JP2013182973A - Substrate bonding method and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and appropriately bond a substrate on which a plurality of semiconductor devices are formed.SOLUTION: A substrate bonding method comprises the steps of: forming a device region higher than a scribe line region and a liquid supply region on a first wafer (S1, S2); activating surfaces of the device region and the liquid supply region (S3); forming a device region on a second wafer (S4); forming a liquid supply hole and a through hole (S7); forming a through electrode (S8); hydrophilically forming a bonded region by patterning insulating films at the positions corresponding to the device region and the liquid supply region (S10); activating a surface of the bonded region (S11); superposing the first wafer on the second wafer (S12); supplying pure water from a liquid supply hole of the second wafer to a liquid supply region of the first wafer (S13); adjusting the positions of the first wafer and the second wafer with the pure water (S14); and bonding the first wafer and the second wafer (S15).

Description

  The present invention relates to a substrate bonding method for bonding a first substrate on which a plurality of semiconductor devices are formed and a second substrate on which a plurality of semiconductor devices are formed, and a substrate on which a plurality of semiconductor devices are formed. The present invention relates to a semiconductor device bonded to a plurality of layers.

  In recent years, semiconductor devices have been highly integrated. When a plurality of highly integrated semiconductor devices are arranged in a horizontal plane and these semiconductor devices are connected by wiring to produce a product, the wiring length increases, thereby increasing the wiring resistance and wiring delay. There is concern about becoming.

  Therefore, a three-dimensional integration technique for stacking semiconductor devices in three dimensions has been proposed. In this three-dimensional integration technology, bonding of semiconductor wafers (hereinafter referred to as “wafers”), bonding of semiconductor chips, and the like are performed. And in order to laminate | stack a semiconductor device appropriately, joining with a high positional accuracy is requested | required.

  In order to join with high positional accuracy in this way, for example, Patent Document 1 proposes a joining method for deformed base material. Specifically, an arbitrary region of the first base material is selectively hydrophilized, and the bonding surface of the second base material is hydrophilized, and then the first base is passed through the liquid having a hydroxyl group. The arbitrary area | region of a base material and the joint surface of a 2nd base material are joined.

JP 2000-252543 A

  However, in the joining method described in Patent Document 1, it is necessary to perform a plurality of treatments in order to hydrophilize an arbitrary region of the first base material. Specifically, according to the method described in Patent Document 1, first, after forming a metal film on the surface of the first base material, a photolithography process and an etching process are performed to selectively select a metal film in an arbitrary region. To remove. Then, the 1st base material is immersed in an alkaline hydrophilization treatment liquid, and the arbitrary field which is not covered with a metal film is hydrophilized. In such a case, the joining process becomes complicated, and the processing cost of the joining process becomes expensive.

  Moreover, when joining the wafer in which the several semiconductor device was formed using the joining method described in this patent document 1, a hydrophilic treatment is needed with respect to each semiconductor device. As a result, the joining process is further complicated, and the processing cost of the joining process is further increased.

  This invention is made | formed in view of this point, and it aims at joining the board | substrate with which the several semiconductor device was formed simply and appropriately.

  In order to achieve the above object, the present invention provides a method of bonding a first substrate on which a plurality of semiconductor devices are formed and a second substrate on which a plurality of semiconductor devices are formed, the first substrate In the surface of the substrate on which the plurality of semiconductor devices are formed, a semiconductor device region that is higher than a region that becomes a scribe line between the semiconductor devices, and the semiconductor device region that is adjacent in the region that becomes the scribe line A first step of forming a liquid supply region having the same height and connecting the adjacent semiconductor device regions, and the second substrate at a position corresponding to the liquid supply region. A second step of forming a liquid supply hole penetrating in the thickness direction of the second substrate, a third step of overlapping the first substrate and the second substrate, and passing the liquid supply hole. The liquid supplying a process liquid to the supply area, is characterized by having a fourth step of bonding the first substrate and the second substrate Te.

  According to the present invention, in the first step, the semiconductor device region of the first substrate is formed higher than the region that becomes the scribe line, and the liquid supply region that has the same height as the semiconductor device region becomes the scribe line. Form in the area. Then, in the third step, even if the processing liquid is supplied between the first substrate and the second substrate, the processing liquid may flow out of the semiconductor device region and the liquid supply region due to a so-called pinning effect. Absent. In addition, a restoring force that moves at least the first substrate or the second substrate acts by the surface tension of the processing liquid. Then, the position adjustment of the first substrate and the second substrate is performed with high positional accuracy. Then, the first substrate and the second substrate can be appropriately bonded thereafter. Moreover, in the first substrate, the first substrate and the second substrate can be appropriately bonded only by forming the semiconductor device region and the liquid supply region higher than the region serving as the scribe line. It is not necessary to perform the additional processing described in Patent Document 1 described above on this substrate. Therefore, the bonding process between the first substrate and the second substrate can be simplified, and the processing cost of the bonding process can be reduced.

  Here, in the joining method described in Patent Document 1 described above, when joining the first base material and the second base material, the first base material and the second base material are placed in the treatment liquid. Soaked. When such a method is used, the pinning effect of the present invention cannot be used. In this regard, in the present invention, the liquid supply hole of the second substrate is formed at a position corresponding to the liquid supply region of the first substrate in the second step, and therefore, through the liquid supply hole in the subsequent third step. The treatment liquid can be supplied to the liquid supply area. Then, the processing liquid efficiently diffuses over the liquid supply region and the semiconductor device region, and the position adjustment and bonding of the first substrate and the second substrate can be performed as described above. In addition, since it is not necessary to individually supply the processing liquid to each semiconductor device region, the bonding process between the first substrate and the second substrate can be performed easily and efficiently.

  In the second step, the liquid supply hole and the through hole in the semiconductor device of the second substrate may be simultaneously formed, and a through electrode may be formed in the through hole.

  The bonding method may include a fifth step of forming another through electrode in the semiconductor device of the first substrate after the fourth step.

  Prior to the second step, air holes penetrating in the thickness direction of the second substrate may be formed in the second substrate other than regions corresponding to the semiconductor device region and the liquid supply region. .

  The treatment liquid may be pure water.

  After the first step and before the third step, the surface of the semiconductor device region is activated, and after the second step and before the third step, the second step The surface of the second substrate on which the plurality of semiconductor devices are not formed may be activated.

  Activation of the surface of the semiconductor device and activation of the surface of the second substrate on which the plurality of semiconductor devices are not formed may be performed by ammonia, respectively.

  At least in the third step or the fourth step, a position adjustment mechanism for adjusting the relative position between the first substrate and the second substrate is used to determine a predetermined distance between the first substrate and the second substrate. The interval may be maintained.

  According to another aspect of the present invention, there is provided a semiconductor device in which a substrate on which a plurality of semiconductor devices are formed is bonded to a plurality of layers, and a scribe line between the semiconductor devices on a surface on which the plurality of semiconductor devices are formed. And a liquid supply region that has the same height as the adjacent semiconductor device region and connects the adjacent semiconductor device regions in the region that becomes the scribe line. A first substrate formed; and a second substrate having a liquid supply hole penetrating in a thickness direction at a position corresponding to the liquid supply region; and the liquid supply region through the liquid supply hole. The processing liquid is supplied to the first substrate, and the first substrate and the second substrate are bonded to each other.

  In the second substrate, air holes penetrating in the thickness direction of the second substrate may be formed in addition to regions corresponding to the semiconductor device region and the liquid supply region.

  The treatment liquid may be pure water.

  The surface of the semiconductor device region and the surface of the second substrate on which the plurality of semiconductor devices are not formed may be activated.

  Activation of the surface of the semiconductor device and activation of the surface of the second substrate on which the plurality of semiconductor devices are not formed may be performed by ammonia, respectively.

  When the processing liquid is supplied to the liquid supply region through the liquid supply hole and the first substrate and the second substrate are bonded, a predetermined interval is provided between the first substrate and the second substrate. A position adjusting mechanism that maintains the position may be used.

  ADVANTAGE OF THE INVENTION According to this invention, the board | substrate with which the several semiconductor device was formed can be joined simply and appropriately.

It is the flowchart which showed each process of the bonding method of the wafer concerning this Embodiment. It is explanatory drawing of the longitudinal cross-section which shows a mode that the device layer was formed in the 1st wafer. It is a top view which shows the outline of a structure of the device layer of a 1st wafer. It is explanatory drawing of the plane which shows arrangement | positioning of the device area | region and liquid supply area | region of a 1st wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the liquid supply area | region was formed in the 1st wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the scribe line area | region was formed in the 1st wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the device layer was formed in the 2nd wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the support wafer was arrange | positioned to the 2nd wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the liquid supply hole and the through-hole were formed in the 2nd wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the penetration electrode was formed in the 2nd wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the insulating film was formed in the 2nd wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the to-be-joined area | region was formed in the 2nd wafer. It is explanatory drawing of the plane which shows the to-be-joined area | region of a 2nd wafer, and arrangement | positioning of a liquid supply hole. It is explanatory drawing of the longitudinal cross-section which shows a mode that the 2nd wafer was arrange | positioned above the 1st wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the 1st wafer and the 2nd wafer were position-adjusted and joined. It is explanatory drawing of the longitudinal cross-section which shows a mode that the pure water was supplied on the device area | region and liquid supply area | region of a 1st wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the pure water was supplied on the device area | region of a 1st wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the liquid supply hole and the through-hole were formed in the 1st wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the penetration electrode was formed in the 1st wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the semiconductor device was manufactured. It is explanatory drawing of the plane which shows the to-be-joined area | region of 2nd wafer and arrangement | positioning of a liquid supply hole in other embodiment. It is explanatory drawing of the longitudinal cross-section which shows a mode that the support wafer in which the air hole was formed in other embodiment was arrange | positioned in the 2nd wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the air hole was formed in the 2nd wafer in other embodiment. It is explanatory drawing of the longitudinal cross-section which shows a mode that the 1st wafer and the 2nd wafer were position-adjusted and joined in other embodiment. It is explanatory drawing of the longitudinal cross-section which shows a mode that the 2nd wafer was arrange | positioned above the 1st wafer in other embodiment. It is explanatory drawing of the longitudinal cross-section which shows a mode that the 1st wafer and the 2nd wafer were position-adjusted and joined in other embodiment. It is explanatory drawing of the longitudinal cross-section which shows a mode that the 1st wafer and the 2nd wafer were position-adjusted and joined in other embodiment. It is explanatory drawing of the longitudinal cross-section which shows a mode that the raising / lowering mechanism was provided in the support wafer in other embodiment. It is explanatory drawing of the longitudinal cross-section which shows a mode that the raising / lowering mechanism was provided in the support wafer in other embodiment.

  Embodiments of the present invention will be described below. In this embodiment mode, a method for bonding a wafer as a substrate according to the present invention and a semiconductor device in which wafers bonded by the bonding method are stacked in a plurality of layers will be described. FIG. 1 shows a main processing flow of the wafer bonding method according to the present embodiment. In this embodiment mode, a first wafer as a first substrate and a second wafer as a second substrate are bonded. More specifically, the first wafer and the second wafer are bonded together in a state where the first wafer is disposed relatively downward and the second wafer is disposed relatively upward. In the drawings used in the following description, the dimensions of each component do not necessarily correspond to the actual dimensions in order to prioritize easy understanding of the technology.

  First, as shown in FIG. 2, the device layer 12 is formed on the bulk layer 11 of the first wafer 10. Hereinafter, in the bulk layer 11, the surface on the device layer 12 side is referred to as a front surface 11a, and the surface on the opposite side to the device layer 12 is referred to as a back surface 11b. Further, in the device layer 12, a surface opposite to the bulk layer 11 is referred to as a front surface 12a, and a surface on the bulk layer 11 side is referred to as a back surface 12b.

  The device layer 12 of the first wafer 10 is formed with a device 13 as a semiconductor device (hereinafter also referred to as “device region 13”) (step S1 in FIG. 1). As shown in FIG. 3, a plurality of devices 13 are uniformly formed on the first wafer 10 within the wafer surface. In this embodiment, the wafer stacking method in which the first wafer 10 and a later-described second wafer 20 are stacked at the wafer level before the first wafer 10 is cut into semiconductor chips including the individual devices 13. Is used.

  A plurality of circuits 14 are formed in the device 13 as shown in FIG. In the circuit 14, a plurality of transistors and memory cells (not shown) are arranged. Although not shown, in the device 13, wiring for connecting the circuit 14 and a through electrode 42 described later, various circuits, electrodes, and the like are also formed. The plurality of circuits 14 and the like are formed at the same time in the series of device layer 12 forming steps.

  A scribe line 15 (hereinafter sometimes referred to as “scribe line region 15”) is formed between the plurality of devices 13. The device region 13 is formed higher than the scribe line region 15. Note that the scribe line is a line when the wafer is cut and divided into a plurality of semiconductor chips.

  Thereafter, as shown in FIGS. 3 and 4, in the scribe line region 15, a liquid supply region 16 that connects the adjacent device regions 13 is formed (step S2 in FIG. 1). In the present embodiment, the device region 13 has a quadrangular shape in plan view, and the plurality of device regions 13 are arranged in a lattice shape. Therefore, four liquid supply regions 16 are connected to the inner device region 13 of the first wafer 10, and two liquid supply regions 16 are connected to the outer device region 13. The liquid supply region 16 has the same height as the device region 13 as shown in FIG. On the other hand, in the scribe line region 15 where the liquid supply region 16 is not formed, nothing is formed as shown in FIG. 4, or the inspection element has a height lower than the height of the device region 13 as shown in FIG. An element 17 such as is formed. In any case, the scribe line region 15 in which the liquid supply region 16 is not formed is lower than the device region 13. For convenience of explanation, the formation of the device region 13 and the liquid supply region 16 has been described in order, but the device region 13 and the liquid supply region 16 are actually formed at the same time. Since the liquid supply area 16 is formed in the scribe line area 15, the liquid supply area 16 does not adversely affect the device 13. In addition, since the scribe line area 15 is an area where the device 13 is not originally formed, the connection area 16 does not adversely affect the yield of the device 13 from one wafer 10.

  Thereafter, ammonia (ammonia water obtained by diluting ammonia to a predetermined concentration) is supplied onto the device region 13 and the liquid supply region 16. This ammonia activates the surfaces of the device region 13 and the liquid supply region 16, in other words, the surface of the first wafer 10 (step S3 in FIG. 1). Specifically, molecular bonds on the surfaces of the device region 13 and the liquid supply region 16 are cut, and then the surfaces are activated so as to be easily hydrophilized. Note that if organic residue or the like remains on the bonding surface, it causes subsequent bubbles. Therefore, SC1 (Standard Clean 1) is sprayed onto the surface of the first wafer 10 with a two-fluid nozzle before activation with ammonia. Therefore, it is better to perform pre-cleaning. Thereafter, for example, the surfaces of the device region 13 and the liquid supply region 16 are washed with pure water, and then the pure water is dried. The first wafer 10 may be dried by heating or the like. In the present embodiment, the surfaces of the device region 13 and the liquid supply region 16 are activated by ammonia. However, the liquid for activating the device region 13 and the liquid supply region 16 is not limited thereto, and various liquids such as pure water are used. be able to. An aqueous alkali solution such as potassium hydroxide can also be used.

  In this way, the next process is performed on the second wafer 20 in parallel with or before and after the processes S1 to S3.

  First, as shown in FIG. 7, the device layer 22 is formed on the bulk layer 21 of the second wafer 20. Hereinafter, in the bulk layer 21, the surface on the device layer 22 side is referred to as a front surface 21a, and the surface on the opposite side to the device layer 22 is referred to as a back surface 21b. Further, in the device layer 22, the surface opposite to the bulk layer 21 is referred to as a front surface 22a, and the surface on the bulk layer 21 side is referred to as a back surface 22b.

  In the device layer 22 of the second wafer 20, a device 23 (hereinafter, also referred to as “device region 23”) is formed (step S4 in FIG. 1). Similar to the device 13 of the first wafer 10, a plurality of devices 23 are uniformly formed in the wafer surface on the second wafer 20.

  In the device 13, a plurality of circuits 24 are formed as shown in FIG. In the circuit 24, a plurality of transistors and memory cells (not shown) are arranged. Although not shown, in the device 23, wiring for connecting the circuit 24 and a through electrode 31 described later, various circuits, electrodes, and the like are also formed. The plurality of circuits 24 and the like are simultaneously formed in a series of device layer 22 formation steps.

  A scribe line 25 (hereinafter sometimes referred to as “scribe line region 25”) is formed between the plurality of devices 23. Although the liquid supply region 16 is formed in the scribe line region 15 in the first wafer 10, a region similar to the liquid supply region 16 may be formed or formed in the second wafer 20. It does not have to be. In the present embodiment, the region 26 is formed on the second wafer 20.

  Thereafter, as shown in FIG. 8, a support wafer 27 as a support substrate is disposed on the surface 22a of the device layer 22 (step S5 in FIG. 1). The support wafer 27 is bonded to the device layer 22 by, for example, a peelable adhesive. The support wafer 27 is formed with a liquid supply hole 28 penetrating in the thickness direction. The liquid supply hole 28 is formed at a position that communicates with a liquid supply hole 29 of the second wafer 20 described later and that corresponds to the liquid supply region 16 of the first wafer 10. A silicon wafer or a glass substrate is used as the support substrate.

  After that, as shown in FIG. 8, the back surface 21b of the bulk layer 21 is polished to thin the second wafer 20 (step S6 in FIG. 1).

  Thereafter, as shown in FIG. 9, the front and back surfaces of the second wafer 20 are reversed, the device layer 22 is disposed below the bulk layer 21, and then the liquid supply hole that penetrates the bulk layer 21 and the device layer 22 in the thickness direction. 29 and the through hole 30 are formed (step S7 in FIG. 1). The liquid supply hole 29 is a position communicating with the liquid supply hole 28 of the support wafer 27 described above, and is formed at a position corresponding to the liquid supply region 16 of the first wafer 10. The through hole 30 is formed so as to be connected to a circuit (not shown) connected to the circuit 24 so as to be connected to the circuit 24. A plurality of through holes 30 are formed in the second wafer 20. The plurality of liquid supply holes 29 and the plurality of through holes 30 are simultaneously formed by, for example, a photolithography process and an etching process. That is, after a predetermined resist pattern is formed on the bulk layer 21 by photolithography, the bulk supply layer 21 and the device layer 22 are etched using the resist pattern as a mask to form the liquid supply hole 29 and the through hole 30. . After the liquid supply hole 29 and the through hole 30 are formed, the resist pattern is removed by ashing, for example.

  Thereafter, a conductive material is filled in each through hole 30 to form a through electrode (TSV: Through Silicon Via) 31 as shown in FIG. 10 (step S8 in FIG. 1). At this time, the conductive material is prevented from flowing into the liquid supply hole 29. In practice, a barrier film, an insulating film, and the like are formed on the inner wall of each through hole 30 before the conductive material is filled, but this is omitted for the sake of simplicity.

  Thereafter, as shown in FIG. 11, an insulating film 32 is formed on the back surface 21b of the bulk layer 21 (step S9 in FIG. 1). At this time, the insulating film 32 is not formed at a position corresponding to the liquid supply hole 29. The insulating film 32 is formed by a method such as CVD (chemical vapor deposition) by appropriately selecting a material from, for example, a silicon oxide film.

  Thereafter, as shown in FIG. 12, the insulating film 32 is patterned into a predetermined pattern (step S10 in FIG. 1). In this patterning, a scribe line region where the liquid supply region 16 is not formed, leaving the insulating film 32 at positions corresponding to the device region 13 and the liquid supply region 16 of the first wafer 10 as shown in FIGS. The insulating film 32 at a position corresponding to 15 is removed. The insulating film 32 patterned in this way constitutes a bonded region 33 that is bonded to the device region 13 and the liquid supply region 16. Then, due to the pinning effect described later, the bonded region 33 is relatively hydrophilized and the region 34 other than the bonded region 33 is relatively hydrophobized on the back surface of the second wafer 20. The hydrophilicity of the bonded region 33 is not limited to the patterning of the insulating film 32 as described above, and the surface of the bonded region 33 may be modified to perform the hydrophilic treatment. Further, the liquid supply hole 29 is formed at a position corresponding to the liquid supply region 16 of the first wafer 10 in the bonded region 33.

  Thereafter, ammonia (ammonia water obtained by diluting ammonia to a predetermined concentration) is supplied onto the bonded region 33. By this ammonia, the surface of the bonded region 33, in other words, the back surface of the second wafer 20 is activated (step S11 in FIG. 1). More specifically, the surface of the bonded region 33 is broken so that the surface is activated so as to be easily hydrophilized. If organic residue or the like remains on the bonding surface, it may cause later bubbles. Therefore, SC1 (Standard Clean 1) is sprayed onto the back surface of the second wafer 20 with a two-fluid nozzle before activation with ammonia. Therefore, it is better to perform pre-cleaning. Thereafter, for example, the surface of the bonded region 33 is washed with pure water, and then the pure water is dried. The second wafer 20 may be dried by heating or the like. In the present embodiment, the surface of the bonded region 33 is activated by ammonia, but the liquid for activating this is not limited to this, and various liquids can be used. An aqueous alkali solution such as potassium hydroxide can also be used.

  When the predetermined processing of steps S1 to S11 is performed on the first wafer 10 and the second wafer 20 in this way, the bonding processing of the first wafer 10 and the second wafer 20 is performed next.

  First, as shown in FIG. 14, the second wafer 20 is disposed on the device layer 12 side of the first wafer 10, and the first wafer 10 and the second wafer 20 are overlaid (steps in FIG. 1). S12). The second wafer 20 is arranged such that the bulk layer 21 faces the device layer 12 of the first wafer 10. Note that the position of the bonded region 33 of the bulk layer 21 and the positions of the device region 13 and the liquid supply region 16 of the device layer 12 do not need to correspond exactly. As shown in FIG. 14, even when these positions are slightly shifted, the position adjustment of the first wafer 10 and the second wafer 20 is performed in step S14 described later. Further, there may be a gap between the device layer 12 of the first wafer 10 and the bonded region 33 of the second wafer 20, or the device layer 12 and the bonded region 33 may be in close contact with each other.

  Thereafter, as shown in FIG. 15, pure water P as a processing liquid is supplied from the liquid supply hole 28 of the support wafer 27 and the liquid supply hole 29 of the second wafer 20 onto the liquid supply region 16 of the first wafer 10. (Step S13 in FIG. 1). The pure water P supplied to the liquid supply area 16 diffuses over the liquid supply area 16 and the device area 13. At this time, the second wafer 20 is raised by the surface tension of the pure water P. Here, as described above, the device region 13 and the liquid supply region 16 are formed higher than the scribe line region 15 in which the liquid supply region 16 is not formed. Further, the bonded region 33 of the second wafer 20 corresponding to the device region 13 and the liquid supply region 16 is also made hydrophilic. Therefore, the pure water P has a large predetermined contact angle due to the surface tension at the edges of the device region 13 and the liquid supply region 16. Then, the pure water P remains on the device region 13 and the liquid supply region 16 as shown in FIGS. The phenomenon of suppressing the spread of pure water P in this way is known as a so-called pinning effect. The pure water P diffuses over the device region 13 and the liquid supply region 16. In this embodiment, pure water P is used as the treatment liquid. However, various liquids can be used as long as the liquid has a hydroxyl group.

  Thereafter, due to the surface tension of the pure water P filled between the first wafer 10 and the second wafer 20 described above, a restoring force (in FIG. 15) moves the second wafer 20 as shown in FIG. An arrow) acts on the second wafer 20. Then, even when the position of the liquid supply region 16 of the bulk layer 21 and the position of the device region 13 and the liquid supply region 16 of the device layer 12 are shifted, the second wafer 20 moves so that they face each other, Position adjustment of the first wafer 10 and the second wafer 20 is performed with high accuracy (submicron order) (step S14 in FIG. 1). For convenience of explanation, the supply of pure water P and the movement of the second wafer 20 have been described in order, but actually these phenomena proceed almost simultaneously.

  Thereafter, the pure water P filled between the first wafer 10 and the second wafer 20 causes hydroxyl groups to adhere to the device region 13 and the liquid supply region 16 of the first wafer 10, and the device region 13 and While the surface of the liquid supply region 16 is hydrophilized, a hydroxyl group adheres to the bonded region 33 of the second wafer 20 and the surface of the bonded region 33 is hydrophilized. Since the surfaces of the device region 13 and the liquid supply region 16 and the surface of the bonded region 33 are activated in steps S3 and S11, respectively, first, the surfaces of the device region 13 and the liquid supply region 16 are bonded to each other. Van der Waals force is generated between the surfaces of the regions 33 and the surfaces are joined to each other. Thereafter, the surfaces of the device region 13 and the liquid supply region 16 and the surface of the bonded region 33 are made hydrophilic as described above. The hydroxyl groups of these are hydrogen-bonded and the surfaces are bonded more firmly (step S15 in FIG. 1). When the first wafer 10 and the second wafer 20 are bonded, the pure water P between the first wafer 10 and the second wafer 20 is removed, and the first wafer 10 and the second wafer 20 are bonded. The second wafer 20 is dried.

  Thereafter, as shown in FIG. 18, the back surface 11b of the bulk layer 11 in the first wafer 10 is polished to thin the first wafer 10 (step S16 in FIG. 1). At this time, the front and back surfaces of the first wafer 10 are reversed, and the device layer 12 is disposed below the bulk layer 11.

  Thereafter, as shown in FIG. 18, the liquid supply hole 40 and the through hole 41 are formed in the first wafer 10 (step S17 in FIG. 1). The liquid supply hole 40 is formed so as to penetrate the bulk layer 11 and the device layer 12 of the first wafer 10 in the thickness direction. The liquid supply hole 40 is formed at a position communicating with the liquid supply hole 29 of the second wafer 20. The through hole 41 is also formed so as to penetrate the bulk layer 11 and device layer 12 of the first wafer 10 and the insulating film 32 of the second wafer 20 in the thickness direction. The through hole 41 is formed at a position corresponding to the through electrode 31 of the second wafer 20. Note that the method for forming the liquid supply hole 40 and the through hole 41 is the same as the method in step S7 described above, and a description thereof will be omitted.

  Thereafter, each through hole 41 is filled with a conductive material to form a through electrode 42 as another through electrode as shown in FIG. 19 (step S18 in FIG. 1). At this time, the conductive material is prevented from flowing into the liquid supply hole 40. The through electrode 42 is connected to the circuit 14 and is connected to the through electrode 31 of the second wafer 20. In addition, since the method for forming the through electrode 42 is the same as the method in step S8 described above, description thereof is omitted. In practice, a bump or the like is formed between the through electrode 42 and the through electrode 31, but is omitted for the sake of simplicity.

  Here, when the through electrode 42 of the first wafer 10 is formed before bonding to the second wafer 20, the through electrode 42 of the first wafer 10 and the through electrode 31 of the second wafer 20 are formed by the insulating film 32. Not electrically conductive. Therefore, the through electrode 42 of the first wafer 40 is formed after bonding to the second wafer 20 as in the present embodiment.

  Thereafter, in the first wafer 10, an insulating film 32 is formed on the back surface 11b of the bulk layer 11 (step S19 in FIG. 1), and the insulating film 32 is further patterned into a predetermined pattern to form a bonded region 33. (Step S20 in FIG. 1). Thereafter, the surface of the bonded region 33, in other words, the back surface of the first wafer 10 is activated with ammonia (ammonia water diluted with ammonia to a predetermined concentration) (step S21 in FIG. 1). Since the formation of the insulating film 32, the formation of the bonded region 33, and the activation of the surface of the bonded region 33 are the same as the above-described steps S9 to S11, the description thereof is omitted.

  As described above, the same processing as the back surface of the second wafer 20 (back surface 21b of the bulk layer 21) is performed on the back surface of the first wafer 10 (back surface 11b of the bulk layer 11). Then, the first wafer 10 is caused to function in the same manner as the second wafer 20, and the first wafer 10 (hereinafter sometimes referred to as the “old first wafer 10”) and the new first wafer 10. The wafer 10 (hereinafter may be referred to as “the new first wafer 10”) is bonded. The new first wafer 10 is processed in the same manner as the above-described steps S1 to S3. And the process similar to process S12-S15 mentioned above is performed, and the old 1st wafer 10 and the new 1st wafer 10 are joined. In this way, as shown in FIG. 20, a plurality of first wafers 10 are stacked, and the support wafer 27 is further peeled off to manufacture a semiconductor device 100 in which the wafers 10 and 20 are stacked in a plurality of layers (FIG. 1). Step S22). In the illustrated example, the case where the wafers 10 and 20 are stacked in four layers will be described. However, the number of stacked wafers 10 and 20 is not limited to this and can be arbitrarily set.

  According to the above embodiment, the device region 13 of the first wafer 10 is formed higher than the scribe line region 15, and the liquid supply region 16 having the same height as the device region 13 is formed in the scribe line region 15. doing. Then, even if pure water P is supplied between the first wafer 10 and the second wafer 20 thereafter, the pure water P may flow out of the device region 13 and the liquid supply region 16 due to a so-called pinning effect. Absent. And the restoring force which moves the 2nd wafer 20 acts with the surface tension of this pure water P. Then, the position adjustment of the first wafer 10 and the second wafer 20 is performed with high positional accuracy so that the device region 13 and the liquid supply region 16 correspond to the bonded region 33 accurately. If it does so, the 1st wafer 10 and the 2nd wafer 20 can be joined appropriately after that. In addition, in the first wafer 10, the first wafer 10 and the second wafer 20 can be appropriately bonded only by forming the device region 13 and the liquid supply region 16 higher than the scribe line region 15. The bonding process between the first wafer 10 and the second wafer 20 can be simplified, and the processing cost of the bonding process can be reduced.

  Further, the liquid supply region 16 that connects the adjacent device regions 13 is formed in the first wafer 10, and the liquid supply hole 29 of the second wafer 20 is formed at a position corresponding to the liquid supply region 16. The pure water P can be efficiently diffused into the plurality of device regions 13 and the plurality of liquid supply regions 16 only by supplying the pure water P from the liquid supply hole 29 to the liquid supply region 16 once. Therefore, since it is not necessary to supply the pure water P to the plurality of device regions 13 individually, the bonding process between the first wafer 10 and the second wafer 20 can be further simplified.

  Further, since the liquid supply hole 29 of the second wafer 20 is formed at the same time as the through hole 30, it is not necessary to separately perform a process for forming the liquid supply hole 29. Therefore, the bonding process between the first wafer 10 and the second wafer 20 can be further simplified.

  In addition, the surfaces of the device region 13 and the liquid supply region 16 of the first wafer 10 are activated and the surface of the bonded region 33 of the second wafer 20 is activated. The two wafers 20 can be bonded more firmly.

  In addition, since the first wafer 10 and the second wafer 20 are bonded with accurate positional adjustment as described above, the through-hole electrode 42 is formed in the first wafer 10 after that. The electrode 42 can be formed at an appropriate position. Then, the semiconductor device 100 can be manufactured appropriately.

  In the present embodiment, when the first wafer 10 and the second wafer 20 are bonded, it is not necessary to heat the first wafer 10 and the second wafer 20. Therefore, the devices 13 and 23 can be prevented from being damaged, and the reliability of the devices 13 and 23 can be improved.

  In the second wafer 20 of the above embodiment, as shown in FIG. 21, regions other than the bonded region 33 of the second wafer 20 (in the device region 13 and the liquid supply region 16 of the first wafer 10). A plurality of air holes 110 may be formed in a region other than the corresponding region. The air hole 110 is formed for each space closed in the bonded region 33, for example. As shown in FIG. 22, the support wafer 27 provided on the second wafer 20 has an air hole 111 that penetrates the support wafer 27 in the thickness direction and communicates with the space closed by the bonded region 33. Is formed.

  The plurality of air holes 110 are formed so as to penetrate in the thickness direction of the second wafer 20 as shown in FIG. The plurality of air holes 110 are formed at the same time as the liquid supply hole 29 and the through hole 30 in the above-described step S7, that is, simultaneously formed by a photolithography process and an etching process. Note that the other steps for the second wafer 20 are the same as the steps S4 to S6 and S8 to S11 described above, and thus the description thereof is omitted.

  In such a case, after supplying the second wafer 20 on the device layer 12 side of the first wafer 10 in step S12, when supplying pure water P to the first wafer 10 in step S13, as shown in FIG. The air existing in the space closed by the device region 13 and the bonded region 33 is exhausted to the outside through the air holes 110 and 111. As described above, since the atmospheric pressure in the space closed by the device region 13 and the bonded region 33 can be appropriately maintained similarly to the external atmospheric pressure, the position adjustment of the first wafer 10 and the second wafer 20 in the subsequent step S14 can be performed. The first wafer 10 and the second wafer 20 can be appropriately bonded in step S15.

  Further, when pure water P is filled between the first wafer 10 and the second wafer 20, the pure water P may vaporize. In this case, latent heat is generated as the pure water P is vaporized, and the air in the space closed by the device region 13 and the bonded region 33 is cooled. If it does so, condensation will generate | occur | produce on the side surface of the device area | region 13, and there exists a possibility of having a bad influence on the position adjustment by the surface tension of the pure water P. FIG. In this regard, in the present embodiment, since air is exhausted from the air holes 110 and 111, this condensation can be prevented. Furthermore, the periphery of the first wafer 10 and the second wafer 20 may be depressurized in order to promote exhaust from the air holes 110 and 111.

  In the above embodiment, the first wafer 10 and the second wafer 20 are placed in a state where the first wafer 10 is disposed relatively downward and the second wafer 20 is disposed relatively upward. Although bonded, the arrangement of the first wafer 10 and the second wafer 20 may be reversed. That is, even when the first wafer 10 and the second wafer 20 are bonded in a state where the first wafer 10 is disposed relatively upward and the second wafer 20 is disposed relatively to the other. Good.

  In such a case, in step S12, as shown in FIG. 25, the first wafer 10 is disposed on the device layer 21 side of the second wafer 20, and the first wafer 10 and the second wafer 20 are overlaid. . Thereafter, in step 13, as shown in FIG. 26, pure water P is supplied from the liquid supply hole 28 of the support wafer 27 and the liquid supply hole 29 of the second wafer 20 to the liquid supply region 16 of the first wafer 10. That is, the pure water P is supplied from below to above. Thereafter, in step S14, the restoring force (FIG. 26) moves the first wafer 10 as shown in FIG. 26 by the surface tension of the pure water P filled between the first wafer 10 and the second wafer 20. ) Acts on the first wafer 10. Thus, the position adjustment of the first wafer 10 and the second wafer 20 is performed. Thereafter, in step S15, the first wafer 10 and the second wafer 20 are appropriately bonded.

  Also in the present embodiment, the same effects as those of the above embodiment can be obtained, and the first wafer 10 and the second wafer 20 can be simply and appropriately bonded.

  Also in the present embodiment, air holes 110 and 111 may be formed in the second wafer 20 and the support wafer 27, respectively, as shown in FIG.

  The support wafer 27 of the above embodiment has an elevating mechanism 120 as a position adjustment mechanism for adjusting the vertical relative positions of the first wafer 10 and the second wafer 20 as shown in FIG. It may be. A plurality of lifting mechanisms 120 are provided on the outer peripheral portions of the first wafer 10 and the second wafer 20. The elevating mechanism 120 extends vertically downward from the surface of the support wafer 27, bends further, and extends in the horizontal direction so as to be positioned between the first wafer 10 and the second wafer 20. In addition, for example, a telescopic lifting pin is used for a portion extending in the vertical direction of the lifting mechanism 120.

  In such a case, when the second wafer 20 is disposed on the device layer 12 side of the first wafer 10 in step S12, the lifting mechanism 120 supports the space between the first wafer 10 and the second wafer 20. And the space | interval between the 1st wafer 10 and the 2nd wafer 20 is maintained by the raising / lowering mechanism 120 at a suitable space | interval. At this stage, since the second wafer 20 is supported by the elevating mechanism 120, the level state can be maintained more precisely than when the elevating mechanism 120 is not provided. Thereafter, in step S13, pure water P is supplied from the liquid supply hole 29 onto the liquid supply region 16 of the first wafer 10, and the reduction of the lifting mechanism 120 is started. When the elevating mechanism 120 starts to be reduced, the second wafer 20 is supported only by the pure water P, and the position adjustment of the first wafer 10 and the second wafer 20 in step S14 proceeds. Thereafter, in step S15, the first wafer 10 and the second wafer 20 are bonded.

  According to the present embodiment, since the interval between the first wafer 10 and the second wafer 20 can be controlled to an appropriate interval by the lifting mechanism 120, the position adjustment of the first wafer 10 and the second wafer 20 can be performed. A joining process can be performed appropriately. Further, if the distance between the first wafer 10 and the second wafer 20 is very small and the weight of the second wafer 20 and the support wafer 27 is large, the distance may not be properly maintained with pure water P alone. . In this case, the present embodiment in which the distance between the first wafer 10 and the second wafer 20 can be physically maintained by the elevating mechanism 120 is particularly useful.

  In addition, the structure of the raising / lowering mechanism 120 is not limited to the said embodiment, A various structure can be taken. For example, as shown in FIG. 29, the lifting mechanism 120 may be configured to extend in the vertical direction from the surface of the support wafer 27 at the outer peripheral portions of the first wafer 10 and the second wafer 20. For the elevating mechanism 120, for example, a telescopic elevating pin is used. The lifting mechanism 120 is supported at its end by a mounting table 121 on which the first wafer 10 is mounted.

  Even in such a case, the distance between the first wafer 10 and the second wafer 20 can be controlled to an appropriate distance by the elevating mechanism 120 as in the above embodiment, and the position of the first wafer 10 and the second wafer 20 can be controlled. Adjustment and joining processing can be performed appropriately.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood. The present invention is not limited to this example and can take various forms.

DESCRIPTION OF SYMBOLS 10 1st wafer 11 Bulk layer 12 Device layer 13 Device (device area)
15 Scribe line (scribe line area)
16 Liquid supply area 20 Second wafer 21 Bulk layer 22 Device layer 23 Device (device area)
25 Scribe line (scribe line area)
27 Support wafer 28 Liquid supply hole 29 Liquid supply hole 30 Through hole 31 Through electrode 32 Insulating film 33 Bonded region 40 Liquid supply hole 41 Through hole 42 Through electrode 100 Semiconductor device 110 Air hole 111 Air hole 120 Elevating mechanism P Pure water

Claims (14)

A method of bonding a first substrate on which a plurality of semiconductor devices are formed and a second substrate on which a plurality of semiconductor devices are formed,
In the surface of the first substrate on which the plurality of semiconductor devices are formed, the semiconductor device region that is higher than the region that becomes the scribe line between the semiconductor devices and the region that becomes the scribe line are adjacent to each other. A first step of forming a liquid supply region having the same height as the semiconductor device region and connecting the adjacent semiconductor device regions;
A second step of forming a liquid supply hole penetrating in a thickness direction of the second substrate at a position corresponding to the liquid supply region in the second substrate;
A third step of superimposing the first substrate and the second substrate;
A substrate bonding method comprising: a fourth step of supplying a processing liquid to the liquid supply region through the liquid supply hole and bonding the first substrate and the second substrate. The said 2nd process WHEREIN: The said liquid supply hole and the through-hole in the said semiconductor device of the said 2nd board | substrate are formed simultaneously, and also a through-electrode is formed in the said through-hole. A method for bonding substrates as described in 1. The bonding method according to claim 2, further comprising a fifth step of forming another through electrode in the semiconductor device of the first substrate after the fourth step. Before the second step, an air hole penetrating in the thickness direction of the second substrate is formed in the second substrate other than the region corresponding to the semiconductor device region and the liquid supply region. The method for bonding substrates according to any one of claims 1 to 3. The substrate bonding method according to claim 1, wherein the treatment liquid is pure water. Activating the surface of the semiconductor device region after the first step and before the third step;
The surface of the second substrate on which the plurality of semiconductor devices are not formed is activated after the second step and before the third step. 6. The method for bonding substrates according to any one of 5 above. The substrate according to claim 6, wherein activation of a surface of the semiconductor device and activation of a surface of the second substrate on which the plurality of semiconductor devices are not formed are each performed by ammonia. Joining method. At least in the third step or the fourth step, a position adjustment mechanism for adjusting the relative position between the first substrate and the second substrate is used to determine a predetermined distance between the first substrate and the second substrate. The substrate processing method according to any one of claims 1 to 7, wherein the substrate is maintained at an interval of. A semiconductor device in which a substrate on which a plurality of semiconductor devices are formed is bonded to a plurality of layers,
In the surface on which the plurality of semiconductor devices are formed, a semiconductor device region that is higher than a region that becomes a scribe line between the semiconductor devices, and a region that becomes the scribe line has the same height as the adjacent semiconductor device region. And a first substrate on which a liquid supply region that connects the adjacent semiconductor device regions is formed,
A second substrate having a liquid supply hole penetrating in the thickness direction at a position corresponding to the liquid supply region;
A semiconductor device, wherein a processing liquid is supplied to the liquid supply region through the liquid supply hole, and the first substrate and the second substrate are bonded to each other. The air hole penetrating in the thickness direction of the second substrate is formed in the second substrate other than the region corresponding to the semiconductor device region and the liquid supply region. The semiconductor device described. The semiconductor device according to claim 9, wherein the treatment liquid is pure water. 12. The semiconductor according to claim 9, wherein a surface of the semiconductor device region and a surface of the second substrate where the plurality of semiconductor devices are not formed are respectively activated. apparatus. The semiconductor device according to claim 12, wherein the activation of the surface of the semiconductor device and the activation of the surface of the second substrate where the plurality of semiconductor devices are not formed are each performed by ammonia. . When the processing liquid is supplied to the liquid supply region through the liquid supply hole and the first substrate and the second substrate are bonded, a predetermined interval is provided between the first substrate and the second substrate. The semiconductor device according to claim 9, wherein a position adjusting mechanism that maintains the position is used.

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