Method for increasing the volume and height of solder bumps, solder ball injection device, and controller for the device.
The solder ball injection device with a capillary, laser, and gas system adjusts solder bump height and volume efficiently, addressing mask-dependent issues and ensuring defect-free electronic connections.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- PAC TECH PACKAGING TECH
- Filing Date
- 2024-09-24
- Publication Date
- 2026-07-02
AI Technical Summary
Existing methods for forming solder bumps on substrates often require masks to achieve uniform height, which can cause issues in bonding applications and necessitate high compressive forces, leading to potential contact defects.
A method involving a solder ball injection device that uses a capillary, laser, and pressurized gas to liquefy and discharge solder balls onto existing bumps, transferring thermal and kinetic energy to fuse them, allowing height and volume adjustment without masks.
Enables precise adjustment of solder bump height and volume, creating coplanar connection planes without defects, facilitating secure electronic component bonding.
Smart Images
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Abstract
Description
[Technical Field]
[0001]
[0001] This disclosure relates to a method for increasing the volume and height of solder bumps present on a contact pad of a substrate.
[0002]
[0002] U.S. Patent No. 6,468,893 discloses a method for forming solder bumps by: a) forming a first solder paste layer on each electrode / pad of a substrate by printing solder paste onto the electrode / pad using a first mask; b) forming a first solder bump on each electrode / pad by removing the first mask, melting the first solder paste layer, and solidifying the first solder paste layer; c) forming a second solder paste layer on each first solder bump by printing solder paste onto the first solder bump using a second mask; and d) forming a second solder bump on each electrode / pad by removing the second mask, melting the first solder bump and the second solder paste layer together to integrate them, and solidifying the first solder bump and the second solder paste layer. The above method allows for the formation or printing of solder bumps having a desired volume or height onto a substrate.
[0003]
[0003] Generally, when solder bumps have different heights, it is known from the prior art that the heights of multiple solder bumps present on a substrate can be made uniform by using a mask with openings and applying solder paste to the solder bumps through the openings. Solder bumps with different heights can cause problems in certain bonding applications, for example, when connecting certain electronic components, such as chips or other substrates, to a substrate via solder bumps. In particular, when mounting electronic components or other substrates, high compressive force is required to avoid contact defects such as openings after mounting. Therefore, after applying solder paste to solder bumps with different heights via the mask, the openings of the mask may be individually sized so that all solder bumps have a uniform size. The solder bumps may be heated in a reflow oven to achieve a reliable bond.
[0004]
[0004] In view of the above problems, the objective is to provide a method for increasing the volume and height of solder bumps present on the contact pads of a substrate, wherein the volume and height of the solder bumps can be easily adjusted without a mask. Furthermore, the objective is to provide a solder ball injection device for carrying out such a method.
[0005]
[0005] This objective is solved by the methods described in independent claims 1 and 10. Preferred embodiments are the subject of the dependent claims.
[0006]
[0006] The present disclosure provides a method for increasing the volume and height of a solder bump present on a contact pad of a substrate, which may include: a) positioning a solder ball having a predetermined volume in a capillary positioned above the solder bump; b) liquefying the solder ball by applying laser energy from a laser source to the solder ball through the capillary; c) discharging the liquefied solder ball from the capillary onto the solder bump by adding pressurized gas to the liquefied solder ball through the capillary; and d) melting the solder bump by transferring thermal and kinetic energy from the discharged liquefied solder ball to the solder bump, thereby fusing the liquefied solder ball with the molten solder bump.
[0007]
[0007] In the above method, the energy of the liquefied solder ball, particularly in the form of kinetic and thermal energy, can be used to melt the solder bump in contact with the liquefied solder ball, so that the liquefied solder ball can completely penetrate and fuse with the solder bump. This method makes it possible to easily increase the volume and height of the solder bump without using a mask. It should be noted that the term "solder ball" does not limit the shape of the solder ball to a perfect sphere, but includes any solder preform that is substantially spherical. The material of the solder ball may differ from the material of the solder bump. For example, the solder ball may be made of solder alloy SAC305, and the solder bump may be made of SnBi alloy.
[0008]
[0008] In further embodiments, during step d), laser energy, preferably from a laser source, is further applied to the solder bump.
[0009]
[0009] Specifically, in order to ensure that the solder ball is liquefied in step b) and that the liquefied solder ball completely penetrates the solder bump and fuses with the solder bump in step d), the laser source can be activated during steps a) to d).
[0010]
[0010] In further embodiments, before step a), laser energy, preferably from a laser source, is applied to the solder bump.
[0011]
[0011] Before step a), the solder bump can be preheated or pre-melted by transferring laser energy, preferably from a laser source, to the solder bump so that in step d), the solder ball can easily and completely enter the solder bump and fuse with it.
[0012]
[0012] In further embodiments, the thermal and kinetic energy of the liquefied solder balls, and / or the laser energy required for the step of melting the solder bumps, can be adjusted by setting the gas pressure to 25 mbar to 130 mbar and / or setting the laser energy to 2 mJ to 150 mJ.
[0013]
[0013] In a further embodiment, the substrate comprises at least two solder bumps of different heights, and steps a) to d) are performed to adjust the height of the first solder bump to the height of the second solder bump, with the first solder bump having a lower height than the second solder bump having a higher height.
[0014]
[0014] The above method allows the height of the first solder bump to be easily adjusted to the height of the second solder bump. In particular, this method can be used to adjust the height of all solder bumps present on the substrate to the height of the highest solder bump, thereby creating a coplanar connection plane on the substrate. Electronic components, such as chips or other substrates, can then be securely connected to the substrate without contact defects, such as solder bridges.
[0015]
[0015] In a further embodiment, the method further includes e) measuring the height difference between a first solder bump and a second solder bump, and f) calculating the total volume of solder material required to be added to the first solder bump so that the volume and height of the first solder bump reach the height of the second solder bump, wherein steps e) and f) are performed before steps a) to d), and steps a) to d) are repeated if the predetermined volume of the solder ball is less than the calculated total volume of solder material.
[0016]
[0016] Thus, by performing the above method, the height of the first solder bump can be easily and reliably increased to the height of the second solder bump. The measurement of the height difference between the first solder bump and the second solder bump can be performed in any way. However, optical measurement using a camera or laser, for example, is preferred. Processing speed can be increased because, by calculating the total volume of solder material that needs to be added to the first solder bump to increase the volume and height of the first solder bump to reach the height of the second solder bump, it is not necessary to perform a comparison between the height of the second solder bump and the height of the first solder bump after each liquefied solder ball has been added to the first solder bump.
[0017]
[0017] In a further embodiment, the method further includes g) measuring the actual height of the solder bump and h) calculating the total volume of solder material to be added to the solder bump so that the volume and height of the solder bump reach a predetermined target height, wherein steps g) and h) are performed before steps a) to d), and steps a) to d) are repeated if the predetermined volume of the solder ball is less than the calculated total volume of solder material.
[0018]
[0018] By performing the above method, the height of the solder bump can be easily and reliably increased to the target height. Processing speed can be increased because, by calculating the total volume of solder material required to add to the solder bump to increase the volume and height of the solder bump to a predetermined target height, it is not necessary to measure the height of the solder bump after adding each liquefied solder ball to the solder bump.
[0019]
[0019] In further embodiments, the step of measuring the actual height of the solder bump is performed optically.
[0020]
[0020] Optical measurement of the height of the solder bump is preferably performed using, for example, a camera or a laser.
[0021]
[0021] In a further embodiment, the predetermined volume of the solder ball is 1,4e -5 mm 3 ~0.015mm 3 Preferably 3,3e -5 mm 3 That is the case.
[0022]
[0022] That is, 1,4e -5 mm 3 ~0.015mm 3By applying solder balls with relatively small, predetermined volumes, the volume and height of solder bumps can be adjusted with extreme precision. Even the smallest height differences of solder bumps within a micrometer range can be compensated for, making it possible to form coplanar connection planes on the substrate.
[0023]
[0023] The present disclosure discloses a solder ball injection apparatus comprising a capillary, a laser source, a pressurized gas source, and a controller, wherein the controller may be configured to control the capillary, the laser source, and the pressurized gas source to perform a method according to any of the above embodiments. Specifically, the solder ball injection apparatus may be configured to perform a method comprising: a) positioning a solder ball having a predetermined volume in a capillary positioned above a solder bump present on a contact pad of a substrate; b) liquefying the solder ball by applying laser energy from a laser source to the solder ball through the capillary; c) ejecting the liquefied solder ball from the capillary onto the solder bump by adding pressurized gas from a pressurized gas source to the liquefied solder ball through the capillary; and d) melting the solder bump and fusing the liquefied solder ball with the molten solder bump by transferring thermal and kinetic energy from the ejected liquefied solder ball to the solder bump.
[0024]
[0024] The solder balls may be stored in a reservoir and separated by a rotating singulation disk, which also transfers the solder balls to a capillary. The solder balls may fall into the capillary and may block the capillary opening by having a diameter slightly larger than the diameter of the capillary opening. The laser source may apply short near-infrared laser pulses that interact in the millisecond range to liquefy the solder balls. The pressurized gas source may add a pressurized gas, such as N2, into the capillary so that the liquefied solder balls can be ejected from the capillary onto the solder bump. The energy of the liquefied solder balls is directly related to the speed at which the liquefied solder balls are ejected from the capillary. The speed of the liquefied solder balls, in turn, depends on the pressure of the pressurized gas source controlled by the controller. The above solder ball ejection device or capillary may be controlled by the controller to be movable along three axes so as to be positioned above any solder bump on a substrate whose volume and height are to be increased. The controller may be further configured to calculate the total volume of solder material required to add to the solder bumps so as to increase the volume and height of the solder bumps until reaching the height of a further solder bump or a predetermined height.
[0025]
[0025] In the above device, the energy of the liquefied solder balls, particularly in the form of kinetic energy and thermal energy, can be used to melt the solder bumps in contact with the liquefied solder balls, so that the liquefied solder balls can fully penetrate into the solder bumps and fuse with the solder bumps. With this device, it becomes possible to easily increase the volume and height of the solder bumps without using a mask.
[0026]
[0026] Furthermore, during step d), laser energy, preferably laser energy from a laser source, can be further applied to the solder bump. That is, the laser source can be activated during steps a) to d) to ensure that the solder ball is liquefied in step b), and the liquefied solder ball in step d) fully enters the solder bump and fuses with the solder bump.
[0027]
[0027] The present disclosure discloses a controller for a solder ball ejection device including a capillary, a laser source, and a pressurized gas source, and the controller can be configured to control the capillary, the laser source, and the pressurized gas source to execute a method according to any of the above aspects. Specifically, the controller for the solder ball ejection device includes: a) positioning a solder ball having a predetermined volume in a capillary positioned above a solder bump existing on a contact pad of a substrate; b) liquefying the solder ball by applying laser energy from the laser source through the capillary; c) discharging the liquefied solder ball from the capillary onto the solder bump by applying pressurized gas to the liquefied solder ball through the capillary; d) melting the solder bump and fusing the liquefied solder ball with the melted solder bump by transferring thermal energy and kinetic energy from the ejected liquefied solder ball to the solder bump. The solder ball ejection device or the capillary may be controlled by the controller to be movable along three axes so as to be positioned above any solder bump on a substrate whose volume and height are to be increased. The controller may be further configured to calculate the total volume of solder material required to be added to the solder bump so as to increase the volume and height of the solder bump until reaching the height of a further solder bump or a predetermined height.
[0028]
[0028] A pressurized gas source may be added to the capillary to pressurize a gas, such as N2, so that the liquefied solder balls can be discharged from the capillary onto the solder bumps. The energy of the liquefied solder balls is directly related to the speed at which the liquefied solder balls are discharged from the capillary. The speed of the liquefied solder balls, in turn, depends on the pressure of the pressurized gas source, which is controlled by the controller.
[0029]
[0029] The above-described controller can melt solder bumps in contact with liquefied solder balls by controlling and using the energy of the liquefied solder balls, particularly in the form of kinetic and thermal energy. As a result, the liquefied solder balls can completely penetrate the solder bumps and fuse with them. This controller makes it possible to easily increase the volume and height of solder bumps without using a mask.
[0030]
[0030] Furthermore, during step d), laser energy, preferably from a laser source, can be further applied to the solder bump. That is, the laser source can be activated during steps a) to d) to ensure that the solder ball is liquefied in step b) and that the liquefied solder ball completely penetrates the solder bump and fuses with the solder bump in step d). [Brief explanation of the drawing]
[0031]
[0031] Hereinafter, one embodiment of the present disclosure will be described with reference to several figures. [Figure 1] This shows a front view of a solder ball injection device according to one embodiment, which adds solder balls to solder bumps present on a circuit board. [Figure 2] Figure 1 shows an enlarged front view of the solder ball injection device and solder bump. [Figure 3] This demonstrates the application of a solder ball injection device to equalize the height of solder bumps on an uneven substrate.
[0032]
[0032] The figures are essentially schematic and intended solely for the purpose of understanding this disclosure. The proportions of the elements shown in the figures have been adjusted as appropriate to make this disclosure easier to understand. [Modes for carrying out the invention]
[0033]
[0033] Figure 1 discloses a solder ball injection device 10 according to one embodiment, comprising a movable capillary 1, a laser source (not shown), a pressurized gas source (not shown), and a controller (not shown) configured to control the capillary 1, the laser source, and the pressurized gas source.
[0034]
[0034] As shown in Figure 1, the capillary 1 is positioned at a certain distance above the solder bump 5a, which is located on the contact pad 3 of the substrate 4. Further solder bumps 5b are located on the contact pad 3 on the substrate 4, and each solder bump 5a is lower in height than the solder bumps 5b, which are all of the same height. Although not shown in Figure 1, the height difference between the solder bumps 5a and 5b is measured optically, and the total volume of solder material required to be added to the solder bumps 5a is calculated so that the volume and height of the solder bumps 5a reach the height of the solder bumps 5b. Furthermore, the number of solder balls having a predetermined volume corresponding to the total volume of solder material is calculated.
[0035]
[0035] Furthermore, solder balls 2 of a predetermined volume, which are located within the capillary 1 and liquefied by the application of laser energy from the laser source through the capillary 1, are ejected from the capillary 1 onto the solder bump 5a. Specifically, pressurized gas from a pressurized gas source is added to the liquefied solder balls 2 through the capillary 1, thereby causing the liquefied solder balls 2 having a specific temperature to be ejected from the capillary 1 at a specific speed. That is, the liquefied solder balls 2 ejected from the capillary 1 have a constant kinetic energy and a constant thermal energy, depending on the temperature and speed of the solder balls 2. The speed of the liquefied solder balls 2 then depends on the pressure of the pressurized gas, which is controlled by the controller.
[0036]
[0036] By using the kinetic and thermal energy of the liquefied solder balls 2 to melt the solder bumps 5a that are in contact with the liquefied solder balls 2, the liquefied solder balls 2 can completely penetrate into the solder bumps 5a and fuse with them. Furthermore, to ensure that the liquefied solder balls 2 completely penetrate into the solder bumps 5a and fuse with them, laser energy from a laser source can be transmitted to the solder bumps 5a. The above method is repeated until the calculated number of solder balls 2 are added to the solder bumps 5a, that is, until the total volume of solder material is added to the solder bumps 5a. As shown by the dashed lines in Figure 2, the volume and height of the solder bumps 5a are increased for each solder ball 2 added to the solder bumps 5a. It should be further noted that when the solder ball 2 comes into contact with the solder bump 5a, it penetrates completely into the solder bump 5a and fuses with it, thereby giving the solder bump 5a a uniform structure. According to the solder ball injection apparatus 10 and method described above, the volume and height of the solder bump 5a can be easily increased without using a mask.
[0037]
[0037] Furthermore, as shown on the left side of Figure 3, a ridged substrate 4 is provided on which multiple solder bumps are positioned. Note that contact pads are not depicted in Figure 3. The solder bumps are all the same size. However, due to the ridges of the substrate 4, the solder bump indicated by reference numeral 5b is the highest relative to the bottom surface of the substrate 4. The solder bump 5a can be enlarged using the solder ball injection device 10 and method described above so as to create a coplanar connection plane shown by the dashed line on the right side of Figure 3.
[0038]
[0038] In particular, using the solder ball injection apparatus 10 and method, regardless of whether the different heights of the solder bumps arise from solder bumps of different sizes as shown in Figure 1 or from the uneven substrate 4 as shown in Figure 3, the height of all solder bumps present on the substrate 4 that are lower than the height of the highest solder bump can be adjusted so that a coplanar connection plane is created on the substrate 4. Electronic components, such as chips or other substrates, can then be securely connected to the substrate 4 without contact defects, such as solder bridges. In general, the above method makes it easy to adjust each individual solder bump present on the substrate to a desired height. [Item of the invention] [Item 1] A method for increasing the volume and height of solder bumps present on the contact pads (3) of a substrate (4), a) A step of positioning a solder ball (2) having a predetermined volume within a capillary (1) positioned above the solder bump, b) A step of liquefying the solder ball (2) by applying laser energy from a laser source to the solder ball (2) through the capillary (1), c) A step of discharging the liquefied solder ball (2) from the capillary (1) onto the solder bump by applying pressurized gas to the liquefied solder ball (2) via the capillary (1), d) A step of transferring thermal energy and kinetic energy from the discharged liquefied solder ball (2) to the solder bump to melt the solder bump and fusing the liquefied solder ball (2) with the molten solder bump, Methods that include... [Item 2] The method according to item 1, wherein during step d), laser energy from the laser source is further applied to the solder bump. [Item 3] The method according to item 1, wherein, prior to step a), laser energy from the laser source is applied to the solder bump. [Item 4] The method according to item 1, wherein the gas pressure can be set to 25 mbar to 130 mbar and / or the laser energy can be set to 2 mJ to 150 mJ to adjust the thermal energy and kinetic energy of the liquefied solder ball (2), and / or the laser energy required for the step of melting the solder bump. [Item 5] The method according to item 1, wherein the substrate (4) comprises at least two solder bumps of different heights, and steps a) to d) are performed on the first solder bump (5a), which is lower in height than the second solder bump (5b), which is higher in height, to adjust the height of the first solder bump (5a) to the height of the second solder bump (5b). [Item 6] e) A step of measuring the height difference between the first solder bump (5a) and the second solder bump (5b), f) A step of calculating the total volume of solder material required to be added to the first solder bump (5a) so as to increase the volume and height of the first solder bump (5a) until it reaches the height of the second solder bump (5b), It further includes, Steps e) and f) are performed before steps a) to d), The method according to item 5, wherein if the predetermined volume of the solder ball (2) is less than the total volume of the calculated solder material, steps a) to d) are repeated. [Item 7] g) A step of measuring the actual height of the solder bump, h) A step of calculating the total volume of solder material to be added to the solder bump so as to increase the volume and height of the solder bump until it reaches a predetermined target height, It further includes, Steps g) and h) are performed before steps a) to d), The method according to item 1, wherein if the predetermined volume of the solder ball (2) is less than the total volume of the calculated solder material, steps a) to d) are repeated. [Item 8] The method according to item 7, wherein the step of measuring the actual height of the solder bump is performed optically. [Item 9] The predetermined volume of the solder ball (2) is 1,4e -5 mm 3 ~0.015mm 3 , or 3,3e -5 mm 3 The method described in any one of items 1 to 8. [Item 10] A solder ball ejection device (10) comprising a capillary (1), a laser source, a pressurized gas source, and a controller, wherein the controller is a) A step of positioning a solder ball (2) having a predetermined volume within the capillary (1) located above a solder bump present on the contact pad (3) of the substrate (4), b) A step of liquefying the solder ball (2) by applying laser energy from the laser source to the solder ball (2) through the capillary (1), c) The step of discharging the liquefied solder ball (2) from the capillary (1) onto the solder bump by adding pressurized gas from the pressurized gas source to the liquefied solder ball (2) via the capillary (1), d) A step of transferring thermal energy and kinetic energy from the discharged liquefied solder ball (2) to the solder bump, thereby melting the solder bump and fusing the liquefied solder ball (2) with the molten solder bump, A solder ball ejector (10) is configured to control the capillary (1), the laser source, and the pressurized gas source to perform a method including the following: [Item 11] A controller for a solder ball ejection device (10) comprising a capillary (1), a laser source, and a pressurized gas source, wherein the controller a) A step of positioning a solder ball (2) having a predetermined volume within the capillary (1) located above a solder bump present on the contact pad (3) of the substrate (4), b) A step of liquefying the solder ball (2) by applying laser energy from the laser source to the solder ball (2) through the capillary (1), c) A step of discharging the liquefied solder ball (2) from the capillary (1) onto the solder bump by applying pressurized gas to the liquefied solder ball (2) via the capillary (1), d) A step of transferring thermal energy and kinetic energy from the discharged liquefied solder ball (2) to the solder bump, thereby melting the solder bump and fusing the liquefied solder ball (2) with the molten solder bump, A controller configured to control the capillary (1), the laser source, and the pressurized gas source to perform a method including the following:
Explanation of Symbols
[0039]
[0039] 1...Capillary, 2...Solder ball, 3...Contact pad, 4...Substrate, 5a...Solder bump, 5b...Solder bump, 10...Solder ball injection device
Claims
1. A method for increasing the volume and height of solder bumps present on the contact pads (3) of a substrate (4), a) A step of positioning a solder ball (2) having a predetermined volume within a capillary (1) positioned above the solder bump, b) A step of liquefying the solder ball (2) by applying laser energy from a laser source to the solder ball (2) through the capillary (1), c) A step of discharging the liquefied solder balls (2) from the capillary (1) onto the solder bump by applying pressurized gas to the liquefied solder balls (2) via the capillary (1), d) A step of fusing the solder bump by transferring thermal and kinetic energy from the discharged liquefied solder ball (2) to the solder bump, thereby melting the solder bump, and as a result, the liquefied solder ball (2) completely penetrates the solder bump and fuses with the molten solder bump, Methods that include...
2. The method according to claim 1, wherein during step d), laser energy from the laser source is further applied to the solder bump.
3. The method according to claim 1, wherein, before step a), laser energy from the laser source is applied to the solder bump.
4. The method according to claim 1, wherein the gas pressure can be set to 25 mbar to 130 mbar and / or the laser energy can be set to 2 mJ to 150 mJ to adjust the thermal energy and kinetic energy of the liquefied solder ball (2) and / or the laser energy required for the step of melting the solder bump.
5. The method according to claim 1, wherein the substrate (4) comprises at least two solder bumps of different heights, and steps a) to d) are performed on a first solder bump (5a) having a lower height than a second solder bump (5b) having a higher height, to adjust the height of the first solder bump (5a) to the height of the second solder bump (5b).
6. e) A step of measuring the height difference between the first solder bump (5a) and the second solder bump (5b), f) A step of calculating the total volume of solder material required to be added to the first solder bump (5a) so as to increase the volume and height of the first solder bump (5a) to reach the height of the second solder bump (5b), It further includes, Steps e) and f) are performed before steps a) to d), The method according to claim 5, wherein if the predetermined volume of the solder ball (2) is smaller than the total volume of the calculated solder material, steps a) to d) are repeated.
7. g) A step of measuring the actual height of the solder bump, h) A step of calculating the total volume of solder material to be added to the solder bump so as to increase the volume and height of the solder bump until it reaches a predetermined target height, It further includes, Steps g) and h) are performed before steps a) to d), The method according to claim 1, wherein if the predetermined volume of the solder ball (2) is smaller than the total volume of the calculated solder material, steps a) to d) are repeated.
8. The method according to claim 7, wherein the step of measuring the actual height of the solder bump is performed optically.
9. The predetermined volume of the solder ball (2) is 1,4e －５ mm ３ ~0.015 mm ３ , or 3,3e －５ mm ３ The method according to any one of claims 1 to 8.
10. A solder ball ejection device (10) comprising a capillary (1), a laser source, a pressurized gas source, and a controller, wherein the controller is a) A step of positioning a solder ball (2) having a predetermined volume within the capillary (1) positioned above the solder bumps present on the contact pad (3) of the substrate (4), b) A step of liquefying the solder ball (2) by applying laser energy from the laser source to the solder ball (2) through the capillary (1), c) The step of discharging the liquefied solder ball (2) from the capillary (1) onto the solder bump by adding pressurized gas from the pressurized gas source to the liquefied solder ball (2) via the capillary (1), d) A step of fusing, in which thermal energy and kinetic energy are transferred from the discharged liquefied solder ball (2) to the solder bump, thereby melting the solder bump, and as a result, the liquefied solder ball (2) completely penetrates the solder bump and fuses with the molten solder bump, A solder ball ejector (10) is configured to control the capillary (1), the laser source, and the pressurized gas source to perform a method including the following:
11. A controller for a solder ball ejection device (10) comprising a capillary (1), a laser source, and a pressurized gas source, wherein the controller a) A step of positioning a solder ball (2) having a predetermined volume within the capillary (1) positioned above the solder bumps present on the contact pad (3) of the substrate (4), b) A step of liquefying the solder ball (2) by applying laser energy from the laser source to the solder ball (2) through the capillary (1), c) A step of discharging the liquefied solder balls (2) from the capillary (1) onto the solder bump by applying pressurized gas to the liquefied solder balls (2) via the capillary (1), d) A step of fusing, in which thermal energy and kinetic energy are transferred from the discharged liquefied solder ball (2) to the solder bump, thereby melting the solder bump, and as a result, the liquefied solder ball (2) completely penetrates the solder bump and fuses with the molten solder bump, A controller configured to control the capillary (1), the laser source, and the pressurized gas source to perform a method including the following: