JP5448860B2 - Separation method and separation apparatus - Google Patents

Description

  The present invention relates to a separation method and a separation apparatus for separating a bonded support substrate and a wafer.

  In recent years, with the enhancement of functions of mobile phones, digital AV devices, IC cards, and the like, there is an increasing demand for downsizing, thinning, and high integration of semiconductor silicon chips to be mounted.

  For example, a thin chip is obtained by slicing a high-purity silicon single crystal or the like to form a wafer, etching a predetermined circuit pattern such as an IC on the surface of the wafer, and incorporating an integrated circuit. Grind to a predetermined thickness. After grinding, the wafer is diced into chips. At this time, the thickness of the wafer is generally about 100 to 600 μm, and when the through electrode is formed, it is further ground to a thickness of about 50 to 100 μm.

  As described above, in the manufacture of semiconductor chips, since the thickness of the wafer is thin, the strength of the wafer itself is low, and the circuit pattern formed on the wafer has irregularities, so that an external force is applied during conveyance to the grinding process or dicing process. It is easy to break when added. Further, in the grinding process, in order to remove polishing debris generated by grinding the wafer or to remove heat generated during polishing, the grinding process is performed while cleaning the back surface of the wafer using purified water. At this time, in order to protect the circuit pattern surface of the wafer and prevent the wafer itself from being damaged, each processing process is performed after a support substrate (hereinafter also referred to as “plate” or “support”) is bonded to the wafer. ing.

  Further, it is necessary to remove this support substrate after each processing of the wafer is completed. So far, various methods for peeling the support substrate from the wafer have been used.

  For example, Patent Document 1 discloses a wafer peeling apparatus that peels off a wafer attached to a plate. In this wafer peeling apparatus, first, a plate to which a wafer is attached is supported in an inclined state. A scraper is brought close to the peripheral edge of the wafer, and the edge of the scraper is brought into contact with the peripheral edge. Thereafter, the wafer is peeled from the plate by moving the other part of the scraper blade surface so as to be in contact with the other part of the peripheral edge of the wafer.

  Patent Document 2 also discloses a method for peeling a wafer bonded to a support. In this method, a blade is inserted from the horizontal direction into the layer of the double-sided PSA sheet to which the wafer and the support are bonded, and inserted to the back. Thereby, a part of double-sided pressure-sensitive adhesive sheet is divided, and a peeling interface (starting point of peeling) occurs between the wafer and the support. In this state, when the arm arranged on the dicing tape attached to the upper surface of the wafer is raised and the blade is vibrated up and down while urging the wafer upward, vibration energy is added to the peeling interface and peeling occurs. Progresses.

  On the other hand, an adhesive wafer formed by bonding a wafer such as a silicon wafer is known and applied to an LSI that requires radiation resistance strength, high-speed operation, and the like. In the production of this bonded wafer, if air bubbles are mixed in the boundary between the bonded wafers, they are handled as defective products, and as a countermeasure, for example, a technique for peeling and reusing the bonded wafers is disclosed in Patent Document 3. Has been.

  In the adhesive wafer peeling method disclosed in Patent Document 3, first, an adhesive wafer in which two silicon wafers are bonded together is placed and fixed on a suction table so that an insertion portion of a fixed peeling jig is fitted. Next, the movable peeling jig having an insertion portion at the tip is moved toward the bonding wafer, and the movable peeling jig is inserted into the bonding surface of the bonding wafer. At this time, the insertion portion is inserted into the bonding surface from one side of the bonded wafer by the pressing force of the movable peeling jig, and the upper wafer of the bonded wafer is peeled from the lower wafer.

Japanese Patent Laid-Open No. 11-111824 (published on April 23, 1999) JP 2006-32506 A (published February 2, 2006) Japanese Patent Laid-Open No. 7-240355 (published on September 12, 1995)

  However, in the techniques disclosed in Patent Documents 1 to 3, the operation of inserting the insertion member between the support substrate and the wafer (or between the wafers) only gives a trigger for the separation, and the size. If a larger wafer is handled, it cannot be easily separated.

  For example, in the wafer peeling apparatus disclosed in Patent Document 1, the blade edge surface of the scraper is brought into direct contact with the peripheral edge portion of the wafer, and a part of the blade edge surface is inserted between the wafer and the plate. Therefore, if the width of the interface between the wafer and the scraper is not larger than the edge of the scraper, the peripheral edge of the wafer may be damaged by the edge of the scraper. Further, the direct peeling by the scraper blade edge surface remains at the peripheral edge of the wafer and does not reach the area near the center of the wafer. Therefore, when handling a wafer having a larger size, there is a possibility that the wafer cannot be peeled off from the plate simply by inserting the edge of the scraper into the peripheral edge of the wafer.

  Moreover, in the method disclosed in Patent Document 2, a part of the double-sided pressure-sensitive adhesive sheet is divided to generate a peeling interface, but this is only a starting point for peeling. In other words, the reason why the wafer and the support are substantially separated is that the arm is lifted to lift the wafer, and at the same time, the blade is vibrated to cause peeling. In this method, when the bonding surface is not sufficiently peeled, the wafer may be bent when the wafer is lifted. This deflection is likely to occur as the wafer size increases, and the wafer may fall off the arm and fall, and there is also a problem that the wafer is damaged by the deflection itself.

  Moreover, in patent document 3, even if it uses the said technique for the form which adhere | attached the wafer and the support substrate, the silicon wafers adhere | attached only by the hydrogen bond with a weak bond strength are fixed peeling jig | tool. In the method of peeling the wafers only by inserting the insertion portion of the movable peeling jig into the peripheral edge portion of the wafer, the same problem as in Patent Document 1 occurs.

  By the way, as a peeling method of the bonded body between the wafer and the support substrate, a method of injecting a dissolving liquid from a through-hole formed in the support substrate in advance to dissolve the adhesive, and pulling up the support substrate and peeling it can be considered. FIG. 2 is a schematic process diagram for explaining one of the peeling methods considered by the present inventors.

  In this method, in the bonded body in which the support substrate 21 and the wafer 22 are bonded with an adhesive, first, a solution is injected from a plurality of through holes formed in the support substrate 21, and after the adhesive is partially dissolved, Several ends of the support substrate 21 are held by the clamps 26 ((a) of FIG. 2). Next, the clamp 26 holding the support substrate 21 is raised, and the support substrate 21 is peeled off from the adhesive layer 23 (FIG. 2B). ((C) of FIG. 2). As a result, the support substrate 21 is completely peeled from the wafer 22 (FIG. 2D). However, in this peeling method, when the wafer is peeled from the support substrate, there is a risk of damaging the support substrate or the wafer.

  That is, in the peeling method shown in FIG. 2, the clamp 26 is raised to bend the support substrate 21 and advance the peeling. However, as the size of the wafer 22 increases, the support substrate 21 that supports the wafer 22 also needs to be increased. In this case, the amount of deflection of the support substrate 21 also increases. As a result, the support substrate 21 may come off from the clamp 26, or the support substrate 21 itself may be damaged by bending.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a separation method and a separation apparatus that can separate a support substrate and a wafer without damaging them.

  A separation method according to the present invention is a separation method for separating a flexible support substrate and a wafer, which are bonded by an adhesive, and a dissolution step for dissolving the adhesive, and after the dissolution step, A holding step of moving the holding member in a direction away from the wafer in a state where the peripheral edge portion of the support substrate is held by the holding member, and forming a gap between the peripheral edge portion and the wafer, and a peeling member from the gap And a passing step of passing between the support substrate and the wafer.

  The separation device according to the present invention is a separation device for separating a flexible support substrate and a wafer bonded by an adhesive, and the adhesive is disposed between the support substrate and the wafer. Injecting means for injecting a dissolving solution, holding means for holding the peripheral edge of the support substrate, and holding the peripheral edge, the holding means is moved away from the wafer, and the peripheral edge A moving means for forming a gap between the wafer and a peeling means that is inserted from the gap and passes between the support substrate and the wafer to separate the support substrate and the wafer; Yes.

  According to the present invention, it is possible to provide a separation method and a separation apparatus that can separate the support substrate and the wafer without damaging them.

It is a schematic process drawing explaining one Embodiment of the separation method of this invention. It is a schematic process drawing explaining one of the peeling systems which the present inventors considered.

  One embodiment of the separation method according to the present invention will be described below. It should be noted that the scope of the present invention is not limited to these descriptions, and other than the following examples, the scope of the present invention can be appropriately changed and implemented without departing from the spirit of the present invention.

[1. Separation method)
The separation method according to the present invention is a separation method for separating a flexible support substrate and a wafer bonded by an adhesive, the dissolution step of dissolving the adhesive, and the support substrate after the dissolution step The holding member is moved in a direction away from the wafer in a state where the peripheral edge of the wafer is held by the holding member, and a moving step for forming a gap between the peripheral edge and the wafer, and a peeling member is inserted from the gap and supported. A passing step of passing between the substrate and the wafer.

  The support substrate is a substrate that can be supported to protect the wafer when the wafer is subjected to processing such as polishing. The supporting substrate is not particularly limited as long as it has flexibility, and a substrate known to those skilled in the art may be used. Examples of the material of the flexible support substrate include metals such as glass, silicon, alumina, silicon carbide, aluminum, resin, stainless steel, and iron-nickel alloy.

  The shape of the support substrate may be appropriately designed according to the shape of the wafer, but a plurality of through holes are preferably formed. For example, if a plurality of through holes each having an opening surface are formed on both surfaces of the support substrate, the dissolving liquid can be injected from the through holes in the dissolving step, and the adhesive can be easily dissolved. In addition, what is necessary is just to use a well-known method for those skilled in the art for the formation method of the through-hole in a support substrate.

  For example, a circuit pattern is formed on the surface of the wafer, and the surface on which the circuit pattern is formed can be bonded to a support substrate. As the wafer, a known wafer that can be used by those skilled in the art may be used, and examples of the material include compound semiconductors such as quartz, silicon, sapphire, and GaAs (gallium arsenide).

  Further, when the support substrate and the wafer are separated by the separation method of the present invention, the support substrate and the wafer are bonded to each other with an adhesive. That is, an adhesive can be applied to the interface between the support substrate and the wafer to form an adhesive layer.

  As an adhesive, for example, an acrylic resin, a hydrocarbon resin (polycycloolefin resin, terpene resin, petroleum resin, etc.), or an adhesive composition containing a novolac type phenol resin material, an organic solvent, etc. It is preferable to use adhesives that are soluble to these, and these may be used alone or in combination.

  The melting step is a step of dissolving the adhesive that bonds the support substrate and the wafer. Here, “dissolving” is sufficient if at least a part of the adhesive applied to the interface is dissolved, and not all (all) of the adhesive need be dissolved.

  As for the method for dissolving the adhesive, for example, when a plurality of through holes are provided in the support substrate, it is preferable to inject the dissolving liquid from the through holes and dissolve the adhesive. That is, in this method, since the dissolving liquid can be brought into direct contact with the adhesive, the adhesive can be more reliably dissolved.

  As the solution, a conventionally known solvent used for an adhesive may be used. Examples of such a solvent include p-menthane, d-limonene, acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone. Ketones such as: ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether Or polyhydric alcohols such as monophenyl ether and derivatives thereof; cyclic ethers such as dioxane; and methyl lactate, ethyl lactate , Methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, esters such as ethyl ethoxypropionate, or and the like and mixtures thereof. Which of these dissolving solutions is used may be appropriately selected according to the adhesive to be used. Moreover, what is necessary is just to select suitably various conditions, such as the temperature of a solution, or injection amount, according to the kind etc. of a solution or an adhesive agent, for example.

  The moving step is a step of forming a gap between the support substrate and the wafer by moving the support substrate. Specifically, after at least a part of the adhesive is dissolved in the melting step, first, the peripheral edge of the support substrate is held by the holding member, and in this state, the holding member is moved away from the wafer to support it. A gap is formed between the peripheral edge of the substrate and the wafer.

  The holding member may be any member that can hold the peripheral edge of the support substrate and is movable, and includes, for example, a clamp or a suction pad. Further, the position held by the holding member is not particularly limited as long as it can lift the support substrate. For example, two positions facing each other, three positions arranged at equal intervals, or more The location may be retained.

  Further, to move the holding member in the direction away from the wafer is intended to move the holding member to the side where the support substrate is bonded to the wafer. For example, when the support substrate is bonded to the upper surface of the wafer, if the holding member is moved upward, it is moved in a direction away from the wafer.

  Note that the “movement” here is only required to move to such an extent that a gap is formed between the peripheral edge of the support substrate and the wafer, and its range is not particularly limited, but it is between the peripheral edge and the wafer. It is preferable to move the holding member until the gap is equal to or higher than the height of the peeling member described later. That is, the gap formed in the moving process may be a width that allows the peeling member to be inserted in the passing process. Therefore, the holding member may be moved at this time as long as the peeling member can be inserted in the minimum necessary range. For example, even if the holding member is raised, the support substrate is greatly bent. There is no.

  The passing step is a step of inserting a peeling member from the gap formed in the moving step and passing between the support substrate and the wafer. That is, in the passing step, by passing the peeling member between the support substrate and the wafer, the adhesion between the support substrate and the wafer is peeled off and separated.

  The peeling member is desirably smaller than the width of the gap formed in the moving step, and examples of the shape include a thread shape, a triangle shape, a rectangle shape, a thin blade shape, and the like. preferable. If the peeling member is thread-like, the amount of movement of the holding member may be small, so that bending of the support substrate when forming the gap can be suppressed. As the peeling member, for example, a wire or the like can be used. Further, if the peeling member has a thin blade shape, a blade or the like can be used. As these materials, resin, metal, glass, alumina, rubber, or the like can be used.

  The passage of the peeling member means that the peeling member inserted from the gap may be moved so as to be taken out from the other peripheral edge different from the peripheral edge where the gap is formed. It is preferable to sweep the entire area between the wafers. Thereby, since all the area | regions with which the adhesive agent was apply | coated can be peeled with a peeling member, a support substrate and a wafer can be isolate | separated easily.

  The way to pass is not particularly limited, and for example, it may be passed in one direction from one gap to the opposite gap. For example, when a thread-like peeling member larger than the diameter of the support substrate is used, one end of the peeling member may be fixed and the other end may be moved so as to draw an arc. Further, a plurality of peeling members may be passed. In this case, the two peeling members may be inserted from different positions on the peripheral edge and moved so as to be aligned at the center.

  Furthermore, in the passing step, it is preferable that the peeling member is disposed and passed at a position where the distance between the wafer and the peeling member is larger than the distance between the support substrate and the peeling member. That is, by passing the peeling member closer to the support substrate than the wafer, the peeling member does not contact the wafer, and the circuit pattern formed on the surface of the wafer is not damaged. In this case, in order not to damage the support substrate, it is more preferable to pass the peeling member without contacting the support substrate. Thus, neither the wafer nor the support substrate is damaged by the peeling member.

  As described above, in the separation method of the present invention, since the separation is performed by moving the support substrate, not the wafer, the possibility of damaging the wafer is low. In addition, the support substrate is not simply moved and separated, but the adhesive surface is peeled off by the peeling member. That is, the holding member is moved to form a gap between the peripheral edge of the support substrate and the wafer, and then the peeling member is inserted and passed through the gap.

  Therefore, even when handling a wafer with a large size, the support substrate does not bend greatly. Therefore, the possibility that the support substrate is detached from the holding member can be reduced, and the support substrate itself is also damaged by the bending. Can be prevented. Therefore, these can be separated without damaging the support substrate and the wafer.

  Note that the separation method of the present invention can be executed by the separation apparatus of the present invention.

[2. Separation device
The separation device of the present invention is a separation device for separating a flexible support substrate and wafer bonded by an adhesive, and injecting a solution for dissolving the adhesive between the support substrate and the wafer. Injection means, holding means for holding the peripheral edge of the support substrate, and moving means for moving the holding means in a direction away from the wafer while holding the peripheral edge to form a gap between the peripheral edge and the wafer And a peeling means that is inserted from the gap and passes between the support substrate and the wafer to separate the support substrate and the wafer.

  The injection means injects a solution between the support substrate and the wafer. The injection means is not particularly limited, and for example, a substrate provided with a supply hole for supplying a solution and a suction hole for sucking the supplied solution can be used as the injection means. That is, in the injection means having such a structure, the supply hole is provided at the center and the suction hole is provided at the position farthest from the center on the surface facing the through hole provided in the support substrate, and the solution is supplied. However, it may be sucked. As another example of the structure of the injection means, it is possible to physically suppress the dispersion of the solution by providing a convex portion on the outer periphery of the injection means. In addition, an ultrasonic generator may be attached to the injection means in order to promote the penetration of the solution into the adhesive.

  The holding means holds the peripheral edge portion of the support substrate. An example of the holding means is a clamp. The holding means may be any means as long as it can grip the peripheral edge of the support substrate and peel the support substrate from the wafer. The holding means only needs to be able to grip the outer peripheral end of the support substrate, but in particular, when a chamfered portion is provided at the outer peripheral end of the support substrate, the holding means grips the chamfered portion. It is preferable. In other words, a glass plate or the like is usually used as the support substrate for supporting the wafer, but the outer peripheral side end of such a plate may be chamfered in an R shape. The holding means can hold the supporting substrate more reliably by holding the chamfered portion.

  The moving means moves the holding means holding the peripheral edge of the support substrate in a direction away from the wafer. Note that the holding unit and the moving unit may be separate members or the same member having these functions.

  The peeling means peels between the support substrate and the wafer by passing between the support substrate and the wafer. As the peeling means, for example, a wire or a blade can be used, and as the material thereof, resin, metal, glass, alumina, rubber or the like can be used.

  According to the separation apparatus of the present invention, even when a large wafer is handled, the support substrate and the wafer can be damaged because the support substrate can be separated without greatly bending the support substrate. These can be separated without.

[3. Flow of separation method)
An example of a specific procedure of the separation method according to the present embodiment will be described below with reference to FIG. FIG. 1 is a schematic process diagram illustrating one embodiment of the separation method of the present invention. The separation apparatus shown below includes a holding base 4, a clamp (holding means, moving means) 6, and a wire (peeling means) 7. The wafer 2 bonded to the support substrate 1 with an adhesive is dicing. It is held by the holding table 4 on the tape 5. The support substrate 1 is provided with a plurality of through holes.

  First, an injection means (not shown) injects the solution into a plurality of through holes provided in the support substrate 1. Thereby, after at least a part of the adhesive layer 3 is dissolved, the support substrate 1 is held by the clamp 6 ((a) of FIG. 1). Here, the clamp 6 holds two peripheral edge portions facing each other, but the present invention is not limited to this.

  Next, the clamp 6 holding the support substrate 1 is raised and the peripheral edge of the support substrate 1 is lifted ((b) of FIG. 1). As a result, a gap is formed between the peripheral edge portion of the support substrate 1 and the wafer via the adhesive layer 3, so that the wire 7 is inserted from this gap, and the wire 7 is passed toward the opposite gap. (In FIG. 1 (c), the direction of the arrow pointing to the left). The support substrate 1 can be separated from the wafer 2 by completely passing the wire 7 up to the gap on the opposite side ((d) in FIG. 1).

  Further, after passing through the wire 7, the support substrate 1 peeled off from the adhesive layer 3 is further lifted by the clamp 6, and the support substrate 1 is completely separated from the wafer 2. As described above, these can be separated without damaging the support substrate and the wafer.

  Examples will be shown below, and the embodiments of the present invention will be described in more detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various aspects are possible in detail. Further, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims, and the present invention is also applied to the embodiments obtained by appropriately combining the disclosed technical means. It is included in the technical scope of the invention. Moreover, all the literatures described in this specification are used as reference.

  Examples of the present invention will be described below.

  In this example, a glass substrate that is the same as or slightly larger than the wafer was used as the support substrate, and a silicon wafer having a diameter of 300 mm was used as the wafer. In addition, an acrylic adhesive was used as an adhesive for bonding the support substrate and the wafer, and PGMEA (propyleneglycol monomethyl ether acetate) was used as the solution.

  In addition, since the structure of the separation apparatus used in the present Example is the same as that of the separation apparatus shown in FIG. 1, for convenience of explanation, the same members are denoted by the same reference numerals.

  First, the solution was injected into the plurality of through holes provided in the support substrate 1, and then the support substrate 1 was held by the clamp 6 and the clamp 6 was raised. At this time, the peripheral portion of the support substrate 1 held by the clamp 6 is lifted, but the periphery thereof is not lifted. From this state, the clamp 6 was further raised to lift the entire peripheral edge of the support substrate 1. As a result, a gap was formed between the entire peripheral edge portion and the wafer 2.

  Next, the wire 7 was inserted from the formed gap. A resin wire was used as the wire 7. At this time, the wire 7 was disposed so as to pass through the side close to the support substrate 1 so as not to damage the wafer 2 disposed on the holding table 4. The wire 7 was passed between the support substrate 1 and the wafer 2. Thereby, all the adhesion between the support substrate 1 and the wafer 2 was peeled off. Thereafter, the support substrate 1 was lifted by the clamp 6 and completely separated from the wafer 2.

  As described above, according to the separation method of this embodiment, even when a support substrate having a diameter of 300 mm is used, the amount of bending when the support substrate is lifted is minimized, and the support substrate is separated from the wafer for separation. We were able to. Therefore, the support substrate is not detached from the clamp, and the support substrate is not damaged by the bending.

  The present invention can be used for manufacturing a semiconductor chip mounted on a mobile phone, a digital AV device, an IC card, or the like.

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Wafer 3 Adhesive layer 4 Holding stand 6 Clamp (holding member)
7 Wire (peeling member)

Claims (7)

A separation method for separating a flexible support substrate and a wafer bonded by an adhesive,
A dissolution step of dissolving the adhesive;
After the melting step, in a state where the peripheral portion of the support substrate is held by the holding member, the holding member is moved in a direction away from the wafer, and a moving step for forming a gap between the peripheral portion and the wafer; ,
A separation method comprising a passing step of inserting a peeling member from the gap and passing between the support substrate and the wafer.   2. The separation method according to claim 1, wherein in the passing step, the entire region between the peripheral edge portion and the wafer is swept by the peeling member.   3. The separation method according to claim 1, wherein, in the moving step, the holding member is moved until a gap between the peripheral edge portion and the wafer is equal to or higher than a height of the peeling member.   In the passing step, the separation member is arranged to pass through a position where a distance between the wafer and the separation member is larger than a distance between the support substrate and the separation member. The separation method according to claim 3.   The separation method according to claim 1, wherein the peeling member has a thread shape or a blade shape. The support substrate is provided with a plurality of through holes,
The separation method according to claim 1, wherein in the dissolving step, the adhesive is dissolved by injecting a solution from the through-hole. A separation device for separating a flexible support substrate and a wafer bonded by an adhesive,
Injection means for injecting a solution for dissolving the adhesive between the support substrate and the wafer;
Holding means for holding the peripheral edge of the support substrate;
Moving means for moving the holding means in a direction away from the wafer in a state where the peripheral edge is held, and forming a gap between the peripheral edge and the wafer;
A separation apparatus comprising: a peeling unit that is inserted from the gap and passes between the support substrate and the wafer to separate the support substrate and the wafer.

Images