US 12,169,188 B2
Bonding layer evaluation system and bonding layer evaluation method
Sota Kamo, Tokyo (JP); Kiyoka Takagi, Tokyo (JP); Naoki Matsuda, Kyoto (JP); and Naoki Mori, Shiga (JP)
Assigned to MITSUBISHI HEAVY INDUSTRIES, LTD., Tokyo (JP); KYOTO UNIVERSITY, Kyoto (JP); and THE RITSUMEIKAN TRUST, Kyoto (JP)
Appl. No. 17/639,471
Filed by MITSUBISHI HEAVY INDUSTRIES, LTD., Tokyo (JP); KYOTO UNIVERSITY, Kyoto (JP); and THE RITSUMEIKAN TRUST, Kyoto (JP)
PCT Filed Aug. 26, 2020, PCT No. PCT/JP2020/032172
§ 371(c)(1), (2) Date Mar. 1, 2022,
PCT Pub. No. WO2021/044920, PCT Pub. Date Mar. 11, 2021.
Claims priority of application No. 2019-159852 (JP), filed on Sep. 2, 2019; and application No. 2019-222750 (JP), filed on Dec. 10, 2019.
Prior Publication US 2022/0299479 A1, Sep. 22, 2022
Int. Cl. G01N 29/12 (2006.01); G01N 29/44 (2006.01); G01N 29/46 (2006.01)
CPC G01N 29/12 (2013.01) [G01N 29/4436 (2013.01); G01N 29/46 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A bonding layer evaluation system, comprising:
an elastic wave generation device configured to generate an elastic wave at an evaluation object including a bonding layer;
an elastic wave detection device configured to detect the elastic wave from the evaluation object; and
a control device configured to evaluate a parameter related to the bonding layer of the evaluation object, wherein
the control device is configured to
compare an actual value of a frequency characteristic of the elastic wave detected by the elastic wave detection device and a theoretical value of the frequency characteristic of the elastic wave calculated based on a theoretical model related to the evaluation object and
evaluate the parameter related to the bonding layer based on a result of the comparison,
the elastic wave generation device is an ultrasonic wave generation device configured to generate an ultrasonic wave at the evaluation object,
the elastic wave detection device is an ultrasonic wave detection device configured to detect the ultrasonic wave from the evaluation object,
the ultrasonic wave generation device and the ultrasonic wave detection device are each provided on a side to which the ultrasonic wave is reflected by the evaluation object, and
the control device is further configured to
calculate the actual value of a reflection coefficient of the elastic wave as the actual value of the frequency characteristic of the elastic wave based on the elastic wave detected by the elastic wave detection device,
calculate a notch frequency of the actual value, which is the frequency at which the value becomes a minimum based on the actual value of the reflection coefficient of the elastic wave,
obtain a theoretical notch frequency, which is a frequency at which the theoretical value of a reflection coefficient of the elastic wave as the theoretical value of the frequency characteristic of the elastic wave is minimum,
adjust a difference between the notch frequency of the theoretical value and the notch frequency of the actual value to be within a predetermined range by changing the parameters related to the bonding layer in the theoretical model,
derive parameters regarding the bonding layer at that time, and
evaluate that the bonding layer has a weak bond when the derived parameter related to the bonding layer is lower than a parameter related to the bonding when an appropriate bond is formed.