JP3970732B2 - Joining method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bonding method and apparatus for bonding objects to be bonded having a metal bonding portion on the surface of a base material such as a chip, a wafer, and various circuit boards.
[0002]
[Prior art]
As a method for bonding objects to be bonded having metal bonding portions, when bonding the bonding surfaces of silicon wafers, an inert gas ion beam or an inert gas fast atom beam is irradiated in a vacuum at room temperature prior to bonding. A silicon wafer bonding method in which sputter etching is performed is disclosed (see, for example, Patent Document 1). In this bonding method, oxides, organic substances, and the like on the bonding surface of the silicon wafer are formed by atoms activated by being blown by the beam, and the surfaces are bonded to each other by a high bonding force between the atoms. . Therefore, this method basically eliminates the need for heating for bonding, and enables bonding at a room temperature or a temperature close thereto by simply bringing the activated surfaces into contact with each other.
[0003]
However, in order to perform bonding at room temperature or a temperature close to that in this bonding method, when bonding the bonding surfaces of the metal bonding portions surface-activated by the energy wave etching as described above, Until it is bonded, it must be maintained in the surface activated state necessary for the bonding. In the above-mentioned Patent Document 1, cleaning and bonding are performed in a vacuum chamber, and although it is possible to perform bonding at a target normal temperature or a temperature close thereto as a test apparatus, actual production is possible. In most machines, it is required to perform cleaning and joining at different locations, and the workpieces that have been cleaned must be transferred from the cleaning location to the joining location and set in the layout required for joining. I must. Therefore, a means for holding and transporting the object to be joined is required.
[0004]
Such a conveying means is required to have a function of holding an object to be bonded so as not to touch the previously cleaned bonding surface. As a means to satisfy such a requirement, the object to be bonded is touched to the cleaned bonding surface. Means for adsorbing and holding so as not to be present has been proposed (for example, Patent Document 2).
[0005]
[Patent Document 1]
Japanese Patent No. 2794429 (Claims)
[Patent Document 2]
JP 2002-64266 A (Claims, FIGS. 1 and 3-6)
[0006]
[Problems to be solved by the invention]
However, the means proposed in Patent Document 2 is sufficient for simply holding the object to be bonded so as not to touch the cleaned bonded surface, but the metal surface is cleaned by cleaning the bonded surface with energy waves. In order to obtain the excellent effect that joining between the joints becomes much easier and joining at a low temperature is possible more reliably, until the moment of actual joining after washing, It is desired to maintain a predetermined surface activation state without causing oxidation or the like. In the method described in Patent Document 2, an object to be bonded whose surface has been cleaned is taken out from the cleaning unit, transported to the bonding operation unit, set to a predetermined bonding posture in the bonding operation unit, and actually Until the metal joints are joined, there is a risk of exposure to the atmosphere, which is an oxidizing atmosphere, and the joint surface is maintained in a highly purified surface activated state without oxide film or impurities until just before joining. Difficult to do.
[0007]
  Therefore, the object of the present invention is to bond the cleaned bonded surfaces as much as possible during the period from cleaning to bonding when bonding the objects to be bonded that have cleaned the bonding surfaces of the metal bonded portions by energy waves.ProperlyIt is possible to maintain a preferable surface activation state, especially while the workpiece is being transported.ProperlyIt is an object of the present invention to provide a joining method and apparatus that can maintain a preferable surface activation state and can join metal joints better and easily.
[0008]
[Means for Solving the Problems]
  In order to solve the above-described problems, the bonding method according to the present invention uses the energy of the bonding surface of the metal bonded portion of the bonded object in the cleaning portion when bonding the bonded objects having the metal bonded portion to the surface of the base material. After washing with waves, the object to be bonded is conveyed to the bonding operation part in a non-contact state with respect to the bonding surface, and the metal bonding parts are bonded to each other after the objects to be bonded are arranged opposite to each other in the bonding operation part The bonding surface is at least a part of a transport path of an object to be bonded from the cleaning unit to the facing position of the bonding operation unit.An oxide film or an organic substance layer is formed on the bonding surface of the metal bonding portion cleaned by the energy wave by maintaining an atmosphere of an inert gas such as Ar gas or a non-oxidizing gas such as nitrogen gas. It is a gas that can prevent the adhesion ofSpecial gasofIn a state exposed to the atmosphere,Has a holding and conveying process in a special gas atmosphere that holds and conveys the object to be joinedIn addition, the holding and conveying step in the special gas atmosphere includes a step of adsorbing and holding an object to be bonded using an attachment having a gas blowing / suction hole for sucking out the special gas after being blown out, and in the adsorption holding step, The special gas is ejected from the gas blowout / suction hole of the attachment toward the object to be joined, so that the attachment is filled with the special gas and the atmosphere on the object to be joined is replaced with the special gas. The bonding surface is placed in a special gas atmosphere, and in that state, the attachment is brought into contact with the object to be bonded in a non-contact state with respect to the bonding surface, and then the attachment is filled through the gas blowing / suction holes. The special gas that has been sucked in is sucked and held by the attachment.It consists of the method characterized by this.
[0009]
Here, the special gas refers to an inert gas such as Ar gas or a non-oxidizing gas such as nitrogen gas. By maintaining the gas atmosphere, an oxide film is formed on the joint surface of the metal joint cleaned by the energy wave. It is a gas that can prevent the formation of organic layers and the adhesion of impurities. In other words, it refers to a gas that can maintain a predetermined surface activation state by keeping the cleaned bonding surface in a pure state by maintaining the gas atmosphere.
[0010]
  The holding and transporting process under the special gas atmosphereAs above,Including a step of adsorbing and holding an object to be bonded using an attachment, and in the adsorption holding step, the attachment is brought into contact with the object to be bonded in a state where a special gas is ejected from the attachment side and the inside of the attachment is filled with the special gas. After that, the gas in the attachment is sucked to adsorb the object to be joined..In addition, even when vacuum breaking is performed after delivery of an object to be bonded, the vacuum state can be broken to atmospheric pressure by ejecting a special gas, and the object to be bonded can be released. In this suction holding process, when one of the objects to be bonded is sucked and held and then reversed and transferred to the above-mentioned opposed arrangement position (for example, when there is a so-called flip chip process), this suction is held in that process. It is preferred to apply retention. Moreover, it is also preferable to apply this adsorption holding to the step of directly taking out the object to be bonded from the cleaning section.
[0012]
Furthermore, in the case of having a step of placing the transferred workpiece once in the bonding operation unit, in addition to the holding and transporting step in the special gas atmosphere, the bonding surface of the workpiece at the once placement place It is preferable to have a step of locally ejecting the special gas toward the surface, that is, a step of locally purging the atmosphere of the joining surface portion of the object to be joined with the special gas. Furthermore, it is also preferable to include a step of locally ejecting a special gas between the objects to be bonded after the objects to be bonded are arranged opposite to each other in the bonding operation part. That is, after being taken out from the cleaning section, until the actual joining, in addition to the above-mentioned holding and transporting process in the special gas atmosphere, by performing a local purge of the special gas when the holding and transporting is not performed, The surface of the cleaned object to be bonded is prevented from being exposed to an oxidizing atmosphere or air as much as possible, and the surface activation state can be maintained.
[0013]
Moreover, in the above-mentioned joining method, it is preferable to join at least one of pressurization, heating, and ultrasonic wave application as a joining method between the metal joints, thereby enabling easier and more reliable joining. It becomes like this. The joining of the objects to be joined can be performed in the air, can be performed in a reduced pressure (in a vacuum), or can be performed in an inert gas.
[0014]
For cleaning with energy waves, it is preferable to use plasma from the viewpoints of ease of handling, ease of control, etc. Among them, it is preferable to use Ar plasma generated in an Ar gas atmosphere.
[0015]
In the cleaning by the energy wave, it is preferable to etch to a depth of 1 nm or more on the entire surface to which the metal joint portion is joined. By irradiating energy waves that can be etched to such a depth or more, it is possible to obtain surface properties necessary for joining metal joints even in the atmosphere.
[0016]
The joining according to the present invention is particularly suitable for joining metal joining parts whose surfaces are composed of any of gold, copper, Al, In, and Sn. For example, as a combination of metal joints to be joined together, the same kind of metal of gold, copper, Al, In, or Sn, or any two different kinds of metals, or one of which is gold and the other is copper, Al , In, or Sn. In particular, in the case of bonding between gold, bonding can be reliably performed even at room temperature. However, even in cases other than the bonding of gold (for example, bonding of gold / copper, gold / aluminum, etc.), bonding at room temperature or a temperature close thereto can be made possible. Further, when at least one of the metal joints is made of a specific metal, for example, gold, the entire electrodes and the like forming the metal joint can be made of gold, but only the surface can be made of gold. . The form for configuring the surface with gold is not particularly limited, and a form of gold plating or a form in which a gold thin film is formed by sputtering or vapor deposition may be employed.
[0017]
In addition, the surface hardness of at least one of the metal joints is 120 or less in terms of Vickers hardness Hv, more preferably, the hardness is reduced to 100 or less by annealing so that the surfaces can be satisfactorily adhered to each other when joining the metal joints. Is good. For example, the surface hardness Hv is preferably in the range of 30 to 70 (for example, the average Hv is 50). By setting it as such low hardness, the surface of a metal joint part deform | transforms appropriately finely at the time of joining pressure application, and more close joining is attained.
[0018]
  A joining apparatus according to the present invention is an apparatus for joining objects to be joined each having a metal joint on the surface of a base material, the cleaning means for cleaning the joint surface of the metal joint by an energy wave, and the cleaning means. In a state of non-contact with the bonding surface provided between the cleaning means and the bonding means, the bonding means for bonding the metal bonded portions to each other after the objects to be bonded are arranged opposite to each other, and cleaned by the cleaning means And a means for conveying the object to be bonded to the bonding operation unit, wherein at least a part of the conveying means includes the bonding surface.An oxide film or an organic substance layer is formed on the bonding surface of the metal bonding portion cleaned by the energy wave by maintaining an atmosphere of an inert gas such as Ar gas or a non-oxidizing gas such as nitrogen gas. It is a gas that can prevent the adhesion ofSpecial gasofIn a state exposed to the atmosphere,From a holding and conveying means in a special gas atmosphere that holds and conveys the object to be joined.The special gas atmosphere holding and conveying means has a gas blowout / suction hole for sucking and sucking the special gas after jetting, and has an attachment for sucking and holding the object to be joined. By spouting a special gas from the hole toward the object to be bonded, the attachment gas is filled with the special gas, and the atmosphere on the object to be bonded is replaced with the special gas, so that the bonding surface of the object to be bonded is a special gas atmosphere. Place the attachment underneath and bring the attachment into contact with the object to be joined in a non-contact state with the joint surface, and then suck the special gas filled in the attachment through the gas blowing / suction holes. And means for adsorbing and holding the object to be attached to the attachment.It consists of what is characterized by this.
[0019]
  As the special gas atmosphere holding and conveying means,As above,It has an attachment that holds and holds the object to be joined. Special gas is ejected from the attachment side and the attachment is filled with the special gas. It consists of means to adsorb the object to be joinedTo do.In addition, even when the vacuum break is performed after delivering the object to be bonded, the vacuum state can be broken to atmospheric pressure by ejecting the special gas, and the object to be bonded can be separated. The special gas atmosphere holding / conveying means having such an attachment can be provided in the means for holding one of the objects to be bonded by suction and then inverting it and delivering it to the opposed arrangement position. Moreover, it can also provide in the means to take out a to-be-joined object directly from the said washing | cleaning means.
[0021]
Further, when a place for placing the object to be joined once is provided in the joining operation part, the place once placed so that the cleaned joining surface is not exposed to an undesired atmosphere as much as possible. In addition, a means for locally ejecting the special gas toward the bonding surface of the objects to be bonded can be provided. In addition, a means for locally ejecting a special gas between the objects to be bonded can be provided at a position where the objects to be bonded are opposed to each other in the bonding operation section.
[0022]
The joining means preferably includes at least one means of a pressurizing means, a heating means for heating to 180 ° C. or less, preferably less than 150 ° C., and an ultrasonic wave applying means in order to promote joining between metals in a solid phase. . This joining means can be composed of means for joining metal joints in the atmosphere, or can be composed of means for joining metal joints together in a reduced pressure, and further, metal in an inert gas. It can also consist of means for joining the joints.
[0023]
Moreover, as said washing | cleaning means, a plasma irradiation means is preferable and especially an Ar plasma irradiation means is preferable.
[0024]
In addition, the cleaning means etches with a depth of 1 nm or more on the entire surface to which the metal joints are joined in order to perform the necessary surface etching even when the metal joints are joined in the air. It is preferable to comprise means for irradiating an energy wave with energy higher than possible.
[0025]
In addition, as described above, the combination of the surface metal species of the two metal joints to be joined may be the same kind of gold, copper, Al, In, Sn, or any two different kinds of metals, or One can be made of gold and the other can be made of copper, Al, In, or Sn. Especially, when it is set as the combination of gold | metal | money, joining becomes the easiest.
[0026]
Further, it is desirable that the surface hardness of at least one of the metal joints is 120 or less, preferably 100 or less in terms of Vickers hardness Hv so that the metal joints are joined more closely.
[0027]
In the bonding method and apparatus according to the present invention as described above, the surface of the metal bonding portion of the object to be bonded is irradiated with energy waves, the surfaces are cleaned by etching, and the activated metal bonding portions are at room temperature or the like. Bonded under. Between cleaning and actual joining, there are processes such as transporting the objects to be joined, various handling and placement at predetermined positions, etc. During the cleaning, the atmosphere in contact with the cleaned joint surface is maintained in a special gas atmosphere, and a predetermined holding and conveying operation is performed in that state. Therefore, during this holding and conveying, the bonding surface of the metal bonding portion whose surface has been activated by cleaning substantially contacts only the special gas, and does not touch the atmosphere. As a result, the joining surface can be maintained in a desirable pure state, and subsequent actual joining can be performed more easily and the joining reliability is improved.
[0028]
Furthermore, if the special gas is locally supplied toward the bonding surface at the place where the object to be bonded is placed or opposed to the bonding surface, the bonding surface is preferably used in other processes than the holding process in the special gas atmosphere. Can be maintained in a stable state. Therefore, from cleaning to actual bonding, it is possible to prevent the bonding surface from touching an undesired atmosphere as much as possible, and actual bonding can be performed easily and reliably while maintaining a desired pure state.
[0029]
As described above, it is possible to reliably maintain the effect of the surface activation of the joint surface by the energy wave cleaning until the actual joining, and to maximize the effect of facilitating the joining by the energy wave cleaning.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a bonding apparatus 1 according to an embodiment of the present invention, in which an object to be bonded 4 or 5 having a metal bonding part 2 or 3 on the surface of a substrate is irradiated with plasma as a cleaning means by energy waves. The joint surfaces of the metal joints 2 and 3 are cleaned by etching with the plasma 9 irradiated from the means 8 (cleaning step). In the present embodiment, the bonding surfaces of the metal bonding portions 2 and 3 are cleaned by etching in the chamber 7 that is depressurized by the vacuum pump 6 and has a predetermined degree of vacuum (cleaning step). . Furthermore, in this embodiment, Ar gas can be supplied into the chamber 7 by the pump 10, and plasma irradiation can be performed in an Ar gas atmosphere. The cleaned objects 4 and 5 are taken out from the cleaning chamber 7, and the metal bonding parts 2 and 3 are bonded to each other in, for example, the atmosphere in a bonding process (bonding operation unit 11). However, the joining operation unit 11 is enclosed, for example, entirely or locally by a chamber (not shown), and the inside is in a reduced pressure state (or a vacuum state) or a reduced pressure state of an inert gas (or an atmospheric pressure state), Bonding can also be performed under the special atmosphere.
[0031]
In the above description, the object to be bonded 4 is made of, for example, a chip, and the object to be bonded 5 is made of, for example, a substrate. Here, the term “chip” refers to all forms on the side to be bonded to the substrate regardless of the type and size, such as an IC chip, a semiconductor chip, an optical element, a surface mount component, and a wafer. For example, bumps are formed on the workpiece 4 as the metal bonding portion 2. Moreover, a board | substrate refers to the thing of all the forms of the side joined to a chip | tip irrespective of a kind and magnitude | size, such as a resin substrate, a glass substrate, a film substrate, a chip | tip, a wafer, for example. Further, the positions of the chip and the substrate may be interchanged.
[0032]
In the bonding operation unit 11, for example, the cleaned objects to be bonded 4 and 5 are once placed on a predetermined standby unit after being transported. From this placement place 12, the workpiece 4 is sucked and held via an attachment, which will be described later, so as not to touch the cleaning surface to the head portion 14 of the reversing mechanism 13, and then turned upside down, and then the bonding head 15. It is transferred to the bonding tool 16 provided at the lower part of the metal plate, and held in the bonding tool 16 by suction or the like in a form in which the metal joint portion 2 is directed downward. The workpiece 5 is temporarily transferred from the placement place 12 and is held on the bonding stage 17 by suction or the like in a form in which the metal bonding portion 3 is directed upward. Although the transfer mechanism for the workpiece 4 and the transfer mechanism for the workpiece 5 can be shared, they may be provided separately. When provided separately, the reversing mechanism 13 is provided in the transfer mechanism for the article 4 as described above. In the present embodiment, a heater 18 as a heating means is built in the bonding tool 16, and either bonding at normal temperature or bonding under heating is possible in a special atmosphere or in the air. Further, the bonding tool 16 is provided with an ultrasonic wave application unit 22 and is bonded using at least one of the ultrasonic wave application unit 22, the heater 18 as the heating unit described above, and the pressurizing unit described later. You can also.
[0033]
In this embodiment, the bonding head 15 can press the workpiece 4 downward by the pressurizing means 19 via the bonding tool 16, and applies a predetermined bonding pressure to the workpiece 5. It can be applied and controlled. In this embodiment, the bonding head 15 can be moved and positioned in the vertical direction (Z direction).
[0034]
Further, in this embodiment, the bonding stage 17 holding the workpiece 5 is controlled in the horizontal position in the X and Y directions and the rotational position in the θ direction by the position adjustment table 20 provided in the lower part. Control and tilt adjustment control around the X-axis and Y-axis enable the relative alignment and parallelism adjustment with the workpiece 4 to be performed. It is also possible to reduce the variation in the gap. The relative alignment and the parallelism adjustment are performed by a recognition means inserted so as to be able to advance and retreat between the objects to be joined 4 and 5, for example, a two-field recognition means 21 (for example, a two-field camera). This is implemented by reading recognition marks (not shown) attached to these holding means and making necessary corrections of the position and angle based on the read information. The two-view recognition means 21 can be adjusted in position in the X and Y directions, and in some cases in the Z direction. In this embodiment, the relative alignment and parallelism adjustment are performed mainly on the bonding stage 17 side, but can be performed on the bonding head 15 or the bonding tool 16 side, or can be performed on both sides. is there. When performing on both sides, if necessary, not only the elevation control on the bonding head 15 side but also the rotation control and / or translation control are performed, and the rotation control, translation control and elevation control are performed on the bonding stage 17 side as well. These control modes can be arbitrarily combined as necessary.
[0035]
In this embodiment, first, as shown in FIG. 2, a predetermined attachment 31 is attached to the head portion 14 of the reversing mechanism 13 of the joining apparatus 1 configured as described above, and the object 4 to be joined is attached via the attachment 31. However, the object to be bonded 4 is turned upside down by the reversing mechanism 13 and then transferred to the bonding tool 16 so that the metal bonding portion 2 is not exposed to the cleaning surface of the metal bonding portion 2. The bonding portion 2 is held by the bonding tool 16 by suction or the like in a form directed downward. The attachment 31 of a predetermined size for the workpiece 4 may be selected and taken out from an appropriately provided attachment place. The attachment method of the attachment 31 to the head portion 14 is not particularly limited, and may be a mechanical attachment method. As shown in FIG. 2, a suction hole 32 is provided in the head portion 14, and the suction hole 32 passes through the suction hole 32. The attachment 31 may be sucked and held by the head unit 14 by suction.
[0036]
The attachment 31 is provided with a gas blowing / suction hole 33 for ejecting a special gas made of an inert gas, a non-oxidizing gas, or the like and sucking from the inside of the attachment 31 after the ejection. A gas passage 34 provided in the head portion 14 communicates with the gas blowing / suction hole 33, and special gas supply means and suction means (not shown) are connected to the gas passage 34 via a switching valve. It is connected. The operation of this part will be described later.
[0037]
Note that the attachment 31 has been described as being used in a conveyance path 71 until the workpiece 4 is temporarily transferred from the placement place 12 to the bonding tool 16 via the reversing mechanism 13 as shown in FIG. However, the attachment having the same configuration is also applied to the conveyance path 72 for directly taking out the article 4 (or / and the article 5) from the cleaning chamber 7, for example, the conveyance path 72 once to the placement place 12. it can. Further, common to both the conveyance path 72 for taking out the article 4 from the cleaning chamber 7 and the conveyance path 71 provided with the reversing mechanism 13 directly from the path 72 or once via the placement place 12. The attachment 31 can also be used. Furthermore, the structure using the same attachment can be adopted for the transport path 73 for once transferring the workpiece 5 from the mounting place 12 onto the bonding stage 17.
[0038]
Further, once at the placement place 12 and at the opposing arrangement positions of the objects to be joined 4 and 5, the same special gas as described above is locally ejected to the cleaned joining surfaces of the metal joining parts 2 and 3. A gas purge can be performed to maintain the atmosphere in contact with the bonding surface substantially in a special gas atmosphere. For example, as shown in FIG. 4, a nozzle 81 is provided as a means for locally ejecting a special gas once at the mounting place 12, and the special gas is locally disposed at a position where both the objects to be joined 4 and 5 are opposed to each other. Nozzle 82 can be provided as means for ejecting water.
[0039]
The joining method according to the present invention using the joining apparatus as described above is performed as follows. First, in a chamber 7 having a predetermined degree of vacuum, the metal joint portion 2 (for example, bump) of the chip 4 as the object to be bonded 4 and the metal joint portion 3 (for example, the substrate 5 as the object to be bonded 5) Electrode) is cleaned with Ar plasma and the surface is activated. In plasma cleaning, the plasma irradiation intensity and time are set so that etching can be performed at 1 nm or more on the entire surface to which the metal joint portion is bonded in order to remove the surface foreign material layer and sufficiently activate the surface for subsequent bonding. It is preferable.
[0040]
The chip 4 and the substrate 5 whose surfaces have been cleaned are temporarily placed on the placement place 12, and the chip 4 is turned upside down and held on the bonding tool 16, and the substrate 5 is held on the bonding stage 17 without being turned upside down. The chip 4 and the substrate 5 held opposite to each other are aligned so as to fall within a predetermined accuracy based on information read by the recognition means 21 for two fields of view, and the parallelism is also adjusted to fall within the predetermined accuracy. The
[0041]
From this state, the bonding tool 16 is lowered, a predetermined bonding pressure is applied by the pressurizing means 19, and heating by the heater 18 or ultrasonic application by the ultrasonic application means 22 is used in combination as necessary, and the metal of the chip 4. The joint 2 (bump) and the metal joint 3 of the substrate 5 are joined, for example, in the atmosphere.
[0042]
In such a series of operations, the objects to be bonded 4 and 5 are transferred from the cleaning chamber 7 to the final opposing positions of both objects to be bonded. A special gas atmosphere holding and conveying step is provided. In particular, in the special gas atmosphere holding and transporting process using the attachment 31, the object to be joined is held and transported as shown in FIGS.
[0043]
First, as shown in FIG. 5, the special gas supplied through the gas passage 34 is jetted from the gas blowing / suction hole 33 toward the workpiece 4 in a state where the attachment 31 is brought close to the workpiece 4 to some extent. As a result, the object 4 is filled with the special gas, and the atmosphere on the object 4 is replaced with the special gas. In this state, the attachment 31 is brought into contact with the workpiece 4 in a non-contact state with respect to the bonding surface. In this contact state, as shown in FIG. 6, the attachment 31 is filled with the special gas and is confined. After the contact, as shown in FIG. 7, the special gas filled in the attachment 31 is sucked through the gas blowing / suction hole 33, and the object to be bonded 4 is adsorbed and held on the attachment 31. In a state where the attachment 31 is sucked and held, the workpiece 4 is transported along with the attachment 31 along a predetermined route. Note that, when sucking the special gas, it is preferable to suck after contacting the object to be joined. However, when sucking from an atmosphere already filled with the special gas, the suction may be started before the contact.
[0044]
When transported in such an adsorbed and held state, the joining surface of the article to be joined 4 is substantially placed in a special gas atmosphere from the start of the operation and comes into contact with only the special gas. Therefore, generation of an oxide film or organic layer and adhesion of foreign substances are effectively prevented, and the bonding surface is maintained in a desirable surface activation state, and subsequent bonding is performed in a more desirable state.
[0045]
The holding and transporting in the special gas atmosphere using the attachment 31 as well as the reverse transporting process of the workpiece 4 using the reversing mechanism 13, and the workpiece 5 once on the bonding stage 17 from the mounting place 12. Can also be applied to the process of transporting the workpieces 4 and 5 from the cleaning chamber 7 to the mounting place 12 once, and in the same manner as described above, the bonding surface can be maintained in a desirable surface activation state. it can.
[0046]
After holding and transporting in the special gas atmosphere using the attachment 31, the objects 4 and 5 are transferred onto the bonding tool 16 and the bonding stage 17 and held there, so that the suction holding by the attachment 31 is released. To do. At this time, since it is necessary to release the reduced pressure (vacuum) state in the attachment 31, it is necessary to increase (release) the pressure in the attachment 31. Also at the time of this pressure release, it is preferable to spout the special gas into the attachment 31. If air is blown out at this time, there is a possibility that oxidation or foreign matter may adhere to the joint surfaces, which is not preferable.
[0047]
Further, as shown in FIG. 4, the special gas is ejected locally at the placement position 12 and the positions where the two objects 4 and 5 are opposed to each other, and the atmosphere in contact with the joining surface is purged with the special gas. By doing so, the atmosphere in contact with the bonding surface can be maintained in the special gas atmosphere even when the holding and conveyance are not performed, and the desirable surface activation state of the bonding surface can be maintained. Therefore, in this way, the desired surface activation state of the bonding surface can be more reliably maintained from the removal from the cleaning chamber 7 to the actual bonding, and the bonding surface can be easily bonded by energy wave cleaning. It is possible to maximize the effect. As a result, the bonding itself can be performed in the air, and further, bonding between different metals (for example, gold / copper, etc.), which has been difficult to bond in the conventional air, is also possible. In addition, the reliability of the bonding is improved, and the bonding conditions can be relaxed (decrease in pressure, heating temperature, ultrasonic energy, etc.). Therefore, bonding at room temperature or a temperature close to it, and further bonding in the atmosphere is possible.
[0048]
  In addition,In the above embodiment, the case where the object to be bonded is directly held and conveyed has been described.The technical idea related toAlso in the case of having a process of placing an object to be joined on a tray and holding and transporting the trayApplicable.For exampleAs a reference example,When the object to be cleaned is placed on the tray and cleaned with energy waves in the chamber 7, and the cleaned article to be cleaned is placed on the tray and then transported to the mounting place 12, for example. The method shown in FIG.Can be mentioned.
[0049]
FIG. 8 shows a case where the cleaned articles 4 and 5 are transported from the cleaning chamber 7 on the tray 91. The tray 91 is held by holding means 92 so as to be sandwiched mechanically, for example, and from the special gas supply path 93 provided in the holding means 92, the joining surface of the articles 4 and 5 to be joined on the tray 91, particularly on the tray 91. The special gas is ejected toward the surface, and the atmosphere on the workpieces 4 and 5 is purged. The inside of the holding space surrounded by the holding means 92 and the tray 91 is replaced with a special gas, and the atmosphere in contact with the bonding surfaces of the objects 4 and 5 is maintained in the special gas atmosphere during the holding and transporting of the tray 91. The bonding surface is maintained in the desired surface activation state. After the tray 91 is once transported to the placement place 12, the atmosphere in contact with the joining surface may be maintained in the special gas atmosphere by the same method as described above. Even in such a system, the desired surface activation state of the bonding surface can be reliably maintained from the removal from the cleaning chamber 7 to the actual bonding, and the maximum effect of facilitating the bonding by the energy wave cleaning of the bonding surface can be achieved. It is possible to make the best use of it.
[0050]
  In the present invention holding and transporting in a special gas atmosphere,AboveIt can be applied to various places likeHowever, when using a tray as described aboveExamples of desirable overall configuration applied to various locationsAs a reference exampleAs shown in FIG. In FIG. 9, for example, the tray 43 is taken out from the tray changer 44 in which the trays (work trays) 43 containing the chips 41 and the substrates 42 are stacked, and are carried into the cleaning chamber 45. For this take-out and carry-in, a tray loader for taking out a tray, which will be described later, may be used, or another dedicated means may be used. The inside of the cleaning chamber 45 is evacuated, for example, and then replaced with a plasma generating reaction gas 46 (for example, Ar gas), and the bonding surface between the chip 41 and the substrate 42 is plasma cleaned under reduced pressure. The tray 43 on which the cleaned chip 41 and the substrate 42 are placed is taken out from the cleaning chamber 45 by the tray loader 47, and the atmosphere on the tray 43 on which the chip 41 and the substrate 42 are placed is purged with the special gas 48 according to the present invention. While being carried, it is conveyed to the standby unit 50 on the stage table 49. The purge in the tray loader 47 is performed by supplying a special gas through the porous plate 51, for example.
[0051]
In the standby section 50 on the stage table 49, while the purge is performed with the special gas 53 blown from the purge nozzle 52, the standby tray 43 is covered with the movable lid 54 and the special gas 53 is confined. After waiting, the lid 54 is opened, the substrate 42 is held by suction by the holding head 56 attached to the tip of the substrate transfer mechanism 55, and the held substrate 42 is transferred onto the bonding stage 57. Even in this case, since the special gas 53 is purged on the tray 43 by the purge nozzle 52, other chips and substrates are also covered with the special gas. At this time, after the special gas 58 is blown into the holding head 56, the substrate 42 is sucked and held by suction, and the special gas 58 is blown again into the holding head 56 when the suction is released when the substrate 42 is transferred onto the bonding stage 57. As a result, the vacuum state in the head is destroyed. Also on the chip 41 side, the lid 54 is opened, the chip 41 is held by suction by the holding head 60 attached to the tip of the chip reversing mechanism 59, and the held chip 41 is reversed and then bonded. Transferred onto the lower surface of the tool 61. Even in this case, since the special gas 53 is purged on the tray 43 by the purge nozzle 52, other chips and substrates are also covered with the special gas. At this time, after the special gas 62 is blown into the holding head 60, the chip 41 is sucked and held by suction, and the special gas 62 is blown again into the holding head 60 at the time of releasing the suction when transferred to the bonding tool 61. As a result, the vacuum inside the head is destroyed.
[0052]
For both the bonding tool 61 on which the chip 41 is set and the bonding stage 57 on which the substrate 42 is set, the atmosphere on the surface of the chip 41 and the surface of the substrate 42 by the special gases 65 and 66 blown from the purge nozzles 63 and 64, respectively. While the upper atmosphere is purged, alignment is performed using the two-field recognition means 67. After the alignment, the two-field recognition means 67 is retracted, the bonding head 68 is lowered, and the chip 41 held by the bonding tool 61 is pressed against the substrate 42 held by the bonding stage 57, and in some cases. It is joined together with heating. After the chip 41 is mounted on the substrate 42, the mounted product is taken out by, for example, the substrate transfer mechanism 55 and stored in the finished product tray 69. When the finished product tray 69 is filled with the finished products that are sequentially taken out, the finished product tray 69 is delivered to the tray changer 44 that stacks the finished product trays 69 by, for example, the tray loader 47. In this way, purging with a special gas can be applied at various points in the series of operation steps.
[0053]
【The invention's effect】
As described above, according to the joining method and apparatus according to the present invention, when joining the objects to be joined, in which the joining surfaces of the metal joining portions are cleaned by energy waves, in the transport path from the cleaning portion to the joining operation portion. The joining surfaces can be appropriately maintained in a desired surface activation state, and the effects of energy wave cleaning can be maximized to easily join the objects to be joined with high reliability.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a bonding apparatus according to an embodiment of the present invention.
FIG. 2 is an enlarged schematic configuration diagram of a holding and conveying means section in a special gas atmosphere in the apparatus of FIG.
3 is a schematic configuration diagram showing a transport path to which a special gas atmosphere holding transport means can be applied in the apparatus of FIG.
4 is a schematic partial configuration diagram of a joining operation unit when special gas local jetting means is provided in the apparatus of FIG. 1; FIG.
FIG. 5 is a schematic configuration diagram showing the operation of the holding and conveying means in the special gas atmosphere of FIG.
6 is a schematic configuration diagram of a holding and conveying means in a special gas atmosphere showing the next operation of FIG.
FIG. 7 is a schematic configuration diagram of a holding and conveying unit under a special gas atmosphere showing the next operation of FIG.
FIG. 8 is a schematic configuration diagram illustrating an example of a holding and conveying unit in a special gas atmosphere using a tray.
FIG. 9 shows the present invention.Reference exampleIt is a schematic block diagram of the joining apparatus which concerns on this.
[Explanation of symbols]
1 Joining device
2, 3 Metal joint
4 Bonded object (chip)
4a, 5a Substrate base material
5 Substrate (substrate)
6 Vacuum pump
7 Chamber
8 Plasma irradiation means
9 Plasma
10 Ar gas supply pump
11 Joining operation part
12 Place once
13 Reverse mechanism
14 Head part of reversing mechanism
15 Bonding head
16 Bonding tool
17 Bonding stage
18 Heater as heating means
19 Pressurizing means
20 Position adjustment table
21 Two field of view recognition means
22 Ultrasonic wave application means
31 Attachment
32 Suction hole
33 Gas blowout / suction holes
34 Gas passage
41 chips
42 Substrate
43 Tray (work tray)
44 Tray Changer
45 Cleaning chamber
46 Replacement gas
47 Tray loader
48 Special gas
49 Stage table
50 standby section
51 porous plate
52 Purge nozzle
53 Special gas
54 lid
55 Substrate transfer mechanism
56 Holding head
57 Bonding stage
58 Special gas
59 Chip reversal mechanism
60 Holding head
61 Bonding tool
62 Special gas
63, 64 Purge nozzle
65, 66 Special gas
67 Two-field recognition means
68 Bonding head
69 Finished product tray
71, 72, 73 Transport path
81, 82 Nozzle as means for locally ejecting special gas
91 trays
92 Holding means
93 Special gas supply path

Claims (28)

When joining objects to be joined having metal joints on the surface of the base material, the joining surface of the metal joining part of the object to be joined is washed with an energy wave in the washing part, and then brought into a non-contact state with respect to the joining surface. Transporting the object to be bonded to the bonding operation part and arranging the objects to be bonded oppositely in the bonding operation part, and bonding the metal bonding parts to each other, the cleaning part facing the bonding operation part By at least part of the transport path of the object to be arranged up to the arrangement position, the joining surface is made of an inert gas such as Ar gas or a non-oxidizing gas such as nitrogen gas, and is kept in the gas atmosphere by the energy wave. in a state where the oxide films or organic layer on the bonding surface impurity or formed is exposed to the atmosphere of the special gas is a gas that can prevent the or adheres the cleaning metal joints, conveying holds object to be bonded Hold in a special gas atmosphere With a step, the under special gas atmosphere holding and conveying step includes the step of sucking and holding the object to be bonded with the attachment having a gas blowing and suction holes for sucking after the ejected special gas ejection, the adsorption retention In the process, the special gas is blown out from the gas blowing / suction hole of the attachment toward the object to be joined, so that the attachment is filled with the special gas and the atmosphere on the object to be joined is replaced with the special gas. Place the joint surface of the joint under a special gas atmosphere, and in that state, contact the attachment with the joint in a non-contact state with respect to the joint surface, and then inside the attachment through the gas blowing / suction holes. A special gas filled in the container is sucked to hold the object to be bonded to the attachment . The joining method according to claim 1 , wherein the suction holding step includes a step of sucking and holding one object to be joined and then inverting it and transferring it to the opposed arrangement position. The suction holding step comprises taking out the object to be bonded directly from the cleaning unit, the bonding method according to claim 1 or 2. Furthermore, it has the process of once placing the to-be-joined object conveyed in the said joining operation | movement part , and spouts special gas locally toward the joining surface of a to-be-joined object in this once placement place The joining method according to any one of claims 1 to 3 , further comprising a step of: Further, after the counter is arranged both objects to be bonded by the bonding operation part, having both objects to be bonded between a step of locally jetted special gas, bonding method according to any one of claims 1-4. Pressurization, heating, bonding using at least one method the application of ultrasound bonding method according to any one of claims 1-5. It joined in the atmosphere, the bonding method according to any one of claims 1-6. Joined in vacuo bonding method according to any one of claims 1-6. Bonding in an inert gas, bonding method according to any one of claims 1-6. Using plasma as the energy wave bonding method according to any one of claims 1-9. The bonding method according to claim 10 , wherein Ar plasma is used as the energy wave. The bonding method according to any one of claims 1 to 11 , wherein etching is performed to a depth of 1 nm or more on the entire surface to which the metal bonding portion is bonded by cleaning with the energy wave. The joining method according to any one of claims 1 to 12 , wherein metal joining portions whose surfaces are made of any of gold, copper, Al, In, and Sn are joined together. The joining method according to any one of claims 1 to 13 , wherein the surface hardness of at least one of the metal joints is 120 or less in terms of Vickers hardness Hv. An apparatus for joining objects to be joined having metal joints on the surface of a substrate, wherein the joining surfaces of the metal joints are cleaned by energy waves, and the objects to be joined are cleaned after washing by the washing means. A joining means for arranging and joining the metal joining parts, and a joining operation part which is provided between the cleaning means and the joining means and which joins the objects to be joined in a non-contact state with respect to the joining surface cleaned by the cleaning means And at least a part of the means for conveying the bonding surface is an inert gas such as Ar gas or a non-oxidizing gas such as nitrogen gas and has a gas atmosphere thereof. In a state exposed to an atmosphere of a special gas , which is a gas that can prevent the formation of an oxide film or an organic substance layer or adhesion of impurities on the joint surface of the metal joint cleaned by the energy wave by maintaining , Covered Compound Ri Do from the special gas atmosphere holding and conveyance means for holding and transporting a said special gas atmosphere holding and conveying means, the article to be welded together with a gas blowing and suction holes for sucking after ejection jetted said special gas A special gas is blown toward the object to be bonded from the gas blowout / suction hole of the attachment, and the attachment is filled with the special gas so that the atmosphere on the object to be bonded is a special gas. The bonding surface of the object to be bonded is placed in a special gas atmosphere by replacing the attachment with the attachment in contact with the object to be bonded in a non-contact state with respect to the bonding surface, and then the gas blowing - through the suction holes by sucking the special gas which has been filled in the attachment junction instrumentation, characterized in that it comprises means for sucking and holding the object to be bonded to the attachment . The bonding apparatus according to claim 15 , wherein the holding and conveying unit in the special gas atmosphere is provided in a unit that sucks and holds one object to be bonded, and then reverses and transfers the object to the opposed arrangement position. The joining apparatus according to claim 15 or 16 , wherein the special gas atmosphere holding and conveying means is provided in a means for directly taking out an object to be joined from the cleaning means. Furthermore, a place for temporarily placing the object to be joined that has been transported is provided in the joining operation section, and special gas is locally ejected to the place of placement once toward the joining surface of the object to be joined. The joining device according to any one of claims 15 to 17 , wherein means are provided. Further, the opposed position of the object to be bonded in the bonding operation part, means for locally jetted special gas between two objects to be bonded is provided, the bonding apparatus according to any one of claims 15-18 . The joining apparatus according to any one of claims 15 to 19 , wherein the joining means includes at least one means of pressurization, heating, and ultrasonic application. The joining apparatus according to any one of claims 15 to 20 , wherein the joining means includes means for joining objects to be joined in the atmosphere. The joining apparatus according to any one of claims 15 to 20 , wherein the joining means includes means for joining objects to be joined together under reduced pressure. The joining apparatus according to any one of claims 15 to 20 , wherein the joining means includes means for joining objects to be joined in an inert gas. Wherein the cleaning means comprises a plasma irradiation device, joining device according to any one of claims 15-23. The bonding apparatus according to claim 24 , wherein the cleaning means comprises Ar plasma irradiation means. The joining according to any one of claims 15 to 25 , wherein the cleaning means comprises means for irradiating energy waves with energy higher than that capable of etching at a depth of 1 nm or more on the entire surface to which the metal joint portion is joined. apparatus. 27. The joining apparatus according to any one of claims 15 to 26 , wherein a surface of each metal joint to be joined is made of any one of gold, copper, Al, In, and Sn. The joining device according to any one of claims 15 to 27 , wherein the surface hardness of at least one of the metal joints is 120 or less in terms of Vickers hardness Hv.

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