JP2007109838A - Device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and its manufacturing method which are capable of obtaining gettering effect due to formed mechanical damage and also securing strength and which obtain the foregoing effects and satisfy both strength and high performance. <P>SOLUTION: There is removed mechanical damage imparted to a rear surface of a polishing processing surface of a thinned wafer 1, and a mask 30 is applied to the rear surface via a resist film 20. The exposed part of the resist film 20 is removed after being exposed, and there is formed anew a mechanical damage layer 4 by sand blast at the center of the rear surface exposed through an opening 31 of the mask 30. The circumference of the elliptical mechanical damage layer 4 is made a strength maintenance region 5. Thereafter, the wafer 1 is cut and divided along a street 2 to obtain a semiconductor chip 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a device such as a semiconductor chip obtained by dividing a wafer such as a semiconductor wafer, and more particularly to a device in which a mechanical damage layer is formed on the back surface of the device and a manufacturing method thereof.

  As represented by small digital devices such as mobile phones and digital cameras, various electronic devices in recent years have been noticeably light and thin, and semiconductor chips or semiconductors that play an important role as components to achieve this. It is necessary to reduce the size and thickness of package parts. The semiconductor chip is particularly required to be thinned, and in order to make it thinner, it is possible to process the semiconductor wafer before it is cut into a semiconductor chip. A semiconductor wafer is obtained by slicing a single crystal rod of a material such as silicon, but before chipping, the back surface side opposite to the surface, which is an element formation surface, is ground to a predetermined thickness. Thinned.

  In order to thin the semiconductor wafer, machining such as grinding with a grindstone is generally employed, but mechanical damage due to fine scratches remains on the processed surface of the semiconductor wafer thinned by such machining. . Semiconductor wafers or semiconductor chips with mechanical damage remaining tend to be difficult to maintain strength as the thickness is thinner. Therefore, mechanical damage is removed by methods such as chemical etching and polishing. To maintain strength.

  However, mechanical damage that lowers the strength may be effectively used on the one hand to produce a gettering effect. The gettering effect is an element in which impurities mainly composed of heavy metals contained in a semiconductor wafer in the manufacturing process of a semiconductor chip are collected in a strain field outside the formation region of an element such as an electronic circuit formed on the semiconductor chip. This is to clean the formation region, and a portion where mechanical damage is formed is used as a strain field. This gettering effect makes it difficult for impurities to be present in the element formation region, which suppresses problems such as generation of crystal defects and deterioration of electrical characteristics, thereby stabilizing the characteristics of the semiconductor chip and improving the performance. Methods for obtaining a gettering effect are described in Patent Documents 1 and 2 and the like.

JP 10-70099 A Japanese Patent Laying-Open No. 2005-93869

  Some semiconductor chips have a structure that depends on the above-described gettering effect, and in such a semiconductor chip, removing mechanical damage for the purpose of ensuring strength is a loss of gettering effect. In addition, there is a problem that the yield as a product is lowered.

  Therefore, the present invention can obtain the gettering effect due to the formation of the mechanical damage while ensuring the strength, and both the strength and the high performance can be obtained together, and the yield is reduced. An object of the present invention is to provide a device and a method for manufacturing the same.

  The device of the present invention is characterized in that in a device having an electronic circuit formed on the front surface, a mechanical damage layer is formed on a part of the back surface of the device. According to the device of the present invention, a gettering effect is obtained by the mechanical damage layer formed on a part of the back surface, and the mechanical damage layer is formed on a part of the back surface and other than the damage layer. The portion can be a region effective for maintaining strength. As a result, both a gettering effect and strength maintenance can be obtained. The size of the mechanical damage layer is set to an appropriate size while balancing the loss of strength due to the formation of the mechanical damage layer and the obtained gettering effect.

  In this invention, it is set as the preferable form that the location in which the mechanical damage layer is formed is a center part of a back surface. In this configuration, the area around the mechanical damage layer is an effective area for maintaining the strength, and this strength maintaining area forms the outer peripheral portion of the device, so that the rigidity of the device is improved and resistance to external impacts, etc. This is effective in securing strength. Further, when the mechanical damage layer has a shape including a curve, it is difficult for stress to concentrate on the boundary between the mechanical damage layer and the strength maintaining region, so that the strength can be improved. Further, when the mechanical damage layer has a shape consisting only of a curve, the strength is further improved, so that it is the most preferable form.

  The device of the present invention can be preferably manufactured by the manufacturing method of the present invention. The manufacturing method is a device manufacturing method in which a plurality of devices with electronic circuits formed on the surface are divided into individual devices from a wafer partitioned by a predetermined dividing line, and the back side of the wafer is ground. A grinding step for reducing the thickness to a predetermined thickness, a mechanical damage removing step for removing mechanical damage remaining on the back surface of the wafer, and a protective film coating step for coating a protective film on the entire back surface of the wafer; A mask coating step for covering the protective film with a mask in which a part of each region corresponding to the device is opened, an exposure step for exposing the back surface of the wafer on which the protective film is masked, and exposure of the protective film Protective film exposure part removal process of removing the exposed part and exposing the back side of the wafer of the part, and mechanical damage layer formation to form a mechanical damage layer on the exposed part of the back side of the wafer And degree, is characterized by comprising a dividing step of obtaining a device by dividing the wafer along the dividing lines.

  According to the above manufacturing method, mechanical damage is imparted to the entire back surface of the wafer in the grinding process, and therefore mechanical damage remaining on the back surface of the wafer after the grinding process is temporarily removed. Examples of the removing means include chemical etching and polishing. Then, the back surface is covered with a protective film and a mask in this order and exposed. In this case, the protective film is preferably a positive resist film (exposed portion is soluble in a developer and non-exposed portion remains) used in the photoresist method. In addition, the mask has an opening corresponding to the shape and dimensions of the mechanical damage layer formed in the subsequent mechanical damage layer forming process for each region corresponding to each device, and the protective film is exposed through the opening. The

  Subsequently, after removing the mask, the exposed portion of the protective film is removed, and the removed portion of the protective film on the back surface of the wafer, that is, the portion corresponding to the opening of the mask is exposed. Next, a mechanical damage layer is formed on the exposed portion. As a means for forming the mechanical damage layer, sandblasting in which abrasive grains having an appropriate particle diameter are sprayed at a high pressure can be easily and reliably formed. Thereafter, by dividing the line to be divided and dividing the wafer, a device having a mechanical damage layer formed on a part of the back surface is obtained.

  In the above manufacturing method, it is possible to omit the covering of the protective film on the back surface, and to simplify the process so that the mechanical damage layer is formed after the mask is directly covered on the back surface of the wafer. That is, the manufacturing method includes a grinding process for grinding the back side of the wafer to a predetermined thickness, a mechanical damage removing process for removing mechanical damage remaining on the back side of the wafer, and a back side of the wafer. And a mask covering step for covering a mask in which a part of each region corresponding to the device is opened, and a mechanical damage layer forming step for forming a mechanical damage layer on an exposed portion not covered with the mask on the back surface of the wafer. And a dividing step of dividing the wafer along the planned dividing line to obtain a device.

  In the manufacturing method described above, the mechanical damage applied in the grinding process is temporarily removed, and the mechanical damage layer is formed again in the mechanical damage layer forming process. However, the mechanical damage layer applied in the grinding process is removed. The method of leaving as it is is also mentioned as the production method of the present invention. That is, the manufacturing method includes a grinding process for grinding the back surface side of the wafer to a predetermined thickness, a protective film coating process for coating the entire back surface of the wafer with a protective film, and a protective film on the device. A mask coating process for covering the mask in which the central area of each corresponding area opens, an exposure process for exposing the back surface of the wafer with the mask applied to the protective film, and removing the mask and exposing the protective film Protective film non-exposed part removal process that removes the unexposed part and exposes the back side of the wafer of that part, and mechanical damage remaining on the exposed part of the back side of the wafer is removed, thereby grinding the unexposed part Characterized in that it comprises a mechanical damage partial remaining process for remaining mechanical damage applied in the process, and a dividing step for dividing the wafer along a planned dividing line to obtain a device. To have.

  In this manufacturing method, mechanical damage imparted in the grinding process is utilized, and a protective film and a mask are covered in this order on the back surface of the wafer to which the mechanical damage has been imparted and exposed. The protective film in this case is preferably a negative resist film used in the photoresist method (the unexposed portion is soluble in the developer and the exposed portion remains). Further, the mask is the same as the above manufacturing method, that is, a mask having an opening corresponding to the shape and size of the mechanical damage layer formed in the subsequent mechanical damage layer forming step, and a protective film is formed through the opening. Are exposed.

  Subsequently, when the mask is removed and a portion of the protective film that has not been exposed is removed, a portion of the back surface of the wafer where the protective film is removed, that is, a portion other than the opening of the mask is exposed. Next, the mechanical damage imparted in the grinding process of the exposed portion is removed by a method such as chemical etching or polishing. As a result, mechanical damage remains in the portion corresponding to the opening of the mask on the back surface of the wafer. Thereafter, by dividing the line to be divided and dividing the wafer, a device having a mechanical damage layer formed on a part of the back surface is obtained.

  According to this manufacturing method, in order to leave a part of the mechanical damage preliminarily applied in the grinding process and to make this a mechanical damage layer for obtaining a gettering effect, the mechanical damage layer is changed again in a later process. There is an advantage that it is not necessary to form.

  In each of the manufacturing methods according to the present invention, the mechanical damage layer formed on the back surface has a shape and dimensions corresponding to the opening of the mask. Therefore, the mechanical damage layer is formed at the center of the back surface by arranging the opening of the mask at a position corresponding to the center of the device. If the opening of the mask is formed into a shape including a curve or a shape consisting only of a curve, a mechanical damage layer having a shape corresponding to the shape is formed.

  According to the present invention, a mechanical damage layer for obtaining a gettering effect is formed on a part of the back surface of the device, and a portion other than the mechanical damage layer is secured as an effective area for maintaining strength. As a result, it is possible to obtain a device that achieves both high performance and high performance, and to suppress a decrease in yield.

Hereinafter, first to third embodiments of the present invention will be described with reference to the drawings.
[1] First Embodiment FIG. 1 shows a disk-shaped semiconductor wafer (hereinafter abbreviated as a wafer) 1 made of a silicon wafer or the like. The thickness of the wafer 1 before processing is, for example, about 700 μm, and a plurality of rectangular semiconductor chips (devices) 3 are partitioned on the surface by grid-like streets (division planned lines) 2. An electronic circuit (not shown) is formed on the surface of the semiconductor chip 3.

  In the present embodiment, the back surface side of the wafer 1 is ground to thin the wafer 1 to a predetermined thickness, and a mechanical damage layer is formed on a part of the region corresponding to each semiconductor chip 3 on the back surface of the thinned wafer 1. Is formed, and the wafer 1 is divided to obtain the semiconductor chips 3 individually. In the following description, the “front surface” of the wafer 1 or the semiconductor chip 3 is defined as the surface on the side where the electronic circuit is formed, and the “back surface” is defined as the surface on the side opposite to the front surface where the electronic circuit is not formed. .

(1) Grinding Step As a pretreatment for grinding the back surface of the wafer 1, a protective tape 10 is applied to the entire surface of the wafer 1 as shown in FIG. As the protective tape 10, for example, a tape in which an acrylic adhesive or the like having a thickness of about 5 to 20 μm is applied to one side of a base material such as a polyolefin having a thickness of about 70 to 200 μm is preferably used. Affix it to the surface of the wafer 1. This protective tape 10 protects the electronic circuit.

  Next, as shown in FIG. 2B, the back surface of the wafer 1 with the protective tape 10 attached to the front surface is ground to reduce the thickness of the wafer 1 to a required thickness (for example, about 25 to 100 μm). Turn into. As an apparatus for grinding, for example, as described in JP-A-2002-25961, a wafer is adsorbed and held on a vacuum chuck type chuck table, and the chuck table is rotated and disposed above the chuck table. A device for lowering the ground grinding wheel and grinding the back surface of the wafer with a grindstone can be used.

(2) Mechanical damage removal process The mechanical damage is given to the back surface of the wafer 1 ground by the said grinding process by grinding, and this mechanical damage is removed. As a method for that purpose, the wafer 1 is immersed in a predetermined chemical etching solution to dissolve and remove the mechanical damage layer on the back surface, or the mechanical damage layer is removed by polishing by performing buffing or the like. Can be mentioned.

(3) Protective film coating step As shown in FIG. 2 (c), a positive resist film used in the photoresist method as a protective film on the back surface of the wafer 1 (exposed part is soluble in a developer, non-exposed part is 20) is applied by a generally known method such as spin coating. The film thickness of the resist film 20 is sufficient if it is about 1 μm or more.

(4) Mask Covering Step As shown in FIG. 2D, the resist film 20 is covered with a mask 30. The mask 30 is formed of a thin metal plate such as stainless steel in the shape of a disk having substantially the same diameter as the wafer 1, and has a plurality of elliptical openings 31 arranged in a grid as shown in FIG. ing. When the outer peripheral edges are aligned with each other and the mask 30 is overlaid on the wafer 1 and the relative position in the circumferential direction is adjusted, the opening 31 is located at the center of each region of the semiconductor chip 3 and the major axis direction is the longitudinal direction of the semiconductor chip 3. It becomes a state along. As shown in FIG. 4, the mask 30 is overlaid on the resist film 20 covering the back surface of the wafer 1 so as to be in such a state, and is detachably mounted on the wafer 1.

  FIG. 5 is a diagram showing the steps for the wafer 1 in the order of (a) to (f) by extracting a portion of one semiconductor chip 3 from the wafer 1. As shown in FIG. 5A, the opening 31 of the mask 30 covered with the resist film 20 in the mask coating process is located at the center of the semiconductor chip 3.

(5) Exposure Step As shown in FIG. 5B, the back surface of the wafer 1 in which the mask 30 is applied to the resist film 20 is exposed by the exposure device 40. In the resist film 20, an elliptical portion that is exposed from the opening 31 of the mask 30 in the central portion of the semiconductor chip 3 is exposed. As described above, since the resist film 20 is a positive type, an exposed portion of the resist film 20 other than the portion covered with the mask 30 is removed.

(6) Protective film exposure part removal process The mask 30 is removed, and the back surface of the wafer 1 coated with the resist film 20 is exposed to a predetermined developer. Then, as shown in FIG. 5C, the exposed portion of the resist film 20 is dissolved and removed by the developer, and corresponds to the removed portion of the resist film 20 on the back surface of the wafer 1, that is, the opening 31 of the mask 30. The part to be exposed is exposed.

(7) Mechanical Damage Layer Formation Step As shown in FIG. 5D, sand blasting is performed by the sand blasting device 50 on the back surface of the wafer 1 where the non-exposed portion of the resist film 20 remains. In this case, the sandblasting uses alumina particles or silicon carbide particles equivalent to No. 2000 and having a particle size of about 4 to 5 μm as abrasive grains. The abrasive grains are mixed with a high-pressure fluid of air or water, and the back surface of the wafer 1 is used. For about 5 to 10 seconds. By this sandblasting, the portion where the resist film 20 on the back surface of the wafer 1 is removed is struck with abrasive grains to form a mechanical damage layer. Thereafter, the remaining resist film 20 is removed by exposure to a predetermined removal solution, and an elliptical mechanical damage layer 4 is formed at the center of the back surface of the semiconductor chip 3 as shown in FIG. Get a wafer 1.

(8) Division Step The resist film 20 is removed, then the protective tape 10 is removed, the wafer 1 is washed appropriately, and then all the streets 2 are cut and divided into individual semiconductor chips 3. As an apparatus for dividing the wafer 1 into the semiconductor chips 3, for example, a dicing apparatus as described in JP-A-2001-85365 can be used. As shown in FIG. 5F, the obtained semiconductor chip 3 has an elliptical mechanical damage layer 4 formed by sandblasting at the center of the back surface.

  According to the semiconductor chip 3 obtained by the above manufacturing method, the gettering effect can be obtained by the mechanical damage layer 4 formed in the central portion of the back surface. Further, since the mechanical damage is removed in the portion around the mechanical damage layer 4 on the back surface in the mechanical damage removal process, the region effective for maintaining the strength of the semiconductor chip 3 itself (reference numeral in FIG. 5 (f)). 5). As a result, both the gettering effect and strength maintenance can be obtained, and both strength and high performance can be achieved.

  Further, the mechanical damage layer 4 is formed at the center of the back surface, and the surrounding strength maintaining region 5 forms the outer peripheral portion of the semiconductor chip 3, so that it has high rigidity and resistance to external impacts and the like. As a result, the strength is improved. In particular, in the present embodiment, the mechanical damage layer 4 has an elliptical shape consisting of only a curve, so that stress is less likely to concentrate on the boundary between the mechanical damage layer 4 and the strength maintaining region 5 and the strength is further improved. It becomes.

  Note that the shape of the mechanical damage layer 4 (that is, the shape of the opening 31 of the mask 30) is not limited to the elliptical shape including only the curve as in the above embodiment, and the straight line shown in FIG. In addition, the shape may be an ellipse, or may be a perfect circle shown in FIG. 6B or a rectangle shown in FIG.

[2] Second Embodiment Next, a manufacturing method according to a second embodiment of the present invention will be described.
The manufacturing method of the second embodiment is the same from the grinding step to the mechanical damage removal step in the first embodiment, but the following protective film coating step is changed to the next step.

(1) Mask Covering Step As shown in FIGS. 7 and 8A, the mask 30 is formed on the back surface of the wafer 1 that has undergone the grinding step and the mechanical damage removal step in the same manner as in the second embodiment. As in the embodiment, the openings 31 are directly stacked on the back surface of the wafer 1 so that the openings 31 are located at the center of each region of the semiconductor chip 3 and are detachably mounted. FIG. 8 is a view similar to FIG. 5 showing a part of one semiconductor chip 3 in the wafer 1 and showing steps for the wafer 1 in the order of (a) to (d).

(2) Mechanical Damage Layer Forming Step As shown in FIG. 8B, sandblasting is performed on the back surface of the wafer 1 on which the mask 30 has been applied in the same manner as in the first embodiment. By this sandblasting, the exposed portion of the opening 30 of the mask 30 on the back surface of the wafer 1 is struck with abrasive grains, and a mechanical damage layer 4 is formed as shown in FIG.

(3) Dividing Step The mask 30 is removed, then the protective tape 10 is removed, the wafer 1 is washed appropriately, and then the wafer 1 is divided along all the streets 2 to obtain individual semiconductor chips 3. In the obtained semiconductor chip 3, as shown in FIG. 8D, an elliptical mechanical damage layer 4 is formed by sandblasting at the center of the back surface, and the periphery of the mechanical damage layer 4 is subjected to a grinding process. It remains as the strength maintaining region 5 from which the applied mechanical damage is removed.

  In the manufacturing method of the second embodiment described above, the coating of the resist film 20 on the back surface of the wafer 1 in the first embodiment is omitted, and the mask 30 is directly covered on the back surface of the wafer 1 to perform sandblasting and perform mechanical damage. The layer 4 is formed, and the process can be simplified as compared with the first embodiment.

[3] Third Embodiment Next, a manufacturing method according to a third embodiment of the present invention will be described.
(1) Grinding step As in the first embodiment, after the protective tape 10 is applied to the back surface of the wafer 1, the back surface of the wafer 1 is ground to thin the wafer 1 to a thickness as required. As shown in FIG. 9A, mechanical damage 6 is imparted to the entire back surface of the wafer 1 by grinding. FIG. 9 is a diagram showing a process for the wafer 1 in the order of (a) to (g) by extracting a portion of one semiconductor chip 3 in the wafer 1.

(2) Protective film coating step As shown in FIG. 9B, on the back surface of the ground wafer 1, a negative resist film 21 (non-exposed portion is soluble in a developer) used as a protective film by a photoresist method. The exposed portion remains) is applied by a generally known method such as spin coating.

(3) Mask Covering Step As shown in FIG. 9C, the resist film 21 is covered with the mask 30 in the same manner as in the first embodiment, and the opening 31 of the mask 30 is formed at the center of each region of the semiconductor chip 3. To be located.

(4) Exposure Step As shown in FIG. 9D, the exposure apparatus 40 exposes the back surface of the wafer 1 in which the resist film 21 is masked 30. In the resist film 21, an elliptical portion that is exposed at the opening 31 of the mask 30 at the center of the semiconductor chip 3 is exposed. Since the resist film 21 is a negative type as described above, it becomes a region where the non-exposed portion covered with the mask 30 is removed.

(5) Protective film non-exposed part removing step The mask 30 is removed, and the back surface of the wafer 1 coated with the resist film 21 is exposed to a predetermined developer. Then, as shown in FIG. 9 (e), the unexposed portion of the resist film 21 is dissolved and removed by the developer, and the resist film 21 is removed from the back surface of the wafer 1, that is, other than the opening 31 of the mask 30. The part corresponding to is exposed.

(6) Mechanical Damage Partially Remaining Step Mechanical damage remaining on the exposed portion by exposing a predetermined chemical etching solution to the back surface of the wafer 1 whose central portion on the back surface is protected by the elliptical resist film 21. 6 is removed. As a result, as shown in FIG. 9F, the mechanical damage layer 6 applied in the grinding process remains in an elliptical shape only in the central portion covered with the resist film 21. In this case, the chemical etching may be acid etching mainly containing hydrofluoric acid and nitric acid, or may be dry etching using a fluorine-based gas.

(7) Dividing Step The resist film 21 is dissolved and removed with a predetermined removing solution, then the protective tape 10 is removed, the wafer 1 is washed appropriately, and then all the streets 2 are cut to obtain individual semiconductor chips. Divide into three. As shown in FIG. 9G, the obtained semiconductor chip 3 has an elliptical mechanical damage layer 6 formed at the center of the back surface.

  In the manufacturing method of the third embodiment described above, the mechanical damage 6 applied in the grinding process is used as a mechanical damage layer for obtaining a gettering effect, and the mechanical damage layer is sandblasted again in a later process. Thus, there is an advantage that the labor of forming by such a method can be saved.

  The mask 30 used in the first and third embodiments is a mask used for partitioning an exposure region. Therefore, an exposure-only mask in which a light shielding paint is applied to a glass plate, such as a reticle, can be used instead of the metal as described above. Such an exposure-exclusive mask transmits light through a transparent portion that is not shade-painted, and the mask opening referred to in the present invention indicates the light-transmitting portion. On the other hand, the mask 30 in the second embodiment defines a sandblasting hitting area, and an opening 31 that is a space through which abrasive grains pass is essential. Therefore, an exposure-only mask such as a reticle cannot be used, A metal thin plate or the like in which an opening is opened is suitable.

BRIEF DESCRIPTION OF THE DRAWINGS (a) Whole top view (enlarged part is a semiconductor chip) of the wafer divided | segmented into a semiconductor chip in embodiment of this invention, (b) It is a side view. It is a side view of a wafer which shows a mask covering process from a grinding process of a semiconductor chip manufacturing method concerning a 1st embodiment in order of (a)-(d). It is a top view of a mask. It is a reverse view of the wafer with which the mask was mounted | worn. It is sectional drawing and a partial back view of a wafer which show from a mask covering process of a semiconductor chip manufacturing method concerning a 1st embodiment to a division process in order of (a)-(f). It is a back view of the semiconductor chip which shows the other example of a mechanical damage layer. It is a side view of the wafer with which the mask was mounted | worn at the mask coating | coated process which concerns on 2nd Embodiment of this invention. It is sectional drawing and a partial back view of a wafer which show from a mask covering process of a semiconductor chip manufacturing method concerning a 2nd embodiment to a division process in order of (a)-(d). It is sectional drawing and a partial back view of a wafer which show from a grinding process of a semiconductor chip manufacturing method concerning a 3rd embodiment to a division process in order of (a)-(g).

Explanation of symbols

1 ... Semiconductor wafer 2 ... Street (scheduled line)
3 ... Semiconductor chip (device)
4, 6 ... mechanical damage layer 5 ... strength maintaining area 20, 21 ... resist film (protective film)
DESCRIPTION OF SYMBOLS 30 ... Mask 31 ... Mask opening 40 ... Exposure apparatus 50 ... Sand blasting apparatus

Claims (7)

  A device having an electronic circuit formed on a surface thereof, wherein a mechanical damage layer is formed on a part of the back surface of the device.   The device according to claim 1, wherein the mechanical damage layer is formed in a central portion of the back surface.   The device according to claim 1, wherein the mechanical damage layer has a shape including a curve.   The device according to claim 1, wherein the mechanical damage layer has a shape consisting only of a curve. A method of manufacturing a device obtained by individually dividing a plurality of devices having electronic circuits formed on a surface thereof from a wafer partitioned by dividing lines,
A grinding step of grinding the back side of the wafer to a predetermined thickness;
A mechanical damage removing step for removing mechanical damage remaining on the back surface of the wafer;
A protective film coating step for coating a protective film on the entire back surface of the wafer;
A mask coating step of covering the protective film with a mask in which a part of each region corresponding to the device is opened; and
An exposure step of exposing a back surface of the wafer having the mask applied to the protective film;
Removing the exposed portion of the protective film and exposing the back surface of the wafer in that portion;
A mechanical damage layer forming step of forming a mechanical damage layer on the exposed portion of the back surface of the wafer;
A dividing step of dividing the wafer along the division line to obtain the device. A method of manufacturing a device obtained by individually dividing a plurality of devices having electronic circuits formed on a surface thereof from a wafer partitioned by dividing lines,
A grinding step of grinding the back side of the wafer to a predetermined thickness;
A mechanical damage removing step for removing mechanical damage remaining on the back surface of the wafer;
A mask coating step of coating a mask in which a part of each region corresponding to the device is opened on the back surface of the wafer;
A mechanical damage layer forming step of forming a mechanical damage layer on an exposed portion of the back surface of the wafer that is not covered with the mask;
A dividing step of dividing the wafer along the division line to obtain the device. A method of manufacturing a device obtained by individually dividing a plurality of devices having electronic circuits formed on a surface thereof from a wafer partitioned by dividing lines,
A grinding step of grinding the back side of the wafer to a predetermined thickness;
A protective film coating step for coating a protective film on the entire back surface of the wafer;
A mask coating step of covering the protective film with a mask in which a central region of each region corresponding to the device is opened;
An exposure step of exposing a back surface of the wafer having the mask applied to the protective film;
Removing the non-exposed portion of the protective film, and exposing the back surface of the wafer in that portion;
Removing mechanical damage remaining on the exposed portion of the back surface of the wafer, thereby leaving the mechanical damage imparted in the grinding step on the non-exposed portion;
And a dividing step of dividing the wafer along the scheduled dividing line to obtain the device.

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