Non-pressurizing bonding apparatus and bonding method using the same

Abstract

A non-pressurized bonding device is provided, comprising: a stage capable of fixing a carrier substrate; an ultrasonic application device configured to provide ultrasonic waves to a carrier substrate on the stage; a laser irradiation device configured to simultaneously irradiate a laser beam to a plurality of semiconductor devices disposed on the carrier substrate; and a control device configured to control the operation of the ultrasonic application device and the laser irradiation device.

Description

Technology Field

[0001] The present invention relates to a non-pressure bonding device and a bonding method using the same, and more specifically, to a non-pressure bonding device and a bonding method using the same that can mass-produce highly reliable bonded semiconductor devices with a low defect rate. Background Technology

[0002] Laser-based methods for bonding semiconductor devices onto substrates are relatively widely used. However, when bonding using a laser, the temperature gradient varies significantly depending on the location within the semiconductor device, and in some cases, the semiconductor device may suffer thermal damage, thus requiring improvement. The problem to be solved

[0003] The first technical objective of the present invention is to provide a non-pressurized bonding device capable of mass-producing highly reliable bonded semiconductor devices with a low defect rate.

[0004] The second technical objective of the present invention is to provide a non-pressurized bonding method capable of mass-producing highly reliable bonded semiconductor devices with a low defect rate. means of solving the problem

[0005] To achieve the first technical objective, the present invention provides a non-pressurized bonding device comprising: a stage capable of fixing a carrier substrate; an ultrasonic application device configured to provide ultrasonic waves to a carrier substrate on the stage; a laser irradiation device configured to simultaneously irradiate a laser beam to a plurality of semiconductor devices disposed on the carrier substrate; and a control device configured to control the operation of the ultrasonic application device and the laser irradiation device.

[0006] To achieve the second technical objective, the present invention provides a non-pressurized bonding method comprising: a step of fixing a carrier substrate on a stage; a step of irradiating a laser beam onto a plurality of semiconductor devices on the carrier substrate in a non-contact manner without applying pressure; a step of applying ultrasound to the carrier substrate; and a step of cooling the carrier substrate and the plurality of semiconductor devices, wherein the step of irradiating the laser beam starts earlier than the step of applying ultrasound. Effects of the invention

[0007] By using the non-pressurized bonding device and bonding method of the present invention, highly reliable bonded semiconductor devices can be mass-produced with a low defect rate. Brief explanation of the drawing

[0008] FIG. 1 is a schematic diagram showing a non-pressurized bonding device according to one embodiment of the present invention. FIG. 2 is a timing diagram showing the start and end times of laser irradiation of the laser irradiation device and the start and end times of ultrasound application of the ultrasound application device according to one embodiment of the present invention. FIGS. 3a to 3c are schematic diagrams showing cross-sectional shapes of ultrasonic horns according to embodiments of the present invention. FIGS. 4 and 5 are schematic diagrams showing non-pressurized bonding devices according to other embodiments of the present invention. Figure 6 is a graph showing the temperature change of a solder bump when both a laser and ultrasound are applied using the non-pressurized bonding device shown in Figure 1, and the temperature change of a solder bump when only a laser is irradiated using a conventional bonding device. Figure 7 shows scanning electron microscope (SEM) images of cross-sections of solder bumps bonded in the examples and comparative examples. FIG. 8 is a flowchart illustrating a non-pressurized bonding method according to one embodiment of the present invention. Specific details for implementing the invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Identical components in the drawings are denoted by the same reference numerals, and redundant descriptions thereof are omitted.

[0010] FIG. 1 is a schematic diagram showing a non-pressurized bonding device (1) according to one embodiment of the present invention.

[0011] Referring to FIG. 1, a non-pressurized bonding device (1) may include a stage (110) capable of fixing a carrier substrate (10), an ultrasonic application device (130) configured to provide ultrasonic waves to a carrier substrate (10) on the stage (110), a laser irradiation device (120) configured to simultaneously irradiate a laser beam to a plurality of semiconductor devices (20) disposed on the carrier substrate (10), and a control device (140) configured to control the operation of the ultrasonic application device (130) and the laser irradiation device (120).

[0012] The above stage (110) may be made of a porous ceramic material and / or metal and may be configured to fix a carrier substrate (10) placed thereon by various methods such as vacuum adsorption, electrostatic adsorption, etc. Although FIG. 1 illustrates fixing the carrier substrate (10) by vacuum suction through a vacuum forming hole (112), a person skilled in the art will understand that the above stage (110) may be configured to fix the carrier substrate (10) by various methods.

[0013] In some embodiments, a heating member (114) for heating may be provided within the stage (110). The heating member (114) may be configured to heat the stage (110) to a constant temperature.

[0014] A laser irradiation device (120) capable of irradiating a laser beam onto the plurality of semiconductor devices (20) and further onto the stage (110) is provided on the upper portion of the plurality of semiconductor devices (20). The laser irradiation device (120) is positioned above the plurality of semiconductor devices (20) at a distance from the plurality of semiconductor devices (20).

[0015] In FIG. 1, the plurality of semiconductor devices (20) are illustrated as having a plurality of core chips (24) stacked vertically on a base substrate (22) that includes a plurality of buffer chips in a horizontal direction, for example; however, a person skilled in the art will understand that various arrangements of the plurality of semiconductor devices (20) are possible. For example, the plurality of semiconductor devices (20) may have corresponding core chips (24) arranged horizontally on a base substrate (22) that includes a plurality of buffer chips, without additional stacking in a vertical direction. In some other embodiments, the plurality of semiconductor devices (20) may have two or more core chips (24) stacked vertically only on a single buffer chip.

[0016] In some embodiments, the laser irradiation device (120) may be configured as a sequential irradiation surface light source that sequentially irradiates individual points within a laser irradiation area by irradiating a laser beam in a scanning manner. In some embodiments, the laser irradiation device (120) may be configured as a simultaneous irradiation surface light source that simultaneously irradiates all points within a laser irradiation area.

[0017] The laser irradiation device (120) may be configured to heat the temperature of the plurality of semiconductor devices (20) to a constant temperature. In some embodiments, the laser irradiation device (120) may be configured to heat the temperature of the plurality of semiconductor devices (20) to a constant temperature in cooperation with the heating member (114).

[0018] The laser irradiation device (120) heats the upper surface of the plurality of semiconductor devices (20), and the heat transferred downward from the upper surface raises the temperature of a connection terminal, such as a solder bump. In particular, the non-pressurized bonding device (1) may be configured so that the plurality of semiconductor devices (20) are not pressurized when a laser beam is irradiated from the laser irradiation device (120) to the plurality of semiconductor devices (20).

[0019] A conventional bonding device is configured to apply pressure to the upper part of semiconductor devices when irradiating a laser, so productivity is significantly reduced. On the other hand, the non-pressurized bonding device (1) according to the embodiments of the present invention does not require applying pressure to the upper part of semiconductor devices when irradiating a laser, so no pressure is applied to the upper part of semiconductor devices, and thus productivity can be significantly improved compared to a conventional bonding device.

[0020] The above ultrasonic application device (130) applies ultrasonic waves to the stage (110) to induce corresponding vibration of the stage (110).

[0021] The above ultrasonic application device (130) may include an ultrasonic generation controller (132) and an ultrasonic horn (134).

[0022] The above-described ultrasonic generating controller (132) can control an ultrasonic horn (134) to generate ultrasonic vibrations by receiving a control signal from a control device (140) described later. The ultrasonic horn (134) can be configured to generate ultrasonic waves of a corresponding frequency by receiving a signal from the ultrasonic generating controller (132).

[0023] Ultrasound generated in the ultrasonic horn can be transmitted to the stage (110). In some embodiments, in order to transmit ultrasound generated in the ultrasonic horn (134) to the stage (110), the ultrasonic horn (134) may be extended at least partially from the side of the stage (110) into the interior of the stage (110).

[0024] The ultrasound may have a frequency of, for example, about 10 kHz to about 100 kHz. In some embodiments, the ultrasound may have a range of about 10 kHz to about 100 kHz, about 15 kHz to about 95 kHz, about 20 kHz to about 90 kHz, about 25 kHz to about 85 kHz, about 30 kHz to about 80 kHz, about 35 kHz to about 75 kHz, about 40 kHz to about 70 kHz, about 45 kHz to about 65 kHz, about 50 kHz to about 60 kHz, or between any two of these values.

[0025] Generally, frequencies exceeding the audible frequency range, that is, frequencies exceeding 20 kHz, are referred to as ultrasound, but here, frequencies of 10 kHz or higher are referred to as ultrasound.

[0026] If the frequency of the above ultrasound is too low, the effect of raising the temperature of the connection terminals of the plurality of semiconductor devices (20) is insufficient. If the frequency of the above ultrasound is too high, it may result in heating the connection terminals of the plurality of semiconductor devices (20) to an excessively high temperature.

[0027] The control device (140) may be configured to control the operation of the ultrasonic application device (130) and the laser irradiation device (120). That is, the control device (140) may transmit a signal to the laser irradiation device (120) commanding the start and end of laser irradiation by the laser irradiation device (120). In addition, the control device (140) may transmit a signal to the ultrasonic application device (130) commanding the start and end of ultrasonic application by the ultrasonic application device (130).

[0028] In some embodiments, the control device (140) may be configured to measure the temperature of the stage (110), the carrier substrate (10), and / or a plurality of semiconductor devices (20), and to receive feedback on the temperature to determine the initiation and termination of the laser irradiation and / or the initiation and termination of the ultrasonic application.

[0029] FIG. 2 is a timing diagram showing the start and end times of laser irradiation by the laser irradiation device (120) and the start and end times of ultrasound application by the ultrasound application device (130) according to an embodiment of the present invention. As shown in FIG. 2, the period during which a laser is irradiated from the laser irradiation device (120) and the period during which ultrasound is applied from the ultrasound application device (130) may overlap at least partially in time.

[0030] Referring to FIG. 2, in some embodiments, the control device (140) may be configured such that the ultrasonic application device (130) begins ultrasonic application after the laser irradiation device (120) begins laser irradiation and a predetermined time (t1) has elapsed. For example, the control device (140) may be configured such that the ultrasonic application device (130) begins ultrasonic application after the laser irradiation device (120) begins laser irradiation and after about 0.5 seconds have elapsed, after about 0.8 seconds have elapsed, after about 1 second has elapsed, after about 1.2 seconds have elapsed, after about 1.5 seconds have elapsed, after about 1.8 seconds have elapsed, after about 2 seconds have elapsed, after about 3 seconds have elapsed, and after about 5 seconds have elapsed.

[0031] In some embodiments, the predetermined time (t1) may be about 0.5 seconds to about 10 seconds, about 0.6 seconds to about 9 seconds, about 0.7 seconds to about 8 seconds, about 0.8 seconds to about 7 seconds, about 0.9 seconds to about 6 seconds, about 1 second to about 5 seconds, or a range between any two of these values.

[0032] In some embodiments, the control device (140) may be configured such that the ultrasonic application device (130) begins ultrasonic application when the temperature of the stage (110) reaches at least 230°C after the laser irradiation device (120) begins laser irradiation. In some embodiments, the predetermined time (t1) may be the time taken for the temperature of the stage (110) to reach at least 230°C after the laser irradiation device (120) begins laser irradiation.

[0033] Referring to FIG. 2, in some embodiments, the control device (140) may be configured such that the laser irradiation device (120) terminates laser irradiation after the ultrasonic application device (130) terminates ultrasonic application and a predetermined time (t2) has elapsed. For example, the control device (140) may be configured such that the laser irradiation device (120) begins laser irradiation after the ultrasonic application device (130) terminates ultrasonic application and after about 0.5 seconds have elapsed, after about 0.8 seconds have elapsed, after about 1 second has elapsed, after about 1.2 seconds have elapsed, after about 1.5 seconds have elapsed, after about 1.8 seconds have elapsed, after about 2 seconds have elapsed, after about 3 seconds have elapsed, and after about 5 seconds have elapsed.

[0034] In some embodiments, the predetermined time (t2) may be about 0.5 seconds to about 10 seconds, about 0.6 seconds to about 9 seconds, about 0.7 seconds to about 8 seconds, about 0.8 seconds to about 7 seconds, about 0.9 seconds to about 6 seconds, about 1 second to about 5 seconds, or a range between any two of these values.

[0035] FIGS. 3a to 3c are schematic diagrams showing cross-sectional shapes of ultrasonic horns (134) according to embodiments of the present invention.

[0036] Referring to FIG. 3a, two or more ultrasonic horns (134) may be inserted into the stage (110), and they may have a circular cross-sectional shape. Referring to FIG. 3b, two or more ultrasonic horns (134) may be inserted into the stage (110), and they may have a polygonal cross-sectional shape, such as a rectangular or square cross-section. By extending a plurality of ultrasonic horns (134) having a relatively small cross-section into the stage (110), interference with other structures provided inside the stage (110), such as a vacuum forming hole (112) (see FIG. 1), a heating member (114) (see FIG. 1), etc., may be prevented or reduced.

[0037] Referring to FIG. 3c, a single ultrasonic horn (134) may be inserted into the stage (110). The ultrasonic horn (134) may have a considerable width in the horizontal direction to apply sufficient vibration to the stage (110).

[0038] A person skilled in the art will understand that, in addition to the ultrasonic horns (134) having cross-sections illustrated in FIGS. 3a to 3c, ultrasonic horns having various cross-sections may be provided. As described with reference to FIG. 1, only a part of the ultrasonic horn (134) may extend into the interior of the stage (110), or the entire ultrasonic horn (134) may be inserted into the interior of the stage (110).

[0039] FIG. 4 is a schematic diagram showing a non-pressurized bonding device (1a) according to another embodiment of the present invention.

[0040] The non-pressurized bonding device (1a) illustrated in FIG. 4 differs from the non-pressurized bonding device (1) described with reference to FIG. 1 in that the ultrasonic horn (134) is not inserted into the stage (110). Therefore, the following description will focus on this difference.

[0041] Referring to FIG. 4, the ultrasonic horn (134) is in contact with the side of the stage (110) and does not extend into the interior of the stage (110). The ultrasonic horn (134) is in contact with the side of the stage (110), and ultrasonic waves can be transmitted to the stage (110) through the contact surface between the ultrasonic horn (134) and the stage (110).

[0042] Since the ultrasonic horn (134) does not extend into the stage (110), interference with other structures provided inside the stage (110), such as a vacuum forming hole (112) and a heating member (114), can be prevented.

[0043] FIG. 5 is a schematic diagram showing a non-pressurized bonding device (1b) according to another embodiment of the present invention.

[0044] The non-pressurized bonding device (1b) illustrated in FIG. 5 differs from the non-pressurized bonding device (1a) described with reference to FIG. 4 in that the ultrasonic horn contacts the upper surface (110a) and / or lower surface (110b) of the stage (110) rather than the side surface of the stage (110). Therefore, the following description will focus on these differences.

[0045] Referring to FIG. 5, the ultrasonic application device (130) may include a first ultrasonic horn (134a) in contact with the upper surface (110a) of the stage (110) and / or a second ultrasonic horn (134b) in contact with the lower surface (110b) of the stage (110).

[0046] In some embodiments, the ultrasonic application device (130) may include both the first ultrasonic horn (134a) and the second ultrasonic horn (134b). In this case, the temperature of the solder bump can be raised more effectively by adjusting the phase of the ultrasonic applied to each of the first ultrasonic horn (134a) and the second ultrasonic horn (134b). For example, the ultrasonic application device (130) may be configured such that the phases of the ultrasonic applied to each of the first ultrasonic horn (134a) and the second ultrasonic horn (134b) are opposite to each other. In another embodiment, the ultrasonic application device (130) may be configured such that the phases of the ultrasonic applied to each of the first ultrasonic horn (134a) and the second ultrasonic horn (134b) match each other.

[0047] In some other embodiments, the ultrasonic application device (130) may include only one of the first ultrasonic horn (134a) and the second ultrasonic horn (134b).

[0048] In FIGS. 4 and 5, only one ultrasonic horn is shown provided on the side, top surface (110a), and bottom surface (110b) of the stage (110), but a person skilled in the art will understand that two or more ultrasonic horns may be provided on one surface.

[0049] FIG. 6 is a graph showing the temperature change of a solder bump when both a laser and an ultrasonic wave are applied using the non-pressurized bonding device (1) shown in FIG. 1 (Example) and the temperature change of a solder bump when only a laser is irradiated using a conventional bonding device (Comparative Example). In the Example and the Comparative Example, the power and operation method of the laser irradiation device are the same.

[0050] As shown in Fig. 6, when a laser and ultrasound are applied together, a temperature approximately 40°C to approximately 60°C higher is obtained compared to the case where only the laser is irradiated. In other words, compared to the case where only the laser is irradiated, the heating caused by the laser is reduced, and the reduced heating can be compensated for by the application of ultrasound.

[0051] As previously explained, the laser irradiation device (120) heats the plurality of semiconductor devices (20) from above. Therefore, in the case where the plurality of semiconductor devices (20) are flip-chip mounted, if heating is performed solely by the laser irradiation device (120), the temperature of the semiconductor chip must inevitably be higher than the temperature of the solder bump. However, if ultrasound is applied through the ultrasonic application device (130), the temperature of the solder bump can be further increased through ultrasound even if the temperature of the semiconductor chip is relatively lowered. Therefore, bonding is possible while maintaining the temperature of the plurality of semiconductor devices (20) at 250°C or lower, and thereby, damage to the semiconductor components provided within the semiconductor chip due to heat can be prevented or reduced.

[0052] Figure 7 shows scanning electron microscope (SEM) images of cross-sections of solder bumps bonded in the above examples and comparative examples.

[0053] Referring to FIG. 7, it is observed that the grain size of the example bonded by laser irradiation and ultrasound application is much smaller than that of the comparative example bonded by laser irradiation alone. Specifically, in the case of the comparative example bonded by laser irradiation alone, it was observed that the size generally ranged from several micrometers (μm) to several tens of μm. However, in the case of the example bonded by laser irradiation and ultrasound application, it was observed that the size was less than 1 μm, for example, several hundred nanometers.

[0054] This is presumed to be due to the vibration caused by the application of ultrasound reducing porosity within the tissue, but the present invention is not limited to a specific theory.

[0055] In addition, the bonding strength can be improved because the grain size of the solder bump in the example is significantly smaller than the grain size of the solder bump in the comparative example.

[0056] FIG. 8 is a flowchart illustrating a non-pressurized bonding method according to one embodiment of the present invention.

[0057] Referring to FIG. 1 and FIG. 8 together, a carrier substrate (10) can be fixed on a stage (110) (S110). A plurality of semiconductor devices (20) may be attached to the carrier substrate (10). However, the plurality of semiconductor devices (20) may not yet be electrically connected. For example, the plurality of semiconductor devices (20) may be attached to the carrier substrate (10) by a non-conductive film (NCF).

[0058] Subsequently, a laser beam is irradiated onto the plurality of semiconductor devices (20) in a non-contact manner (S120). As described above, the laser beam may be configured as a sequential irradiation surface light source that sequentially irradiates individual points within the laser irradiation area. In another embodiment, the laser beam may be configured as a simultaneous irradiation surface light source that simultaneously irradiates all points within the laser irradiation area.

[0059] Next, ultrasonic waves can be applied to the carrier substrate (10) (S130). In order to apply ultrasonic waves to the carrier substrate (10), an ultrasonic horn (134) can be brought into contact with the stage (110). That is, ultrasonic waves emitted from the ultrasonic horn (134) can be transmitted to the carrier substrate (10) and the plurality of semiconductor devices (20) through the stage (110).

[0060] Then, the carrier substrate (10) and the plurality of semiconductor devices (20) can be cooled (S140). Through the cooling, the solder bumps that were heated and reflowed can be cured again. In some embodiments, a low-temperature environment lower than room temperature can be provided to the carrier substrate (10) and the plurality of semiconductor devices (20) for the cooling. In other embodiments, the carrier substrate (10) and the plurality of semiconductor devices (20) can be left at room temperature for a predetermined time for the cooling.

[0061] As described above, although embodiments of the present invention have been described in detail, a person skilled in the art to which the present invention pertains will be able to modify and implement the present invention in various ways without departing from the spirit and scope of the present invention as defined in the appended claims. Therefore, future modifications to the embodiments of the present invention will not depart from the technology of the present invention. Explanation of the symbols

[0062] 1, 1a, 1b: Non-pressurized bonding device 10: Carrier substrate 20: Multiple semiconductor devices 110: Stage 112: Vacuum forming hole 114: Heating element 120: Laser irradiation device 130: Ultrasonic application device 132: Ultrasonic generation controller 134: Ultrasonic horn 140: Control unit

Claims

Claim 1 A non-pressurized bonding device comprising: a stage capable of fixing a carrier substrate; an ultrasonic application device configured to provide ultrasonic waves to a carrier substrate on the stage; a laser irradiation device configured to simultaneously irradiate a laser beam to a plurality of semiconductor devices disposed on the carrier substrate; and a control device configured to control the operation of the ultrasonic application device and the laser irradiation device, wherein the laser irradiation device is spaced apart from the upper portion of the plurality of semiconductor devices, and the plurality of semiconductor devices are not pressurized when the laser beam is irradiated, and the time at which ultrasonic waves are applied from the ultrasonic application device and the time at which a laser is irradiated from the laser irradiation device overlap at least partially, and the time at which a laser is irradiated from the laser irradiation device begins before the time at which ultrasonic waves are applied from the ultrasonic application device. Claim 2 delete Claim 3 A non-pressurized bonding device according to claim 1, wherein the ultrasonic application device includes an ultrasonic horn, and at least a portion of the ultrasonic horn is disposed within the stage. Claim 4 A non-pressurized bonding device according to claim 1, characterized in that the control device is configured to apply ultrasound to the ultrasonic application device after the temperature of the stage reaches at least 230℃. Claim 5 A non-pressurized bonding device according to claim 1, characterized in that the ultrasonic application device is configured to apply ultrasonic waves having a frequency of 10 kHz to 100 kHz to the stage. Claim 6 delete Claim 7 delete Claim 8 A non-pressurized bonding device according to claim 1, characterized in that the time at which a laser is irradiated from the laser irradiation device ends later than the time at which ultrasound is applied from the ultrasound application device. Claim 9 A non-pressurized bonding method comprising: a step of fixing a carrier substrate on a stage; a step of irradiating a laser beam onto a plurality of semiconductor devices on the carrier substrate in a non-contact manner without applying pressure to the plurality of semiconductor devices; a step of applying ultrasound to the carrier substrate; and a step of cooling the carrier substrate and the plurality of semiconductor devices; wherein the step of irradiating the laser beam starts earlier than the step of applying ultrasound, and a laser irradiation device for performing the step of irradiating the laser beam is spaced apart from the upper portion of the plurality of semiconductor devices, and the plurality of semiconductor devices are not pressurized when the laser beam is irradiated. Claim 10 A non-pressure bonding method according to claim 9, characterized in that the temperature of the plurality of semiconductor devices does not exceed 250℃.

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