Sound-assisted crack propagation for semiconductor wafering
View Patent ↗Systems and methods are described for controlled crack propagation in a material using ultrasonic waves. A first stress in applied to the material such that the first stress is below a critical point of the material and is insufficient to initiate cracking of the material. A controlled ultrasound wave is then applied to the material causing the total stress applied at a crack tip in the material to exceed the critical point. In some implementations, the controlled cracking is used for wafering of a material.
1 . A sound-assisted cleaving system comprising:
a holder to hold a material;
a first stress system configured to apply a first stress to the material;
a first ultrasound source; and
an electronic controller communicatively coupled to the first ultrasound source, the electronic controller configured to:
apply a first ultrasound wave from the first ultrasound source to the material to propagate cracking of the material, and
dynamically control a velocity of the cracking of the material during propagation of the cracking by adjusting at least one of frequency, amplitude, or phase of the first ultrasound wave applied to the material.
2 . The sound-assisted cleaving system of claim 1 , wherein the holder comprises a clamp.
3 . The sound-assisted cleaving system of claim 1 , wherein the first stress system regulates temperature of the material.
4 . The sound-assisted cleaving system of claim 1 , wherein the first stress system applies a mechanical load to the material.
5 . The sound-assisted cleaving system of claim 4 , further comprising a second ultrasound source communicatively coupled to the electronic controller.
6 . The sound-assisted cleaving system of claim 1 , further comprising a crack initiator to generate an indentation in the material.
7 . The sound-assisted cleaving system of claim 6 , wherein the crack initiator comprises a laser.
8 . The sound-assisted cleaving system of claim 6 , wherein the crack initiator comprises an indenter.
9 . The sound-assisted cleaving system of claim 1 , wherein the first ultrasound source includes a transducer to transmit the first ultrasound wave into the material.
10 . The sound-assisted cleaving system of claim 1 , further comprising a second ultrasound source communicatively coupled to the electronic controller, the second ultrasound source configured to apply a second ultrasound wave into the material.
11 . The sound-assisted cleaving system of claim 10 , wherein the first ultrasound source and the second ultrasound source are operable at the same or different frequencies.
12 . The sound-assisted cleaving system of claim 10 , further comprising an absorbing material applied to the material to absorb the ultrasound wave as the ultrasound wave reaches an edge of the material.
13 . The sound-assisted cleaving system of claim 12 , wherein the absorbing material surrounds a perimeter of the material.
14 . The sound-assisted cleaving system of claim 1 , further comprising:
a crack initiator to create an indentation in the material; and
an absorbing material to absorb the ultrasound wave as the ultrasound wave reaches an edge of the material.
15 . The sound-assisted cleaving system of claim 1 :
further comprising a laser to create an indentation in the material;
wherein the first stress system regulates temperature of the material; and
wherein the first ultrasound source includes a transducer to transmit the first ultrasound wave into the material.
16 . The sound-assisted cleaving system of claim 15 , wherein the electronic controller includes a second ultrasound source to transmit a second ultrasound wave into the material, wherein the first ultrasound source and the second ultrasound source are operable at the same or different frequencies.
17 . The sound-assisted cleaving system of claim 15 , further comprising an absorbing material applied to the material to absorb the first ultrasound wave as the first ultrasound wave reaches an edge of the material, wherein the absorbing material surrounds a perimeter of the material.
18 . The sound-assisted cleaving system of claim 1 :
further comprising a laser to create an indentation in the material;
wherein the first stress system applies a mechanical load to the material; and
wherein the first ultrasound source includes a transducer to transmit the first ultrasound wave into the material.
19 . The sound-assisted cleaving system of claim 18 , wherein the first stress system is communicatively coupled to a second ultrasound source.
20 . The sound-assisted cleaving system of claim 19 , further comprising an absorbing material applied to the material to absorb the first ultrasound wave as the first ultrasound wave reaches an edge of the material, wherein the absorbing material surrounds a perimeter of the material.
21 . The sound-assisted cleaving system of claim 1 , wherein the at least one of frequency, amplitude, or phase of the first ultrasound wave are adjusted in real time in response to a detected crack propagation parameter.
22 . The sound-assisted cleaving system of claim 1 , wherein the electronic controller is configured to maintain the velocity of the cracking at or below 30% of a Rayleigh wave velocity of the material.
23 . The sound-assisted cleaving system of claim 21 , wherein the detected crack propagation parameter comprises crack position and crack velocity, the crack position and crack velocity being determined by measuring at least one of:
acoustic emission generated by propagation of the crack,
optical emission associated with the crack front,
strain relaxation of the material, or
a change in electrical properties of the material during crack propagation.
24 . The sound-assisted cleaving system of claim 1 , wherein the electronic controller forms a closed-loop feedback system configured to continuously modify the first ultrasound wave while the crack propagates through the material.