Method and system for 3D alignment in wafer scale integration

A substrate bonding method comprising:

• holding a first substrate with a first orientation on a first substrate table,
• holding a second substrate with a second orientation on a second substrate table, the first substrate table having a first table position relative to a second table position of the second substrate table, wherein the first substrate has a front surface comprising a first target portion that includes a first device and a back surface comprising a first back surface alignment marker, the first device having first contact pads, and wherein the second substrate has a second front surface comprising a second target portion that includes a second device and a second back surface comprising a second back surface alignment marker, the second device having second contact pads;
• receiving a first and a second measured optical signal generated on the first back surface alignment mark of the first substrate and the second back surface alignment mark of the second substrate respectively;
• determining from the received first and second measured optical signals the first orientation of the first substrate and the second orientation of the second substrate, and
• altering the first table position and first orientation of the first substrate table relative to the second table position and second orientation of the second substrate table in such a way that alignment and overlap of the first contact pads of the first device and the second contact pads of the second device are achieved,
• wherein the first and second device are bonded so that a circuit is formed by the first and second device.

A controller for a substrate bonding system comprising a first substrate table configured to hold a first substrate with a first orientation, and a second substrate table configured to hold a second substrate with a second orientation, wherein the first substrate has a front surface comprising a first target portion that includes a first device, the first device having first contact pads, wherein the second substrate has a second front surface comprising a second target portion that includes a second device, the second device having second contact pads, wherein the substrate bonding system is arranged to bond the first and second device in such a way that a circuit may be formed by the first and second device;

• wherein the first substrate table comprises a first work space surface configured to hold the first substrate, a first position sensor arranged to measure a first optical signal generated on a first back surface alignment marker of the first substrate and a first actuator arranged to alter first table position and the first orientation of the first substrate table, and wherein the second substrate table comprises a second work space surface configured to hold the second substrate, a second position sensor arranged to measure a second optical signal generated on a second back surface alignment mark of the second substrate and a second actuator arranged to alter second table position and the second orientation of the second substrate table, said controller being configured to:
• (a) receive a first and a second measured optical signal from the first and second position sensors respectively;
• (b) determine from the received first and second measured optical signals the first orientation of the first substrate and the second orientation of the second substrate, and
• (c) send a control signal to a first of the first and second actuators to alter the first table position and first orientation of the first substrate table relative to the second table position and second orientation of the second substrate table so that alignment and overlap of the first contact pads of the first device and the second contact pads of the second device are achieved.

A controller program product to be loaded by a controller for use in a substrate bonding system, the substrate bonding system comprising a first substrate table configured to hold a first substrate with a first orientation, a second substrate table configured to hold a second substrate with a second orientation, wherein the first substrate has a front surface comprising a first target portion that includes a first device, the first device having first contact pads, wherein the second substrate has a second front surface comprising a second target portion that includes a second device, the second device having second contact pads;

• wherein the substrate bonding system is arranged to bond the first and second device in such a way that a circuit may formed by the first and second device;
• wherein the first substrate table comprises a first work space surface configured to hold the first substrate, a first position sensor arranged to measure a first optical signal generated on a first back surface alignment marker of the first substrate and a first actuator arranged to alter first table position and the first orientation of the first substrate table, wherein the second substrate table comprises a second work space surface configured to hold the second substrate, a second position sensor arranged to measure a second optical signal generated on a second back surface alignment mark of the second substrate and a second actuator arranged to alter second table position and the second orientation of the second substrate table, said controller program including machine executable instructions executable by said controller to perform the bonding of said first substrate and said second substrate according to a method comprising:
• receiving a first and a second measured optical signal from the first and second position sensors respectively;
• determining from the received first and second measured optical signals the first orientation of the first substrate and the second orientation of the second substrate, and
• sending a control signal to a first of the first and second actuators to alter the first table position and first orientation of the first substrate table relative to the second table position and second orientation of the second substrate table so that alignment and overlap of the first contact pads of the first device and the second contact pads of the second device are achieved.

An alignment feedback system of a substrate bonding system for bonding a first substrate and a second substrate, the first device having first contact pads, the second device having second contact pads, the alignment feedback system comprising:

• a laser source configured to generate a laser beam;
• a first beam splitter configured to split a first beam portion and a second beam portion from the laser beam;
• a first position sensor arranged to measure a first optical signal generated on a first back surface alignment marker of the first substrate by the first beam portion of the laser beam;
• a second position sensor arranged to measure a second optical signal generated on a second back surface alignment marker of the second substrate by the second beam portion of the laser beam;
• an actuator configured to alter a first table position and a first orientation of the first substrate and to alter a second table position and a second orientation of the second substrate;
• a controller configured to control said actuator, and
• a first detector and a second detector, the first detector being arranged in an optical path of the first beam portion and the second detector being arranged in a second optical path of the second beam portion,
• wherein the first detector is configured to measure a first interferometer signal with at least said first optical signal, and
• wherein the second detector is configured to measure a second interferometry signal with at least said second optical signal.

An arrangement of a first substrate and a second substrate, the first substrate having a first orientation and having a front surface comprising a first target portion that includes a first device, the first device having first contact pads;

• the second substrate having a second orientation and having a second front surface comprising a second target portion that includes a second device, the second device having second contact pads, the first and second substrate being aligned and in overlap in accordance with the method comprising:
• holding the first substrate on a first substrate table,
• holding the second substrate on the second substrate table, the first substrate table having a first table position relative to a second table position of the second substrate table, wherein the first substrate has a back surface comprising a first back surface alignment marker, and wherein the second substrate has a second back surface comprising a second back surface alignment marker;
• receiving a first and a second measured optical signal generated on the first back surface alignment mark of the first substrate and the second back surface alignment mark of the second substrate respectively;
• determining from the received first and second measured optical signals the first orientation of the first substrate and the second orientation of the second substrate, and
• altering the first table position and first orientation of the first substrate table relative to the second table position and second orientation of the second substrate table in such a way that alignment and overlap of the first contact pads of the first device and the second contact pads of the second device are achieved.