JP2003318223A - Method and device for mounting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting method and a mounting device which can greatly improve junction reliability when junction matters are mounted mutually, by preventing air from being involved in application of a sealing matter and by preventing air from being involved also in mounting accompanied by junction. <P>SOLUTION: When junction matters are jointed mutually, a sealing matter is applied to a junction surface of one junction matter. At least a part between both the junction matters before junction is airtightly closed from a circumference by a local chamber for setting an inside thereof in a vacuum state. The junction matters are jointed mutually under the vacuum state. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting method and a mounting apparatus for bonding objects to be bonded made up of chips, substrates, etc., and particularly to suppressing entrapment of air in a sealing material applied to a bonding portion. The present invention relates to a mounting method and a mounting device that achieve a highly reliable bonded state.

[0002]

2. Description of the Related Art Bonding of objects to be joined, for example, bumps are formed on a chip, a sealing material made of a non-conductive adhesive or the like is applied to the chip side or the substrate side, and the chip is placed face down on the substrate. A method for mounting a chip in which the bump of the chip is brought into contact with the pad of the substrate and then the bump of the chip is heated and melted to be bonded to the pad of the substrate is well known. Conventionally, the application of the sealing material in such a mounting method has been performed in the atmosphere, so that there is a problem that air is likely to be entrapped during the application. Even if a small amount of air is entrapped, the volume of the air may increase due to heating, and a relatively large void may be generated. If such a void remains, the reliability of bonding is reduced. Further, bubbles generated by vaporization of vaporized components contained in the monomers, oligomers, solvents, etc. may become voids by heating. The voids generated during this heating are also effective because they can be degassed in a vacuum.

Conventionally, the above-described chip mounting has also been carried out in the atmosphere, so that even if air is not entrained in the sealing material to be used or the applied sealing material. However, there is a problem that when the chip is mounted, air is likely to be entrained when the sealing material is extruded between the chip and the substrate. Even if the encapsulant is extruded from the center of the chip toward the outer periphery to prevent air from being entrapped, the bumps are present there, especially around the bumps, especially at the roots of the bumps. Air is less likely to be pushed out, and as a result, air may remain locally. Residual air and the like remain as voids after heating and joining, and the joining reliability is reduced.

[0004]

Therefore, an object of the present invention is to pay attention to the above-mentioned problems, to improve the reliability of application of the sealing material, in particular to prevent air from being entrapped during the application, and to mount it with bonding. An object of the present invention is to provide a mounting method and a mounting apparatus capable of significantly improving the bonding reliability in mounting objects to be bonded by preventing air from being entrapped at any time.

[0005]

In order to solve the above-mentioned problems, the mounting method according to the present invention applies a sealing material to the bonding surface of one of the objects to be bonded when bonding the objects to be bonded together. A method for locally sealing at least a portion between both objects to be bonded before bonding from a surrounding by a local chamber to bring the inside into a predetermined vacuum state, and bonding the objects to be bonded under the vacuum state Consists of.

In this mounting method, after the sealing material is applied, at least the portion between the objects to be joined before joining can be sealed by the local chamber to bring the inside into a predetermined vacuum state. First, at this stage, the air contained in the adhesive is defoamed. By making a predetermined vacuum state, the residual air in the joint can be greatly reduced, so that the mounting with a significantly reduced void is possible.

Alternatively, the sealing material can be applied after at least the portion between the objects to be joined before joining is sealed by the local chamber and the inside thereof is brought into a predetermined vacuum state. By applying after applying a vacuum state, air entrapment during application of the sealing material is significantly reduced, and since bonding is performed in this state, more voidless mounting is possible.

Furthermore, after at least the portion between the objects to be joined before joining is sealed by the local chamber and the inside thereof is brought into a predetermined vacuum state, the joining surface of the objects to be joined is washed with energy waves or energy particles. It is also possible to apply the sealing material later. Since the sealing material is applied with the surface of the joint surface being activated by cleaning with energy waves or energy particles, it is possible to further improve the joint reliability while achieving voidlessness.

Plasma, ion beam, atomic beam, radical beam, laser or the like can be used as the energy wave or energy particles for cleaning the bonding surface before the application of the sealing material. From the viewpoint of the cost of the device and the simplicity of the structure, it is preferable to use plasma.

In addition, the predetermined vacuum state is preferably a vacuum degree of 260 × 10 Pa (20 Torr) or less in order to efficiently achieve voidlessness after mounting the sealing material and after mounting.

Further, in order to carry out high-accuracy mounting, it is necessary to align the relative positions of the two objects to be joined by a method of inserting a recognition means between the objects to be joined. After the recognition means is retracted, it is preferable that at least the portion between the objects to be joined before joining is sealed by the local chamber. As a result, the space between the objects to be joined is efficiently sealed in the local chamber in a small space state without being restricted by the space for the recognition means,
A predetermined vacuum state can be easily and quickly obtained.

A mounting apparatus according to the present invention is a mounting apparatus for bonding objects to be bonded to each other, and at least sealing means applying means for applying a sealing material to a bonding surface of one object to be bonded before bonding. A local chamber for locally sealing the portion between the objects to be joined before joining from the surroundings to bring the inside into a predetermined vacuum state.

In this mounting apparatus, the sealing material applying means can be sealed in the local chamber after applying the sealing material as a device different from the device having the local chamber. That is, it is possible to bond with a device according to the present invention such as a substrate to which a sealing material is applied in advance. Also,
With the configuration in which the sealing material applying means is provided in the local chamber, it is possible to apply the sealing material in a state in which the local chamber is sealed and the inside thereof is in a predetermined vacuum state, which is higher. It becomes possible to achieve the boydless state.

Further, in this mounting apparatus, it is preferable that a cleaning means for cleaning the bonding surface of the objects to be bonded by energy waves or energy particles is provided in the local chamber. As the energy wave or energy particles of the cleaning means, plasma is preferable as described above.

Further, in order to carry out mounting with higher accuracy, this mounting apparatus has a recognition means which is advanced and retracted for alignment of relative positions of both objects to be bonded before sealing by the local chamber. It is preferable to have.

In such a mounting method and apparatus according to the present invention, before or after the sealing material is applied, the portion between the objects to be joined is locally sealed to the surroundings by the local chamber and the inside thereof is predetermined. In this state, the air entrapped in the encapsulant that was conventionally applied or between the encapsulant and the bonding surface is removed, so there is no entrapment of encapsulant before joining. Is achieved. In this state, that is, under a predetermined vacuum condition, the two objects to be joined are pressed together for joining the objects to be joined, and the sealing material applied at that time is applied to the center part between the objects to be joined. Although it is extruded from the outside toward the outside, since there is substantially no problematic amount of air under the predetermined vacuum state, entrapment of air does not occur at the time of joining. As a result, it becomes possible to bond voidless members, and highly reliable mounting is performed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. 1 to 4 show a mounting method using the mounting apparatus 1 according to the first embodiment of the present invention. FIG. 1 shows an alignment process for aligning the relative positions of both objects to be bonded within a predetermined accuracy range. As an object to be bonded, one is a chip 2 and the other is a substrate 3. . A plurality of bumps 4 (two bumps 4 are shown in FIG. 1) are provided on the chip 2, and corresponding pads 5 (for example, electrodes) are provided on the substrate 3. In this embodiment, a stage 6 for holding the substrate 3 and a tool 7 for holding the chip 2 are provided, and the stage 6 has the X, Y directions (horizontal direction) or X,
The position can be adjusted in the Y direction and the rotation direction (θ direction), and the tool 7 can be adjusted in the Z direction (vertical direction). By lowering the tool 7, both objects to be joined 2 and 3 are opposed to each other with an appropriate interval before joining, and in this state, the recognition means 8 is provided between the objects to be joined 2 and 3.
(For example, a two-field of view recognizing means having a field of view in the vertical direction) is inserted, an identification mark (not shown) for alignment provided on the chip 2 side and the substrate 3 side is read, and the chip 2 is read based on the read information. The movement of the stage 6 is controlled so that the relative position between the substrate 3 and the substrate 3 falls within a predetermined accuracy range. In the present embodiment, the local chamber 9 is provided on the tool 7 side that holds the chip 2, but the local chamber 9 is in an open state in the alignment step,
Alignment is performed in the open atmosphere.

In the above description, the chip 2 is, for example, an IC chip, a semiconductor chip, an optical element, a surface-mounted component, a wafer, or the like, whichever is on the side to be bonded to the substrate 3 regardless of its type or size. Say. The bumps 4 are, for example, solder bumps, stud bumps, and all other parts that are bonded to the pads 5 provided on the substrate 3. Further, the substrate 3 means, for example, a resin substrate, a glass substrate, a film substrate, a chip, a wafer, or the like on the side to be bonded to the chip 2, regardless of the type or size. The pad 5 refers to, for example, an electrode accompanied with an electric wiring, a dummy electrode not connected to the electric wiring, or any other member that is bonded to the bump 4 provided on the chip 2.

The stage 6 as described above is generally mounted so as to be movable in parallel and / or rotatable.
If necessary, they may be mounted in a combined manner of lifting and lowering. Further, the tool 7 side may have a device form capable of performing not only the raising / lowering operation but also the parallel movement and / or the rotation operation.

In this embodiment, after the alignment, the recognition means 8 is retracted, and as shown in FIG.
On the bonding surface of one object to be bonded (the substrate 3 in this embodiment),
The sealing material 11 is applied from a dispenser 10 (sealing material application nozzle) as an encapsulating material applying means. The sealing material 11 to be applied is not particularly limited, and a non-conductive adhesive agent, an anisotropic conductive adhesive agent, or the like can be used. Further, the form of the sealing material 11 is not limited to the paste-like one applied from the dispenser 10, and a film-like one may be applied. In that case, a film sticking means may be used as the sealing material applying means. Even in the film form, the fluidity is imparted by heating at the time of joining.

Subsequently, as shown in FIG. 3, the tool 7 (on the head side) is lowered, and the local chamber 9 locally seals at least the portion between the objects to be joined before joining to the surroundings. On the lower side of the local chamber 9, a stretchable elastic seal member 12 having, for example, a bellows structure is provided.
Is provided, and the closed state is automatically formed as the tool 7 descends. Such an elastic seal material 1
In addition to the sealing mechanism by 2, the sealing mechanism may be configured by a sliding chamber wall (not shown). After the sealing, the sealed internal space 14 is brought into a predetermined vacuum state by suction by the vacuum pump 13, for example. The degree of vacuum is set so that the amount of air that can be trapped is sufficiently low, that is, even if it is trapped, it does not develop into a void of a problematic size.
It is preferably 0 × 10 Pa (20 Torr) or less.

Under this predetermined vacuum condition, the objects to be bonded (chip 2 and substrate 3) are bonded as shown in FIG. The tool 7 is lowered and the bumps 4 of the chip 2 are placed on the substrate 3
The pad 4 is pressure-bonded to the pad 5, and the bump 4 is melted by heating by a heater incorporated in the tool 7, for example, and is electrically bonded to the pad 5. At the time of this pressure bonding, the applied sealing material 11 is pushed outward from the central portion in the portion between the objects to be joined, but since it is the joining under a predetermined vacuum state, it is substantially caught. There is no air to be trapped, and air entrapment, which has been a problem in the past, does not occur. Therefore, even when heated, it is not necessary to consider the void generation due to the increase in the volume of the entrained air,
The desired bond form of the voidless is achieved. As a result, it becomes possible to perform highly reliable mounting.

FIG. 5 shows a mounting method using the mounting apparatus 21 according to the second embodiment of the present invention. In this embodiment, the alignment is performed in the atmosphere as shown in FIG. 1, but before the encapsulating material 11 is applied, the local chamber 9 locally seals the area between the objects to be joined with the surroundings. Then, the inside thereof is brought into a predetermined vacuum state, and under the predetermined vacuum state, a bonding surface (in the present embodiment, the bonding surface of the substrate 3 is joined from the dispenser 22 as the sealing material applying means provided in the local chamber 9). ) Is applied with the sealing material 11. Since the application is performed after a predetermined vacuum state, air entrapment during application of the sealing material 11 is also possible (for example, entrapment in the applied sealing material 11 or the applied sealing material 11 and the bonding surface). It will be surely suppressed. Therefore, by bonding in this state in the same manner as shown in FIG. 4, the voidless mounting can be performed more reliably.

FIG. 6 shows a mounting method using the mounting apparatus 31 according to the third embodiment of the present invention. In this embodiment, compared with the second embodiment, the sealing material 1 is further added.
Prior to the application of No. 1, the local chamber 9 under a predetermined vacuum condition
Inside, the joining surface of the article to be joined is washed by a washing means using energy waves or energy particles, and then the sealing material 11 is applied to the joining surface from the dispenser 22.

In this embodiment, the plasma 32 is used as an energy wave or energy particles. The plasma 32 alternately switches the polarities of the plasma generation electrode 33 provided on the chip holding tool 7 side and the plasma generation electrode 34 provided on the substrate holding stage 6 side, thereby forming a bonding surface on the chip 2 side and Both of the joint surfaces on the side of the substrate 3 can be cleaned. By this cleaning, it becomes possible to apply the sealing material 11 in an activated state in which the oxide film and the contamination layer on the surfaces of the bumps 4 and the pads 5 are removed, and further the oxide film and the contamination layer are removed. Since it is possible to join in the state where
Bonding can be performed under the condition that no foreign matter exists, and the reliability of bonding is significantly improved. That is, in addition to the voidless state as described above, the joining is performed in the state where the surface is cleaned, so that the reliability of mounting is further improved.

As the energy waves or energetic particles used for cleaning the bonding surface, an ion beam, an atomic beam, a radical beam, a laser or the like can be used instead of plasma. However, it is preferable to use plasma from the viewpoint of the cost of the apparatus and the ease of implementing the energy wave irradiation structure. Further, in the above-mentioned embodiment, the plasma is irradiated under a predetermined vacuum state, but it is also possible to perform the plasma cleaning in a state where the atmosphere is replaced with an inert gas atmosphere such as argon gas, and the hydrogen plasma is used to oxidize. It is also possible to remove the membrane. In this case, in order to achieve the voidless mounting in the present invention,
It is effective to evacuate the inside of the local chamber 9 after plasma cleaning and before applying the sealing material.

[0027]

As described above, according to the mounting method and the mounting apparatus of the present invention, since the mounting is performed in the local vacuum state by the local chamber, the entrainment of air in the encapsulant is performed. It is possible to reliably suppress the above, and it becomes possible to mount by voidless, and it is possible to greatly improve the bonding reliability in mounting.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an alignment step in a mounting apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a sealing material applying step in the mounting apparatus of FIG.

3 is a schematic configuration diagram showing a process of sealing and vacuuming by a local chamber in the mounting apparatus of FIG.

FIG. 4 is a schematic configuration diagram showing a joining process in the mounting apparatus of FIG.

FIG. 5 is a schematic configuration diagram of a mounting apparatus according to a second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a mounting apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

1, 21, 31 mounting device 2 Chip as one object to be bonded 3 Substrate as the other object 4 bumps 5 pads 6 stages 7 tools 8 recognition means 9 Local chamber 10, 22 Dispenser as means for applying sealing material 11 Sealant 12 Elastic seal material 13 Vacuum pump 14 sealed internal space 32 plasma 33, 34 Plasma generation electrode

Claims (13)

[Claims] 1. When joining objects to be joined together, a sealing material is applied to a joining surface of one object to be joined, and at least a portion between both objects to be joined before joining is locally localized from the surroundings by a local chamber. A mounting method, which comprises hermetically sealing the inside of the container to a predetermined vacuum state and bonding the objects to be bonded together under the vacuum state. 2. The mounting method according to claim 1, wherein after the sealing material is applied, at least the portion between the objects to be joined before the joining is sealed by the local chamber and the inside thereof is brought into a predetermined vacuum state. 3. The mounting method according to claim 1, wherein at least a portion between the objects to be joined before joining is sealed by a local chamber to bring the inside into a predetermined vacuum state, and then the sealing material is applied. 4. A local chamber is used to seal at least a portion between the objects to be joined before joining and to bring the inside into a predetermined vacuum state, and then the joining surface of the objects to be joined is washed with energy waves or energy particles. The mounting method according to claim 1, wherein the sealing material is applied later. 5. The mounting method according to claim 4, wherein the energy wave or the energy particle is plasma. 6. The predetermined vacuum state is 260 × 10 Pa
The mounting method according to claim 1, which has the following vacuum degree. 7. An object to be joined at least before joining by the local chamber after the recognition means is inserted between the objects to be joined to align the relative positions of the objects to be joined and the identifying means is retracted. Sealing the space portion, Claims 1 to 6.
The mounting method described in any one of. 8. A mounting apparatus for joining objects to be joined together, wherein a sealing material applying means for applying a sealing material to a joining surface of one object to be joined before joining, and at least both joined objects before joining. A mounting apparatus comprising: a local chamber that locally seals a space between objects from the surroundings to bring the inside into a predetermined vacuum state. 9. The encapsulating material applying means is provided as a device different from the device having the local chamber.
The mounting apparatus according to claim 8. 10. The mounting apparatus according to claim 8, wherein the encapsulating material applying means is provided in the local chamber. 11. The mounting apparatus according to claim 8, wherein a cleaning means for cleaning a bonding surface of an object to be bonded by an energy wave or energy particles is provided in the local chamber. 12. The mounting apparatus according to claim 11, wherein the energy wave or energy particles of the cleaning means is plasma. 13. The recognizing means is further provided for advancing and retracting between the objects to be joined for sealing the relative positions of the objects to be joined before sealing by the local chamber.
13. The mounting device according to any one of to 12.