Mounting apparatus

Abstract

The present invention makes it possible to measure the temperature of a substrate in a mounting apparatus using a laser. Specifically, a mounting apparatus 1 comprises: a chip holding unit 10 that holds a chip C and mounts the chip C on the substrate W; an irradiation unit 20 that emits a laser L; and a thermometer 30 that measures the temperature T of the substrate W. The laser L is emitted to the substrate W from the irradiation unit 20 through the chip holding unit 10. The thermometer 30 measures the temperature T of the substrate W by detecting thermal radiation R emitted from the substrate W.

Description

Mounting apparatus

[0001] The present disclosure relates to a mounting apparatus.

[0002] A mounting apparatus for mounting a chip onto a substrate is known. The mounting apparatus disclosed in Patent Document 1 mounts a chip onto a substrate by pressing the chip against the substrate while holding the chip heated by a heater.

[0003] Japanese Patent Application Laid-Open No. 2023-101866

[0004] In the conventional mounting apparatus according to Patent Document 1, the chip and the substrate are heated by a heater. In this type of conventional mounting apparatus, a contact-type thermometer such as a thermocouple is brought into contact with the substrate, and the temperature of the substrate is measured by the contact-type thermometer.

[0005] Incidentally, there are mounting apparatuses that use a laser instead of a heater. In a mounting apparatus using a laser, the chip and the substrate are heated by the laser. In a mounting apparatus using a laser, if a contact-type thermometer is brought into contact with the substrate in the same manner as in a mounting apparatus using a heater, part of the laser irradiated onto the substrate will be absorbed by the contact-type thermometer. For this reason, in a mounting apparatus using a laser, the temperature of the substrate cannot be measured with a contact-type thermometer.

[0006] An object of the present disclosure is to enable measurement of the temperature of a substrate in a mounting apparatus using a laser.

[0007] The mounting apparatus according to the present disclosure includes: a chip holding portion that holds a chip and mounts the chip onto a substrate; an irradiation portion that irradiates a laser; and a thermometer that measures the temperature of the substrate. The laser is irradiated from the irradiation portion through the chip holding portion onto the substrate, and the thermometer measures the temperature of the substrate by detecting thermal radiation emitted from the substrate.

[0008] The thermometer measures the temperature of the substrate by detecting thermal radiation emitted from the substrate. The thermometer measures the temperature of the substrate without coming into contact with the substrate. Absorption of the laser irradiated from the irradiation portion onto the substrate by the thermometer can be suppressed. In a mounting apparatus using a laser, the temperature of the substrate can be measured.

[0009] In one embodiment, the mounting device comprises a housing that accommodates the irradiation unit and the thermometer, the chip holding unit is provided in the portion of the housing facing the substrate, and the chip holding unit transmits the laser and the thermal radiation.

[0010] By housing the irradiation unit and thermometer within the enclosure, the temperature of the circuit board can be measured even when the enclosure and the circuit board are in close proximity during mounting.

[0011] In one embodiment, the mounting device includes a control unit that controls the output of the irradiation unit based on the temperature measurement value of the thermometer, the control unit performs a first mode and a second mode, the control unit continuously increases the output over time so that the temperature measurement value continuously increases over time until it reaches a target value, and the control unit, in the second mode, after the first mode, varies the output so that the temperature measurement value falls between an upper limit value greater than the target value and a lower limit value smaller than the target value.

[0012] In the first mode, it is possible to suppress the substrate temperature from overshooting the target value. In the second mode, it is possible to maintain the substrate temperature near the target value.

[0013] According to this disclosure, the temperature of a substrate can be measured in a mounting device using a laser.

[0014] Figure 1 shows the mounting device. Figure 2 shows a block diagram of the mounting device. Figure 3 shows a graph of the relationship between time and output. Figure 4 shows a graph of the relationship between time and temperature measurement values.

[0015] Embodiments of the present disclosure will be described in detail below with reference to the drawings. The following description of preferred embodiments is illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses in any way.

[0016] (Mounting device) Figure 1 shows the mounting device 1. The mounting device 1 is also called a bonding device. The mounting device 1 mounts the chip C onto the substrate W. The mounting device 1 comprises a chip holding unit 10, an irradiation unit 20, a thermometer 30, a housing 40, and a control unit 50.

[0017] (Substrate) Substrate W is a printed circuit board. Substrate W is mainly made of resin. Substrate W is in the shape of a plate. Substrate W is placed on stage 2. Stage 2 extends horizontally. The surface W1 of substrate W faces away from stage 2. The back surface W2 of substrate W faces stage 2 and is in contact with stage 2. Substrate W extends horizontally along stage 2. Multiple electrodes W3 are formed on the surface W1 of substrate W in a grid pattern.

[0018] (Stamp) The stamp S is plate-shaped. The stamp S extends horizontally along the substrate W. The surface S1 of the stamp S faces away from the substrate W. The surface S1 of the stamp S is the side of the stamp S opposite to the substrate W. The back surface S2 of the stamp S faces the surface W1 of the substrate W. The back surface S2 of the stamp S is the side of the stamp S facing the substrate W. Multiple chip bases S3 are provided on the back surface S2 of the stamp S.

[0019] (Chip) Chip C is based on a semiconductor material such as silicon, and integrates a complex electronic circuit by forming a fine circuit pattern. Note that Chip C may also be based on a material other than silicon.

[0020] Chip C is plate-shaped. Chip C is placed between stamp S and substrate W. Surface C1 of chip C faces away from substrate W. Surface C1 of chip C is the side of chip C opposite to substrate W. There are multiple chips C. Chip C corresponds to chip base S3. The surfaces C1 of multiple chips C face multiple chip bases S3 on the back surface S2 of stamp S. Surface C1 of chip C is bonded to the chip base S3 on the back surface S2 of stamp S with adhesive.

[0021] The back surface C2 of chip C faces the front surface W1 of substrate W. The back surface C2 of chip C is the side of chip C that faces substrate W. The back surface C2 of chip C is placed on the front surface W1 of substrate W. Multiple solder balls C3 are formed on the back surface C2 of chip C, arranged in a grid pattern. The solder balls C3 correspond to the electrodes W3.

[0022] (Chip holding section) The chip holding section 10 is also called a bonding head. The chip holding section 10 has a holding surface 11. Adsorption holes (not shown) are formed in the holding surface 11. The adsorption holes are in communication with a negative pressure pump (not shown).

[0023] The holding surface 11 of the chip holding portion 10 faces the surface S1 of the stamp S. The holding surface 11 of the chip holding portion 10 faces the substrate W via the stamp S and the chip C. The holding surface 11 of the chip holding portion 10 attracts the surface S1 of the stamp S by the negative pressure of the suction hole. The chip base S3 on the back surface S2 of the stamp S adheres to the surface C1 of the chip C by adhesive force. The chip holding portion 10 holds the chip C. More specifically, the holding surface 11 of the chip holding portion 10 holds the chip C via the stamp S.

[0024] The chip holder 10 and the stamp S are made of, for example, glass (more specifically, quartz glass). The chip holder 10 and the stamp S are transparent to the laser L. When the irradiation unit 20 (described later) irradiates the chip holder 10 with the laser L, the chip holder 10 mounts (bonds) the chip C to the substrate W.

[0025] (Irradiation Unit) The irradiation unit 20 irradiates with the laser L. The irradiation unit 20 includes a laser oscillator 21 and a bend mirror 22.

[0026] The laser oscillator 21 emits a laser L. The bending mirror 22 bends and changes the direction of the laser L emitted from the laser oscillator 21. The laser L bent by the bending mirror 22 is then irradiated.

[0027] The laser L is irradiated from the irradiation unit 20, through the chip holding unit 10, and onto the substrate W. More specifically, the laser L is irradiated from the irradiation unit 20, through the chip holding unit 10 and the stamp S, and onto the surface W1 of the substrate W. A portion of the laser L is absorbed by the surface C1 of the chip C. The remaining portion of the laser L reaches the surface W1 of the substrate W by passing through the chip C (through the back surface C2 of the chip C) or by passing between the chips C.

[0028] When the chip C and substrate W are heated by the laser L, the solder balls C3 on the chip C and the electrodes W3 on the substrate W melt, and the chip C and substrate W are pressed together. As a result, the chip C held by the chip holding unit 10 via the stamp S is mounted on the substrate W. In this way, when the irradiation unit 20 irradiates with the laser L, the chip holding unit 10 mounts the chip C onto the substrate W.

[0029] Laser L is, for example, infrared light. The wavelength λ of laser L is, for example, between 0.76 μm and 1000 μm.

[0030] (Thermometer) Thermometer 30 is a non-contact thermometer. Thermometer 30 is a radiation thermometer. Thermometer 30 measures the temperature T of the substrate W. More specifically, thermometer 30 detects the thermal radiation R emitted from the substrate W. Thermometer 30 measures the temperature T of the substrate W by detecting the thermal radiation R emitted from the substrate W.

[0031] Thermal radiation R is electromagnetic radiation emitted from an object, and it depends on the object's temperature. In this example, electromagnetic radiation R is emitted from the substrate W, depending on the substrate W's temperature T. The main component of thermal radiation R is infrared radiation.

[0032] (Housing) The housing 40 houses the irradiation unit 20 and the thermometer 30. The housing 40 has a facing portion 41 that faces the substrate W. The facing portion 41 extends along the substrate W. The chip holding portion 10 is provided on the facing portion 41 of the housing 40 that faces the substrate W. The holding surface 11 of the chip holding portion 10 is exposed to the outside of the housing 40. The substrate W is placed outside the housing 40. The housing 40 is made of, for example, metal.

[0033] As described above, the chip holder 10 is made of glass, for example (more specifically, quartz glass). The chip holder 10 transmits the laser L and thermal radiation R. The laser L starts from the irradiation unit 20 inside the housing 40, passes through the chip holder 10, and reaches the substrate W outside the housing 40. The thermal radiation R starts from the substrate W outside the housing 40, passes through the chip holder 10, and reaches the thermometer 30 inside the housing 40.

[0034] The thermometer 30 (located inside the housing 40) faces the substrate W via the chip holding section 10.

[0035] (Control Unit) Figure 2 shows a block diagram of the mounting device 1. The control unit 50 includes a processor and a memory. The memory stores a program for executing a predetermined algorithm to operate the processor. The control unit 50 has a PLC 51 and a personal computer 52. PLC 51 is an abbreviation for Programmable Logic Controller. The PLC 51 is connected to the laser oscillator 21 and thermometer 30 of the irradiation unit 20 by wire or wireless. The personal computer 52 is connected to the PLC 51 by wire or wireless. The personal computer 52 includes an input unit for receiving commands from the user and a display unit for displaying output results to the user.

[0036] The control unit 50 controls the output P of the irradiation unit 20 based on the temperature measurement value Ta of the thermometer 30. Specifically, the control unit 50 controls the voltage applied as the output P to the laser oscillator 21 of the irradiation unit 20. The temperature measurement value Ta is the temperature T of the substrate W measured by the thermometer 30 through thermal radiation R.

[0037] Figure 3 shows a graph illustrating the relationship between time t and output P. Figure 4 shows a graph illustrating the relationship between time t and the measured temperature value Ta. In Figure 3, the horizontal axis represents time t, and the vertical axis represents output P. In Figure 4, the horizontal axis represents time t, and the vertical axis represents the measured temperature value Ta. The unit of time t is, for example, [s]. The unit of output P is, for example, [W] representing power or [V] representing voltage. The unit of the measured temperature value Ta is, for example, [°C].

[0038] The control unit 50 executes a first mode M1 and a second mode M2. The first mode M1 is performed before the second mode M2. The second mode M2 ​​is performed after the first mode M1.

[0039] In the first mode M1, the control unit 50 continuously increases the output P as time t progresses so that the temperature measurement value Ta continuously increases as time t progresses until it reaches the target value To. The first mode M1 is started by irradiation with the laser L by the irradiation unit 20 and ends when the temperature measurement value Ta reaches the target value To. In the first mode M1, the output P of the irradiation unit 20 continuously increases as time t progresses. The output P increases, for example, linearly. In the first mode M1, the temperature measurement value Ta continuously increases as time t progresses. The temperature measurement value Ta increases, for example, nonlinearly.

[0040] In the first mode M1, the control unit 50 determines, for example, at a period of 1 ms, whether the measured temperature value Ta is greater than the target value To. If the control unit 50 determines that the measured temperature value Ta is greater than the target value To, it terminates the first mode M1. If the control unit 50 determines that the measured temperature value Ta is less than the target value To, it continues the first mode M1.

[0041] In the second mode M2, after the first mode M1, the control unit 50 varies the output P so that the temperature measurement value Ta falls between the upper limit value Tu and the lower limit value Tl. The upper limit value Tu is greater than the target value To. The lower limit value Tl is less than the target value To. The second mode M2 ​​is started when the temperature measurement value Ta reaches the target value To and ends when a stop command is issued by the user or when a predetermined time has elapsed.

[0042] In the second mode M2, the control unit 50 determines, for example, at a cycle of 1 ms, whether the measured temperature value Ta is larger than the upper limit value Tu and whether the measured temperature value Ta is smaller than the lower limit value Tl. In the second mode M2, when the control unit 50 determines that the measured temperature value Ta is larger than the upper limit value Tu, it reduces the output P. In the second mode M2, when the control unit 50 determines that the measured temperature value Ta is smaller than the lower limit value Tl, it increases the output P. In the second mode M2, when the control unit 50 determines that the measured temperature value Ta is smaller than the upper limit value Tu and larger than the lower limit value Tl, it does not change the output P.

[0043] Since heat remains accumulated in the substrate W, even if the output P is reduced in the second mode M2, the measured temperature value Ta hardly decreases and is maintained constant.

[0044] (Operational effect) In the mounting apparatus 1 using the laser L, if a contact-type thermometer (e.g., a thermocouple) is brought into contact with the substrate W, similar to the case of a mounting apparatus using a heater, part of the laser L irradiated onto the substrate W will be absorbed by the contact-type thermometer. For this reason, in the mounting apparatus 1 using the laser L, the temperature T of the substrate W cannot be measured with a contact-type thermometer.

[0045] In the present embodiment, the thermometer 30 measures the temperature T of the substrate W by detecting the thermal radiation R emitted from the substrate W. The thermometer 30 measures the temperature T of the substrate W without coming into contact with the substrate W (in a non-contact manner). This can suppress absorption of the laser L irradiated from the irradiation unit 20 onto the substrate W by the thermometer 30. In the mounting apparatus 1 using the laser L, the temperature T of the substrate W can be measured.

[0046] By housing the irradiation unit 20 and the thermometer 30 in the housing 40, the temperature T of the substrate W can be measured even in a state where the housing 40 and the substrate W are close to each other during mounting.

[0047] The thermometer 30 (disposed inside the housing 40) faces the substrate W via the chip holding unit 10. This allows the thermometer 30 and the substrate W to be brought close to each other. This can improve the measurement accuracy of the temperature T of the substrate W by the thermometer 30.

[0048] In the first mode M1, overshoot of the temperature T of the substrate W from the target value To can be suppressed. In the second mode M2, the temperature T of the substrate W can be maintained close to the target value To.

[0049] The substrate W, the chip C, the stamp S, the stage 2, and the holding surface 11 of the chip holding portion 10 may extend obliquely with respect to the horizontal direction.

[0050] (Other Embodiments) The present disclosure has been described above with reference to preferred embodiments, but such description is not limiting, and various modifications, substitutions, or combinations can of course be made.

[0051] The laser L does not need to be infrared light.

[0052] The thermometer 30 may be arranged outside the housing 40.

[0053] The stamp S may be omitted.

[0054] The chip holding portion 10 does not need to be made of glass.

[0055] The present disclosure is applicable to mounting apparatuses, and thus is extremely useful and has high industrial applicability.

[0056] W Substrate W1 Front surface W2 Back surface W3 Electrode C Chip C1 Front surface C2 Back surface C3 Solder ball S Stamp S1 Front surface S2 Back surface S3 Chip stage L Laser R Thermal radiation t Time T Temperature Ta Measured temperature value To Target value Tu Upper limit value Tl Lower limit value P Output M1 First mode M2 Second mode 1 Mounting apparatus 2 Stage 10 Chip holding portion 11 Holding surface 20 Irradiation portion 21 Laser oscillator 22 Bend mirror 30 Thermometer 40 Housing 41 Facing portion (portion) 50 Control portion 51 PLC 52 Personal computer

Claims

1. A mounting device comprising: a chip holding unit for holding a chip and mounting the chip onto a substrate; an irradiation unit for irradiating a laser; and a thermometer for measuring the temperature of the substrate, wherein the laser is irradiated from the irradiation unit through the chip holding unit onto the substrate, and the thermometer measures the temperature of the substrate by detecting the thermal radiation emitted from the substrate.

2. The mounting apparatus according to claim 1, comprising a housing that houses the irradiation unit and the thermometer, wherein the chip holding unit is provided in the portion of the housing facing the substrate, and the chip holding unit transmits the laser and the thermal radiation.

3. The mounting device according to claim 1 or 2, comprising a control unit that controls the output of the irradiation unit based on the temperature measurement value of the thermometer, wherein the control unit performs a first mode and a second mode, wherein in the first mode, the control unit continuously increases the output over time so that the temperature measurement value continuously increases over time until it reaches a target value, and in the second mode, after the first mode, the control unit varies the output so that the temperature measurement value falls between an upper limit value greater than the target value and a lower limit value less than the target value.

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