JP3589159B2 - Bonding apparatus and bonding method for electronic component with bump - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a bonding apparatus and a bonding method for electronic components with bumps for bonding electronic components with bumps such as flip chips to a work.
[0002]
[Prior art]
As a method of bonding an electronic component such as an electronic component with a bump to a work such as a substrate, a method using ultrasonic pressure welding is known. In this method, ultrasonic vibrations are applied while pressing the bumps of the electronic component against the substrate, and the bumps and the bonding surfaces such as the electrodes of the substrate are rubbed against each other for bonding. In this bonding, there are various types of substrates to which the electronic components are bonded, and the electronic components may be bonded to a small package-shaped substrate. In this case, mounting and bonding of electronic components are performed in a state where the package is held on the substrate holding unit by a method such as vacuum suction.
[0003]
[Problems to be solved by the invention]
However, in a package made of a material such as ceramics, the accuracy of the outer shape is not always maintained due to an error or deformation at the time of manufacture, and in general, vertical warpage or bending is likely to occur. Therefore, in many cases, the posture of the package is not stable even when the package is held by vacuum suction in the bonding apparatus. If the electronic component is pressed while applying the ultrasonic vibration while the posture is unstable, the package is likely to be displaced at the time of bonding, thereby causing a bonding failure. As described above, the conventional bonding apparatus has a problem that it is difficult to stably hold the package when performing ultrasonic bonding on a small package, and the bonding quality is not ensured.
[0004]
Therefore, an object of the present invention is to provide a bonding apparatus and a bonding method for an electronic component with bumps, which can hold a substrate to which an electronic component is bonded in a stable posture and can ensure bonding quality.
[0005]
[Means for Solving the Problems]
2. The bonding apparatus for an electronic component having bumps according to claim 1, wherein the electronic component having the bump formed on its lower surface is pressed against a substrate by a bonding head to apply ultrasonic vibration to bond the electronic component. An apparatus, elastic holding means for abutting on the lower surface of the substrate and elastically holding the substrate, elevating means for elevating the bonding head, a bonding tool mounted on the bonding head and abutting on an electronic component, Vibration applying means for applying ultrasonic vibration to the bonding tool, and pressurizing means for pressing the electronic component against the work via the contact surface, wherein the electronic component of the bonding action portion of the bonding tool The size of the contact surface is the upper limit dimension defined by the external dimensions of the electronic component to be bonded. Remote small and by setting larger than the lower limit size defined by the inner dimension between the electrodes facing each outermost edge of the lower surface of the electronic component, entirely abut the bonding working portion to the electronic component To prevent partial wear.
[0006]
3. The bonding method for an electronic component having bumps according to claim 2, wherein the electronic component having the bump formed on the lower surface is pressed against a substrate by a bonding head and ultrasonic vibration is applied to bond the electronic component. A method comprising: placing a substrate on elastic holding means abutting against a lower surface of the substrate and elastically holding the substrate; mounting an electronic component on the substrate; and bonding the electronic component to a bonding tool. A step of elastically holding the substrate by elastic holding means by pressing against the substrate, and a step of joining the electronic component to the substrate by applying ultrasonic vibration to the electronic component via a bonding tool. The size of the contact surface of the bonding action portion where the bonding tool contacts the electronic component with the electronic component is determined by the size of the bonding target. Smaller than the upper limit size defined by the outer dimensions of the parts, and by setting larger than the lower limit size defined by the inner dimension between the electrodes facing each outermost edge of the lower surface of the electronic component, the bonding working portion Was brought into full contact with the electronic component to prevent partial wear.
[0007]
According to the present invention, there is provided an elastic holding means which abuts on the lower surface of the substrate and elastically holds the substrate, and at the time of bonding, the ultrasonic vibration is applied while pressing the substrate against the elastic holding means and elastically holding the substrate. By applying, the posture of the substrate at the time of bonding can be stabilized and the bonding quality can be ensured.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of an electronic component bonding apparatus according to one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a relative size of a bonding tool of the electronic component bonding apparatus according to one embodiment of the present invention with respect to the electronic component. FIG. 3 is an explanatory view of bonding of electronic components by the bonding apparatus according to one embodiment of the present invention. FIG. 4A is a perspective view of a substrate holding carrier according to one embodiment of the present invention, and FIG. FIG. 2 is a partial cross-sectional view of the substrate holding unit according to the embodiment of the present invention.
[0009]
First, an electronic component bonding apparatus will be described with reference to FIG. In FIG. 1, the substrate positioning unit 1 includes a moving table 2, and a substrate holding unit 3 having a heating unit is provided on the moving table 2. The substrate holding unit 3 holds a package-shaped substrate 4 (see FIG. 3A) which is a work to which the electronic component 5 with the bump is bonded.
[0010]
A plate member 3 a made of an elastic material such as rubber or resin is mounted on the upper surface of the substrate holding unit 3. When the electronic component 5 is bonded, the substrate 4 is placed on the plate member 3a, and the substrate 4 is pressed against the plate member 3a via the electronic component 5. At this time, the plate member 3a elastically holds the substrate 4. Therefore, the plate member 3a is an elastic holding means which abuts on the lower surface of the substrate and elastically holds the substrate 4.
[0011]
Above the reference positioning section 1, a bonding section 10 is provided. A guide member 12 is disposed in a vertical frame 11 of the bonding portion 10 in a vertical direction, and the elevating block 13 can be moved up and down by the guide member 12. A nut member 14 is fixed to the lifting block 13, and a feed screw 15 driven by a Z-axis motor 16 is screwed into the nut member 14.
[0012]
A bonding head 17 is provided below the lifting block 13, and the bonding head 17 has a built-in pressure unit 18. The pressing unit 18 is connected to a bonding tool 19. The electronic component 5 is sucked and held on a lower surface of the bonding tool 19 by a suction hole 19 b (see FIG. 2), and the electronic component 5 is pressed against the substrate 4 for bonding. A joining action portion 19a is provided.
[0013]
A vibrator 20 serving as a vibration applying unit is mounted on the bonding tool 19, and by driving the vibrator 20, ultrasonic vibration is applied to the electronic component 5 via the joining action portion 19 a of the bonding tool 19. . By driving the Z-axis motor 16, the lifting block 13 moves up and down, so that the bonding head 17 also moves up and down. The Z-axis motor 16, the feed screw 15, and the nut member 14 serve as an elevating unit for the bonding head 17.
[0014]
The pressurizing unit 18 is connected to a pressure source (not shown), and by supplying air set to a predetermined pressure from the pressure source to the pressurizing unit 18, the pressurizing unit 18 is connected to the electronic unit via the joint operating unit 19 a. The component 5 is pressed against the board 4 held by the board holding section 3. Therefore, the pressing unit 18 is a pressing unit that presses the electronic component 5 against the substrate 4.
[0015]
Next, with reference to FIG. 2, a description will be given of the relative size of the bonding action portion 19 a of the bonding tool 19 and the electronic component 5 with a bump to be bonded. As shown in FIGS. 2A and 2B, the size TX, TY of each side of the rectangular joining action portion 19a is smaller than the upper limit dimension defined by the outer dimensions PX, PY of the electronic component 5, In addition, the lower limit dimension defined by the inner dimension between the joining toes of the opposing bumps 5b located at the outermost edge of the lower surface of the electronic component, that is, the inner dimension BX, BY between the opposing electrodes 5a at the outermost edge. It is set large.
[0016]
Setting the dimensions of the joining action portion 19a in this manner has the following significance. In other words, when the contact surface of the joining action portion 19a with the electronic component 5 is excessively large with respect to the electronic component 5 and the joining action portion 19a protrudes outside the electronic component 5, the joining action portion 19a is Only the portion of the lower surface that is in contact with the electronic component 5 is worn, and a step is generated on the lower surface of the joining action portion 19a with use. When the stepped portion comes into contact with the upper surface of the electronic component 5, the electronic component 5 is tilted at the time of bonding, and a bonding failure occurs.
[0017]
Further, when the bonding action portion 19a is too small with respect to the electronic component 5, all the bumps 5b formed on the electrodes 5a of the electronic component 5 cannot be uniformly pressed against the bonding surface. Causes bonding failure. On the other hand, by setting the relative dimensions as shown in the present embodiment, the joining action portion 19a comes into full contact with the electronic component 5, so that partial wear does not occur. In addition, since the bonding action portion 19a has a dimension capable of effectively transmitting the pressing load to all the bumps 5b, it is possible to ensure good bonding quality without causing the above-described bonding failure. it can.
[0018]
This electronic component bonding apparatus is configured as described above, and the bonding operation will be described below. First, a package-shaped substrate 4 on which an electronic component 5 is mounted is placed on a plate member 3a of the substrate holding unit 3 in FIG. At this time, the substrate 4 may not have a perfect planar shape due to an error in manufacturing, and may have an upwardly convex or downwardly convex warp as shown in FIG. 3B. .
[0019]
Next, the bumped electronic component 5 is taken out from a component supply unit (not shown). The electronic component 5 is sucked and held by the bonding action portion 19a of the bonding tool 19 by the suction hole 19b. Then, the electronic component 5 is mounted on the substrate 4 by lowering the bonding tool 19 with respect to the substrate 4 on the substrate holding unit 3, and then the electronic component 5 is pressed against the substrate 4 by the pressing unit 18. 4 is pressed against the plate member 3a. The bonding of the electronic component 5 is performed by driving the vibrator 20 and applying the ultrasonic vibration to the electronic component 5 via the bonding tool 19.
[0020]
In the bonding process, even if the substrate 4 is warped as described above, since the plate member 3a having high elasticity is mounted on the upper surface of the substrate holding portion 3, FIG. As shown in (1), when the electronic component 5 is pressed, the substrate 4 sinks on the surface of the plate member 3a, and the substrate 4 is elastically held in a stable posture by the plate member 3a. Therefore, a bonding defect due to the warpage of the substrate 4 does not occur, which occurs in the conventional electronic component mounting apparatus.
[0021]
In the above-described embodiment, an example is shown in which the plate member 3a made of an elastic material is directly mounted on the upper surface of the block-shaped substrate holding section 3 as the elastic holding means. However, the present invention is not limited to this, and various forms are possible. is there. For example, as shown in FIG. 4A, in a case where bonding is performed in a state where the substrate 4 is held by the carrier 6, an elastic support type in which an elastic plate 7 as an elastic holding means is attached to the lower surface. The carrier 6 is used. Thereby, when the substrate 4 is pressed from above, the substrate 4 is elastically held, and the elastic deformation can be absorbed by the elastic plate 7 to maintain a good posture.
[0022]
Further, as shown in FIG. 4B, when bonding is performed while the substrate 4 is held by the tray 8, an elastic plate as an elastic holding means is provided on the upper surface of the lower receiving member 9 provided at the bonding station. 9a is used. As a result, the lower receiving member 9 is raised, and the substrate 4 can be elastically held from below by the elastic plate 9a, and similarly, the posture of the substrate 4 during bonding can be favorably held.
[0023]
【The invention's effect】
According to the present invention, there is provided an elastic holding means which abuts on the lower surface of the substrate and elastically holds the substrate, and at the time of bonding, the ultrasonic vibration is applied while pressing the substrate against the elastic holding means and elastically holding the substrate. Since the voltage is applied, the posture of the substrate at the time of bonding can be stabilized and the bonding quality can be ensured. In addition, the size of the contact surface of the bonding action portion of the bonding tool with the electronic component is smaller than the upper limit dimension defined by the external dimensions of the electronic component to be bonded, and the outermost edge of the lower surface of the electronic component is opposed to the outermost edge. It is set to be larger than the lower limit dimension defined by the inner dimension between the electrodes , so that the joint action part is brought into full contact with the electronic component so that partial wear does not occur, and all bumps are It is possible to effectively transmit the pressing load and secure good bonding quality.
[Brief description of the drawings]
FIG. 1 is a front view of an electronic component bonding apparatus according to an embodiment of the present invention; FIG. 2 is a diagram illustrating relative sizes of a bonding tool and an electronic component of the electronic component bonding apparatus according to an embodiment of the present invention; FIG. 3 is an explanatory view of bonding an electronic component by a bonding apparatus according to one embodiment of the present invention. FIG. 4A is a perspective view of a substrate holding carrier according to one embodiment of the present invention, and FIG. 1 is a partial cross-sectional view of a substrate holding unit according to one embodiment.
3 Board holding unit 3a Plate member 4 Board 5 Electronic component 5a Electrode 5b Bump 13 Elevating block 17 Bonding head 18 Pressurizing unit 19 Bonding tool 19a Bonding unit

Claims (2)

An electronic component bonding apparatus for bonding an electronic component by applying an ultrasonic vibration by pressing an electronic component having a bump formed on a lower surface thereof with a bonding head and applying ultrasonic vibration, wherein the bonding device abuts on a lower surface of the substrate. Elastic holding means for elastically holding the bonding head, elevating means for elevating and lowering the bonding head, a bonding tool mounted on the bonding head and abutting on an electronic component, and vibration applying means for applying ultrasonic vibration to the bonding tool. Pressurizing means for pressing the electronic component against the work through the contact surface, and determining the size of the contact surface of the bonding action portion of the bonding tool with the electronic component by the electronic component to be bonded. smaller than the upper limit size defined by the outer dimensions, and electrostatic facing each outermost edge of the lower surface of the electronic component By setting larger than the lower limit size defined by the inner dimension between the bumps, characterized in that said bonding working portion totally brought into contact with the electronic component partial wear was not caused Electronic device bonding equipment. A method of bonding an electronic component in which an electronic component having a bump formed on a lower surface is pressed against a substrate by a bonding head and ultrasonic vibration is applied to bond the electronic component. Placing the substrate on elastic holding means for elastically holding the electronic component, mounting the electronic component on the substrate, and pressing the electronic component against the substrate with a bonding tool to elastically hold the substrate. And a step of bonding the electronic component to the substrate by applying ultrasonic vibration to the electronic component via the bonding tool, wherein the bonding tool contacts the electronic component. The size of the contact surface with the electronic component is smaller than the upper limit dimension specified by the external dimensions of the electronic component to be bonded. And by setting larger than the lower limit size defined by the inner dimension between the electrodes facing each outermost edge of the lower surface of the electronic component, partially in fully abut the bonding working portion to the electronic component A method for bonding electronic parts with bumps, wherein wear is prevented.

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