 mm, a semiconductor substrate material processed into a thickness of about 0.7 mm is used. Then, the semiconductor device substrate, after the semiconductor first half process is finished, after polishing the back surface to reduce the electrical resistance of the substrate and thin plate for thin mounting, after being cut into individual integrated circuits, The process will shift to the mounting process (semiconductor second half process).

By the way, conventionally, semiconductor wafers have been
In order to prevent cracking during the semiconductor first half process and dust generation due to the semiconductor first half process, the periphery thereof is chamfered. Usually, the chamfering of the semiconductor wafer is performed in a semiconductor wafer manufacturing process, and the chamfered semiconductor mirror-polished wafer is used as a raw material for the semiconductor first half process. As described above, as a method for chamfering a semiconductor substrate in the process of manufacturing a semiconductor wafer, for example, there is a method described in Japanese Patent Laid-Open No. 6-114745.

In Japanese Patent Laid-Open No. 6-114745,
Both upper and lower edge portions of the semiconductor wafer are ground by using a grindstone or the like to form taper portions, and processing is performed before the semiconductor first half process. However, the chamfering of the semiconductor wafer facilitates the problem of cracking or chipping of the semiconductor device substrate when performing grinding from the back surface for thinning the semiconductor device substrate. Therefore, some proposals have been made as solutions.

For example, in Japanese Unexamined Patent Publication No. 6-267913, the back surface grinding processed surface (working strained layer) of a semiconductor wafer and the outer peripheral surface do not intersect, that is, the grinding surface intersects the chamfered portion. The shape of the chamfered portion of the semiconductor wafer is optimized. In addition, JP-A-7-455
In Japanese Patent Publication No. 68, a new proposal is made to grind the outer peripheral surface of a semiconductor device substrate into a shape such that a chamfer is re-formed at the grinding position at the end of the back surface grinding step after the semiconductor first half process is completed. According to this method, it is possible to prevent cracking or chipping of the semiconductor wafer and cutting of the wafer carrier by the semiconductor wafer that occur during the back surface grinding step or when the wafer carrier is accommodated. In addition, JP-A-9-14828
In the publication No. 3, when thinning a semiconductor wafer,
The semiconductor wafer is attached to the supporting substrate with wax. Since the semiconductor wafer is fixed to the supporting substrate with wax, the wax is exposed when the plate is thinned, and the grinding blade is clogged. As a result, shavings, burns, and cracks occur on the processed surface. Therefore, in order to solve the above-mentioned generation of cracks and cracks, after sticking a semiconductor wafer to a supporting substrate, the surface opposite to the supporting substrate is roughly ground with a rough grinding blade, and the wax is removed by using an etching solution of wax. After etching, a fine grinding blade is used to finish to a predetermined thickness. Furthermore, after the semiconductor wafer is attached to the supporting substrate with wax, the outer peripheral portion is scraped off by using an end face processing grindstone. Then, it is also disclosed that the surface of the semiconductor wafer opposite to the supporting substrate is ground with a grinding blade.

[0007]

As described above, according to the method of preventing cracks and chips of the semiconductor wafer in the above-described conventional manufacturing processes of semiconductor devices, chamfering is simply performed on the edge of the outer peripheral surface of the semiconductor wafer. It is possible to obtain the effect of suppressing the occurrence of cracks and chips in the semiconductor wafer, which cannot be prevented only by itself. However, one of them has the following problems.

First, in the above-mentioned Japanese Patent Laid-Open No. 6-267913, in order to make the shape of the chamfered portion of the semiconductor wafer such that the backside ground surface and the chamfered portion intersect,
There is a problem in that it is necessary to change the chamfered shape of the semiconductor wafer according to the target thinning thickness, which causes an increase in material cost.

Further, there are the following problems. That is, as described above, when the back-grinding surface is stopped within the range up to the chamfered portion or the outer peripheral surface of the semiconductor wafer, the effect is sufficiently obtained. However, for example,
When a large amount of backside grinding is performed to a plate thickness of several tens of μm or less, backside grinding is performed up to the chamfered part of the edge on the front side of the semiconductor wafer (that is, the side on which semiconductor elements are formed). . Therefore, even if the processing strained layer is removed as disclosed in this publication, there is a tapered plate thickness portion that is thinner than the thinned plate thickness in the peripheral portion of the semiconductor wafer. Therefore, cracks and chips easily occur around the semiconductor wafer. Therefore, in order to suppress the phenomenon that the peripheral part becomes tapered when the plate thickness is several tens of μm or less, the plate thickness obtained by thinning (in this case, it is very thin, several tens of μm or less). ) Compared with this, the chamfer must be made sufficiently small. Therefore, the effect of the chamfered portion is hardly obtained, and the shape tends to cause cracking or chipping in the semiconductor first half process step.

Also, in the case of the above-mentioned Japanese Patent Laid-Open No. 7-45568, even if the outer peripheral surface of the semiconductor wafer is ground into a shape such that a chamfer is re-formed at the grinding position at the end of the back surface grinding process, When thinning is performed to the extent that the thickness is several tens of μm or less, the edge portion of the semiconductor wafer has a tapered film thickness portion that is thinner than the thinned thickness. It may cause cracks or chips.

Further, in the above-mentioned Japanese Patent Laid-Open No. 9-148283, a semiconductor wafer is fixed to a supporting substrate with a wax, a solvent supply nozzle is provided in a backside grinding device to melt the wax at the edge portion during backside grinding, and thinning is performed. Prevents wax from being exposed on the ground surface. However, it is difficult to dissolve the wax at the edge portion of the semiconductor wafer into a shape and size exactly the same as the shape and size of the semiconductor wafer, and in order to prevent the wax from being exposed,
At least it is necessary to perform over-etching. When the over-etching is performed, a wedge-shaped thin portion is formed in the chamfered portion, that is, the peripheral portion of the semiconductor wafer, similarly to the above, and there is a problem that cracking or chipping easily occurs in the portion.

Further, the chamfered portion around the semiconductor wafer is ground from the end face direction with a grindstone to completely remove the chamfered portion before thinning and grinding, and the fixing wax is also removed with an etching solution to remove the wax. There is no contact with the grinding blade, and there is no knife edge thinning around the semiconductor wafer. For this reason, it is disclosed that the machined surface is prevented from being roughened and rusted due to the clogging of the grinding blade, and the occurrence of cracks around the semiconductor wafer can be reduced. However, a new grindstone for grinding the end face is additionally required, which increases the cost. Further, it is necessary for the grindstone to be mounted with a small distance so as not to come into contact with the supporting substrate of the semiconductor wafer, and a special structure for that purpose is required. Further, when the grindstone is a fixed type grindstone, there is a problem that the life of the grindstone is short because only the portion in contact with the semiconductor wafer is worn.

Therefore, an object of the present invention is to reduce the plate thickness to several tens of μm.
some manufacturers how the semiconductor device cracking and chipping on the periphery of the semiconductor device substrate be subjected to back grinding is not generated becomes equal to or less than m to be Hisage <br/> subjected.

[0014]

In order to achieve the above object, a method of manufacturing a semiconductor device according to a first aspect of the present invention is directed to a chamfered portion and a flat portion on an outer periphery of a front surface side of a semiconductor wafer in which a semiconductor element is formed. After the notch is formed at the boundary between and, the back surface of the semiconductor wafer is ground until the thickness of the semiconductor wafer becomes smaller than the notch depth.

According to the above structure, the flat portion of the surface of the semiconductor wafer is separated by the notch formed at the boundary with the chamfered portion on the outer periphery thereof. Therefore, when the back surface grinding is performed until the plate thickness of the semiconductor wafer becomes thinner than the cutting depth, the thinned chamfered portion remains around the semiconductor wafer in the shape of an eaves (knife edge). There is no. Therefore, even if the back surface grinding is performed until the plate thickness becomes several tens of μm or less, cracks or chips do not occur around the semiconductor wafer.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect of the invention, prior to the back surface grinding, the boundary between the chamfered portion and the flat portion on the front surface side of the semiconductor wafer is formed. The notch to be formed is, first, at the boundary between the chamfered portion and the flat portion on the surface side of the semiconductor wafer, a blade of a high-speed rotating outer peripheral blade processing device for dicing is cut in a direction perpendicular to the surface, and then the semiconductor wafer Is formed by rotating the semiconductor wafer with the center of the semiconductor wafer as the center of rotation.

According to the above structure, the notch formed at the boundary between the chamfered portion and the flat portion on the surface of the semiconductor wafer is performed by using the high-speed rotating outer peripheral blade processing device that has been conventionally used for dicing. . In this way, backside grinding with a plate thickness of several tens of μm or less is performed without using a new device without generating cracks or chips around the semiconductor wafer.

According to a third aspect of the present invention, in the method of manufacturing a semiconductor device according to the second aspect, the blade of the high-speed rotating outer peripheral blade processing device has a width wider than the width of the chamfered portion of the semiconductor wafer. A blade having a blade, and after cutting the blade by aligning the position of the axial outer side surface of the blade with the position closer to the center than the boundary between the chamfered portion and the flat portion, the semiconductor is rotated by rotating the semiconductor wafer. The chamfered portion of the wafer is removed at a predetermined depth.

According to the above construction, the chamfered portion on the surface of the semiconductor wafer is removed to a predetermined depth by a very simple operation. Therefore, when the backside grinding is performed on the semiconductor wafer until the plate thickness becomes thinner than the predetermined depth, the chamfered portion does not remain like a canopy around the semiconductor wafer.

According to a fourth aspect of the present invention, in the method for manufacturing a semiconductor device according to the second aspect, the blade of the high-speed rotating outer peripheral blade processing device has a width narrower than the width of the chamfered portion of the semiconductor wafer. A blade having a groove, and after cutting the blade by aligning the position of the axially outer side surface of the blade at a position closer to the center than the boundary between the chamfered portion and the flat portion, the semiconductor wafer is gradually rotated while rotating the semiconductor wafer. It is characterized in that the chamfered portion of the semiconductor wafer is removed to a predetermined depth by moving the blade toward the chamfered portion in the axial direction.

According to the above structure, since the chamfered portion on the surface of the semiconductor wafer is removed to a predetermined depth, backside grinding is performed on the semiconductor wafer until the plate thickness becomes thinner than the predetermined depth. When this is performed, the chamfered portion does not remain like eaves around the semiconductor wafer.

According to a fifth aspect of the present invention, in the method of manufacturing a semiconductor device according to the second aspect of the present invention, there is provided a high-speed rotating outer peripheral edge machining apparatus at the boundary between the chamfered portion and the flat portion on the front surface side of the semiconductor wafer. When cutting the blade, the outer peripheral surface of the flat portion is formed in an inversely tapered shape so that the outer diameter of the flat portion increases toward the surface.

According to the above structure, since the outer peripheral surface of the flat portion of the semiconductor wafer has an inverse taper shape, the flat portion has a trapezoidal shape when the back surface is faced up during back surface grinding. Therefore, when backside grinding is performed on the semiconductor wafer until the plate thickness becomes thinner than the cut depth, the eave-shaped thin plate portion does not remain on the outer periphery of the semiconductor wafer. In addition, the force of the grinding applied to the semiconductor wafer in the grinding direction can be dispersed and received in a trapezoidal shape, and the thinned semiconductor wafer can be stably fixed.

According to a sixth aspect of the present invention, in the method of manufacturing a semiconductor device according to the fifth aspect, the blade of the high-speed rotating outer peripheral blade processing apparatus has a tapered shape whose inner diameter increases toward the tip. The blade of the cup-shaped grindstone is formed, the cup-shaped grindstone is moved in the axial direction from the outer peripheral side of the semiconductor wafer toward the center, and the chamfered portion and the flat portion from the outer peripheral side of the semiconductor wafer. After cutting the cup-shaped grindstone to a position closer to the center from the boundary at a predetermined depth, the chamfered portion of the semiconductor wafer is removed at the predetermined depth by rotating the semiconductor wafer, and the flatness is obtained. It is characterized in that the outer peripheral surface of the portion is formed in an inverse tapered shape.

According to the above construction, since the tapered cup-shaped grindstone whose inner diameter increases toward the tip is used as the blade of the high-speed rotating outer peripheral blade processing apparatus, the outer peripheral surface of the flat portion of the semiconductor wafer is It is easily formed in a reverse taper shape.

According to a seventh aspect of the invention, in the method of manufacturing a semiconductor device according to the first aspect of the invention, the semiconductor element protection tape is provided on the surface of the semiconductor wafer on which the notch is formed prior to the backside grinding. By sticking, a knife is positioned at the position of the outer peripheral surface of the flat part on the surface, and the semiconductor wafer is rotated with the center of the semiconductor wafer as the center of rotation to cut off excess semiconductor element protection tape, It is characterized in that the outer diameter of the protective tape is not larger than the outer diameter of the flat portion.

According to the above construction, after the semiconductor element protection tape is attached to the surface of the semiconductor wafer, the blade is positioned at the position of the outer peripheral surface of the flat portion, so that the teaching die can be easily used without using a learning die. Excessive semiconductor element protection tape protruding from the flat portion is cut off. Furthermore, since the semiconductor element protection tape is attached in the same shape as the flat portion, the semiconductor element protection tape is caught between the semiconductor wafer and the grindstone for backside grinding or the semiconductor element during the backside grinding. The flat portion outside the protective tape is not thinned. As a result, cracking and chipping of the semiconductor wafer Ru is reduced.

[0028]

DETAILED DESCRIPTION OF THE INVENTION hereinafter be described in detail by way of embodiments thereof illustrated in the accompanying drawings. <First Embodiment> FIG. 1 is a schematic perspective view of a semiconductor device manufacturing apparatus according to the present embodiment. 2 to 4 are conceptual cross-sectional views showing the procedure of the method for manufacturing a semiconductor device according to the present embodiment.

In the present embodiment, a silicon substrate is assumed as the semiconductor device substrate for explanation, but the present invention can be applied to other semiconductor device substrates. However, in that case, the mechanical strengths of the respective semiconductor device substrates are different, and therefore the numerical values described below must be values suitable for the type of each semiconductor device substrate. Further, in the sectional conceptual views shown in FIGS. 2 to 4, in order to facilitate understanding, the ratio between the diameter and the thickness of the wafer as the semiconductor device substrate is changed from the actual ratio and enlarged in the thickness direction. is doing. Further, the chamfered portion around the wafer is expanded not only in the thickness direction but also in the diameter direction. Therefore, the proportion of the flat portion is expressed narrowly.

In FIG. 1, reference numeral 1 denotes a substrate on which a semiconductor device (semiconductor element) is built (the above semiconductor device substrate:
It is simply called a wafer). The wafer 1 is rotatable about a rotation axis 2 that passes through the center in the vertical direction.
1a is the surface on which the semiconductor element is formed, and 1b is
Is the back side. Reference numeral 3 denotes a high-speed rotating outer peripheral blade used for dicing, which is rotated at a high speed by a rotating mechanism 4. The rotation mechanism 4 conceptually shows a bearing and a drive unit integrated with each other.

Here, although not described in detail, the above wafer 1
Is placed on the stage of the high-speed rotating outer peripheral blade processing apparatus. This high-speed rotating outer peripheral blade processing device is disclosed in Japanese Patent Laid-Open No. 4-3.
As disclosed in Japanese Patent No. 22442, a sample rotating mechanism having a driving device for endless rotation is mounted on a sample moving stage that slides in a direction perpendicular to a rotation axis 5 of a high-speed rotating outer peripheral blade 3. is there. Then, the sample moving stage rotates in the direction of arrow (a) around the rotation axis 2 with the wafer 1 mounted. The rotation axis 5 of the high-speed rotating outer peripheral blade 3 is set so as to be orthogonal to the rotation axis 2 of the wafer 1 so as to prevent abnormal processing. It should be noted that the processing abnormality referred to here means a displacement of the rotary shaft 5, and when the high-speed rotating outer peripheral blade 3 is brought closer to the wafer 1, that is, when it is relatively lowered, the cutting position (dimension) is the set position. However, it means that an error occurs, the resistance applied to the blade during the processing of the wafer 1 becomes large, and the processing width of the wafer 1 is different from the expected width.

In the above-mentioned structure, the outer surface of the high-speed rotating outer peripheral blade 3 having the rotation axis 5 orthogonal to the rotation axis 2 of the wafer 1 is located slightly at the center of the wafer 1 from the boundary between the chamfered portion and the flat portion of the wafer 1. The outer peripheral portion of the wafer 1 is cut by lowering it to a position closer to it.

FIG. 2 shows the mutual positional relationship between the wafer 1 and the high-speed rotating outer peripheral blade 3 in that case. FIG. 2A shows a case where a thick blade 6 having a large blade thickness is used as the high-speed rotating outer peripheral blade 3. Further, FIG. 2 (b) shows a high-speed rotating outer peripheral blade 3,
This is the case where the thin blade 7 having a small blade thickness is used. Also, FIG. 2 (b)
Shows a case where a cup-shaped grindstone 8 is used as the high-speed rotating outer peripheral blade 3.

As a concrete processing procedure, first, the wafer 1 is placed on the sample moving stage (not shown) with the back surface 1b facing downward. At this time, although not shown, a wafer supporting tape attached to the ring is attached to the back surface 1b of the wafer 1, and the wafer 1 is fixed to the sample moving stage by vacuum suction via the tape. At the time of fixing, the center of the wafer 1 and the center of rotation (rotation shaft 2) are aligned.

Next, while rotating the wafer 1 in the direction of the arrow (a), the outer peripheral side is cut by the high-speed rotating outer peripheral blade 3 from the boundary 1a 'between the chamfered portion and the flat portion in the peripheral portion of the wafer 1. . The cutting depth in that case is set to a depth x which is slightly deeper than the plate thickness when the wafer 1 is thinned later. Here, it is necessary to determine an optimum value for the grinding depth x according to the grinding method and the grinding conditions. In the present embodiment, the depth is set to be about 20 μm deeper than the plate thickness obtained by backside grinding (that is, the cut depth x is about 120 μm when the target plate thickness is 100 μm). The above-mentioned grinding conditions include the roughness of the grindstone in the back surface grinding, the cutting speed, the relative rotation speed of the grindstone and the wafer 1, the kind of the resin sheet or tape for wafer protection, the width of the high-speed rotating outer peripheral blade 3. And the tip shape including the side wall taper and the tip shape. Then, when the back surface is ground without cutting the outer peripheral side from the boundary 1a ′ by the high-speed rotating outer peripheral blade 3, the wafer 1
It is desirable to grasp the plate thickness (which varies depending on the grinding conditions) at which chipping or cracking occurs in the periphery, and to grind more than the plate thickness with the high-speed rotating outer peripheral blade 3.

FIG. 2A shows a case where a thick blade 6 having a blade thickness larger than the cutting width is used as the high-speed rotating outer peripheral blade 3. In this case, the boundary 1a ′ between the chamfered portion and the flat portion
Then, the tip surface of the thick blade 6 is brought into contact with the outer peripheral side and rotated in the direction of arrow (b), and the thick blade 6 is moved in the direction of arrow (c) by the cutting depth x. After that, place the wafer 1 on the arrow (a).
The cutting is performed by rotating in the direction of.

Further, FIG. 2 (b) shows the above high-speed rotating outer peripheral blade 3
As a case, a thin blade 7 having a blade thickness smaller than the cutting width is used. In this case, by rotating the thin blade 7 in the direction of the arrow (b) and moving the thin blade 7 in the direction of the arrow (c) by the cutting depth x, the boundary 1 between the chamfered portion and the flat portion is
Make a depth x cut in a '. And further, wafer 1
The cutting is performed by gradually moving the thin blade 7 to the outer peripheral side from the place where the notch is made (that is, in the direction of arrow (d)) while rotating in the direction of arrow (a). When the thin blade 7 is used, even if a groove having a cutting depth x is formed at the boundary 1a ′ between the chamfered portion and the flat portion on the outer peripheral portion of the wafer 1, cracks or chips in the peripheral portion of the wafer 1 are not formed. Can be prevented.

Further, FIG. 2 (c) shows the above high-speed rotating outer peripheral blade 3
In this case, the cup type grindstone 8 is used. The cup-shaped grindstone 8 used in this case is the above-mentioned JP-A-4-32244.
It is a grindstone for sidewall grinding as disclosed in Japanese Patent Publication No. Here, the cup-shaped grindstone 8 has a wide mouth portion 8 ′ whose outer diameter and inner diameter increase toward the tip. By providing such a wide mouth portion 8 ', cutting is facilitated. First, prior to the above cutting, the cup-shaped grindstone 8
Performs truing. This truing is
As shown in FIG. 2 (d), while rotating the cup-shaped grindstone 8 by the rotating mechanism 4, the chamfering grindstone 9 (truer) is pressed against the inclined surface m inside the wide mouth 8 ′. Then, the cup-shaped grindstone 8 is moved from the position of the surface of the wafer 1 in the direction of the arrow (c) by a depth x, the cup-shaped grindstone 8 is rotated in the direction of the arrow (b), and from the outer peripheral side of the wafer 1. The cup-shaped grindstone 8 is gradually moved in the direction of arrow (e) to the boundary 1a 'between the chamfered portion and the flat portion. Then, the cutting is performed by rotating the wafer 1 in the direction of the arrow (a).

As described above, by using the cup-shaped grindstone 8 having the wide-mouthed portion 8'having the inclined surface m at its tip, as shown by the portion surrounded by the circle 10 in FIG. 2 (c),
The edge of the flat portion of the wafer 1 can be ground into an inverse taper shape. By adjusting the pressing angle of the truer 9 during the truing, the taper angle of the reverse taper formed on the edge of the flat portion of the wafer 1 can be adjusted.

By thus grinding the outer peripheral surface of the flat portion of the wafer 1 in an inversely tapered shape, the flat portion has a trapezoidal shape when the back surface 1b is turned up during back surface grinding. Therefore, when the back surface is ground until the plate thickness of the wafer 1 becomes smaller than the cut depth x, the eave-shaped thin plate portion does not remain.

As described above, in the present embodiment,
A thick blade 6, a thin blade 7, or a cup-shaped grindstone 8 is used as the high-speed rotating outer peripheral blade 3, and the peripheral portion of the surface 1a of the wafer 1 is surrounded by the high-speed rotating outer peripheral blade processing apparatus conventionally used for dicing. The cutting process is performed to a depth x deeper than the target plate thickness at the time of backside grinding.

As described above, when the cutting of the peripheral portion of the surface 1a of the wafer 1 is completed by any of the processing shown in FIGS. 2 (a) to 2 (c), the wafer 1 is placed on the sample moving stage. Peel off the tape used to secure it.

Next, as shown in FIG. 3 (a), a protective tape or protective sheet for protecting the semiconductor elements formed on the surface 1a of the wafer 1 (hereinafter, the protective tape or protective sheet will be collectively referred to as a protective tape or protective sheet). Then semiconductor element protection tape 1
Paste 1). Here, the semiconductor element protection tape 11 is, for example, a tape-shaped body in which an adhesive layer is applied on a resin base material. Then, the semiconductor element protection tape 11
In order to facilitate the sticking work, the sticking is made larger than the flat portion of the wafer 1.

After that, the semiconductor element protection tape 11
Is cut into a circular shape according to the shape of the flat portion.
At this time, if the semiconductor element protection tape 11 protrudes from the periphery of the flat portion, the semiconductor element protection tape 1 is provided between the wafer 1 and the back surface grinding wheel during the subsequent back surface grinding.
1 is involved and causes "galling" and "burning" of the ground surface, which causes cracks and chips in the peripheral portion of the wafer 1. On the contrary, when the semiconductor element protection tape 11 becomes smaller than the flat portion of the wafer 1, the portion of the flat portion protruding from the semiconductor element protection tape 11 becomes an eaves-like shape at the time of backside grinding, and cracks or chips occur in the peripheral portion of the wafer 1. Cause to occur. Therefore, it is desirable that the outer end portion 1c of the flat portion of the wafer 1 and the cutting position of the semiconductor element protection tape 11 coincide with each other.

FIG. 3B shows the semiconductor element protection tape 1 described above.
An example of the cutting method of No. 1 will be shown. By rotating the wafer 1 together with the semiconductor element protection tape 11 while applying a cutting tool 12 such as a razor to the outer end portion 1c of the flat portion of the wafer 1 to form a circle having the same shape as the outer end portion 1c of the flat portion. The semiconductor element protection tape 11 is cut.

Thus, the peripheral portion is cut, the semiconductor element protection tape 11 is attached to the flat portion of the surface 1a, and the periphery of the semiconductor element protection tape 11 is cut into the same shape as the outer end portion 1c of the flat portion. The backside grinding is performed on the thus-formed wafer 1 as follows.

The wafer 1 having the semiconductor element protection tape 11 attached to the flat portion on the front surface 1a side is fixed to the fixed table side of the back surface grinding device (not shown) with the semiconductor element protection tape 11 side. A porous vacuum chuck (not shown) is used as a method of fixing the wafer 1 to the fixing table.

FIG. 4A shows a state in which the back surface 1b of the wafer 1 has been ground. The back grinding wheel 15 is
It has a ring shape having an outer diameter substantially the same as that of the whetstone support 16. The back grinding wheel 15 in the present embodiment is
It is formed by embedding abrasive grains in a support material (such as an adhesive or cast iron). In addition, diamond abrasive grains were used as the polishing abrasive grains. Further, the grindstone support base 16 uses a metal processed product. An iron-based material is generally used as the grindstone support 16, but it is also effective to use a light metal such as an aluminum-based metal in order to reduce the weight for the purpose of improving accuracy.

Backside grinding using the backside grinding wheel 15 and the whetstone support 16 having the above construction is carried out as follows. That is, as shown in FIG. 4A, the wafer 1 is rotated clockwise in the arrow (f) direction about the rotation shaft 17 that passes through the center of the wafer 1 in the vertical direction. On the other hand, the back grinding wheel 15 is rotated clockwise in the direction of arrow (g) about a rotation axis 18 parallel to the rotation axis 17 of the wafer 1. And
The back grinding wheel 15 is brought into contact with the back surface 1b of the wafer 1,
Further, the rear surface is ground by moving it to the front surface 1a side.

At this time, cutting water is supplied to the wafer 1 and the back surface grinding wheel 15 for the purpose of removing the ground facets and cooling and lubricating the wafer 1 and the back surface grinding wheel 15. In the present embodiment, as the cutting water, water (usually pure water or distilled water) in which corrosive ions are not mixed so as not to corrode the metal or the like of the semiconductor element is used. Further, in the present embodiment, as the grinding wheel 15 for backside grinding, a grindstone with a coarse abrasive grain of about No. 400 and a fine abrasive grain with No. 1500 to No. 2 are used.
A grindstone of about No. 000 is prepared, the grindstone having the coarse abrasive grains is used for the back surface grinding, and the fine grindstone having the abrasive grains is used for finishing performed later. Further, carbon dioxide gas is dissolved in order to prevent generation of static electricity and electrification.

Since the selection of the roughness or type of the abrasive grains of the back grinding wheel 15 differs depending on the purpose, the back grinding wheel 15 is not limited to the two-step roughness of rough grinding and finish grinding. In some cases, three, four, or more levels of roughness are required. Also, when selecting the abrasive grains, it is possible to improve the roughness of the finished surface by selecting finer abrasive grains. Here, when fine abrasive grains are selected, the moving speed and rotation speed of the backside grinding wheel 15 and the cutting fluid are adjusted so that "burning" and "galling" do not occur on the ground surface of the wafer 1 due to the backside grinding. It is necessary to optimize the supply method.

Further, in the present embodiment, the rotational speed ratio between the wafer 1 and the back surface grinding wheel 15 during the back surface grinding is set to about 1 to 10, and the moving speed of the back surface grinding wheel 15 during the rough grinding is set. Is several tens of μm / min to several hundreds of μm / min, while the movement speed during finish grinding is from several μm / min to
It is about several tens of μm / min. Here, the present embodiment is an example of the case of grinding a silicon substrate, and the above-mentioned numerical values do not limit the scope of the present invention in any way.

In the present embodiment, the back side is roughly ground from the plate thickness at the start of back side grinding in FIG. It becomes the state of b). Here, the grinding wheel 15 for back surface grinding is replaced with a finishing grinding wheel to perform finishing grinding. In this way, after the back surface of the wafer 1 is ground to the target plate thickness using the finishing grinding wheel as shown in FIG. 4 (c), the facets are washed and the wafer 1 is thinned. Complete.

If the rotating shaft 17 of the wafer 1 and the rotating shaft 18 of the grinding wheel for backside grinding 15 are not one pair as shown in FIG. Finish grinding can be performed by moving the rotary shaft of the wafer 1 to the position of the optimum rotary shaft for grinding by the next finish grinding grindstone without changing the rough grinding to the finish grinding grindstone. .

As described above, in the above-described embodiment, prior to the back surface grinding of the wafer 1, the semiconductor device manufacturing apparatus (high-speed rotating outer peripheral blade processing apparatus) as shown in FIG. From the boundary 1a ′ between the flat portion and the chamfered portion to the outer peripheral portion, cutting is performed at a depth x slightly deeper than the target plate thickness for backside grinding. That is, when the thick blade 6 thicker than the cutting width is used as the high-speed rotating outer peripheral blade 3 shown in FIG. 1, the tip surface of the thick blade 6 is brought into contact with the outer peripheral side from the boundary 1a ′ between the chamfered portion and the flat portion. , Depth of cut x thick blade 6
Is moved to perform the above cutting. Also, high-speed rotating outer peripheral blade 3
When using a thin blade 7 having a blade thickness smaller than the cutting width, a cut having a depth x is made at the boundary 1a ′ between the chamfered portion and the flat portion, and further the thin blade 7 is moved to the outer peripheral side to perform the above cutting. To do. Further, the cup-shaped grindstone 8 is used as the high-speed rotating outer peripheral blade 3.
When using, the cup-shaped grindstone 8 is rotated and moved from the outer peripheral side of the wafer 1 to the boundary 1a ′ between the chamfered portion and the flat portion at the depth x to perform the cutting.

After that, the surface 1 of the wafer 1 is
A semiconductor element protection tape 11 for protecting a semiconductor element is attached to the flat portion of a, and a cutting tool 12 is used to cut into a circular shape according to the shape of the flat portion. In that case, since the shape of the semiconductor element protection tape 11 matches the shape of the flat portion, a wafer such as the semiconductor element protection tape 11 is wound between the wafer 1 and the back surface grinding wheel during back surface grinding. The factor of cracking or chipping of No. 1 can be eliminated.

Thus, prior to the back surface grinding of the wafer 1, the outer peripheral portion of the wafer 1 beyond the boundary 1a ′ between the flat portion, the chamfered portion and the chamfered portion is slightly deeper than the target plate thickness for the back surface grinding x. Cut with. Therefore, when the back surface of the wafer 1 is later ground to a target plate thickness of several tens of μm or less, the chamfered portion around the thinned wafer 1 has an eaves-like (knife-edge) shape. It does not remain as a part. That is, even if the back surface is ground so that the plate thickness is several tens of μm or less, no cracks or chips occur around the wafer 1.

As a semiconductor device manufacturing apparatus used in that case, a high-speed rotating outer peripheral blade processing apparatus conventionally used for dicing can be used as it is. Therefore, backside grinding up to a plate thickness of several tens of μm or less can be performed without using a special manufacturing apparatus so as to prevent cracking or chipping around the wafer 1.

<Second Embodiment> FIG. 5 is a sectional conceptual view showing a procedure of a method for manufacturing a semiconductor device according to the present embodiment. In the present embodiment, prior to backside grinding of the wafer, a chamfered portion around the wafer is cut in advance by using a backside grinding device that performs the backside grinding. After that, the backside grinding is performed using the same backside grinding device.

First, as shown in FIG. 5A, the wafer 21
The semiconductor element protection tape 22 for protection is attached to the surface 21a side on which the semiconductor element is formed. The semiconductor element protection tape 22 is made of the same resin as the semiconductor element protection tape 11 used in the first embodiment, and is attached in the same manner. After that, the extra semiconductor element protection tape 22 is cut off. In that case, the cutting is performed on the wafer 21.
2 between the flat portion and the chamfered portion 21c on the surface 21a of the
Position 1a '. Specifically, in the present embodiment, the one that serves as a cutting guide, such as the outer end portion 1c in FIG. 3A of the first embodiment, is the wafer 21.
Not on. Therefore, although not shown, a disc-shaped guide having an outer diameter smaller than the outer diameter of the wafer 21 by the width of the chamfered portion 21c is placed near the surface 21a of the wafer 21, and the razor-shaped blade 23 is placed along the disc-shaped guide. The semiconductor element protection tape 22 is cut by moving it relative to the semiconductor element protection tape 21.
Depending on the angle of the blade surface of the blade 23, it is not always best for the outer diameter of the disc-shaped guide to be as small as the width of the chamfered portion 21c.

As described above, the wafer 21 of which only the flat portion of the front surface 21a is protected by the semiconductor element protection tape 22 is transferred to the wafer fixing stage of the back grinding machine.
(Not shown). 5 (c) to 5 (e) show how the chamfered portion 21c around the wafer 21 mounted on the wafer fixing stage is cut by the back surface grinding wheel 24. In this case, the chamfered portion 21c to be cut is
Since the volume of 1 is substantially small, a finishing grindstone is used as the backside grinding grindstone 24, and the cutting speed is reduced to perform the cutting process.

The backside grinding wheel 24 is a grinding wheel support 25.
It is a cup-shaped grindstone formed in a ring shape having a larger outer diameter. The outer diameter increases toward the contact surface with the wafer 21, and the outer peripheral surface is tapered. The shape of the inner peripheral surface is not particularly specified, but in the present embodiment, the inner peripheral surface is formed so as to be perpendicular to the processed surface. At least the structure in which the width in the radial direction of the ground surface at the tip portion is larger than the width in the radial direction of the surface in contact with the grindstone support 25 is used to increase the abrasion resistance of the backside grinding wheel 24. There is. Thus, the back grinding wheel 2
To improve the finish of the cutting surface cut by No. 4, the wafer 21 in the back surface grinding process performed thereafter is performed.
It is effective in preventing cracks and chips.

As mentioned above, the back grinding wheel 24 is used.
Is a cup-shaped grindstone whose outer diameter increases toward the grinding surface, so that even if the backside grinding wheel 24 wears, an acute angle can be maintained between the outer peripheral surface and the grinding surface, and the chamfered portion 21c is cut. Can be performed with high precision. On the other hand, when a grindstone whose outer peripheral surface is perpendicular to the grinding surface is used as the back surface grinding wheel 24, the outer peripheral surface and the ground surface may have an obtuse angle depending on the finishing error of the outer peripheral surface. The part 21a cannot be cut accurately.

After cutting the chamfered portion 21c as described above, the rotary shaft 26 of the backside grinding wheel 24 is attached to the wafer 2
5 (f), by moving it relatively to the side of the rotating shaft 27 of FIG.
The back surface grinding process for the wafer 21 shown in FIG. The back surface grinding method is the same as in the case of the first embodiment. In this way, even if the back surface is ground to a target plate thickness of several tens of μm or less, the semiconductor element protection tape 22 is previously formed on the flat portion of the wafer 21 in FIG. Since the chamfered portion 21c is pasted and the chamfered portion 21c is cut in FIG. 5 (f), the chamfered portion 21c of the wafer 21 does not remain in a tapered shape (eave shape). Therefore, as shown in FIG. 5 (h), the back surface of the wafer 21 is ground to a desired plate thickness, leaving only the flat portion.

As described above, in the present embodiment,
Prior to cutting and chamfering the chamfered portion 21c,
A semiconductor element protection tape 22 for protecting the semiconductor element is attached to the front surface 21a side of the wafer 21 according to the size of the flat portion. Therefore, it is possible to prevent extra semiconductor element protection tape 22 from being caught between the back surface grinding wheel 24 and the wafer 21 when the chamfered portion 21c is cut or the back surface is ground. Therefore, it is possible to prevent the semiconductor element protection tape 22 from being wound up and causing "galling" or "burning" of the ground surface, which may cause cracks or chips in the peripheral portion of the wafer 1.

Prior to the backside grinding, the chamfered portion 21c of the wafer 21 is cut in advance. Therefore, when the backside grinding is performed on the wafer 21 to a target plate thickness of several tens of μm or less later, the chamfered portion 21c has a canopy shape (knife edge shape) around the thinned wafer 21. Does not remain as a thin part of. That is, even if the back surface is ground to a plate thickness of several tens of μm or less, no cracks or chips occur around the wafer 21.

6 and 7 show the relative positions of the wafer 21 and the backside grinding wheel 24 when the chamfered portion 21c is cut and when the backside grinding is performed by using the backside grinding apparatus of this embodiment. Show the relationship.

In FIG. 6, FIG. 6A is a plan view.
6B is a sectional view taken along the line α-α ′ in FIG. 6A, showing a state in which the chamfered portion 21c of the wafer 21 is cut (FIGS. 5C to 5E). FIG. 6 (c) is a sectional view taken along the line β-β ′ in FIG. 6 (a), showing a state where the back surface of the wafer 21 is being ground (see FIG. 5).
It is a sectional view showing (f) and (g).

In the figure, h is the position of the rotation center 27 of the wafer fixed stage during the finish grinding of the back surface grinding, that is, the position of the rotation center of the wafer 21. Also, h'is
Position of the center of rotation of the whetstone support 25, that is, the finishing whetstone 2
4 is the position of the rotation center 26. Further, j is the wafer fixing stage (wafer 2 when the chamfer 21c is cut).
This is the position of the rotation center 27 in 1). Further, i is a wafer fixing stage (wafer 21) at the time of rough grinding of backside grinding.
This is the position of the rotation center 27. Further, i ′ is the position of the center of rotation of the grindstone support 25 (coarse grinding wheel 28). Here, at the time of the back grinding, the wafer 21 and the back grinding wheel 2
As for the positional relationship with Nos. 4 and 28, the rotation center h, i of the wafer 21 is the back grinding wheel 2 so that the entire surface of the wafer 21 can be ground.
It is within the outer circle of 4,28 and overlaps by a distance T.

Reference numeral 31 is a turntable (turntable). The rotary table 31 holds a wafer rotating mechanism (not shown) that rotates the wafer 21 on the wafer fixing stage, and also moves the wafer 21 from the rotation center position j when cutting the chamfered portion 21c to the back surface rough grinding. Rotation center position i
And further to the rotation center position h at the time of back surface finish grinding. Here, the rotary table 31 moves to the center of rotation at the time of cutting the chamfered portion 21c and at the time of grinding the back surface, as well as at the loading (or wafer loader) position of the wafer 21 or the recovering (or unloader) position of the wafer 21 or the wafer. The wafer 21 is moved to a work position or the like where the cleaning / drying process of 21 is performed, and the back surface of the wafer 21 is consistently ground.

The rotational center position j of the wafer 21 when the chamfered portion 21c of the wafer 21 is cut is determined by changing the relative positional relationship between the center of the wafer 21 and the center of the finishing grindstone 24 by the rotary table 31. It is possible to deal with wafers 21 having various diameters. In that case, the rotary table 31 has a structure that can be fixed at any position. The method of determining the fixed position of the rotary table 31 is performed as follows. As shown in FIG.
Assuming that the width of the chamfered portion 21c around the wafer 21 (that is, the overlapping width of the backside grinding wheel 24 and the wafer 21) is the cutting width s, the chamfered portion 21c of the wafer 21 having the diameter R1 is cut by the backside grinding wheel 24 having the diameter R3. If you do, turntable 3
1 rotation center K, wafer 21 center M, and back grinding wheel 2
The fixed position of the rotary table 31 is determined at a position where the center L of the 4 forms a positional relationship with the triangle KLM as shown in FIG.

In this case, an angle ∠ formed by a straight line KL connecting the center K of the rotary table 31 and the center L of the back surface grinding wheel 24 and a straight line KM connecting the center K of the rotary table 31 and the center M of the wafer 21. By determining the LKM, it is possible to determine the positional relationship (fixed position of the rotary table 31) between the wafer 21 and the back surface grinding wheel 24 suitable for cutting the chamfered portion 21c. Therefore, the back surface grinding apparatus according to the present embodiment has an angle origin, and the rotary table 31 can be moved (rotated) from this angle origin to an arbitrary angle.

In the conventional back surface grinding machine, the fixed angle of the rotary table is determined by a mechanical method such as a notch provided in the rotary table. The rotary shaft of the rotary table is the rotary shaft of the back surface grinding wheel, It is fixed only at a preset position according to the wafer cleaning device, the wafer transfer position, and the like.

On the other hand, in the back surface grinding apparatus of the present embodiment, the index of the fixed angle of the rotary table 31 suitable for cutting the chamfered portion 21c can be freely selected according to the outer diameter of the wafer 21. I am trying. That is, by the computing means 32 realized by the computer,
An appropriate value of the angle ∠LKM according to the outer diameter of the wafer 21 is calculated using the following formula (1), and the calculation result is sent to the angle control device 33 of the rotary table 31. Then, the angle control device 33 as the wafer position setting means rotates the rotary table 31 relative to the straight line KL as the angle origin by an angle ∠LKM to rotate the chamfered portion 21c appropriately. The position of the table 31 is determined.

Here, (LK) in the equation (1) is a distance between the rotary axis K of the rotary table 31 and the rotary axis L of the backside grinding wheel 24 and is a fixed value. Further, (KM) is a distance between the rotation axis K of the rotary table 31 and the rotation axis M of the wafer 21 and is a fixed value. Further, (LM) is a dimension determined by the radius of the backside grinding wheel 24, the radius of the wafer 21 and the above-mentioned cutting width s, and depends on the diameter of the wafer 21, the cutting width s or the degree of wear of the backside grinding wheel 24. Is a value that changes. However, the diameter of the wafer 21, the cutting width s, and the diameter of the backside grinding wheel 24 are values that can be known before cutting the chamfered portion 21c. Therefore, (LM) is the formula
It can be calculated in (2).

That is, as described above, (L
The values of (K), (KM) and (LM) are known. Therefore, the angle ∠LKM can be calculated by substituting the respective values into (LK), (KM) and (LM) in the equation (1). In this way, the value of the angle ∠LKM obtained by the calculating means 32 is sent to the angle control device 33 of the rotary table 31, and the angle control device 33 appropriately cuts the chamfered portion 21c according to the value of the angle ∠LKM. Therefore, the position of the rotary table 31 is determined.

Therefore, according to the present embodiment, even if the diameter of the wafer 21 changes from (R1) to (R2), (R1) in the equation (2) is changed to (R2). Only by doing so, the wafer 21 can be installed at the cutting processing position of the chamfered portion 21c suitable for each wafer diameter.

In this way, after the chamfered portion 21c is cut at the center M (or M ') of the wafer 21, the rotation center 31 of the wafer 21 is moved to the position of i in FIG. Rough grinding is carried out, and the surface is further moved to the position h in FIG. 6 for back surface finish grinding. Thus, after the back surface grinding of the wafer 21 is completed, the wafer 2
1 is washed to collect the wafer 21, the semiconductor element protection tape 22 is peeled off, and the thinning process of the wafer 21 is completed.

As described above, in the present embodiment, the back surface grinding device, the calculating means 32 and the angle control device 33 constitute a semiconductor device manufacturing apparatus. Then, the wafer 21 whose only flat portion is protected by the semiconductor element protection tape 22 is mounted on the wafer fixing stage of the back surface grinding apparatus, and is rotated under the control of the angle controller 33 based on the calculation result of the calculator 32. By simply rotating the rotation center 27 of the wafer 21 by the table 31, cutting of the chamfered portion 21c according to the diameter of the wafer 21,
Backside rough grinding and backside finish grinding can be automatically and continuously performed optimally. That is, according to the present embodiment, a backside grinding device conventionally used for backside grinding of a wafer is used, and a special manufacturing device is used only by devising a rotation angle control system of the rotary table 31. Instead, the back surface can be ground up to a plate thickness of several tens of μm or less so that cracks and chips do not occur around the wafer 21.

FIG. 8 is a flow chart showing a manufacturing procedure of the semiconductor device according to the present embodiment. The manufacturing procedure of the semiconductor device will be described below with reference to FIG.

In step S1, the surface 2 of the wafer 21 is
The semiconductor element protection tape 22 is attached to the 1a side.
In step S2, the semiconductor element protection tape 22 protruding to the chamfered portion 21c side is cut off. In step S3, the wafer 21 is mounted on the wafer fixing stage of the backside grinding device.

In step S4, the cut width s, the wafer 21
R1 (R2) and the diameter R3 of the back grinding wheel 24 are input. In step S5, the KL and KM, which are the unique values of the back surface grinding machine, are input. Then, the cutting means s, the diameter R1 (R1
2) Using the diameter R3 of the backside grinding wheel 24, the distance ML (M'L) between the center M (M ') of the wafer 21 and the center L of the backside grinding wheel 24 is calculated according to the equation (2). Further, using the input values KL, KM and the calculated value ML (M'L), the fixed angle ∠LKM (∠LKM ') of the rotary table 31 is calculated according to the equation (1).
Is calculated. In step S6, the angle control device 33 rotates the rotary table 31 so that the angle from the straight line KL in FIG. 7 becomes ∠LKM (∠LKM '), and is fixed at that position.

In step S7, the above-mentioned wafer fixing stage
(Wafer 21) and finishing grindstone 24 are rotated. In step S8, the finishing grindstone 24 is lowered to move the chamfer 21c.
Is cut. In step S9, the finishing grindstone 24 is raised and the rotary table 31 is moved to the rough grinding position. In step S10, the rough grinding wheel 28 is lowered to perform back surface rough grinding. In step S11, the rough grinding wheel 28 is raised and the rotary table 31 is moved to the finish grinding position. In step S12, the finish grinding wheel 24 is lowered to perform back surface finish grinding.

In step S13, the finish grinding wheel 24
Is raised and the rotary table 31 is moved to the cleaning position. In step S14, the wafer 21 is rotated and washed with a brush or water. In step S15, the wafer 21 is dried with a blower. In step S16, the wafer 21 is taken out, the semiconductor element protection tape 22 is peeled off, and the manufacturing of the semiconductor device involving backside grinding is completed.

In the above description, the method of inputting the diameter R3 of the back grinding wheel 24 to the computing means 32 is not particularly limited, but the back grinding operation of the back grinding machine is controlled as follows. It may be performed by the control unit. That is, the horizontal relative position between the back grinding wheel 24 to which the voltage is applied and the rotated wafer fixing stage is gradually approached, and the back surface grinding is performed from the position of the wafer fixing stage when a current flows through the wafer fixing stage. The diameter R3 of the grindstone 24 is calculated and input to the calculation means 32. By doing this, the turntable 3
It is possible to accurately determine the fixed angle of 1.

Here, the controller controls the plate of the wafer 21 based on the position of the upper surface of the wafer fixing stage, the thickness of the wafer 21, the position of the grinding surface of the back surface grinding wheel 24, etc. during the back surface grinding. The thickness is accurately controlled to the target plate thickness. The position of the grinding surface of the backside grinding wheel 24 is obtained and stored in advance in the same manner as the method for obtaining the diameter R3 described above.

[0087]

As is apparent from the above, in the method of manufacturing a semiconductor device according to the first aspect of the present invention, a notch is formed at the boundary between the chamfered portion and the flat portion on the front surface side of the semiconductor wafer on which the semiconductor element is formed. Since it is formed, the flat portion of the surface is separated from the chamfered portion on the outer periphery of the flat portion by the cut. Therefore, with respect to the semiconductor wafer, when the back surface grinding is performed until the plate thickness becomes thinner than the cutting depth, the thinned chamfered portion is in the shape of an eaves (knife edge) around the semiconductor wafer. You can prevent it from remaining.

That is, according to the present invention, even if the back surface grinding is performed until the plate thickness becomes several tens of μm or less, no cracks or chips occur around the semiconductor wafer. Therefore, problems such as dust generation from the peripheral portion of the semiconductor wafer and damage to the wafer carrier can be solved. At that time,
As the semiconductor wafer, a wafer having a chamfered portion which has been conventionally used can be used as it is. Therefore, it does not change the material cost.

According to a second aspect of the present invention, there is provided a method for manufacturing a semiconductor device, wherein the notch formed at the boundary between the chamfered portion and the flat portion is formed by using a blade of a high-speed rotating outer peripheral blade processing device for dicing. Since it is formed by rotating the wafer, backside grinding up to a plate thickness of several tens of μm or less can be performed without generating cracks or chips around the semiconductor wafer without using a special device. ..

In the method for manufacturing a semiconductor device according to the third aspect of the present invention, since the blade of the high-speed rotating outer peripheral blade processing device uses a blade having a width wider than the width of the chamfered portion, the chamfered portion and the flat portion The chamfered portion can be removed to a predetermined depth by a simple method in which the semiconductor wafer is rotated after cutting the blade at the boundary between and. Therefore, when the backside grinding is performed on the semiconductor wafer until the plate thickness becomes thinner than the predetermined depth, the chamfered portion can be prevented from remaining like a canopy around the semiconductor wafer.

Further, in the method for manufacturing a semiconductor device of the invention according to claim 4, since the blade of the high-speed rotating outer peripheral blade processing device uses a blade having a width narrower than the width of the chamfered portion, the chamfered portion and the flat portion. The chamfered portion of the semiconductor wafer can be removed to a predetermined depth by moving the blade to the axial chamfered portion side while rotating the semiconductor wafer after cutting the blade at the boundary with. Therefore, when the backside grinding is performed on the semiconductor wafer until the plate thickness becomes thinner than the predetermined depth, the chamfered portion does not remain like a canopy around the semiconductor wafer.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a semiconductor device, wherein the flat portion is cut when the blade of the high-speed rotating outer peripheral blade processing device is cut at the boundary between the chamfered portion and the flat portion on the front surface side of the semiconductor wafer. Since the outer peripheral surface of the is formed in an inverse tapered shape, the flat portion has a trapezoidal shape when the back surface is faced up during back surface grinding. Therefore, when backside grinding is performed on the semiconductor wafer until the plate thickness becomes thinner than the cut depth, it is possible to prevent the eaves-shaped thin plate portion from remaining on the outer periphery of the semiconductor wafer. Further, since the outer peripheral portion of the semiconductor wafer has a trapezoidal shape, the grinding force can be dispersed, and thus stable grinding can be maintained even in the thinned state.

In the method for manufacturing a semiconductor device according to the sixth aspect of the present invention, since the cup-shaped grindstone having a tapered shape is used as the blade of the high-speed rotating outer peripheral blade processing apparatus, the chamfered portion is formed from the outer peripheral side of the semiconductor wafer. After cutting the cup-shaped grindstone at a predetermined depth up to the boundary between the flat portion and the flat portion, the chamfered portion of the semiconductor wafer is removed at the predetermined depth by rotating the semiconductor wafer, and the flat The outer peripheral surface of the portion can be formed in an inverse tapered shape.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a semiconductor device, wherein a semiconductor element protection tape is attached to the surface where the notch is formed prior to the back surface grinding, and a cutter is provided at the position of the outer peripheral surface of the flat portion. Since the semiconductor wafer is rotated while the above is positioned and the excess semiconductor element protection tape is cut off, the excess semiconductor element protection tape protruding from the flat portion can be easily removed without using a learning die. Therefore, the semiconductor element protection tape can be attached in the same shape as the flat portion, and the semiconductor element protection tape is caught between the semiconductor wafer and the grindstone for backside grinding or the semiconductor during the backside grinding. It is possible to prevent the flat portion outside the element protection tape from being thinned.
That is, according to the present invention, it is possible to eliminate cracking or chipping of the semiconductor wafer due to the shape of the semiconductor element protection tape not being exactly the same as the flat portion.
It

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a semiconductor device manufacturing apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional conceptual view showing a procedure of a method for manufacturing a semiconductor device using the manufacturing apparatus shown in FIG.

FIG. 3 is a conceptual sectional view following FIG.

FIG. 4 is a conceptual sectional view following FIG.

FIG. 5 is a sectional conceptual view showing a procedure of a method for manufacturing a semiconductor device according to a second embodiment.

6 is a diagram showing a relative positional relationship between a wafer and a backside grinding wheel in the manufacturing method shown in FIG.

FIG. 7 is an explanatory diagram of fixed position indexing of the rotary table in FIG.

FIG. 8 is a flowchart showing a manufacturing procedure of the semiconductor device according to the second embodiment.

[Explanation of symbols]

1, 21 ... Wafer, 2, 5 ... Rotating shaft, 3, 6, 7 ... High speed rotating outer peripheral blade, 4 ... Rotating mechanism, 8 ... Cup grindstone, 8 '... Wide mouth part, 9 ... Truer, 11, 22 ... Semiconductor Element protection tape, 12, 23 ... Blade, 15, 24 ... Grinding stone for back surface grinding, 16, 25 ... Grinding stone support, 21c ... Chamfering portion, 28 ... Rough grinding grindstone, 31 ... Rotating table, 32 ... Computing means, 33 ... Angle control device h ... Rotation center of wafer during back surface finish grinding, h '... Rotation center of finishing grindstone during back surface finish grinding, j, M ... Wafer center of rotation during chamfer cutting, i ... Back surface rough grinding Wafer rotation center, i '... Rotation center of rough grinding wheel during backside rough grinding, K ... Rotation table rotation center during chamfer cutting, L ... Backside grinding wheel rotation center during chamfer cutting.

Continuation of the front page (56) Reference JP-A-4-263425 (JP, A) JP-A-5-74934 (JP, A) JP-A-5-77148 (JP, A) JP-A-5-211235 (JP , A) JP-A-7-45568 (JP, A) JP-A-7-122524 (JP, A) JP-A-8-107092 (JP, A) JP-A-10-217076 (JP, A) JP-A 59-175913 (JP, A) JP 61-168462 (JP, A) JP 63-62328 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/304

Claims (7)

(57) [Claims] 1. After forming a notch at a boundary between an outer peripheral chamfered portion and a flat portion on the front surface side of a semiconductor wafer having a semiconductor element formed therein, until the plate thickness of the semiconductor wafer becomes thinner than the notch depth. A method of manufacturing a semiconductor device, wherein backside grinding is performed on the semiconductor wafer. 2. The method of manufacturing a semiconductor device according to claim 1, wherein, prior to the back surface grinding, the notch formed at the boundary between the chamfered portion and the flat portion on the front surface side of the semiconductor wafer includes At the boundary between the chamfered portion and the flat portion on the front surface side of the wafer, a blade of a high-speed rotating outer peripheral blade processing device for dicing is cut in a direction perpendicular to the surface, and then the semiconductor wafer is rotated around the center of the semiconductor wafer. A method for manufacturing a semiconductor device, which comprises forming the semiconductor device by rotating the semiconductor device. 3. The method of manufacturing a semiconductor device according to claim 2, wherein the blade of the high-speed rotating outer peripheral blade processing device is a blade having a width wider than that of the chamfered portion of the semiconductor wafer. After cutting the blade by aligning the position of the axial outer surface of the blade with the position closer to the center than the boundary between the flat portion and the flat portion, the chamfered portion of the semiconductor wafer is rotated to a predetermined depth by rotating the semiconductor wafer. A method of manufacturing a semiconductor device, characterized in that 4. The method of manufacturing a semiconductor device according to claim 2, wherein the blade of the high-speed rotating outer peripheral blade processing device is a blade having a width narrower than a width of the chamfered portion of the semiconductor wafer. After cutting the blade by aligning the position of the axial outer surface of the blade at a position closer to the center than the boundary between the flat portion and the flat portion, gradually rotate the semiconductor wafer to the axial chamfered portion side while rotating the semiconductor wafer. A method for manufacturing a semiconductor device, characterized in that the chamfered portion of the semiconductor wafer is removed at a predetermined depth by moving the semiconductor wafer. 5. The method for manufacturing a semiconductor device according to claim 2, wherein when the blade of the high-speed rotating outer peripheral blade processing device is cut at the boundary between the chamfered portion and the flat portion on the front surface side of the semiconductor wafer, the flat portion is formed. The method for manufacturing a semiconductor device, wherein the outer peripheral surface of the flat portion is formed in an inversely tapered shape so that the outer diameter of the flat portion becomes larger toward the surface. 6. The cup-shaped grindstone according to claim 5, wherein the blade of the high-speed rotating outer peripheral blade processing device is formed with a tapered blade whose inner diameter increases toward the tip. Is, by moving the cup-shaped grindstone toward the center from the outer peripheral side of the semiconductor wafer in the axial direction, from the outer peripheral side of the semiconductor wafer to a position closer to the center from the boundary between the chamfered portion and the flat portion. After cutting the cup-shaped grindstone at a depth, by rotating the semiconductor wafer, the chamfered portion of the semiconductor wafer is removed at the predetermined depth, and the outer peripheral surface of the flat portion is inversely tapered. A method of manufacturing a semiconductor device, comprising: 7. The method of manufacturing a semiconductor device according to claim 1, wherein prior to the back surface grinding, a semiconductor element protection tape is attached to a surface of the semiconductor wafer on which the notch is formed, and the flat portion on the surface. By locating a blade at the position of the outer peripheral surface of the semiconductor wafer and rotating the semiconductor wafer around the center of the semiconductor wafer as a rotation center to cut off excess semiconductor element protection tape, so that the outer diameter of the semiconductor element protection tape is the flat portion. A method of manufacturing a semiconductor device, characterized in that the diameter is not larger than the outer diameter.