JP2009105254A - Joining method, device manufactured by the same, and joining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joining method for joining a joining object without damaging the joining object, and also to provide a device manufactured by the method, and its joining device. <P>SOLUTION: A surface activation treatment is performed by irradiating a surface of a junction part 22a formed on a surface of a substrate 22 and formed of gold with energy waves by plasma in a cleaning part so as to remove an oxide film and the like formed on the surface. Thereafter, metal bumps 20a formed on a chip 20 and each having a cross-sectionally pointed shape, and the junction part 22a are grounded and pressed. Since the metal bumps 20a are crushed by the pressing, and a newly formed surface is exposed, the metal bumps 20a are joined to the junction part 22a. By setting the pressing force to 50-700 MPa to reduce the height from the junction surface of the chip 20 to tips of the metal bumps 20a to 20-90%, the metal bumps 20a allow the joining high in junction strength and electrically high accuracy without damaging the chip 20 and the substrate 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a joining technique for joining a plurality of objects having metal joints at room temperature.

  Conventionally, as a method of bonding a plurality of objects to be bonded, an oxide film or an organic material adhesion layer formed on the bonding surface is formed by irradiating the bonding surface of the objects to be bonded with an energy wave that is an atomic beam, an ion beam, or plasma. There is a method in which the objects to be joined are joined by utilizing a phenomenon in which atoms such as metals on the joining surface are attracted by being removed and activated.

  As an example of such a bonding method, in Patent Document 1, after the surface activation treatment is performed by irradiating the surfaces of both objects to be bonded having a bonding portion made of metal with an energy wave by plasma, in a low vacuum or Pressurization is performed by bringing the joints of both workpieces into contact with each other in the air. As a result, the oxide film and the organic matter adhesion layer reattached to the surfaces of both objects to be bonded after the surface activation treatment are crushed and the new surface is exposed. In this method, dangling bonds of metal atoms are generated on the bonding surfaces, and the dangling bonds are bonded to each other to bond both objects to be bonded.

Japanese Patent No. 3790995 (paragraphs 0008 to 0010, 0165, FIG. 19)

  However, in the bonding apparatus according to the method of Patent Document 1, since both objects to be bonded are subjected to surface activation treatment by plasma energy waves, bonding is performed. There is a risk of giving. In addition, depending on the hardness of the object to be bonded, the surface of the object to be bonded is greatly scraped by energy waves, which may cause mechanical damage. For this reason, the bonding apparatus in the method of Patent Document 1 is not suitable for bonding a bonding object that may be damaged by an energy wave, such as a sensing element, for example, a light receiving element, to these substrates. Realization of a bonding apparatus that can perform bonding without damaging an object is desired.

  The present invention has been made in view of the above problems, and provides a bonding method capable of bonding an object to be bonded without damaging the object to be bonded, a device created by the method, and a bonding apparatus therefor. For the purpose.

  In order to solve the above-described problems, a joining method according to the present invention is formed by forming a metal joint having a pointed cross-sectional shape on a joint surface of one object to be joined and gold on the joint surface of the other object to be joined. After forming a bonding portion and surface-treating the bonding objects of the two bonded objects with the energy wave in the bonding object of the other bonded object, the metal bonding part and the other of the one bonded object And pressurizing with a pressing force at which the height from the joining surface of the one article to be joined to the tip of the metal joint is 20% to 90%. The metal joints are crushed and joined (claim 1).

  Further, the bonding method according to the present invention is characterized in that the energy wave is plasma (claim 2).

  In the bonding method according to the present invention, the metal bonding portion formed on the one object to be bonded is a metal bump.

  Further, the joining method according to the present invention is characterized in that the metal joint formed on the one article to be joined is a metal frame formed so as to surround a predetermined region of the article to be joined (claim). 4).

  In addition, the joining method according to the present invention is such that the metal frame of the one article to be joined and the joining portion of the other article to be joined are pressed and pressurized in a vacuum, thereby A space surrounded by the metal frame body between the bonded object and the other bonded object is vacuum-sealed (Claim 5).

  Further, in the joining method according to the present invention, the metal frame body of the one article to be joined and the joining portion of the other article to be joined are pressed and pressurized in an enclosed gas. The sealed gas is sealed in a space surrounded by the metal frame between the object to be bonded and the other object to be bonded (Claim 6).

  Moreover, the joining method according to the present invention is characterized in that the metal joint portion of the one article to be joined is formed by gold plating.

  Moreover, the joining method according to the present invention is characterized in that pressurization is performed so that the applied pressure per one metal joint formed on the one article to be joined is 50 MPa to 700 MPa. .

  In the bonding method according to the present invention, the one object to be bonded is a sensing element (claim 9).

  The device formed by the bonding method according to any one of claims 1 to 9 is characterized by comprising a semiconductor device, an optical device, or a MEMS device (claim 10).

  In order to solve the above-described problem, a bonding apparatus according to the present invention is a bonding apparatus for bonding objects to be bonded held on a head and a stage, and has a pointed cross section on the bonding surface of one of the objects to be bonded. The metal joints of one of the objects to be joined are formed by forming a metal joint having a shape and forming a joint made of gold on the joint surface of the other object to be joined. And the joining portion of the other object to be joined, and the height from the joining surface of the one object to be joined to the tip of the metal joining portion is crushed and becomes a height of 20% to 90%. Pressurizing control means for pressurizing with pressure, wherein the pressurizing control means pressurizes both the objects to be bonded, the surface of which the bonding portion of the other object to be bonded is subjected to surface activation treatment by the energy wave. Crush the metal joint of the object to be joined Serial is characterized by connecting the two objects to be bonded to each other (Claim 11).

  Further, in the joining apparatus according to the present invention, the pressurizing control means pressurizes the pressurizing force per one metal joint formed on the one object to be joined to be 50 MPa to 700 MPa. (Claim 12).

  The bonding apparatus according to the present invention is further characterized by further comprising energy wave irradiation means for performing the surface activation treatment (claim 13).

  In the bonding apparatus according to the present invention, the energy wave irradiation means generates plasma (claim 14).

  The inventor of the present application has said that the metal joint formed on the joint surface of one of the objects to be joined has a pointed cross-sectional shape and is easily crushed by pressurization. If the metal joint is crushed within a range of 20 to 90%, the new surface can be brought out while reliably removing the oxide film and the organic adhesion layer, and can be in contact with other metal joints. It was experimentally found that bonding with good electrical reliability was possible. Therefore, according to invention of Claim 1, 11, the height from the joint surface of one to-be-joined object to the front-end | tip of a metal joint part is 20-90% as for the metal joint part which has the said cross-sectional shape. By crushing within a range, it is possible to break through the adhesion layer of oxide film and organic matter, and as a result, surface activation treatment by energy waves such as plasma before bonding is performed on metal joints having a pointed cross section This can be omitted and the process can be simplified.

  In addition, since the joint formed on the joint surface of the other object to be joined is formed of gold that is not oxidized in the atmosphere, after the surface activation, an oxide film or organic matter is reattached to the surface of the joint. A layer is hardly formed, and good bonding can be performed. In addition, even if organic matter is reattached and a layer is formed, the thickness of the reattached layer is thin within a certain time after the surface of the joint is surface activated. By pressing and pressing the metal joint and the gold joint, the reattachment layer is efficiently scraped off due to slippage at the interface between the metal joint having a pointed cross section and the gold joint. Highly bonding is performed.

According to the invention described in claims 2 and 14, since the energy wave for performing the surface activation treatment of the bonding portion made of gold is plasma, the bonding is performed in a low vacuum space having a degree of vacuum of about 10 ⁻² Torr. The surface activation treatment of the part can be performed. Therefore, the apparatus configuration for performing the surface activation process is simple equipment, and the apparatus can be made compact and the cost can be reduced.

  According to the invention of claim 3, since the metal bump is formed as the metal joint portion having the cross-sectional shape of one of the objects to be joined, the metal bump is crushed by pressurization to join the other object to be joined. By bonding to the part, one of the objects to be bonded and the other of the objects to be bonded can be bonded with high definition in a substrate having a fine electrode or bonding that requires high-precision mounting.

  According to invention of Claim 4, since the metal frame which has a cross-sectional point shape as a junction part is formed in the joining surface of one to-be-joined object, it crushes a metal frame by pressurization and the other By joining with the joint part of a to-be-joined object, the space enclosed by the joint surface of both to-be-joined objects and a metal frame can be sealed by predetermined | prescribed atmosphere. Therefore, a main body of a device such as a semiconductor device such as a surface acoustic wave device or an RF device or a MEMS device having a mechanically movable part is disposed in a space surrounded by the joining surface of both objects to be bonded and a metal frame. Sometimes it is possible to protect a device or the like from external stimuli.

  According to the fifth aspect of the present invention, by joining the joints of both objects to be bonded in a vacuum, the space surrounded by the joint surfaces of both objects to be bonded and the metal frame is easily sealed in a vacuum atmosphere. Can be stopped. Further, if the surface activation treatment of the joined portion of the other object to be joined and the joining of the joint portions of both the objects to be joined are performed in the same chamber, the reaction gas is discharged from the chamber after the surface activation treatment, and the vacuum atmosphere is obtained. Therefore, it is possible to omit procedures such as opening / closing of the chamber and re-evacuation, and the bonding can be performed efficiently.

  According to the sixth aspect of the present invention, the sealed gas can be easily introduced into the space surrounded by the joining surface of the objects to be joined and the metal frame by joining the joined portions of the objects to be joined in the sealed gas. Can be encapsulated. Also, for example, when Ar plasma is used for energy waves and Ar is also used as the sealing gas, the surface activation treatment is performed after the surface activation treatment of the joined portion of the other object to be bonded by the energy waves of Ar plasma. Since the Ar atmosphere used in the treatment can be used as it is for bonding, the bonding can be performed efficiently.

  According to invention of Claim 7, since a metal junction part is formed by gold plating, crystallinity is good and the metal of a metal junction part and the junction surface which consists of gold | metal | money is easy to couple | bond together. Furthermore, since gold, which is the same material as the joint, is used as the material for the metal joint, an oxide film is not formed in the atmosphere, and even if a thin reattachment layer such as an organic substance is formed, the hardness is low. It can be easily crushed by pressurization, and a new surface appears. Therefore, it is possible to perform good bonding with high bonding strength.

  The inventor of the present application, as long as the applied pressure per one metal joint formed on one workpiece is within a range of 50 to 700 MPa, regardless of conditions such as the type of metal and the speed of pressurization. The inventors have experimentally found that the height of the metal joint is in the range of 20 to 90%. Therefore, according to the invention described in claims 8 and 12, by applying pressure so that the applied pressure per one metal joint formed on the one article to be joined is 50 to 700 MPa, Good bonding with high bonding strength and no damage to the objects to be bonded can be performed. Moreover, also in the pressurizing force, for example, it is possible to reduce the pressure as compared with the case where metal bumps having no cross-sectional shape are joined.

  According to the ninth aspect of the present invention, even when a sensing element that is easily damaged by plasma, such as a light receiving element, is used as one object to be joined, Since the light-receiving element that is a bonded body is not subjected to surface activation treatment by energy waves, the light-receiving element can be bonded to the bonding portion of the other bonded object without damaging the light-receiving element.

  According to the invention described in claim 10, for example, even if one of the objects to be bonded is a sensing element that is easily damaged by energy irradiation by plasma or the like, the object to be bonded is formed without being damaged. By joining, it is possible to provide a device that is prevented from being damaged by heat and that has high alignment accuracy.

  According to the thirteenth aspect of the present invention, since the bonding apparatus is provided with the energy wave irradiation means for performing the surface activation process, the surface activation process of the bonded portion of the other object to be bonded and the metal having the pointed cross section The joining operation of one object to be joined and the other object to be joined can be continuously performed with one apparatus. Therefore, it is possible to shorten the time until the bonding is performed after the surface activation treatment of the bonding portion, and it is possible to prevent organic substances and the like from reattaching to the bonding portion after the surface activation treatment. become. Moreover, since a series of joining operations can be performed with one apparatus, it is simple and the apparatus can be made compact.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an embodiment of a bonding apparatus according to the present invention, FIG. 2 is a diagram illustrating a bonding process, FIG. 3 is a schematic diagram of rotation in a crystal direction at a bonding interface during bonding, and FIG. FIG. 5 is an enlarged perspective view showing a part of a chip and metal bumps. In the apparatus configuration according to the present invention shown in FIG. 1, the metal bump 20a as a metal joint portion having a pointed cross section formed on the joint surface of the chip 20 which is one of the objects to be joined and the other object to be joined. As an example, an apparatus for bonding the bonding portion 22a made of gold formed on the bonding surface of the substrate 22 in the atmosphere will be described.

  As shown in FIG. 1, the bonding apparatus according to the present embodiment includes a bonding mechanism 27 including a vertical driving mechanism 25 and a head unit 26, a mounting mechanism 28 including a stage 10 and a stage table 12, a position recognition unit 29, and a conveyance unit 30. The control device 31 and the cleaning unit 40 are provided. The joining mechanism 27 includes a vertical drive mechanism 25 and a head portion 26. The vertical drive mechanism 25 moves the head holding portion 6 up and down while being guided by the vertical guide 3 by the vertical drive motor 1 and the bolt / nut mechanism 2. It is configured to be able to move. The joining mechanism 27 is coupled to the frame 34, and the frame 34 is connected to the gantry 35 by the four support columns 13 disposed so as to surround the periphery of the pressure center of the head portion 26. A part of the support column 13 and the frame 34 is not shown.

  The head holding portion 6 is guided in the vertical direction by the head escape guide 5 and is connected to the bolt / nut mechanism 2 while being pulled by the own weight counter 4 for canceling the own weight. The head unit 26 is coupled to the head holding unit 6.

  The head holding unit 6 is provided with a pressure detection means 32, which can detect pressure applied to an object to be joined such as the chip 20 and the substrate 22 sandwiched between the tip tool 9 and the stage 10. It is configured as follows. Therefore, based on the pressure applied to the object to be bonded detected by the pressure detection means 32, the controller 31 can control the vertical drive mechanism 25 to control the pressure applied to the object to be bonded.

  Further, the head unit 26 includes a chip holding tool 8 and a tip tool 9 for sucking and holding the chip 20, a head side alignment table 7 for correcting a position having a translation axis of translation and rotation, and a head holding unit 6 for supporting them. It is comprised by. The height of the head part 26 can be detected by the head part height detecting means 24.

  The mounting mechanism 28 includes a stage 10 that holds the substrate 22, and a stage table 12 that has a movable shaft that can be moved in parallel and rotationally to adjust the position of the substrate 22 with respect to the chip 20. The stage 10 includes a holding mechanism (not shown) for holding the substrate 22. Here, as a holding mechanism of the chip holding tool 8 and the stage 10, a device using vacuum suction or electrostatic suction may be used. Further, the substrate 22 may be simply placed on the stage 10. A heating heater (not shown) is embedded in the chip holding tool 8, and a stage heater 11 is built in the stage 10.

  The position recognition unit 29 is inserted between the chip 20 and the substrate 22 which are opposed to each other, and the upper and lower mark recognition means 14 and the upper and lower mark recognition means 14 for recognizing the alignment marks for position recognition of the upper and lower chips and the substrate are placed horizontally It comprises a recognition means moving table 15 that moves up and down.

  The transport unit 30 includes a chip supply device 36 that transports the chips 20, a chip tray 38, a substrate transport device 37 that transports the substrate 22, and a substrate tray 39. The chip tray 38 is supplied and stored from the chip tray cassette 41, and the substrate 22 is supplied and stored from the substrate cassette 42.

  The control device 31 includes an operation unit for performing operations necessary for control, and the control device 31 performs overall control of the device. In particular, in the pressure control, the torque of the vertical drive motor 1 is controlled by a signal from the pressure detection means 32, and the pressure applied to the workpiece is controlled.

  In the cleaning unit 40, a surface activation process is performed on the surface of the bonding portion 22 a of the substrate 22 by an energy wave such as plasma to remove an oxide film or an organic substance layer on the bonding portion 22 a surface. Note that surface activation treatment may be performed by an ion beam, an atomic beam, or the like other than an energy wave such as plasma.

  The cleaning unit 40 includes a vacuum chamber 43, an object holding means 44, an energy wave irradiation means 45, an intake pipe and an exhaust pipe (not shown). The object holding means 44 includes a heater (not shown), and the substrate 22 is fixed to an electrode surface to which an alternating power source is connected by a mechanical method.

As the suction gas, for example, Ar gas is used, but nitrogen, oxygen, or the like may be used, or a mixed gas such as Ar and oxygen may be used. For example, when Ar gas is used, plasma is generated at a constant degree of vacuum of about 10 ⁻² Torr.

  The generated plasma collides toward the surface of the bonded portion 22a of the substrate 22 held by the bonded object holding means 44, the deposit layer due to the oxide film or organic matter on the surface is removed, and a new surface appears and the surface Is activated.

  In addition, as a method for performing the surface activation process on the bonding portion 22a of the substrate 22, it is preferable in terms of efficiency to perform the surface activation process on the substrate 22 held on the electrode surface to which the alternating power source is connected. Then, the electrode may be installed in a place other than the holding position of the substrate 22 to perform surface activation treatment.

  In order to continuously perform cleaning and bonding, the cleaning unit 40 is connected to the bonding apparatus by the transport unit 30. However, the cleaning unit 40 may be configured without the cleaning unit 40. In that case, it is necessary to perform surface activation processing of the substrate 22 in advance by another cleaning device or the like.

  Next, a series of joining operations will be described with reference to FIG. In the present embodiment, a bonding operation in which a chip 20 made of a semiconductor, which is one object to be bonded, is bonded to a substrate 22, which is the other object, is exemplified.

  Metal bumps 20a made of copper, which is an electrode and has a sharp tip shape, are formed on the joint surface of the chip 20, and a joint portion 22a made of gold that is an electrode is formed on the joint surface of the substrate 22. The chip is disposed at a position facing the metal bump 20a on the chip side. An example of the shape of the metal bump 20a is shown in FIG. As shown in FIG. 5A, the metal bump 20a has a pyramid shape, and the metal bump 20a has a square shape with a side of 10 μm at the joint surface between the chip 20 and the metal bump 20a. The length to the tip of the metal bump 20a is 10 μm. The shape of the metal bump 20b is not limited to the pyramid shape, but may be other shapes such as other pyramids and cones. For example, as shown in FIG. 5B, the cross-sectional shape may be a columnar shape such as a pentagon as long as it has a pointed cross-sectional shape. Further, the dimensions are not limited to the above-described examples, and any dimensions may be used. Also, gold is preferable.

  Furthermore, the material of the metal bump 20a is not limited to gold, and may be formed of other materials, or the metal bump 20a may be configured by forming a gold film or the like on the surface of a base material made of metal. Good. For example, in order to make it easy to be crushed, the metal bump 20a having a gold film on the surface may be formed using a low hardness tin or an alloy layer of gold and tin as a base material. When the metal bump 20a is formed of a base material and a gold film as described above, if the gold film remains on the surface of the metal bump 20a even after the metal bump 20a is crushed by pressure, the metal bump 20a Since the gold atoms in the bonding portion 22a of the substrate 22 attract each other, it is possible to perform good bonding with high bonding strength. Therefore, it is preferable to adjust the thickness and pressure of the gold film so that the gold film remains on the surface of the metal bump 20a even after pressurization.

  The substrate 22 is carried into the cleaning device 40 from the substrate tray 39 by the substrate transfer device 37. Then, as shown in FIG. 2 (a), an energy wave such as plasma is irradiated on the bonding portion 22a, and a surface activation process is performed to remove an oxide film or an organic matter layer formed on the surface of the bonding portion 22a. Is done. When the surface activation process is completed by the cleaning unit 40, the substrate 22 is taken out from the cleaning unit 40, transported to the stage 10 of the mounting mechanism 28 by the substrate transport device 37, and sucked and held on the stage 10.

  On the other hand, the chip 20 is conveyed from the chip tray 38 to the chip holding tool 8 by the chip supply device 36, and is sucked and held by the chip holding tool 8 with the bonding surface facing the substrate 22 as shown in FIG.

  When the chip 20 and the substrate 22 are sucked and held with the bonding surfaces facing each other, the upper / lower mark recognition means 14 is inserted between the chip 20 and the substrate 22 by the recognition means moving table 15, and the chip 20 and the substrate 22 facing each other. The alignment mark for alignment is detected by the upper and lower mark recognition means 14. Thereafter, the position of the substrate 22 is moved by moving the stage table 12 in parallel and rotating with the chip 20 as a reference, and the positions of the chip 20 and the substrate 22 are adjusted. The positions of the chip 20 and the substrate 22 may be adjusted using the stage table 12 and the head side alignment table 7 or may be adjusted using only the head side alignment table 7. Moreover, the structure of only one of the tables may be used. The alignment method is not limited to two views or a camera, and may be recognized by a recognition means arranged individually.

  Next, the upper and lower mark recognizing means 14 is retracted by the recognizing means moving table 15 in a state where the joining positions of the chip 20 and the substrate 22 are aligned. Next, the head portion 26 is lowered by the vertical drive mechanism 25, and the metal bump 20a of the chip 20 and the joint portion 22a of the substrate 22 are grounded. The position of the head portion 26 in the height direction is detected by the head height detecting means 24. Then, the contact timing of the chip 20 and the substrate 22 is detected by the pressure detection means 32, and the vertical drive motor 1 is switched from position control to torque control, and as shown in FIG. A pressure is applied and bonding is performed.

  A heating heater (not shown) is embedded in the chip holding tool 8 and a stage heater 11 is built in the stage 10, so that the chip 20 and the substrate 22 are heated during pressurization. Can also be joined. By heating, the crystal orientation is efficiently rotated and the particles are moved, the bonding proceeds, and the residual stress is removed, whereby the bonding strength can be increased. Even during pressurization switched to torque control, the head height is monitored by the head height detecting means 24, and the position in the height direction can be adjusted.

  In general, an adhesion layer such as an oxide film or an organic substance is formed on the surface of an object to be bonded such as the chip 20 or the substrate 22 in the atmosphere. However, it is not joined as it is. Therefore, the metal bumps 20a and the joints 22a are continuously joined in vacuum in a state where the metal bumps 20a and the joints 22a are irradiated with energy waves such as plasma to expose the new surfaces in vacuum.

  However, in this embodiment, by pressing the chip 20 and the substrate 22, as shown in FIGS. 3A and 3B, the tips of the metal bumps 20a are crushed, so that the movement of aligned crystals and Rotation in the crystal direction occurs and the new surface is exposed. In other words, the metal bumps 20a of the chip 20 are crushed and spread by pressing, and slip occurs between the metal bumps 20a and the joints 22a. Therefore, an oxide film or adhesion formed on the surface of the metal bumps 20a. The layer of organic matter or the like is crushed and the new surface is exposed.

  In addition, since the oxide film or organic layer formed on the surface of the bonding portion 22a is removed by performing the surface activation process of the bonding portion 22a in the cleaning unit 40 before bonding as described above, the bonding portion 22a. A new surface is exposed on the surface. In addition, since the junction 22a is made of gold, it is difficult to form a redeposition layer such as an oxide film or an organic substance, and even if it is formed, its thickness is small within a certain time after the surface activation treatment. The bump 20a is grounded to the joint 22a and pressed to break it. Therefore, a new surface is exposed again on the surface of the bonding portion 22a, and metal atoms of the metal bump 20a and the bonding portion 22a are attracted by an atomic force, and bonding is performed in the atmosphere as shown in FIG.

  Further, in the prior art, the chip-side joint has a shape that is not easily deformed because it does not have a pointed cross section, so when the chip-side joint is pressed against the substrate-side joint, the chip side The slip between the joints generated when the joints of the chip are crushed and spread is small, and it was necessary to remove the oxide film and the like on the joint surfaces of both the chip side and the substrate side joints by energy waves such as plasma. .

  On the other hand, in the present embodiment, the metal bump 20a of the chip 20 has a pointed cross-sectional shape, and the metal bump 20a is more easily deformed by pressurization than the conventional technology. Therefore, along with the deformation of the metal bump 20a, the slip between the metal bump 20a and the joint 22a that occurs when the metal bump 20a is crushed and spreads increases at the interface between the metal bump 20a and the joint 22a. Therefore, at the same time that the new surface is exposed by the metal bump 20a, the reattachment layer of the joint 22a is easily broken by the slip, and the new surface is easily formed. Further, even when the pressure is applied, the pressure can be reduced as compared with the case where metal bumps not having a pointed cross section are joined.

  Therefore, in this embodiment, the new surface can be exposed on the metal bump 20a without performing the surface activation process of the metal bump 20a of the chip 20. Furthermore, the removal of the reattachment layer formed after the surface activation treatment can be facilitated by slipping between the metal bump 20a and the joint 22a when the joint 22a is pressurized. Therefore, for example, when the bonding portion of the other object to be bonded is a pad, the pad surface after the plasma cleaning also has a pointed cross-sectional shape compared to the case where the metal bump does not have a pointed-shaped cross-sectional shape. Since the redeposition layer is efficiently scraped off due to the slip of the interface between the metal bump 20a and the pad surface, highly reliable bonding is performed.

  In addition, the present inventor reliably removes an adhesion layer such as an oxide film or an organic substance on the surface of the metal bump 20a by crushing the metal bump 20a within a range from 20% to 90% from the joint surface to the tip. As a result, it was experimentally found that the new surface can be exposed and bonding with high electrical reliability is possible. With reference to FIG. 4, the relationship between the height from the bonding surface to the tip of the metal bump 20a and the bonding strength will be described.

  FIG. 4 is a diagram showing the relationship between the height of the metal bump 20a and the bonding strength when the metal bump 20a is Au, Al, or Cu. In the figure, the height of the metal bump 20a is 0% when it is completely crushed and 100% when it is not crushed at all. In the same figure, the bonding strength for good bonding is 15 g or more per bump, and the bonding strength per bump is 15 g or more and the bonding strength is sufficiently good. It can be seen that the height from the joint to the tip of the metal bump 20a may be about 20 to 90% before pressing.

  Moreover, in FIG. 4, when the height of the metal bump 20a after pressurization is 0 to 20% of the height of the metal bump 20a before pressurization, the metal bump 20a is largely crushed and thus is sufficiently bonded. However, it is considered that there is a possibility that the chip 20 and the substrate 22 are not joined, such as excessive damage, and excessive damage to the chip 20 and the substrate 22. Further, when the height of the metal bump 20a is 90% to 100% of the height of the metal bump 20a before pressurization from the joint surface after pressurization, the metal bump 20a is less crushed and may not be joined. It is thought that there is. Considering the above points, the height of the metal bumps for good bonding is the case where the height of the metal bumps after pressurization is 20 to 90% of the height of the metal bumps 20a before pressurization. It is good.

  Therefore, the object to be bonded such as the chip 20 or the substrate 22 is pressurized so that the height from the bonding surface of the metal bump 20a is in the range of 20 to 90% of the height from the bonding surface before pressing. Good.

  Therefore, during pressurization, the height of the metal bump 20a from the substrate 22 is detected by monitoring the height of the head holding the substrate by head height detection means (not shown), and the height of the metal bump 20a is detected. The applied pressure may be adjusted so that the height is 20 to 90% of the height of the metal bump 20a before pressing.

  In addition, the present inventor, when the pressure applied to the metal bump 20a formed on the chip 20 is in the range of 50 to 700 MPa per bump regardless of conditions such as the type of metal and the speed of pressurization, It has been experimentally found that the metal bump 20a is crushed to a height in the range of 20 to 90%. Therefore, a pressing force in the range of 50 to 700 MPa per bump is applied to the chip 20 and the substrate 22, and the control is performed so that the height of the metal bump 20 a is 20 to 90%. it can.

  After the bonding is completed, the adsorption of the chip 20 is released, and the chip 20 is mounted on the substrate 22 side and remains on the stage 10, and the bonded chip 20 and the substrate 22 are again bonded to the substrate tray 39 by the substrate transfer device 37. And the series of joining operations is completed.

  Therefore, according to the first embodiment, the metal bumps 20a formed on the chip 20a have a pointed cross-sectional shape and are easily crushed by pressure. As can be seen from FIG. 4, the metal bumps 20a If the metal bumps are crushed in a range of 20 to 90% of the height, the oxide film formed on the surfaces of the metal bumps 20a and the joints 22a and the organic adhesion layer can be reliably removed, and It has been experimentally found that bonding with high electrical reliability is possible without contact with other bumps. Therefore, by crushing the metal bump 20a having a pointed cross-sectional shape in a range of 20 to 90%, it is possible to smash the oxide film and the organic adhesion layer. As a result, regarding the metal bump 20a, Surface activation treatment by energy waves such as plasma before bonding can be omitted, and the process can be simplified.

  Further, since the bonding portion 22a formed on the bonding surface of the substrate 22 is formed of gold that is not oxidized in the atmosphere, an oxide film or an organic substance is reattached to the surface of the bonding portion 22a after the surface activation process. Layers are rarely formed. Further, even if an oxide film or an organic substance is reattached to form a layer, the thickness of the reattached layer is small if the joint is within a certain time after the surface activation treatment, so that the metal bump 20a The reattachment layer can be pushed through by abutting and pressurizing the joint 22a made of gold and gold. Therefore, according to the present embodiment, the metal bump 20a and the joint portion 22a can be joined even in the atmosphere.

  Further, when the pressing force is controlled in the range of 50 to 700 MPa in the pressing force per metal bump 20a formed on the chip 20, the height of the metal bump 20a is in the range of 20 to 90%. Therefore, it is possible to perform good bonding with a large thickness and no damage to the objects to be bonded.

  Further, since the bonding portion 22a is surface-activated by energy waves such as plasma, bonding at a low temperature is possible. For example, as compared with the conventional tin-lead solder, the heating temperature at the time of bonding between the joints can be solid-phase bonded at 180 ° C. or lower, which is 183 ° C. or lower, which is the melting temperature of tin-lead solder. In addition, depending on the material of the metal bump 20a and the joint portion 22a, it can be performed at 100 ° C. or lower or at room temperature, and the risk of damage to the chip 20 or the substrate 22 due to heating is reduced. In addition, since it can be bonded in a solid phase, the phenomenon that tin-lead solder remelts at a high temperature as in the conventional case occurs in bonding that requires fine pitch electrodes and high-precision mounting within a few μm. In addition, high-definition bonding is possible.

In addition, since the energy wave for performing the surface activation process of the bonding part 22a is plasma, the surface activation process of the bonding part can be performed in a low vacuum space with a degree of vacuum of about 10 ⁻² Torr. Therefore, the apparatus configuration for performing the surface activation process is simple equipment, and the apparatus can be made compact and the cost can be reduced.

  In addition, the modification which makes the junction part 22a the bump shape (it is set as the metal bump 22b) which has a cross-sectional point shape similarly to the metal bump 20a can be considered. In this case, in principle, when joining metal bumps, both metal bumps are crushed and a new surface appears. Therefore, both metal bumps should be joined without performing surface activation treatment by energy waves such as plasma. It is thought that you can. However, in actuality, the positions of the tips of both metal bumps do not match. Therefore, when the metal bump 20a of the chip 20 is pushed into the metal bump 22b of the substrate 22 by pressurization, the positions of both metal bumps are shifted along the sharp tip. become. As a result, the new surfaces of both metal bumps are not pressed together and cannot be joined.

  Therefore, in order to bond at low temperature in the atmosphere, as in the present embodiment, the bonding portion 22a of the substrate 22 is preliminarily surface activated by energy waves such as plasma, and the metal bumps 20a are pressed and bonded. The method is effective.

(Second Embodiment)
Next, a second embodiment of the joining device according to the present invention will be described in detail. The point that this embodiment is greatly different from the first embodiment is that the metal bump 20a of the chip 20 that is the object to be bonded is formed by gold plating, and other configurations are the first embodiment. It is the same. Hereinafter, the second embodiment will be described in detail focusing on the differences from the first embodiment. In addition, about the structure and operation | movement same as 1st Embodiment, the description of the structure and operation | movement is abbreviate | omitted.

  In the second embodiment, the metal bump 20a of the chip 20 is configured as a metal bump formed by gold plating. As an example, the metal bumps 20a are formed by sequentially laminating gold by an electrolytic plating method, for example, in a pyramid shape. By forming by such a method, a metal bump with good crystallinity can be formed. In addition, an adhesion layer made of an oxide film or an organic substance is difficult to adhere to the bonding surface of the metal bump 20a, and since the hardness is low, the oxide film or the like on the surface is easily broken by pressurization, and the bonding is easy in the atmosphere. . Therefore, the heating temperature when heating to match the crystal structure at the bonding interface between the metal bump 20a and the bonding surface 22a can be set to a lower temperature or normal temperature, and damage to the chip 20 and the substrate 22 due to heating can be prevented. can do. The shape of the metal bump 20a is not limited to the pyramid shape, and may be any shape such as other pyramid shape or cone shape.

  In addition, when formed by the above-described method, for example, a stud bump that is bonded by generating a new surface by tearing off the tip does not allow impurities to be mixed into the material, so that the bonding strength is strong and Metal bumps having excellent electrical characteristics can be formed. In the case of a stud bump, the crystal structure changes between the central portion and the peripheral portion of the fracture surface due to plastic deformation due to tearing or pressurization. For example, the central portion of the fracture surface of the stud bump is bonded to the bonding surface 22a. The problem of not doing may occur. However, when the metal bumps 20a are formed by gold plating as described above, the crystallinity of the metal bumps 20a is good, and when crushed, a new surface appears and the crystal structures of the metal bumps 20a and the bonding surfaces 22a are matched. Therefore, bonding is also performed at the center of the metal bump 20a.

  Therefore, according to the second embodiment, since the metal bumps 20a are formed by gold plating, it is possible to form bumps with good crystallinity. Since the new surface is difficult to form such as an oxide film or a layer of deposits, the metal bump 20a can be easily bonded to the bonding portion 22a, and the heating temperature can be lowered. Damage due to heating to 22 can be prevented. Further, even if a layer such as a deposit is formed, the metal bump 20a is formed by gold plating, so the hardness is low, and a new surface appears easily by being crushed by pressure. In addition, since gold, which is the same material as the joining portion 22a, is used as the material for the metal bumps, the metals can be easily bonded to each other, and good bonding with high bonding strength can be performed.

(Third embodiment)
Next, the third embodiment will be described in detail. Hereinafter, differences from the first embodiment will be described, and description of the same configuration and operation as those of the first embodiment will be omitted.

  The present embodiment is greatly different from the first embodiment in that a CMOS image sensor, which is a light receiving element including visible light and infrared light, is bonded to the substrate 22 as the chip 20, and the other points are as follows. The configuration and operation are the same as those in the first embodiment. When the chip 20 is a light receiving element, if surface activation processing is performed before bonding, unnecessary charges or the like are given to the chip 20 by irradiation of energy waves such as plasma, and the chip 20 may be damaged.

  According to the present embodiment, even when a light receiving element that is easily damaged by plasma or the like is used as one object to be joined, the metal bump 20a having a pointed cross section is formed on the chip 20 that is the light receiving element. The surface activation process is not necessary, and the surface activation process can be omitted before the chip 20 and the substrate 22 are bonded. Therefore, the chip 20 that is a light receiving element can be bonded without being damaged. The light receiving element is not limited to a CMOS image sensor, and may be a light receiving element such as a CCD or other sensing elements. Further, the device is not limited to a sensing element, and a device using a material that is easily damaged by plasma, or a device formed with a thin film that may be damaged by etching or a wiring pattern made of silver or the like may be used.

(Fourth embodiment)
Next, the fourth embodiment will be described in detail. This embodiment is greatly different from the first embodiment described above as a metal joint having a pointed cross-sectional shape surrounding a predetermined area on the surface of the substrate body 901a of the device substrate 901 that is one of the objects to be joined. The metal frame 904 is projected and formed, and the lid substrate 902 and the metal frame 904, which are the other objects to be joined, are joined together, and the space surrounded by the metal substrate 904 and the joining surface of the device substrate 901 and the lid substrate 902, It is a point sealed in a predetermined atmosphere. Hereinafter, differences from the first embodiment will be described, and description of the same configuration and operation as those of the first embodiment will be omitted.

  First, the structure of the substrates bonded in the bonding apparatus of the present invention will be described in detail. 6 is a view showing an example of the device substrate and the lid substrate, and FIG. 7 is a cross-sectional view taken along the line AA in FIG.

  An example of the substrate will be described with reference to FIG. As shown in FIG. 6, a metal frame 904 having a pointed cross-sectional shape surrounding a predetermined region is formed on the surface of the substrate body 901a of the device substrate 901 so as to protrude by gold plating. In a region surrounded by the metal frame 904, a main body 903 of a device such as a semiconductor device such as a surface acoustic wave device or an RF device or a MEMS device having a mechanical movable part is formed. Here, the predetermined region is a region where an operation part or a vibration part of a circuit is formed. The material of the metal frame 904 is not limited to gold, but may be other materials such as copper and aluminum.

  Further, a gold thin film 905 is formed as a bonding portion on the surface of the substrate body 902a of the lid substrate 902 by sputtering or metal plating. Instead of the gold thin film 905, a metal frame or the like that protrudes at a position corresponding to the metal frame 904 may be used.

  With such a configuration, gold does not corrode and does not generate gas even when heated. Therefore, as will be described later, the device substrate 901 and the lid substrate 902 are bonded to each other, and both the substrates 901 and 902 are connected. This is practical as a sealing material that encloses a predetermined atmosphere in a space formed by the joint surface and the metal frame 904 and surrounded by a contour, and blocks the space from the external atmosphere.

  In the above example of the substrate, the metal frame 904 having a pointed cross section is formed on the surface of the substrate main body 901a by performing gold plating in a thick film shape. However, the surface of the base material made of metal is formed on the surface. A gold film may be formed.

  For example, in order to make it easy to be crushed, a metal frame 904 having a pointed cross-section with a gold film formed on the surface of a low hardness tin or an alloy layer of gold and tin may be formed. In this case, if the gold film remains on the surface of the metal frame 904 even after the metal frame 904 is crushed by pressure, the gold atoms in the metal frame 904 and the joint portion 905 attract each other. Good bonding with high strength can be performed. Therefore, it is preferable to adjust the thickness and pressure of the gold film so that the gold film remains on the surface of the metal frame 904 even after pressurization. Further, indium may be used instead of tin.

  Further, since the joining device and the joining operation are the same as those in the first embodiment, description thereof will be omitted. In the apparatus shown in FIG. 3, the metal frame 904 and the bonding portion 905 are bonded in the atmosphere. Therefore, in the space surrounded by the bonding surface of the device substrate 901 and the lid substrate 902 and the metal frame 904, The atmosphere will be enclosed.

  FIG. 8 is a diagram showing the relationship between the height of the metal frame 904 and the bonding strength when the metal frame 904 is Au, Al, or Cu. In the figure, the height of the metal frame 904 from the joint surface is 0% when it is completely crushed and 100% when it is not crushed at all. In the figure, the bonding strength for good bonding is 150 g or more per metal frame, and the bonding strength per metal frame is 150 g or more and the bonding strength is sufficiently good. As is the case with the metal bumps, it is understood that the metal frame 904 may be pressed and crushed so that the height of the metal frame 904 is approximately 20 to 90% of the height from the joint surface to the tip of the metal frame 904. . In addition, as in the case of the metal bump, the pressure is controlled in the range of 50 to 700 MPa per metal frame so that the height from the joint surface of the metal frame 904 is 20 to 90%. Also good.

(Fifth embodiment)
Next, a fifth embodiment will be described. In the present embodiment, as in the fourth embodiment, the joining portion 905 of the metal frame body 904 having a pointed cross-sectional shape protruding and surrounding a predetermined region of the device substrate 901 and the lid substrate 902 is performed. This embodiment differs greatly from the fourth embodiment described above in that a bonding apparatus for bonding the metal frame 904 and the bonding portion 905 is disposed in the chamber after the surface activation treatment of the bonding portion 905. It is a point. Hereinafter, this apparatus will be described in detail.

  FIG. 9 is a schematic configuration diagram showing a device configuration in the present embodiment. In the present embodiment, as shown in the figure, a surface activation processing chamber 51 is formed in the chamber 52, and a bonding chamber 55 is formed in the chamber 56. A surface activation processing device 53 is provided in the surface activation processing chamber 51. A bonding device 57 is disposed in the bonding chamber 55. In addition, airtight shutters 54 and 58 are provided at the entrances of the chambers 52 and 56. By closing the airtight shutters 54 and 58, the chambers 52 and 56 are airtight, and surface activation treatment and bonding treatment are performed in a predetermined atmosphere. It can be performed.

  In addition, a transfer mechanism 59 is provided between the surface activation processing chamber 51 and the bonding chamber 55 so that both substrates 901 and 902 can be transferred from the surface activation processing device 53 to the bonding device 57. Yes. With such a configuration, the lid substrate 902 can be transferred from the surface activation processing chamber 51 to the upper electrode 806 of the bonding chamber 55 in the surface activation processing and the bonding processing. As the transfer device 59, various known transfer devices can be adopted, and since the configuration and operation thereof are well known, the description of the configuration and operation is omitted.

  Therefore, according to the present embodiment, after the lid substrate 902 is subjected to the surface activation process, the lid substrate 902 is transported to the bonding chamber by the transport device 59 and held by the upper electrode 806, so that the device substrate 901 The lid substrate 902 can be bonded. Therefore, it is easy to enclose a predetermined space surrounded by the joining surface of the device substrate 901 and the lid substrate 902 and the metal frame 904 in a predetermined atmosphere other than the atmosphere.

(Sixth embodiment)
Then, 6th Embodiment of the joining apparatus concerning this invention is described. The main difference between the present embodiment and the fifth embodiment is that a surface activation / bonding device capable of continuously performing the surface activation process and the bonding process is provided. Before the surface activation process, the device substrate 901 and the lid substrate 902 are set in the same chamber, and after the surface activation process is performed on the lid substrate 902, the device substrate 901 and the lid substrate 902 are subsequently bonded in a predetermined atmosphere. It can be performed. Other configurations are the same as those of the fifth embodiment. Hereinafter, the ninth embodiment will be described focusing on differences from the fifth embodiment.

  FIG. 10 is a schematic configuration diagram showing a device configuration in the present embodiment. Moreover, FIG. 11 is a figure which shows the procedure of a surface activation process and a joining process. FIG. 12 is a diagram showing an alignment process in the atmosphere using the two-field recognition means in the apparatus of FIG.

  As shown in FIG. 10, in the surface activation / bonding apparatus 50, a decompression chamber is configured by a chamber wall 803 configured to be movable up and down by an actuator (not shown) and a chamber table 810. In this surface activation / bonding apparatus 50, the chamber wall 803 is lowered while the lid substrate 902 and the device substrate 901 are held facing each other up and down, the decompression chamber is closed, and surface activation treatment (etching) is performed by Ar plasma in a vacuum. ), The two substrates 901 and 902 can be bonded.

  The apparatus 50 also holds a device substrate 901, a stage unit configured to be able to adjust the position of the held substrate, and a lid substrate 902. And a head portion for performing the above. Further, the head portion includes a piston-type head 802 and an upper electrode 806, and the stage portion includes an alignment table 820 and a lower electrode 809 configured to be capable of position adjustment (alignment processing). In this embodiment, the lid substrate 902 is held by the upper electrode 806, and the device substrate 901 on which the device main body 903 is formed is held by the lower electrode 809. In this embodiment, a metal frame 904 is formed on the device substrate 901, and the device substrate 901 and the lid substrate 902 are joined.

  The Z-axis 801 includes pressure detection means (not shown). A detection signal from the pressure detection means is fed back to a torque control device (not shown) of the Z-axis servomotor, whereby the piston-type head 802 is attached to the substrate 901. , 902 can be controlled in a direction substantially perpendicular to the joining surface. Note that only the stage unit side or both the head unit side and the stage unit side may be configured to be capable of pressure control.

  Then, while the sliding packing 804 is in sliding contact with the Z-axis 801, the chamber wall 803 that can be moved up and down independently of the Z-axis 801 by the actuator is lowered, and the chamber packing 810 is grounded via the fixed packing 805. Can be cut off from outside air. In this state, after opening the discharge valve 814 and operating the vacuum pump 815 to evacuate the chamber through the discharge port 812, the gas switching valve 816 is introduced with Ar gas 817 (see FIG. 12). By switching to, the suction valve 813 is opened, and Ar gas 817 can be introduced into the chamber as a reaction gas through the suction port 811.

  Then, after performing the surface activation treatment of the lid substrate 902 with Ar plasma, both the substrates 901 and 902 can be joined by substituting the inside of the chamber with a predetermined sealed gas atmosphere and lowering the piston type head 802. . Further, the upper electrode 806 and the lower electrode 809 are provided with a heater (not shown), and joint strength between the substrates 901 and 902 can be improved by using heating together when the substrates 901 and 902 are joined.

  As will be described later, after the surface activation treatment, the chambers are replaced with a predetermined atmosphere (Ar gas 817, nitrogen gas 818, vacuum, air, etc.), and the piston-type head 802 is lowered, whereby both substrates 901 are placed. , 902 can be sealed by sealing the predetermined atmosphere in a space surrounded by the metal frame 904 and between the bonding surfaces of 902. For example, by switching the gas switching valve 816 to introduce nitrogen gas 818 (see FIG. 12), nitrogen gas 818 is introduced into the chamber as a sealed gas via the suction port 811, and the nitrogen gas 818 is supplied to the predetermined gas. Can be enclosed in a space.

  Further, the sliding packing (O-ring) 804 of the chamber wall 803 is brought into sliding contact with the Z-axis 801 to hermetically seal the chamber with the O-ring, but the sliding packing (O-ring) 804 is formed on the outer peripheral surface of the piston type head 802. The sliding packing may be brought into sliding contact with the chamber wall 803 to hermetically seal the chamber.

  Next, a processing procedure of the surface activation process (surface activation process) and the bonding process (bonding process) in the surface activation / bonding apparatus 50 will be described with reference to FIG. First, the cover substrate 902 is held by the upper electrode 806 and the device substrate 901 is held by the lower electrode 809 with the chamber wall 803 raised as shown in FIG. The holding method of the substrates 901 and 902 may be a mechanical chucking method, but an electrostatic chuck method is more preferable.

  Then, as shown in FIG. 11B, the chamber wall 803 is lowered, and is grounded to the chamber base 810 via the fixed packing 805. Since the chamber wall 803 is cut off from the atmosphere by the sliding packing 804 being in sliding contact with the Z-axis 801, the exhaust valve 814 is opened while the suction valve 813 is closed, and the vacuum pump 815 is evacuated. The degree of vacuum in the chamber can be increased.

Next, as shown in FIG. 11C, a reaction gas is introduced into the chamber. By adjusting the discharge amount of the discharge valve 814 and the gas intake amount of the suction valve 813 while operating the vacuum pump 815, the chamber can be filled with an arbitrary reaction gas while maintaining a certain degree of vacuum. In this embodiment, as a reaction gas, Ar gas 817 is filled in the chamber at a vacuum degree of about 10 ⁻² Torr, and a voltage is applied to the upper electrode 806 by an alternating power source as shown in FIG. Similarly, Ar plasma is generated, and surface activation processing of the bonding portion 905 formed on the lid substrate 902 is performed.

  Next, as shown in FIG. 11B, the chamber is further evacuated with the suction valve 813 closed to discharge Ar gas. Note that by evacuating while heating both electrodes 806 and 809 to about 100 ° C., Ar ions attached to the surfaces of the substrates 901 and 902 or Ar ions implanted into the substrates 901 and 902 can be discharged.

  Thereafter, as shown in FIG. 11C, the inside of the chamber is replaced with a predetermined sealed gas. Note that the Ar gas 817 and the nitrogen gas 818 are selected by the gas switching valve 816 and introduced into the suction port 811, whereby the two gases of the Ar gas 817 and the nitrogen gas 818 can be switched in one chamber. Further, since the gas switching valve 816 is configured to be able to inhale the atmosphere, the atmosphere can be introduced into the chamber as an enclosed gas. Moreover, after introducing air | atmosphere in a chamber and making the inside of a chamber atmospheric pressure, a chamber can be opened and air-released.

  Therefore, in this embodiment, one gas can be selected from the Ar gas 817, the nitrogen gas 818, the atmospheric gas, and the vacuum as the sealed gas and introduced into the chamber. Note that in the case where the sealed gas is Ar gas 817, the consumption of Ar gas 817 can be suppressed by omitting the process of evacuating the chamber after the surface activation process described above. Further, when the sealed gas is set to a vacuum, after the above-described surface activation process, the inside of the chamber is evacuated, and the bonding process described later may be performed as it is.

  Subsequently, as shown in FIG. 11 (e), the piston-type head 802 is lowered by the Z-axis 801 while the chamber wall 803 and the Z-axis 801 are in contact with each other by the sliding packing 804 in a vacuum or an enclosed gas. At this time, after the bonding portion 905 of the lid substrate 902 is subjected to surface activation treatment by Ar plasma, suspended matter in the deposit layer removed by the surface activation treatment adheres to the bonding portion 905 and the metal frame 904. When the joint 905 and the metal frame 904 are exposed to the atmosphere, a deposit layer such as an organic substance or an oxide film may adhere to the joint 905 and the metal frame 904.

  However, the metal frame 904 formed on the substrate 901 and the bonding portion 905 formed on the lid substrate 902 are brought into contact with each other in a vacuum or an enclosed gas, and are reattached to the metal frame 904 and the bonding portion 905 by pressurization. The adhering material layer is pushed through to join the metal frame 904 and the joining portion 905, and a predetermined atmosphere is created in the space formed between the joining surfaces of both the substrates 901 and 902 and the metal frame 904 in a contour shape. An encapsulating process is performed.

  The inside of the chamber is shut off from the external atmosphere by a sliding packing 804 between the chamber wall 803 and the Z-axis 801, and the piston type head 802 can be lowered while the inside of the chamber is maintained in a vacuum or an enclosed gas atmosphere. . In addition, the bonding strength can be improved by heating at a temperature of about 180 ° C. with a heater provided in both electrodes 806 and 809 during the bonding process. Finally, as shown in FIG. 11 (f), the atmosphere is supplied to the chamber and the pressure is returned to atmospheric pressure, and then the head is raised, and both bonded substrates 901 and 902 are taken out of the chamber to activate the surface. Processing and joining processing are completed.

  By the way, when the device substrate 901 and the lid substrate 902 are joined, the device substrate 901 and the lid substrate 902 can be joined after adjusting the position (alignment). As shown in FIG. 12, by inserting a two-field recognition means 825 between both substrates 901 and 902, a metal frame 904 formed on the device substrate 901, an alignment mark formed on both substrates 901 and 902, etc. Can be detected by the two visual field recognition means 825.

  The two-field recognizing means 825 is inserted between the two substrates 901 and 902, and images of the metal frames 904, alignment marks, etc. of the two substrates 901 and 902 positioned above and below are converted into upper mark recognizing means by the prism 826. 827 and the lower mark recognizing means 828 can be refracted and read. The two-field recognition means 825 is a table (not shown) configured to be movable in the XY axis direction substantially parallel to the bonding surface of both the substrates 901 and 902 and the Z axis direction substantially perpendicular to the surfaces of both the substrates 901 and 902. The position of the metal frame 904, the alignment mark, etc. formed at any position on both the substrates 901 and 902 can be read.

  Then, after reading the positions of the metal frame 904 and alignment marks formed on both the substrates 901 and 902, the alignment table 820 adjusts the position of the device substrate 901 to the position of the lid substrate 902. Note that after the first position adjustment is completed, the two-field recognition means 825 is inserted into both the substrates 901 and 902 again, and the position adjustment is repeated to improve the position accuracy.

  As described above, in the surface activation / bonding apparatus 50, after the surface activation treatment of the bonding portion 905 by Ar plasma, the suspended matter in the deposit layer removed by the surface activation treatment is bonded to the bonding portion 905 and the metal frame 904. Even if it adheres to the metal substrate 901, it is possible to join the metal frame 904 formed on the device substrate 901 and the joint portion 905 formed on the lid substrate 902 by pressing the attached adherent layer by applying pressure. A bonding process can be performed in which a predetermined atmosphere is sealed in a space formed between the bonding surfaces of the substrates 901 and 902 and the metal frame 904.

  Note that by performing the bonding process in a vacuum, the space formed between the bonding surfaces of both the substrates 901 and 902 and the metal frame 904 can be easily sealed in a vacuum atmosphere. Further, by performing the bonding process in an enclosed gas such as Ar gas, nitrogen gas, and the atmosphere, these enclosed gases can be easily formed in the space formed between the bonding surfaces of both the substrates 901 and 902 and the metal frame 904. Can be enclosed.

  Further, if the joint portion is made of gold, the sealed gas is not corroded even if it is not an inert gas, so that the joint gas is not affected. Therefore, gases other than inert gas can also be employed.

  Further, when surface activation treatment is performed with Ar plasma, the etching power for removing the adhering layer of the bonding portion 905 is high and the efficiency is high. However, the surface activation treatment can also be performed by plasma with another reactive gas such as nitrogen or oxygen.

(Seventh embodiment)
Then, 7th Embodiment of the joining apparatus concerning this invention is described. The main difference between the present embodiment and the sixth embodiment is that the surface activation processing chamber and the joining chamber are configured by being partitioned by an airtight shutter in the same chamber, and other configurations are the sixth embodiment. It is the same as the form. Hereinafter, the seventh embodiment will be described in detail focusing on differences from the sixth embodiment. In addition, about the structure and operation | movement same as 6th Embodiment, the description of the structure and operation | movement is abbreviate | omitted.

  FIG. 13 is a schematic configuration diagram showing a device configuration in the present embodiment. As shown in the figure, in the surface activation / bonding apparatus 60, a chamber 61 is composed of a surface activation processing chamber and a bonding chamber, a surface activation processing apparatus 64 is connected to the surface activation processing chamber, and a bonding apparatus 57 is connected to the bonding chamber. Is arranged.

  An airtight shutter 62 is provided at the entrance of the surface activation processing chamber. By closing the airtight shutter 62, the surface activation processing chamber can be airtight. Further, a transport mechanism 63 is disposed between the surface activation processing chamber and the bonding chamber in the chamber 61 so that both substrates 901 and 902 can be transferred from the surface activation processing device 64 to the bonding device 57. . As the transfer device 63, various well-known transfer devices 63 can be adopted, and the configuration and operation thereof are well known, and therefore the description of the configuration and operation is omitted. Also, the description of the configuration and operation of the transfer device described in the following embodiments will be omitted.

  In the present embodiment, while the surface activation process of the lid substrate 902 is performed, the hermetic shutter 62 is closed to make the surface activation processing chamber an Ar atmosphere, and the surface activation process of the lid substrate 902 is performed by Ar plasma.

  Thereafter, the airtight shutter 62 is opened, and the lid substrate 902 is transported to the bonding chamber by the transport mechanism 63 and held by the upper electrode 806. The device substrate 901 is held in advance by the lower electrode 809 in the bonding chamber. Then, the device substrate 901 and the lid substrate 902 are pressurized by the pressurizing means 801 in the bonding chamber to perform bonding.

  During the surface activation process, the bonding chamber may be in any atmosphere such as vacuum, air, or other sealed gas atmosphere. After the surface activation process of the lid substrate 902, the lid substrate 902 is transferred to the bonding chamber and held by the upper electrode 806, and the bonding operation is performed with the bonding chamber as a desired atmosphere.

  For example, when Ar gas is sealed in the space surrounded by the metal frame 904 between the bonding surfaces of both the substrates 901 and 902, the device substrate 901 is placed in the lower part when the lid substrate 902 is surface activated by Ar plasma. If the bonding chamber held by the electrode 809 is in an Ar atmosphere, after the surface activation process, the hermetic shutter 63 is opened and the lid substrate 902 is transferred to the bonding chamber by the transfer mechanism 63 and immediately held by the upper electrode 806. Bonding can be performed.

  By adopting such a configuration, compared to the apparatus configuration of the sixth embodiment, when the surface activation process is performed, the suspended matter in the deposit layer removed by the surface activation process is applied to the device substrate 901. Adhesion can be prevented. Further, since the surface activation processing chamber and the bonding chamber are provided in the same chamber, the metal frame 904 and the bonding portion 905 can be bonded in a short time after the surface activation processing, and the two substrates 901 and 902 are bonded. A predetermined atmosphere can be easily enclosed in the space surrounded by the plane and the metal frame 904.

  In addition, by introducing a predetermined gas into the bonding chamber before bonding and setting it to an ultra high pressure, the bonding process can be performed by pressurizing both substrates 901 and 902 with atmospheric pressure. Further, the chamber 61 can be set to a predetermined gas atmosphere at an arbitrary pressure, or the chamber 61 can be set to a vacuum atmosphere. If it is set as the above structures, there can exist the same effect as above-mentioned 4th thru / or a 6th embodiment.

(Eighth embodiment)
Then, 8th Embodiment of the joining apparatus concerning this invention is described with reference to FIG. 14 and 15. FIG. 14 is a schematic configuration diagram showing an example of the device substrate and the lid substrate of the present embodiment, and FIG. 15 is a schematic configuration diagram of the bonding apparatus.

  The main difference between this bonding operation example and the seventh embodiment is that a metal outer frame body 906 having a pointed cross section surrounding a plurality of metal frame bodies 904 formed on the device substrate 901 is formed. The metal frame 904 is finally joined to the joint 905 after the frame 906 is temporarily joined to the joint 905. Hereinafter, the eighth embodiment will be described focusing on differences from the seventh embodiment.

  FIG. 14 is a diagram showing an example of the substrate according to the present embodiment. As shown in the drawing, a plurality of metal frames 904 are formed on the surface of the substrate body 901a of the device substrate 901. In the figure, a plurality of metal frame bodies 904 each having a pointed cross section surrounding each predetermined region are formed on the surface of the substrate body 901a of the device substrate 901 by gold plating. In each region surrounded by the metal frame 904, a main body 903 of a device such as a semiconductor device such as a surface acoustic wave device or an RF device or a MEMS device having a mechanically movable part is formed. Yes.

  A gold thin film 905 is formed on the surface of the substrate body 902a of the lid substrate 902 by sputtering or metal plating. Instead of the gold thin film 905, a metal frame or the like that protrudes at a position corresponding to the metal frame 904 may be used.

  Note that after bonding the device substrate 901 and the lid substrate 902 formed as shown in FIG. 14, the bonded device substrate 901 and the lid substrate 902 are diced for each region surrounded by the metal frame 904. Thus, a plurality of devices can be formed efficiently.

The device substrate 901 and the lid substrate 902 are a printed circuit board made of resin, a build-up board in which wiring layers are stacked, or a wafer made of Si, SiO ₂ , glass, ceramic, and LT (oxide single crystal), etc. It can be composed of various materials.

  Next, the bonding operation of this embodiment will be described with reference to the bonding apparatus shown in FIG. In the present embodiment, a surface activation / temporary bonding chamber in which a surface activation / temporary bonding apparatus 72 is disposed in a chamber 71 is configured as shown in FIG.

  The surface activation / temporary bonding chamber is a simplified view of the surface activation / bonding apparatus 50 shown in FIG. 10 of the sixth embodiment, and the operation of the apparatus is the same as that of the sixth embodiment. is there. In the present embodiment, after the surface activation process of the lid substrate 902 is performed, the metal outer frame body 906 is subsequently temporarily joined in the apparatus, and then the substrates 901 and 902 that are temporarily joined by the transport device 73. Is carried out to the main joining device 75 in the atmosphere, and the main joining operation is performed.

  Therefore, in this surface activation / temporary bonding apparatus 72, even if the suspended matter in the deposit layer removed by etching after the surface activation treatment of the bonding portion 905 by Ar plasma is reattached to the metal outer frame 906, By pressurizing, the adhered layer reattached can be broken to join the metal outer frame body 906 and the joint portion 905 of both the substrates 901 and 902, and the metal outer frame can be joined between the joint surfaces of both the substrates 901 and 902. Temporary joining processing can be performed in which a predetermined atmosphere is enclosed in a space formed by the body 906 surrounded by a contour.

  Note that the space formed by the metal outer frame body 906 can be easily sealed in a vacuum atmosphere by performing the temporary bonding process in a vacuum. In addition, by performing the bonding process in an enclosed gas such as Ar gas, nitrogen gas, or the atmosphere, these enclosed gases can be easily enclosed in a space surrounded by the metal outer frame body 906.

  In addition, if the joint portion is made of gold, the sealed gas is not corroded even if it is not an inert gas, so that the joint gas is not affected. Therefore, gases other than inert gas can also be employed.

  Further, when surface activation treatment is performed with Ar plasma, the etching power for removing the adhering layer of the bonding portion 905 is high and the efficiency is high. However, the surface activation treatment can also be performed by plasma with another reactive gas such as nitrogen or oxygen.

  It should be noted that the metal frame 904 may be partially contacted and bonded during the temporary bonding process for temporarily bonding the metal outer frame 906. Even in such a case, since the metal frame 904 is bonded in a predetermined atmosphere, the bonding surfaces of both the substrates 901 and 902 are obtained by performing a main bonding process described later after the bonding process. A predetermined atmosphere can be surely enclosed in a space formed by the metal frame 904 and surrounded by a contour.

  Next, the main joining device 75 will be described with reference to FIG. As shown in the figure, the main bonding apparatus 75 collectively presses the stage 221 holding the bonded device substrate 901 and the lid substrate 902 and both the substrates 901 and 902 held on the stage 221 over the entire surface of the substrate. High-pressure press means 220. Therefore, all of the metal frame 904 formed inside the metal outer frame 906 can be reliably bonded by collectively pressing the entire surface of the substrates 901 and 902 temporarily bonded by the high-pressure press means 220. it can.

  In addition, instead of the high-pressure press unit 220, the metal outer frame body is obtained by performing pressurization while shifting the pressurization position of both the substrates 901 and 902 that are temporarily joined by a pressurization unit that pressurizes while shifting the pressurization position. All of the metal frame 904 formed on the inner side of 906 may be securely bonded.

  Further, instead of the high-pressure press means 220 and the stage 221, pressure rollers are provided above and below the bonded device substrate 901 and lid substrate 902, and both temporarily bonded between the upper and lower pressure rollers. It is possible that all the metal frame 904 formed inside the metal outer frame 906 can be reliably bonded by passing the substrates 901 and 902 and applying pressure.

  As described above, the two substrates 901 and 902 are sealed in a state in which a predetermined atmosphere is sealed between the bonding surfaces of the two substrates 901 and 902 and the space formed by the metal outer frame body 906 in a contour shape by the temporary bonding process. By pressurizing the entire surface, all the metal frame members 904 and the joints 905 formed in the space can be joined, and the main joining can be reliably performed. Therefore, it is possible to reliably enclose a predetermined atmosphere in the space formed between the joint surfaces of both the substrates 901 and 902 and the metal frame 904 so as to be surrounded by a contour.

  That is, in the main bonding process, both the substrates 901 and 902 can be pressurized over the entire surface, so that the metal frame 904 and the lid substrate 902 of the device substrate 901 formed inside the metal outer frame 906 are formed. The joining portion 905 can be reliably joined to perform the main joining.

  In addition, by performing the main bonding process in the air, a vacuum chamber is not necessary when performing the main bonding, and the amount of the enclosed gas used can be reduced, and the cost can be reduced.

  Note that even after the surface activation treatment of the bonding portion 905 by Ar plasma and before the bonding processing is performed, the suspended matter in the deposit layer removed by etching adheres to the bonding portion 905 and the metal frame 904. By pressing, the attached adherent layer can be pushed through and the metal frame 904 of the device substrate 901 and the joint portion 905 of the lid substrate 902 can be fully joined, and the joint surface and the metal frame 904 are surrounded by the contour shape. Thus, the main bonding can be performed in which a predetermined atmosphere is sealed in the space formed.

  As described above, according to the present embodiment, the metal outer frame 906 formed on the device substrate 901 and the joining portion 905 of the lid substrate 902 are joined by pressurization, so that the joint surfaces of both the substrates 901 and 902 can be joined. A predetermined atmosphere can be enclosed in the space surrounded by the metal outer frame 906. Therefore, the main frame 904 of the device substrate 901 and the bonding portion 905 of the lid substrate 902 can be securely bonded by applying pressure in a predetermined atmosphere in the space. A predetermined atmosphere is enclosed in a space formed by a contour between the joint surfaces and the metal frame 904, and this space can be reliably shielded from the external atmosphere.

  In this embodiment, prior to bonding, the oxide film or the like formed on the bonding portion 905 of the lid substrate 902 is removed by subjecting the bonding portion 905 of the lid substrate 902 to surface activation treatment with an energy wave that is Ar plasma. Therefore, joining can be performed reliably.

  Further, in the present embodiment, the metal frame body 904 and the metal outer frame body 906 formed on the device substrate 901 and the bonding portion 905 formed on the lid substrate 902 can be brought into close contact with each other by applying pressure, Temporary joining and main joining can be reliably performed.

  Further, in a region surrounded by the metal frame 904 of the device substrate 901, a main body portion of a semiconductor device such as a surface acoustic wave device or an RF device, a main body portion of a MEMS device having a mechanical movable portion, or an electrode of the device Are formed, and temporary bonding and main bonding of the metal frame body 904 and the metal outer frame body 906 of the device substrate 901 and the bonding portion 905 of the lid substrate 902 are performed, and then the device substrate 901 and the lid substrate 902 after bonding. Can be diced for each region surrounded by the metal frame body 904, and the device main body and electrodes are sealed in the space surrounded by the metal frame body 904 between the bonding surfaces of both substrates 901 and 902. A plurality of devices that are shielded from the external atmosphere can be provided.

  In this embodiment, the metal frame 904 and the metal outer frame 906 are formed on the device substrate 901, and the joint portion 905 is formed on the lid substrate 902. The joint portion 905 of the lid substrate 902 is the metal frame 904 and It may be a metal frame or the like that protrudes from a position corresponding to the metal outer frame 906.

  In the present embodiment, it is possible to change the optimal combination from various bonding apparatuses in accordance with the types of substrates 901 and 902 to be bonded and the types of devices formed on the substrate. Hereinafter, a modification of the bonding apparatus will be described with reference to FIG. FIG. 16 is a view showing a modification of the joining device.

  The joining device 90 will be described. As shown in FIG. 16 (a), the bonding apparatus 90 includes a surface activation chamber in which a surface activation apparatus is disposed, a temporary bonding chamber in which a temporary bonding apparatus is disposed, and a main bonding apparatus. And a chamber 91 having a main bonding chamber. In the chamber 91, a transport mechanism 92 for transporting the substrates 901 and 902 between the chambers is disposed. In addition, an airtight shutter (not shown) that can seal each space is disposed at the entrance of each chamber. In this way, all the processes are executed in the same chamber 91. Even with such a configuration, the same effects as those of the first to seventh embodiments described above can be obtained.

  Next, the joining device 95 will be described. As shown in FIG. 16B, the bonding device 95 includes a surface activation device, a bonding device, and a main bonding device. A transport mechanism 96 is disposed in the atmosphere so that the substrates 901 and 902 can be transported between the apparatuses. Even with such a configuration, the same effects as those of the first to seventh embodiments described above can be obtained.

(Other)
The present invention is not limited to the above-described embodiments, and various modifications other than those described above can be made without departing from the spirit of the present invention.

  For example, in the sixth embodiment, the process from the surface activation process of the object to be bonded to the bonding of the object to be bonded is performed as a batch process with the same apparatus, but the surface activation process of the bonding part 905 by the energy wave The joining process for joining the objects to be joined may be performed by separate apparatuses.

  With such a configuration, after the bonding portion 905 of the lid substrate 902 is subjected to the surface activation process, the device substrate 901 and the lid substrate 902 are aligned in the atmosphere, or the lid substrate 902 is bonded in the atmosphere via the atmosphere. When the material is conveyed to the joint portion 905, a deposit layer made of an oxide film, an organic substance, or the like is easily formed on the joint portion 905. However, as described above, the metal frame body 904 and the joint portion 905 can be joined by pressurizing and pressing the re-formed deposit layer.

  Further, as a means for holding the object to be joined, any suction holding method such as a vacuum chuck method or an electrostatic chuck method may be used. Since the inside of the chamber for performing the surface activation process is evacuated in the course of performing the surface activation process, the holding means for the object to be joined inside the chamber is preferably an electrostatic chuck system, but may be a mechanically fixed system. . In addition, a method in which first vacuum holding is performed in the atmosphere, and after close contact is performed, mechanical fixing is preferable.

  Further, for example, in the bonding apparatus according to the first embodiment, a translation axis and a lift axis are arranged on the head side, and a translation axis and a translation axis are arranged on the stage side. The moving axis and the moving axis for moving and rotating may be combined in any way on the head side and the stage side, or may be overlapped. Further, the head and the stage may be arranged left and right or diagonally without being arranged vertically.

  In the above-described embodiment, an elastic material is disposed on the surface of the tip tool 9 and / or the stage 10 of the head portion 26, and both objects to be bonded are pressed via the elastic material when the chip 20 and the substrate 22 are bonded. I do not care. With such a configuration, the parallelism between the objects to be joined can be made uniform. Moreover, if it is a thin to-be-joined object, flatness can also be made equal.

  In the above-described embodiment, spherical bearings are disposed on the stage 10 and / or the head unit 26, and the objects to be joined are contact-pressed during or before joining the objects to be bonded to at least one of the objects to be bonded. You may make it the structure which can match | combine the other inclination. With such a configuration, it is possible to perform bonding by following the parallelism.

  When the chip 20 is a light emitting element, the position recognition unit 29 may include a light emitting point recognition means 33 in addition to the upper and lower mark recognition means 14 for recognizing an alignment mark for position recognition. In this case, the alignment mark is recognized by the upper and lower mark recognizing means 14, the positions of the chip 20 and the substrate 22 are coarsely adjusted, and then the light emitting point is recognized by the light emitting point recognizing means 33 in a state where the light emitting element is electrically emitted. By recognizing and finely adjusting the positions of the chip 20 and the substrate 22, the position can be adjusted with submicron accuracy.

  Further, the position recognition means of the object to be joined may be any means other than the upper / lower mark recognition means 14 and the light emitting point recognition means 33. For example, when the mark is on the opposite surface, the object recognition means using IR (infrared) light is used to recognize the alignment mark made of metal through the object to be bonded, and the positions of the chip 20 and the substrate 22. May be recognized and position adjustment may be performed.

  Further, for example, in the first embodiment, the object to be bonded may be pressed while the head height of the head unit 26 is kept constant for a certain period of time. In this case, at the bonding interface of the objects to be bonded, it becomes impossible to withstand the load, rotation of crystal orientation and movement of particles occur, new surfaces appear and bond, and residual stress is removed by the movement of particles. On the other hand, when the object to be bonded is momentarily pressed, the surface of the object to be bonded is elastically deformed, so that the crystal at the interface does not rotate, or the elastic deformation remains as a residual stress, resulting in a bonding force. On the other hand, since it works in the direction of peeling, the bonding strength may decrease. Accordingly, by maintaining the head height of the head portion 26 constant for a certain period of time when the object to be joined is pressed, it is possible to perform good joining that does not reduce the joining strength. Although this stop time depends on the material and the bonding state, it is effective from 1 second or more, and the effect is not changed after 2 minutes or more.

  Further, when heating is performed at 180 ° C. or less during the stop, the crystal orientation is rotated and the particles are moved efficiently, the bonding proceeds, and the residual stress is removed, whereby the bonding strength can be increased. In addition, as heating temperature, the low temperature heating of 180 degrees C or less is enough. Therefore, in flip chip bonding of a semiconductor chip having a large number of electrode portions to be metal protrusions, there is a high demand for bonding at a low temperature of 180 ° C. or less, preferably at room temperature, due to thermal effects on the semiconductor, and within a few μm such as fine pitch electrodes This is particularly effective because high-precision mounting is desired.

  In addition, by applying ultrasonic vibration instead of the above-described heating at the time of bonding, metal bonding can be more easily performed in a solid phase without being affected by thermal expansion. In this case, an ultrasonic oscillator and a horn may be provided instead of the chip holding tool 8 of the head portion 26. By applying ultrasonic vibration, it is possible to perform bonding at a low temperature from room temperature to about 180 ° C. with a small applied pressure, so that damage to the object to be bonded by pressurization or high temperature heating can be suppressed. . Further, it is possible to mount without positional deviation by suppressing the amplitude to be small, applying vibration after pressurization, and controlling the pressure in proportion to the bonding area as the bonding proceeds.

  For example, an ultrasonic vibration head composed of a horn, a horn holder, and a vibrator is provided, and ultrasonic vibration having an amplitude of 2 μm or less is applied to the object to be bonded at the time of bonding in the atmosphere, a load of 150 MPa or less, 180 ° C. A method and a bonding apparatus for metal bonding in a solid phase by the following heating may be used. When ultrasonic vibration is applied at the time of bonding in the air, bonding becomes easier. Since the surface has already been activated, the ultrasonic energy may be small, and an amplitude of 2 μm or less that can suppress damage and displacement is sufficient, and 1 μm or less is more preferable. In addition, when the metal bump 20a made of gold is bonded to the bonding portion 22a, it cannot be bonded unless it is crushed with a high pressure of about 300 MPa at room temperature, but the bonding load is reduced to 150 MPa or less, which is half or less, by applying ultrasonic waves. be able to.

  In addition, when joining large areas using ultrasonic vibration, it is impossible to perform transverse vibration with a transverse vibration type ultrasonic head, although the joining area is large, but with a longitudinal vibration type ultrasonic head, If so, large area surface bonding is also possible. Although referred to as ultrasonic vibration, the vibration frequency does not have to be particularly in the ultrasonic region. Especially in the case of the longitudinal vibration type, the effect is sufficiently exhibited even at a low frequency.

  In addition, when multiple metal joints are formed on one workpiece, the height and surface roughness can be made uniform by pressing the metal joint against a flat reference table before joining the workpieces. It is also possible to perform leveling to be corrected. By performing the leveling, it is possible to reduce the joint weight to the workpiece. As an example, when leveling is performed on a chip 20 having a metal bump 20a having a height variation of 2 μm and a surface roughness of 200 nm, the height variation and the surface roughness are 50 nm or less due to the leveling, and the applied pressure is 300 MPa before the leveling. However, it was reduced to 150 MPa after leveling.

  In addition, the shape of the metal bump 20a formed on the chip 20 may be any shape as long as it has a pointed cross-sectional shape such as a pyramid shape or a cone shape.

  The object to be bonded may be a device other than a semiconductor, and may be any material such as a semiconductor device such as a surface acoustic wave device or an RF device, a MEMS device having a mechanical movable part, or a wafer. Also, Au, Al, Cu, tin, etc. are suitable for the metal joint part of one object to be joined and the joint part of the other object to be joined. I just need it. Further, the entire surface of the other object to be bonded may be a bonding surface, or a metal bonding portion may be formed to protrude at a position corresponding to the metal bonding portion of the one bonding object.

  Further, in the above-described embodiment, the surface activation treatment of the joined portion of the other object to be joined is performed with an energy wave by Ar plasma. However, the surface activation treatment may be performed with another gas such as nitrogen or oxygen. A mixture may be used. Further, the surface activation treatment may be performed with an ion beam or an atomic beam, instead of an energy wave such as plasma.

  Further, as a method for surface activation treatment of the joint portion of the other object to be joined, it is preferable in terms of efficiency to perform the surface activation treatment on the substrate 22 held on the electrode surface to which the alternating power source is connected. In order to reduce damage, the electrode may be placed in a place other than the holding position of the substrate 22 to perform surface activation treatment.

It is a schematic block diagram of one Embodiment of the joining apparatus concerning this invention. It is a figure showing a joining process. It is a rotation schematic diagram of the crystal direction in the joining interface at the time of joining. It is a figure which shows the relationship between bump height and bonding strength. It is the perspective view which expanded and showed a part of chip | tip and the metal bump. It is a figure which shows an example of a device board | substrate and a lid | cover board | substrate. It is AA arrow sectional drawing of FIG. It is a figure which shows the relationship between the height of a metal frame, and joining strength. It is the schematic block diagram which showed the apparatus structure in 5th Embodiment of this invention. It is a schematic block diagram which showed the apparatus structure in 6th Embodiment of this invention. It is a figure which shows the procedure of the surface activation process and joining process in 6th Embodiment of this invention. It is a figure which shows the alignment process in air | atmosphere using the 2 visual field recognition means in the apparatus of FIG. It is the schematic block diagram which showed the apparatus structure in 7th Embodiment of this invention. It is a figure which shows the other example of a device board | substrate and a lid | cover board | substrate. It is the schematic block diagram which showed the apparatus structure in 8th Embodiment of this invention. It is a figure which shows the modification of the joining apparatus of this invention.

Explanation of symbols

20 ... chip (one object to be joined)
20a ... Metal bump (metal joint)
22 ... Substrate (the other object to be joined)
22a ... Joint portion 25 ... Up / down drive mechanism (pressure control means)
26. Head part (pressure control means)
31 ... Control device (pressure control means)
40. Cleaning part (energy wave irradiation means)
53, 64 ... Surface activation treatment device (energy wave irradiation means)
220 ... High pressure press means (pressure control means)
801 ... Z axis (vertical drive mechanism, pressure control means)
901 ... Device substrate (one object to be joined)
901a ... Device substrate body 902 ... Lid substrate (the other object to be joined)
902a ... Lid substrate body 903 ... Device body 904 ... Metal frame (metal joint)
905 ... Junction 906 ... Metal outer frame

Claims (14)

Forming a metal joint having a pointed cross-sectional shape on the joint surface of one object to be joined, forming a joint made of gold on the joint surface of the other object to be joined,
After the surface activation treatment of the joined portion of the other object to be joined with an energy wave,
The metal joint of the one object to be joined and the joint of the other object to be joined are joined, and the height from the joining surface of the one object to be joined to the tip of the metal joint is 20 A joining method, wherein the metal joint is crushed and joined by pressurizing with a pressing force of about 90% to 90%.   The bonding method according to claim 1, wherein the energy wave is plasma.   The bonding method according to claim 1 or 2, wherein the metal bonding portion formed on the one object to be bonded is a metal bump.   3. The joining method according to claim 1, wherein the metal joining portion formed on the one article to be joined is a metal frame formed so as to surround a predetermined region of the article to be joined.   By joining and pressurizing the metal frame of the one object to be bonded and the bonding part of the other object to be bonded in a vacuum, the one object to be bonded and the other object to be bonded are The bonding method according to claim 4, wherein a space surrounded by the metal frame is vacuum sealed.   The one object to be bonded and the other object to be bonded are obtained by performing abutting and pressurization of the metal frame body of the one object to be bonded and the bonding part of the other object to be bonded in a sealed gas. The joining method according to claim 4, wherein the sealed gas is sealed in a space surrounded by the metal frame between the two.   The joining method according to claim 1, wherein the metal joint portion of the one article to be joined is formed by gold plating.   The joining method according to any one of claims 1 to 7, wherein pressurization is performed so that the applied pressure per one metal joint formed on the one workpiece is 50 MPa to 700 MPa.   The joining method according to claim 1, wherein the one object to be joined is a sensing element.   A device formed by the bonding method according to claim 1, comprising a semiconductor device, an optical device, or a MEMS device. In a joining device that joins workpieces held on the head and stage,
The two joints in which a metal joint having a pointed cross section is formed on the joint surface of one of the workpieces, and a joint made of gold is formed on the joint surface of the other workpiece. An object is abutted between the metal joint portion of the one article to be joined and the joint portion of the other article to be joined, and the height from the joining surface of the one article to be joined to the tip of the metal joint portion is increased. Is provided with a pressurizing control means that pressurizes with a pressing force of 20% to 90%.
The pressure control means includes
The joints of the other object to be joined are pressed against each other and the metal joints of the one object to be joined are pressed between the two objects to be joined. Connecting apparatus characterized by connecting. The pressure control means includes
The joining apparatus according to claim 11, wherein pressurization is performed so that the applied pressure per one metal joint formed on the one article to be joined is 50 MPa to 700 MPa.   The bonding apparatus according to claim 11, further comprising energy wave irradiation means for performing the surface activation treatment.   The bonding apparatus according to claim 13, wherein the energy wave irradiation unit generates plasma.

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