SUBSTRATE PROCESSING METHOD AND SUBSTRATE PROCESSING SYSTEM

A substrate processing method of processing a processing target substrate having a device formed on a front surface thereof includes preparing, in a first separation substrate on a side with the device and a second separation substrate on a side without the device separated from a device substrate, the second separation substrate; and bonding, by reusing the second separation substrate, the second separation substrate to a processing target substrate. A substrate processing system configured to process the processing target substrate having the device formed on the front surface thereof includes a bonding device configured to bond, in the first separation substrate on the side with the device and the second separation substrate on the side without the device separated from the device substrate, the second separation substrate to the processing target substrate by reusing the second separation substrate.

TECHNICAL FIELD

The various aspects and embodiments described herein pertain generally to a substrate processing method and a substrate processing system.

BACKGROUND

Patent Document 1 discloses a manufacturing method for a semiconductor device. In this manufacturing method, a rear surface of a wafer is ground and the wafer is divided in a state that a front surface of the wafer is fixed to a support member. Then, by separating the support member from the wafer, a plurality of semiconductor chips is obtained. The support member has a thickness larger than a thickness of the wafer after being ground. For example, meanwhile the thickness of the wafer ranges from about 700 μm to about 800 μm, the thickness of the support member is in a range of about 1 mm to about 2 mm.

Patent Document 2 discloses a method of manufacturing semiconductor chips. In this manufacturing method, a rear surface of a wafer is ground and the wafer is mounted to a dicing frame in a state that a support member is attached to a front surface of the wafer. Then, by dividing the wafer after separating the support member from the wafer, a plurality of semiconductor chips is obtained.

PRIOR ART DOCUMENT

Patent Document 2: International Patent Publication No. 2003/049164

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

Exemplary embodiments provide a technique capable of reducing a cost in manufacturing a semiconductor device by bonding a substrate thinned by being separated to a processing target substrate to reuse the thinned substrate.

Means for Solving the Problems

In an exemplary embodiment, a substrate processing method of processing a processing target substrate having a device formed on a front surface thereof includes preparing, in a first separation substrate on a side with the device and a second separation substrate on a side without the device separated from a device substrate, the second separation substrate; and bonding, by reusing the second separation substrate, the second separation substrate to a processing target substrate.

Effect of the Invention

According to the exemplary embodiment, it is possible to reduce the cost in manufacturing the semiconductor device by bonding the substrate thinned by being separated to the processing target substrate to reuse the thinned substrate.

DETAILED DESCRIPTION

In a manufacturing process for a semiconductor device, a semiconductor wafer (hereinafter, simply referred to as a wafer) having a plurality of devices formed on a front surface thereof is thinned and diced in a state that a support substrate is attached to the front surface of the wafer. Then, by separating the support substrate from the wafer, semiconductor chips (hereinafter, simply referred to as chips) are produced.

The support substrate is temporarily attached to the wafer and separated from the wafer after a required processing is finished. Thus, from a viewpoint of cost reduction, it is desirable to use the support substrate repeatedly. In this regard, in order to further reduce the cost, the present inventors have come up with the idea of, when thinning the wafer, separating the wafer into a front side wafer having devices formed thereon and a rear side wafer to use the separated rear side wafer as a support wafer.

Further, in the methods described in the aforementioned Patent Documents 1 and 2, since the rear surface of the wafer is ground when thinning the wafer, it is difficult to reuse the separated rear side wafer, unlike in the present disclosure. Particularly, in Patent Document 1, since the thickness of the support substrate (support member) is larger than the thickness of the wafer, reusing the separated rear side wafer is not taken into account at all.

The present disclosure provides a technique of thinning a wafer by separating the wafer and reusing the separated wafer. Hereinafter, a wafer processing system as a substrate processing system and a wafer processing method as a substrate processing method according to exemplary embodiments will be described with reference to the accompanying drawings. In the present specification and the drawings, parts having substantially same functions and configurations will be assigned same reference numerals, and redundant description thereof will be omitted.

First, a configuration of the wafer processing system according to the present exemplary embodiment will be explained.FIG. 1is a plan view schematically illustrating a configuration of a wafer processing system1.

In the wafer processing system1, as shown inFIG. 2, a combined wafer T is formed by bonding a device wafer W as a processing target substrate (device substrate) and a reuse wafer S reused as a support wafer to each other with an adhesive tape B as an adhesive layer therebetween, and a required processing is performed on the combined wafer T. Hereinafter, in the device wafer W, a surface bonded to the reuse wafer S with the adhesive tape B therebetween will be referred to as a front surface Wa, and a surface opposite to the front surface Wa will be referred to as a rear surface Wb. Likewise, in the reuse wafer S, a surface bonded to the device wafer W with the adhesive tape B therebetween will be referred to as a front surface Sa, and a surface opposite to the front surface Sa will be referred to as a rear surface Sb.

The device wafer W is a semiconductor wafer such as, but not limited to, a silicon substrate, and a device layer (not shown) including a plurality of devices is formed on the front surface Wa thereof.

The reuse wafer S is a wafer that supports the device wafer W, and it may be, for example, a silicon wafer. Further, a second separation wafer W2separated from a previously processed device wafer W is used as the reuse wafer S, as will be described later.

In the wafer processing system1of the present exemplary embodiment, the device wafer W in the combined wafer T is separated. In the following description, the separated device wafer W on the front surface Wa side is referred to as a first separation wafer W1as a first separation substrate, as shown inFIG. 3A, and the separated device wafer W on the rear surface Wb side is referred to as a second separation wafer W2as a second separation substrate, as illustrated inFIG. 3B. The first separation wafer W1has the device layer and is divided into a plurality of chips to be produced as products. The second separation wafer W2is used as the reuse wafer S, as will be described later. In addition, a separated surface in the first separation wafer W1is referred to as a separation surface W1a,that is, the separation surface W1ais a surface opposite to the front surface Wa. Further, a separated surface in the second separation wafer W2is referred to as a separation surface W2a,that is, the separation surface W2ais a surface opposite to the rear surface Wb.

Further, in the wafer processing system1, a die attach film (DAF) D and a dicing tape P are attached to the device wafer W (the first separation wafer W1) to fix the device wafer W to a dicing frame F, as shown inFIG. 3A, and a required processing is performed on the fixed device wafer W.

The die attach film D has adhesiveness on both sides thereof, and serves to bond first separation wafers W1when stacking the first separation wafers W1on top of each other. The dicing tape P has adhesiveness only on one surface, and the die attach film D is stuck to the corresponding one adhesive surface. The dicing frame F fixes the dicing tape P attached to the first separation wafer W1with the die attach film D therebetween.

As depicted inFIG. 1, the wafer processing system1is equipped with a bonding apparatus10configured to bond the device wafer W and the reuse wafer S, and a wafer processing apparatus20configured to perform a required processing on the combined wafer T after being bonded. Further, an apparatus configuration in the wafer processing system1is not particularly limited. For example, a module of the bonding apparatus10and a module of the wafer processing apparatus20may be respectively disposed in other apparatuses.

In addition, the wafer processing system1is provided with a control device30. The control device30is, for example, a computer having a CPU, a memory, or the like, and has a program storage (not shown). The program storage stores therein a program for controlling the wafer processing in the wafer processing system1. Further, the program storage also stores therein a program for implementing the wafer processing in the wafer processing system1by controlling operations of various kinds of processing apparatuses and a driving system such as transfer devices. Furthermore, the program may be recorded on a computer-readable recording medium H and installed from the recording medium H to the control device30.

The bonding apparatus10has a configuration in which a carry-in/out station40and a processing station41are connected as one body. The carry-in/out station40and the processing station41are arranged side by side from the negative X-axis side toward the positive X-axis side. In the carry-in/out station40, cassettes Cw, Cs and Ct respectively capable of accommodating therein a plurality of device wafers W, a plurality of reuse wafers S, and a plurality of combined wafers T are carried to/from the outside, for example. The processing station41is equipped with various kinds of processing apparatuses configured to perform required processings on the device wafers W, the reuse wafers S and the combined wafers T.

A cassette placing table50is provided in the carry-in/out station40. In the shown example, a plurality of, e.g., three cassettes Cw, Cs and Ct may be arranged on the cassette placing table50in a row in the Y-axis direction. Further, the number of the cassettes Cw, Cs and Ct placed on the cassette placing table50is not limited to the example of the present exemplary embodiment but may be selected as required.

In the carry-in/out station40, a wafer transfer section60is provided adjacent to the cassette placing table50on the positive X-axis side of the cassette placing table50. Provided in the wafer transfer section60is a wafer transfer device62configured to be movable on a transfer path61extending in the Y-axis direction. The wafer transfer device62is equipped with two transfer arms63configured to hold and transfer the device wafer W, the reuse wafer S and the combined wafer T. Each transfer arm63is configured to be movable in a horizontal direction and a vertical direction and pivotable around a horizontal axis and a vertical axis. Further, the configuration of the transfer arm63is not limited to the present exemplary embodiment, and various other configurations may be adopted. The wafer transfer device62is configured to be capable of transferring the device wafer W, the reuse wafer S and the combined wafer T to/from the cassettes Cw, Ct and Ct of the cassette placing table50and an adhesive layer forming module70and a bonding module71to be described later.

In the processing station41, the adhesive layer forming module70and the bonding module71as a bonding device are arranged in the Y-axis direction on the positive X-axis side of the wafer transfer section60. The number and the layout of these modules70and71are not limited to the example of the present exemplary embodiment but may be selected as required.

In the adhesive layer forming module70, the adhesive tape B is attached to the front surface Wa of the device wafer W. Further, in the adhesive layer forming module70, the adhesive tape B may be attached to the front surface Sa of the reuse wafer S. As the adhesive layer forming module70, a commonly known apparatus may be used.

In the bonding module71, the device wafer W and the reuse wafer S are bonded. For example, in the bonding module71, the device wafer W and the reuse wafer S are pressed and bonded to each other with the adhesive tape B therebetween. As the bonding module71, a commonly known apparatus may be used.

The wafer processing apparatus20has a configuration in which a carry-in/out station80and a processing station81are connected as one body. The carry-in/out station80and the processing station81are arranged from the negative X-axis side toward the positive X-axis side. In the carry-in/out station80, cassettes Ct, Cw1and Cw2respectively capable of accommodating therein a plurality of combined wafers T, a plurality of first separation wafers W1and a plurality of second separation wafers W are carried to/from the outside, for example. The processing station81is equipped with various kinds of processing apparatuses configured to perform required processings on the combined wafers T and the separation wafers W1and W2.

Further, although the cassette Ct and the cassette Cw1are provided separately, they may be the same one. That is, a single cassette may be used to accommodate both the combined wafers T before being processed and the first separation wafers W1after being processed.

A cassette placing table90is provided in the carry-in/out station80. In the shown example, a plurality of, for example, three cassettes Ct, Cw1and Cw2can be arranged on the cassette placing table90in a row in the Y-axis direction. Further, the number of the cassettes Ct, Cw1and Cw2placed on the cassette placing table90is not limited to the example of the present exemplary embodiment but may be selected as required.

In the carry-in/out station80, a wafer transfer section100is provided adjacent to the cassette placing table90on the positive X-axis side of the cassette placing table90. Provided in the wafer transfer section100is a wafer transfer device102configured to be movable on a transfer path101extending in the Y-axis direction. The wafer transfer device102is equipped with two transfer arms103configured to hold and transfer the combined wafer T, the separation wafer W1and the separation wafer W2. Each transfer arm103is configured to be movable in the horizontal direction and the vertical direction and pivotable around a horizontal axis and a vertical axis. Further, the configuration of the transfer arm103is not limited to the present exemplary embodiment, and various other configurations may be adopted. The wafer transfer device102is configured to be capable of transferring the combined wafer T and the separation wafers W1and W2to/from the cassettes Ct, Cw1and Cw2of the cassette placing table90and a transition device110to be described later.

In the carry-in/out station80, the transition device110configured to transfer the combined wafer T and the separation wafers W1and W2are provided adjacent to the wafer transfer section100on the positive X-axis side of the wafer transfer section100.

In the processing station81, a wafer transfer section120, a first processing block130, and a second processing block140are provided. The first processing block130is disposed on the positive Y-axis side of the wafer transfer section120, and the second processing block140is disposed on the negative Y-axis side of the wafer transfer section120.

A wafer transfer device122configured to be movable on a transfer path121extending in the X-axis direction is provided in the wafer transfer section120. The wafer transfer device122is equipped with two transfer arms123configured to hold and transfer the combined wafer T, the separation wafer W1and the separation wafer W2. Each transfer arm123is configured to be movable in the horizontal direction and the vertical direction and pivotable around a horizontal axis and a vertical axis. Further, the configuration of the transfer arm123is not limited to the present exemplary embodiment, and various other configurations may be adopted. The wafer transfer device122is configured to be capable of transferring the combined wafer T and the separation wafers W1and W2to/from the transition device110and various processing modules of the first processing block130and the second processing block140.

In the first processing block130, a modifying module131, a separating module132as a separating device, a grinding module133as a grinding device, an inverting module134, a cleaning module135, and an etching module136as an etching device are arranged in the X-axis direction. The number and the layout of these modules131to136are not limited to the example of the present exemplary embodiment but may be selected as required.

In the modifying module131, a modification layer is formed by radiating laser light to an inside of the device wafer W. As the laser light, one having a wavelength featuring transmissivity for the device wafer W is used. The modification layer is formed along the separation surface W1aof the first separation wafer W1and the separation surface W2aof the second separation wafer W2. In addition, a configuration of the modifying module131is not particularly limited.

In the separating module132, the device wafer W is separated into the first separation wafer W1and the second separation wafer W2, starting from the modification layer formed in the modifying module131. For example, in the separating module132, while keeping the first separation wafer W1and the second separation wafer W2respectively attracted to and held by chucks (not shown), a blade having, for example, a wedge shape (not shown) is inserted to separate the first separation wafer W1and the second separation wafer W2along the separation surfaces W1aand W2aas a boundary. Thereafter, the first separation wafer W1and the second separation wafer W2are separated by moving the chucks away. In addition, a configuration of the separating module132is not particularly limited.

In the grinding module133, the separation surface W1aof the first separation wafer W1or the separation surface W2aof the second separation wafer W2is ground. As the grinding module133, a commonly known apparatus may be used.

In the inverting module134, a front surface and a rear surface of the first separation wafer W1or the second separation wafer W2separated by the separating module132are inverted. As the inverting module134, a commonly known apparatus may be used.

In the cleaning module135, the separation surface W1aof the first separation wafer W1or the separation surface W2aof the second separation wafer W2is scrub-cleaned. As the cleaning module135, a commonly known apparatus may be used.

In the etching module136, the separation surface W1aof the first separation wafer W1or the separation surface W2aof the second separation wafer W2is etched. As the etching module136, a commonly known apparatus may be used.

In the second processing block140, an attaching module141as an attaching device, a dicing module142as a dicing device, a fixing module143as a fixing device, a separating module144as a separating device, and an adhesive layer removing module145are arranged in the X-axis direction. The number and the layout of these modules141to145are not limited to the example of the present exemplary embodiment but may be selected as required.

In the attaching module141, a mounting processing of attaching the die attach film D to the separation surface W1aof the first separation wafer W1is performed. As the attaching module141, a commonly known apparatus may be used.

In the dicing module142, the die attach film D or the first separation wafer W1is diced by using laser lights. The laser light used for the dicing of the die attach film D and the laser light used for the dicing of the first separation wafer W1are different in their specifications. A configuration of the dicing module142is not particularly limited. For example, different laser lights may be radiated from a single laser head, or the different laser lights may be radiated respectively from different laser heads.

In the fixing module143, a mounting processing of attaching the dicing tape P to the first separation wafer W1supported by the reuse wafer S and fixing the first separation wafer W1to the dicing frame F is performed. As the fixing module143, a commonly known apparatus may be used.

In the separating module144, the reuse wafer S is separated from the first separation wafer W1. As the separating module144, a commonly known apparatus may be used.

In the adhesive layer removing module145, the adhesive tape B remaining on the front surface Wa of the first separation wafer W1is removed by being separated. As the adhesive layer removing module145, a commonly known apparatus may be used.

Now, a wafer processing according to a first exemplary embodiment performed in the wafer processing system1having the above-described configuration will be explained. FIG.4is a flowchart illustrating main processes of the wafer processing according to the first exemplary embodiment.FIG. 5AtoFIG. 5Pare explanatory diagrams schematically illustrating individual processes of the wafer processing according to the first exemplary embodiment.FIG. 6AtoFIG. 6Dare explanatory diagrams schematically illustrating some of the processes of the wafer processing according to the first exemplary embodiment, when viewed from the side.

First, in the bonding apparatus10, the cassettes Cw and Cs respectively accommodating therein the plurality of device wafers W and the plurality of reuse wafers S as shown inFIG. 5Aare placed on the cassette placing table50of the carry-in/out station40.

Then, the device wafer W in the cassette Cw is taken out by the wafer transfer device62and transferred into the adhesive layer forming module70. In the adhesive layer forming module70, the adhesive tape B is attached to the front surface Wa of the device wafer W.

Next, the device wafer W is transferred into the bonding module71by the wafer transfer device62. Then, the reuse wafer S in the cassette Cs is also taken out by the wafer transfer device62and transferred into the bonding module71. In the bonding module71, the device wafer W and the reuse wafer S are pressed and bonded with the adhesive tape B therebetween, as illustrated inFIG. 5B(process A1ofFIG. 4).

Then, the combined wafer T in which the device wafer W and the reuse wafer S are bonded to each other is transferred into the cassette Ct on the cassette placing table50by the wafer transfer device62. In this way, the series of operations of the bonding processing in the bonding apparatus10are completed.

Thereafter, the cassette Ct accommodating therein the plurality of combined wafers T is carried out of the carry-in/out station40and transferred into the wafer processing apparatus20. In the wafer processing apparatus20, the cassette Ct is placed on the cassette placing table90of the carry-in/out station80.

Subsequently, the combined wafer T in the cassette Ct is taken out by the wafer transfer device102and transferred into the transition device110. Then, the combined wafer T is taken out of the transition device110by the wafer transfer device122and transferred into the modifying module131. In the modifying module131, laser light is radiated to an inside of the device wafer W, so that a modification layer M is formed as shown inFIG. 5C(process A2ofFIG. 4).

In the process A2, a peripheral modification layer M1and an internal modification layer M2are formed as the modification layer M, as shown inFIG. 6A. The peripheral modification layer M1is formed in an annular shape and serves as a starting point when a peripheral portion We of the device wafer W is removed in edge trimming. The edge trimming is a process of suppressing the peripheral portion We of the device wafer W from having a sharply pointed shape (so-called knife edge shape) after the device wafer W is separated as will be described later. Further, the internal modification layer M2serves as a starting point of separating and thinning the device wafer W. The internal modification layer M2is formed along a plane direction of the device wafer W to extend from a central portion of the device wafer W to the peripheral modification layer Ml.

Thereafter, the combined wafer T is transferred into the separating module132by the wafer transfer device102. In the separating module132, the device wafer W in the combined wafer T is separated into the first separation wafer W1and the second separation wafer W2, as illustrated inFIG. 5D(process A3inFIG. 4).

In the process A3, the device wafer W is separated into the first separation wafer W1and the second separation wafer W2, starting from the peripheral modification layer M1and the internal modification M2, as illustrated inFIG. 6B. At this time, the peripheral portion We is integrated with the second separation wafer W2and removed from the first separation wafer W1.

The first separation wafer W1and the second separation wafer W2separated in the separating module132are subjected to subsequent processings individually.

The second separation wafer W2is transferred into the inverting module134by the wafer transfer device122. In the inverting module134, a front surface and a rear surface of the second separation wafer W2are inverted (process A4ofFIG. 4). That is, in the inverting module134, the separation surface W2aof the second separation wafer W2is turned to face upwards.

Then, the second separation wafer W2is transferred into the cleaning module135by the wafer transfer device122. In the cleaning module135, the separation surface W2aof the second separation wafer W2is scrub-cleaned (process A5ofFIG. 4).

Then, the second separation wafer W2is transferred into the etching module136by the wafer transfer device122. In the etching module136, the separation surface W2aof the second separation wafer W2is wet-etched by an etching liquid, as shown inFIG. 5E(process A6ofFIG. 4). By this etching, the peripheral modification layer M1and the internal modification layer M2remaining on the separation surface W2aare removed.

Then, the second separation wafer W2is transferred into the grinding module133by the wafer transfer device122. In the grinding module133, the separation surface W2aof the second separation wafer W2is ground, as shown inFIG. 5F(process A7ofFIG. 4). By this grinding, a protruding outer peripheral portion of the separation surface W2ais removed, as shown inFIG. 6C.

Next, the second separation wafer W2is transferred into the cleaning module135by the wafer transfer device122. In the cleaning module135, the separation surface W2aof the second separation wafer W2is scrub-cleaned (process A8ofFIG. 4).

Then, the second separation wafer W2is transferred into the etching module136by the wafer transfer device122. In the etching module136, the separation surface W2aof the second separation wafer W2is wet-etched by an etching liquid, as illustrated inFIG. 5G(process A9ofFIG. 4). By this etching, grinding marks left on the separation surface W2aare removed.

Thereafter, the second separation wafer W2after being subjected to all the required processings is transferred into the transition device110by the wafer transfer device122, and then transferred into the cassette Cw2on the cassette placing table90by the wafer transfer device102.

The second separation wafer W2after being subjected to the above-described processings has a thickness of, e.g., 400 μm to 700 μm. Thus, the second separation wafer W2is reused as a reuse wafer S for a device wafer W to be processed next. That is, as shown inFIG. 5AandFIG. 5B, the second separation wafer W2is bonded to the device wafer W to be processed next and functions as the support wafer.

As described above, in parallel with the processes A4to A9being performed on the second separation wafer W2, required processings are performed on the first separation wafer W1.

The first separation wafer W1is transferred into the grinding module133by the wafer transfer device122. In the grinding module133, the separation surface W1aof the first separation wafer W1is ground, as shown inFIG. 5H(process A10ofFIG. 4). By this grinding, the first separation wafer W1is thinned to a required thickness, as illustrated inFIG. 6D.

Subsequently, the first separation wafer W1is transferred into the cleaning module135by the wafer transfer device122. In the cleaning module135, the separation surface W1aof the first separation wafer W1is scrub-cleaned (process A11ofFIG. 4).

Then, the first separation wafer W1is transferred into the etching module136by the wafer transfer device122. In the etching module136, the separation surface W1aof the first separation wafer W1is wet-etched by the etching liquid, as shown inFIG. 5I(process Al2ofFIG. 4). By this etching, the peripheral modification layer M1, the internal modification layer M2and grinding marks remaining on the separation surface W1aare removed.

Next, the first separation wafer W1is transferred into the attaching module141by the wafer transfer device122. In the attaching module141, the die attach film D is attached to the separation surface W1aof the first separation wafer W1, as shown inFIG. 5J(process A13ofFIG. 4).

Thereafter, the first separation wafer W1is transferred into the dicing module142by the wafer transfer device122. In the dicing module142, by radiating laser light to the die attach film D, the die attach film D is diced, as shown inFIG. 5K(process A14ofFIG. 4).

Subsequently, by radiating laser light to the first separation wafer W1in the same dicing module142, the first separation wafer W1is also diced, as shown inFIG. 5L(process A15ofFIG. 4).

Then, the first separation wafer W1is transferred into the fixing module143by the wafer transfer device122. In the fixing module143, the dicing tape P is further attached to the die attach film D attached to the front surface Wa of the first separation wafer W1, as shown inFIG. 5M. Then, the first separation wafer W1is fixed to the dicing frame F with the dicing tape P therebetween (process A16ofFIG. 4).

Afterwards, the first separation wafer W1is transferred into the inverting module134by the wafer transfer device122. In the inverting module134, the front surface and the rear surface of the first separation wafer W1(combined wafer T) are inverted (process A17ofFIG. 4).

Thereafter, the first separation wafer W1is transferred into the separating module144by the wafer transfer device122. In the separating module144, the reuse wafer S is separated from the first separation wafer W1, as shown inFIG. 5N(process A18ofFIG. 4).

Then, the first separation wafer W1is transferred into the adhesive layer removing module145by the wafer transfer device122. In the adhesive layer removing module145, the adhesive tape B is removed from the front surface Wa of the first separation wafer W1, as shown inFIG. 5O(process A19ofFIG. 4).

Thereafter, the first separation wafer W1after being subjected to all the required processings is transferred into the transition device110by the wafer transfer device122, and is then transferred into the cassette Cw1on the cassette placing table90by the wafer transfer device102. At this time, when the cassette Ct is empty, the first separation wafer W1may be transferred into the cassette Ct. In this way, the series of processes of the wafer processing in the wafer processing system1are completed.

Through the above-described processes, chips C are manufactured. Then, the chips C are die-bonded at an outside of the wafer processing system1, as shown inFIG. 5P.

According to the above-described first exemplary embodiment, the device wafer W is separated into the first separation wafer W1and the second separation wafer W2. Then, the first separation wafer W1is divided into the chips C to be produced as the products. Meanwhile, the second separation wafer W2is bonded to a device wafer W to be processed next, and is reused as the reuse wafer S. Then, the reuse wafer S, which is the reused second separation wafer W2, can be repeatedly used for subsequent processings of the device wafer W.

Here, conventionally, a BG tape or a support wafer (not a reuse wafer but a newly prepared support wafer), for example, has been used as a support member for the device wafer W. In this case, a cost for preparing the support member is required. In the first exemplary embodiment, however, since the second separation wafer W2is reused as the reuse wafer S for the device wafer W, the cost can be reduced.

Further, according to the first exemplary embodiment, since the device wafer W is subjected to the required processings after the device wafer W is bonded to the reuse wafer S, these processings can be performed stably. Further, the required processing such as etching can be performed on the thinned device wafer W (the first separation wafer W1) as well.

Further, according to the first exemplary embodiment, since the separation surface W1a of the first separation wafer W1is ground in the process A10after the device wafer W is separated into the first separation wafer W1and the second separation wafer W2in the process A3, the amount of the grinding can be reduced. That is, the grinding of the separation surface W1a can be simplified. Furthermore, if the first separation wafer W1is etched to a required thickness in the process AU, the grinding in the process A10may be omitted.

Further, in the above-described first exemplary embodiment, although the device wafer W is separated into the first separation wafer W1and the second separation wafer W2by performing the processes A2and A3, the rear surface Wb of the device wafer W may be ground. In this case, the process A10is performed instead of the processes A2and A3shown inFIG. 4, and the subsequent processes A11to A19are performed. Further, since the device wafer W is ground, the processes A4to A9are omitted. Additionally, in the wafer processing system1, it may be also possible to omit the modifying module131and the separating module132.

Now, a wafer processing according to a second exemplary embodiment will be discussed.FIG. 7is a flowchart illustrating main processes of the wafer processing according to the second exemplary embodiment.FIG. 8AtoFIG. 8Pare explanatory diagrams schematically illustrating individual processes of the wafer processing according to the second exemplary embodiment. In the wafer processing according to the second exemplary embodiment as well, the wafer processing system1shown inFIG. 1is used.

In the wafer processing of the second exemplary embodiment, processes B1to B9inFIG. 7, which are the same as the processes A1to A9of the wafer processing of the first exemplary embodiment, are performed in sequence. That is, the bonding of the device wafer W and the reuse wafer S in the process B1shown inFIG. 8AandFIG. 8B, the formation of the modification layer M (the peripheral modification layer M1and the internal modification layer M2) in the device wafer W in the process B2shown inFIG. 8C, and the separation of the device wafer W in the process B3shown inFIG. 8Dare carried out sequentially.

Further, the processes B4to B9are performed on the second separation wafer W2after being separated. That is, the inversion of the second separation wafer W2in the process B4, the scrub-cleaning of the separation surface W2ain the process B5, and the etching of the separation surface W2ain the process B6shown inFIG. 8Eare performed sequentially. Thereafter, the grinding of the separation surface W2ain the process B7shown inFIG. 8F, the scrub-cleaning of the separation surface W2ain the process B8, and the etching of the separation surface W2ain the process B9shown inFIG. 8Gare carried out sequentially. Then, the second separation wafer W2after being subjected to all the required processings is transferred to the cassette Cw2.

As mentioned above, since the processes B1to B9are the same as the processes A1to A9of the first exemplary embodiment, description of the processes B1to B9will be omitted here. The wafer processing of the second exemplary embodiment is different from the wafer processing of the first exemplary embodiment in processing the separated first separation wafer W1, as will be described below. Specifically, a timing for performing the dicing of the first separation wafer W1is different.

The first separation wafer W1is transferred into the grinding module133by the wafer transfer device122. In the grinding module133, the separation surface W1aof the first separation wafer W1is ground as shown inFIG. 8H(process1310ofFIG. 7).

Then, the first separation wafer W1is transferred into the dicing module142by the wafer transfer device122. In the dicing module142, laser light is radiated to the first separation wafer W1, so that the first separation wafer W1is diced, as shown inFIG. 8I(process B11ofFIG. 7).

Subsequently, the first separation wafer W1is transferred into the etching module136by the wafer transfer device122. In the etching module136, the separation surface W1a of the first separation wafer W1is wet-etched by an etching liquid, as shown inFIG. 8J(process B12ofFIG. 7).

Next, the first separation wafer W1is transferred into the attaching module141by the wafer transfer device122. In the attaching module141, the die attach film D is attached to the separation surface W1a of the first separation wafer W1, as shown inFIG. 8K(process1313ofFIG. 7).

Subsequently, the first separation wafer W1is transferred into the dicing module142by the wafer transfer device122. In the dicing module142, laser light is radiated to the die attach film D, so that the die attach film D is diced, as shown inFIG. 8L(process B14ofFIG. 7).

Then, the first separation wafer W1is transferred into the fixing module143by the wafer transfer device122. In the fixing module143, the dicing tape P is further attached to the die attach film D which is attached to the front surface Wa of the first separation wafer W1, as shown inFIG. 8M. Then, the first separation wafer W1is fixed to the dicing frame F via the dicing tape P (process B15ofFIG. 7).

Subsequently, the first separation wafer W1is transferred into the inverting module134by the wafer transfer device122. In the inverting module134, the front and rear surfaces of the first separation wafer W1(combined wafer T) are inverted (process B16ofFIG. 7).

Then, the first separation wafer W1is transferred into the separating module144by the wafer transfer device122. In the separating module144, the reuse wafer S is separated from the first separation wafer W1, as shown inFIG. 8N(process B17ofFIG. 7).

Thereafter, the first separation wafer W1is transferred into the adhesive layer removing module145by the wafer transfer device122. In the adhesive layer removing module145, the adhesive tape B is removed from the front surface Wa of the first separation wafer W1, as shown inFIG. 8O(process B18ofFIG. 7).

Afterwards, the first separation wafer W1after being subjected to all the required processings is transferred to the cassette Cw1. Through the above-described processes, chips C are manufactured. Then, the chips C are die-bonded as shown inFIG. 8Pat the outside the wafer processing system1.

In the above-described second exemplary embodiment, the same effects as those of the first exemplary embodiment can be achieved.

Further, in the second exemplary embodiment as described above, the device wafer W is separated into the first separation wafer W1and the second separation wafer W2by performing the processes B2and B3. However, the rear surface Wb of the device wafer W may be ground, the same as in the first exemplary embodiment. In this case, the process B10is performed instead of the processes B2and B3shown inFIG. 7, and the subsequent processes B11to B18are performed. Further, since the device wafer W is ground, the processes B4to B9are omitted.

Now, a wafer processing according to a third exemplary embodiment will be described. In the wafer processings in the first and second exemplary embodiments described above, the dicing of the first separation wafer W1is performed after the device wafer W bonded to the reuse wafer S is separated. In the third exemplary embodiment, however, the device wafer W before being bonded to the reuse wafer S is diced.

For the purpose, in performing the wafer processing according to the third exemplary embodiment, a dicing apparatus150shown inFIG. 9is provided. The dicing apparatus150is provided in the wafer processing system1shown inFIG. 1. An operation of the dicing apparatus150is controlled by the control device30.

As shown inFIG. 9, the dicing apparatus150has a configuration in which a carry-in/out station160and a processing station161are connected as one body. The carry-in/out station160and the processing station161are arranged from the negative X-axis side toward the positive X-axis side. In the carry-in/out station160, cassettes Cw each capable of accommodating therein a plurality of device wafers W are carried to/from the outside, for example. The processing station161is equipped with various kinds of processing apparatuses configured to perform required processings on the device wafer W.

A cassette placing table170is provided in the carry-in/out station160. In the shown example, a plurality of, e.g., three cassettes Cw may be arranged on the cassette placing table170in a row in the Y-axis direction. Further, the number of the cassettes Cw placed on the cassette placing table170is not limited to the example of the present exemplary embodiment but may be selected as required.

In the carry-in/out station160, a wafer transfer section180is provided adjacent to the cassette placing table170on the positive X-axis side of the cassette placing table170. Provided in the wafer transfer section180is a wafer transfer device182which is configured to be movable on a transfer path181extending in the Y-axis direction. The wafer transfer device182is equipped with two transfer arms183each of which is configured to hold and transfer the device wafer W. Each transfer arm183is configured to be movable in the horizontal direction and the vertical direction and pivotable around a horizontal axis and a vertical axis. Further, the configuration of the transfer arm183is not limited to the present exemplary embodiment, and various other configurations may be adopted. The wafer transfer device182is configured to be capable of transferring the device wafer W to/from the cassettes Cw of the cassette placing table170and a protective layer forming module190, a dicing module191and a protective layer removing module192to be described later.

In the processing station161, the protective layer forming module190as a protective layer forming device, the dicing module191as a dicing device, and the protective layer removing module192as a protective layer removing device are arranged in the Y-axis direction on the positive X-axis side of the wafer transfer section180. Here, the number and the layout of these modules190to192are not limited to the example of the present exemplary embodiment, and may be selected as required.

In the protective layer forming module190, a protective agent is spin-coated on the front surface Wa of the device wafer W to form a protective film as a protective layer. A commonly known apparatus may be used as the protective layer forming module190.

In the dicing module191, the device wafer W is diced by using laser light. A configuration of the dicing module191is the same as that of the dicing module142described above, and a commonly known apparatus may be used as the dicing module191.

In the protective layer removing module192, the protective film is removed from the front surface Wa of the device wafer W, and the front surface Wa is cleaned by spinning. In addition, a commonly known apparatus may be used as the protective layer removing module192.

Now, the wafer processing according to the third exemplary embodiment performed in the wafer processing system1configured as described above will be explained.FIG. 10is a flowchart showing main processes of the wafer processing according to the third exemplary embodiment.FIG. 11AtoFIG. 12Sare explanatory diagrams schematically illustrating individual processes of the wafer processing according to the third exemplary embodiment.FIG. 11AtoFIG. 11Hshow the wafer processing up to a process of separating the device wafer W, andFIG. 12ItoFIG. 12Sshow the wafer processing after the separating of the device wafer W.

First, in the dicing apparatus150, the cassette Cw accommodating therein the plurality of device wafers W as shown inFIG. 11Ais placed on the cassette placing table170of the carry-in/out station160.

Next, the device wafer W in the cassette Cw is taken out by the wafer transfer device182and transferred into the protective layer forming module190. In the protective layer forming module190, the protective agent is spin-coated on the front surface Wa of the device wafer W, so that a protective film L is formed, as shown inFIG. 11B(process C1ofFIG. 10).

Thereafter, the device wafer W is transferred into the dicing module191by the wafer transfer device182. In the dicing module191, laser light is radiated to the device wafer W, so that the device wafer W is diced, as shown inFIG. 11C(process C2ofFIG. 10). In this dicing, the device layer formed on the device wafer W is protected by the protective film L.

Then, the device wafer W is transferred into the protective layer removing module192by the wafer transfer device182. In the protective layer removing module192, a solvent of the protective film L is supplied onto the front surface Wa of the device wafer W, so that the protective film L is removed, as shown inFIG. 11D(process C3ofFIG. 10).

Subsequently, the device wafer W is transferred into the cassette Cw of the cassette placing table170by the wafer transfer device182. In this way, the series of processes of the dicing processing in the dicing apparatus150are completed.

Thereafter, the cassette Cw accommodating the plurality of device wafers W is carried out of the carry-in/out station160, and is then transferred into the bonding apparatus10. In the bonding apparatus10, the cassette Cw is placed on the cassette placing table50of the carry-in/out station40. Moreover, in the bonding apparatus10, the cassette Cs accommodating the plurality of reuse wafers S as shown inFIG. 11Eis also placed on the cassette placing table50of the carry-in/out station40.

In the bonding apparatus10, after the adhesive tape B is attached to the front surface Wa of the device wafer W in the adhesive layer forming module70, the device wafer W and the reuse wafer S are pressed and bonded to each other with the adhesive tape B therebetween in the bonding module71, as shown inFIG. 11F(process C4ofFIG. 10). Further, since the process C4is the same as the process A1of first exemplary embodiment, description thereof will be omitted here.

Thereafter, the cassette Ct accommodating therein the plurality of combined wafers T is carried out of the carry-in/out station40and transferred into the wafer processing apparatus20. In the wafer processing apparatus20, processes C5to C12ofFIG. 10, which are the same as the processes A2to A9of the wafer processing of the first exemplary embodiment, are performed in sequence. That is, the formation of the modification layer M (the peripheral modification layer M1and the internal modification layer M2) in the device wafer W in the process C5shown inFIG. 11G, and the separation of the device wafer W in the process C6shown inFIG. 11Hare performed in sequence.

Further, the processes C7to C12are performed on the second separation wafer W2after being separated. That is, the inversion of the second separation wafer W2in the process C7, scrub-cleaning of the separation surface W2ain the process C8, and the etching of the separation surface W2ain the process C9shown inFIG. 12Iare performed sequentially. Subsequently, the grinding of the separation surface W2ain the process C10shown inFIG. 12J, the scrub-cleaning of the separation surface W2ain the process C11, and the etching of the separation surface W2ain the process C12shown inFIG. 12Kare performed sequentially. Then, the second separation wafer W2after being subjected to all the required processings is transferred to the cassette Cw2.

Here, as mentioned above, since the processes C5to C12are the same as the processes A2to A9of the first exemplary embodiment, redundant description thereof will be omitted.

The first separation wafer W1is transferred into the grinding module133by the wafer transfer device122. In the grinding module133, the separation surface W1aof the first separation wafer W1is ground as shown inFIG. 12L(process C13ofFIG. 10).

Then, the first separation wafer W1is transferred into the etching module136by the wafer transfer device122. In the etching module136, the separation surface W1aof the first separation wafer W1is wet-etched by the etching liquid, as shown inFIG. 12M(process C14ofFIG. 10).

Subsequently, the first separation wafer W1is transferred into the attaching module141by the wafer transfer device122. In the attaching module141, the die attach film D is attached to the separation surface W1aof the first separation wafer W1, as shown inFIG. 12N(process C15ofFIG. 10).

Next, the first separation wafer W1is transferred into the dicing module142by the wafer transfer device122. In the dicing module142, laser light is radiated to the die attach film D, so that the die attach film D is diced, as shown inFIG. 12O(process C16ofFIG. 10).

Then, the first separation wafer W1is transferred to the fixing module143by the wafer transfer device122. In the fixing module143, the dicing tape P is further attached to the die attach film D which is attached to the front surface Wa of the first separation wafer W1, as shown inFIG. 12P. Then, the first separation wafer W1is fixed to the dicing frame F with the dicing tape P therebetween (process C17ofFIG. 10).

Subsequently, the first separation wafer W1is transferred into the inverting module134by the wafer transfer device122. In the inverting module134, the front and rear surfaces of the first separation wafer W1(combined wafer T) are inverted (process C18ofFIG. 10).

Next, the first separation wafer W1is transferred into the separating module144by the wafer transfer device122. In the separating module144, the reuse wafer S is separated from the first separation wafer W1, as shown inFIG. 12Q(process C19ofFIG. 10).

Then, the first separation wafer W1is transferred into the adhesive layer removing module145by the wafer transfer device122. In the adhesive layer removing module145, the adhesive tape B is removed from the front surface Wa of the first separation wafer W1, as shown inFIG. 12R(process C20ofFIG. 10).

Thereafter, the first separation wafer W1after being subjected to all the required processings is transferred into the cassette Cw1. Through the above-described processes, chips C are manufactured. Then, the chips C are die-bonded at the outside of the wafer processing system1, as shown inFIG. 12S.

In the above-described third exemplary embodiment, the same effects as those of the first exemplary embodiment may be obtained.

Further, in the above-described third exemplary embodiment, although the device wafer W is separated into the first separation wafer W1and the second separation wafer W2by performing the processes C5and C6, the rear surface Wb of the device wafer W may be ground, the same as in the first and second exemplary embodiments. In this case, the process C13is performed instead of the processes C5and C6shown inFIG. 10, and the subsequent processes C14to C20are performed. Further, since the device wafer W is ground, the processes C7to C12are omitted.

In the above-described first to third exemplary embodiments, when the device wafer W is separated as shown inFIG. 6AtoFIG. 6D, the peripheral portion We is integrated with the second separation wafer W2. However, the way how to separate the device wafer W is not limited thereto.

For example, as depicted inFIG. 13A, the peripheral modification layer M1is formed up to an edge portion of the device wafer W within the device wafer W. If so, when the device wafer W is separated, the first separation wafer W1, the second separation wafer W2, and the peripheral portion We are individually separated, as illustrated inFIG. 13B. Even in such a case, the second separation wafer W2shown inFIG. 13Ccan be reused, and chips C can be fabricated from the first separation wafer W1shown inFIG. 13D.

In the above-described first to third exemplary embodiments, the adhesive tape B is used as the adhesive layer configured to bond the device wafer W and the reuse wafer S to each other. Without being limited thereto, however, an adhesive may be used.

In such a case, in the adhesive layer forming module70, the adhesive is spin-coated on the front surface Wa of the device wafer W. A commonly known apparatus is used as the adhesive layer forming module70.

Further, in the adhesive layer removing module145, the adhesive remaining on the front surface Wa of the first separation wafer W1is removed, and the front surface Wa is cleaned by spinning. In addition, a commonly known apparatus is used as the adhesive layer removing module145.

In the above-described first to third exemplary embodiments, the second separation wafer W2after being subjected to the required processings in the wafer processing system1is reused as the reuse wafer S to be bonded to the device wafer W. However, the reuse of the second separation wafer W2is not limited thereto. By way of example, if the second separation wafer W2after being subjected to the required processing has the thickness of 700 μm, reusing the second separation wafer W2as a substrate for the device wafer W may also be possible.

Further, in the above-described first to third exemplary embodiments, the device wafer W as the processing target substrate is separated into the first separation wafer W1and the second separation wafer W2, and the second separation wafer W2is reused as the reuse wafer S. However, the reuse wafer S may be a wafer separated from a device wafer as another device substrate. For example, a pre-processing performed before the device wafer is transferred into the wafer processing system1includes a process of thinning the device wafer. In this thinning process, the device wafer is separated into a first separation wafer having a device formed thereon and a second separation wafer without having a device thereon. The second separation wafer thus separated may be reused as the reuse wafer S of the present exemplary embodiment.

It should be noted that the above-described exemplary embodiment is illustrative in all aspects and is not anyway limiting. The above-described exemplary embodiment may be omitted, replaced and modified in various ways without departing from the scope and the spirit of claims.

EXPLANATION OF CODES

1: Wafer processing system

20: Wafer processing apparatus

W1: First separation wafer

W2: Second separation wafer