Solid-state imaging device, method of manufacturing the same, and electronic device
Provided is a solid-state imaging device that includes a first semiconductor layer including a first photoelectric conversion element that photoelectrically converts light to a signal charge, and a charge holding region that holds the signal charge, a second semiconductor layer on the first semiconductor layer with a first insulating layer interposed therebetween and includes a second photoelectric conversion element that photoelectrically converts light, a circuit substrate unit on the second semiconductor layer with a second insulating layer interposed therebetween and includes a readout circuit that reads out the signal charge, an element-side first metal pad on the second insulating layer, a circuit-side first metal pad on the circuit substrate unit and is connected to the readout circuit and bonded to the element-side metal pad, and a first contact electrode that penetrates the first and second insulating layers and electrically connects the charge holding region and the element-side first metal pad.
1 . A solid-state imaging device, comprising:
a first semiconductor layer that includes a first photoelectric conversion element and a charge holding region, wherein
the first semiconductor layer has a first surface and a second surface,
the second surface is opposite to the first surface,
the first photoelectric conversion element is configured to photoelectrically convert first light, incident from a side of the second surface, to a first signal charge, and
the charge holding region is configured to hold the first signal charge;
a second semiconductor layer on a side of the first surface of the first semiconductor layer, wherein
the second semiconductor layer includes a second photoelectric conversion element, and
the second photoelectric conversion element is configured to photoelectrically convert second light, incident from the side of the second surface of the first semiconductor layer, to a second signal charge;
a first insulating layer between the first semiconductor layer and the second semiconductor layer:
a circuit substrate unit on a first side of the second semiconductor layer, wherein
the first side of the second semiconductor layer is opposite to a side of the first insulating layer,
the circuit substrate unit includes a first readout circuit and a second readout circuit,
the first readout circuit is configured to read out the first signal charge, and
the second readout circuit is configured to read out the second signal charge;
a second insulating layer between the second semiconductor layer and the circuit substrate unit;
an element-side first metal pad on a side of the second insulating layer, wherein the side of the second insulating layer is opposite to a second side of the second semiconductor layer;
an element-side second metal pad on the side of the second insulating layer;
a circuit-side first metal pad on the circuit substrate unit, wherein the circuit-side first metal pad is electrically connected to the first readout circuit and bonded to the element-side first metal pad;
a circuit-side second metal pad on the circuit substrate unit, wherein
the circuit-side second metal pad is electrically connected to the second readout circuit and bonded to the element-side second metal pad, and
the circuit-side second metal pad opposes the element-side second metal pad;
a first contact electrode that penetrates the first insulating layer and the second insulating layer, wherein the first contact electrode is configured to electrically connect the charge holding region and the element-side first metal pad; and
a second contact electrode that penetrates the first insulating layer and the second insulating layer, wherein the second contact electrode is configured to electrically connect the second photoelectric conversion element and the element-side second metal pad.
2 . The solid-state imaging device according to claim 1 , wherein the first contact electrode extends in a thickness direction of each of the first insulating layer and the second insulating layer.
3 . The solid-state imaging device according to claim 1 , further comprising a pixel region, wherein
in the pixel region, a plurality of pixels is in a matrix arrangement, and
the first contact electrode is in the pixel region in a plan view of the solid-state imaging device.
4 . The solid-state imaging device according to claim 1 , wherein the second light enters the second photoelectric conversion element via the first semiconductor layer.
5 . The solid-state imaging device according to claim 1 , wherein
the first photoelectric conversion element is a visible light photoelectric conversion element,
the visible light photoelectric conversion element is configured to photoelectrically convert, to the first signal charge, the first light that has a wavelength in a visible region,
the second photoelectric conversion element is an infrared photoelectric conversion element, and
the infrared photoelectric conversion element is configured to photoelectrically convert, to the second signal charge, the second light that has a wavelength in an infrared region.
6 . The solid-state imaging device according to claim 1 , wherein
the first semiconductor layer includes silicon (Si),
the second semiconductor layer includes at least one a compound semiconductor material or germanium (Ge), and
the compound semiconductor material includes at least one of indium gallium arsenide (InGaAs), indium arsenide antimony (InAsSb), indium arsenide (InAs), indium antimony (InSb), or mercury cadmium telluride (HgCdTe).
7 . The solid-state imaging device according to claim 1 , wherein the first photoelectric conversion element overlaps with the second photoelectric conversion element in a plan view of the solid-state imaging device.
8 . The solid-state imaging device according to claim 1 , wherein the first contact electrode penetrates the second semiconductor layer.
9 . The solid-state imaging device according to claim 1 , further comprising:
a transfer transistor in the first semiconductor layer, wherein the transfer transistor is configured to transfer the first signal charge to the charge holding region;
an element-side third metal pad on the side of the second insulating layer;
a circuit-side third metal pad that is provided on the circuit substrate unit, wherein
the circuit-side third metal pad is bonded to the element-side third metal pad, and
the circuit-side third metal pad opposes the element-side third metal pad; and
a third contact electrode that penetrates the first insulating layer and the second insulating layer, wherein the third contact electrode is configured to electrically connect a gate electrode of the transfer transistor and the element-side third metal pad.
10 . The solid-state imaging device according to claim 1 , further comprising:
a second electrode on the side of the first insulating layer;
a lead-out electrode on the side of the second insulating layer, wherein
the lead-out electrode penetrates the second semiconductor layer, and
the lead-out electrode is electrically connected to the second electrode;
an element-side fourth metal pad on the side of the second insulating layer;
a circuit-side fourth metal pad on the circuit substrate unit, wherein
the circuit-side fourth metal pad is bonded to the element-side fourth metal pad, and
the circuit-side fourth metal pad opposes the element-side fourth metal pad; and
a fourth contact electrode that penetrates the second insulating layer, wherein the fourth contact electrode is configured to electrically connect the lead-out electrode and the element-side fourth metal pad.
11 . The solid-state imaging device according to claim 1 , further comprising a plurality of first photoelectric conversion elements, wherein
the plurality of first photoelectric conversion elements includes the first photoelectric conversion element, and
the plurality of first photoelectric conversion elements shares the first readout circuit.
12 . The solid-state imaging device according to claim 1 , wherein
in a plan view of the solid-state imaging device, the second semiconductor layer extends in an X direction of the plan view,
in the plan view, the second semiconductor layer is at specific intervals in a Y direction of the plan view, and
the Y direction is orthogonal to the X direction.
13 . The solid-state imaging device according to claim 1 , wherein
positions of the first photoelectric conversion element and the second photoelectric conversion element are eccentric, and
in a plan view of the solid-state imaging device, the first photoelectric conversion element is non-overlapping with the second photoelectric conversion element.
14 . A method of manufacturing a solid-state imaging device, the method comprising:
forming a first photoelectric conversion element and a charge holding region in a first semiconductor layer, wherein
the first semiconductor layer has a first surface and a second surface,
the second surface is opposite to the first surface,
the first photoelectric conversion element is configured to photoelectrically convert first light, incident from a side of the second surface, to a first signal charge, and
the charge holding region is configured to hold the first signal charge;
stacking a second semiconductor layer on a side of the first surface of the first semiconductor layer with a first insulating layer therebetween;
forming a second photoelectric conversion element in the second semiconductor layer, wherein the second photoelectric conversion element is configured to photoelectrically convert second light, incident from the side of the second surface of the first semiconductor layer, to a second signal charge;
forming a first contact electrode that penetrates the first insulating layer and the second insulating layer;
forming a second contact electrode that penetrates the first insulating layer and the second insulating layer;
forming each of an element-side first metal pad and an element-side second metal pad, wherein
the first contact electrode is configured to electrically connect the charge holding region and the element-side first metal pad, and
the second contact electrode is configured to electrically connect the second photoelectric conversion element and the element-side second metal pad;
forming a circuit substrate unit that includes a first readout circuit and a second readout circuit, wherein
the first readout circuit is configured to read out the first signal charge, and
the second readout circuit is configured to read out the second signal charge;
forming each of a circuit-side first metal pad and a circuit-side second metal pad on the circuit substrate unit; and
bonding the circuit substrate unit to the second semiconductor layer with a second insulating layer therebetween, wherein
the circuit substrate unit is on a first side of the second semiconductor layer,
the first side of the second semiconductor layer is opposite to a side of the first insulating layer,
each of the element-side first metal pad and the element-side second metal pad is on a side of the second insulating layer,
the side of the second insulating layer is opposite to a second side of the second semiconductor layer,
the circuit-side first metal pad is electrically connected to the first readout circuit and bonded to the element-side first metal pad,
the circuit-side first metal pad opposes the element-side first metal pad,
the circuit-side second metal pad is electrically connected to the second readout circuit and bonded to the element-side second metal pad, and
the circuit-side second metal pad opposes the element-side second metal pad.
15 . The method of manufacturing the solid-state imaging device according to claim 14 , wherein
the first photoelectric conversion element is a visible light photoelectric conversion element,
the visible light photoelectric conversion element is configured to photoelectrically convert, to the first signal charge, the first light that has a wavelength in a visible region,
the second photoelectric conversion element is an infrared photoelectric conversion element, and
the infrared photoelectric conversion element is configured to photoelectrically convert, to the second signal charge, the second light that has a wavelength in an infrared region.
16 . An electronic device, comprising:
a solid-state imaging device;
an optical lens configured to form, on an imaging surface of the solid-state imaging device, an image of image light from a subject; and
a signal processing circuit configured to execute a signal processing operation on a signal output from the solid-state imaging device, wherein the solid-state imaging device includes:
a first semiconductor layer that includes a first photoelectric conversion element and a charge holding region, wherein
the first semiconductor layer has a first surface and a second surface,
the second surface is opposite to the first surface,
the first photoelectric conversion element is configured to photoelectrically convert first light, incident from a side of the second surface, to a first signal charge, and
the charge holding region is configured to hold the first a signal charge;
a second semiconductor layer on a side of the first surface of the first semiconductor layer, wherein
the second semiconductor layer includes a second photoelectric conversion element, and
the second photoelectric conversion element is configured to photoelectrically convert second light, incident from the side of the second surface of the first semiconductor layer, to a second signal charge;
a first insulating layer between the first semiconductor layer and the second semiconductor layer;
a circuit substrate unit on a first side of the second semiconductor layer, wherein
the first side of the second semiconductor layer is opposite to a side of the first insulating layer,
the circuit substrate unit includes a first readout circuit and a second readout circuit,
the first readout circuit is configured to read out the first signal charge, and
the second readout circuit is configured to read out the second signal charge;
a second insulating layer between the second semiconductor layer and the circuit substrate unit;
an element-side first metal pad on a side of the second insulating layer, wherein the side of the second insulating layer is opposite to a second side of the second semiconductor layer;
an element-side second metal pad on the side of the second insulating layer;
a circuit-side first metal pad on the circuit substrate unit, wherein the circuit-side first metal pad is electrically connected to the first readout circuit and bonded to the element-side first metal pad;
a circuit-side second metal pad on the circuit substrate unit, wherein
the circuit-side second metal pad is electrically connected to the second readout circuit and bonded to the element-side second metal pad, and
the circuit-side second metal pad opposes the element-side second metal pad;
a first contact electrode that penetrates the first insulating layer and the second insulating layer, wherein the first contact electrode is configured to electrically connect the charge holding region and the element-side first metal pad; and
a second contact electrode that penetrates the first insulating layer and the second insulating layer, wherein the second contact electrode is configured to electrically connect the second photoelectric conversion element and the element-side second metal pad.
17 . A solid-state imaging device, comprising:
a first semiconductor layer that includes a first photoelectric conversion element and a charge holding region, wherein
the first semiconductor layer has a first surface and a second surface,
the second surface is opposite to the first surface,
the first photoelectric conversion element is configured to photoelectrically convert first light, incident from a side of the second surface, to a first signal charge, and
the charge holding region is configured to hold the first signal charge;
a second semiconductor layer on a side of the first surface of the first semiconductor layer, wherein
the second semiconductor layer includes a second photoelectric conversion element, and
the second photoelectric conversion element is configured to photoelectrically convert second light, incident from the side of the second surface of the first semiconductor layer, to a second signal charge;
a first insulating layer between the first semiconductor layer and the second semiconductor layer;
a circuit substrate unit on a first side of the second semiconductor layer, wherein
the first side of the second semiconductor layer is opposite to a side of the first insulating layer,
the circuit substrate unit includes a readout circuit,
the readout circuit has a specific circuit configuration, and
the readout circuit is configured to:
read out the first signal charge; and
read out the second signal charge;
a second insulating layer between the second semiconductor layer and the circuit substrate unit;
an element-side first metal pad on a side of the second insulating layer, wherein the side of the second insulating layer is opposite to a second side of the second semiconductor layer;
an element-side second metal pad on the side of the second insulating layer;
a circuit-side first metal pad on the circuit substrate unit, wherein the circuit-side first metal pad is electrically connected to the first readout circuit and bonded to the element-side first metal pad;
a circuit-side second metal pad on the circuit substrate unit, wherein the circuit-side second metal pad is electrically connected to the second readout circuit and bonded to the element-side second metal pad;
a first contact electrode that penetrates the first insulating layer and the second insulating layer, wherein the first contact electrode is configured to electrically connect the charge holding region and the element-side first metal pad; and
a second contact electrode that penetrates the first insulating layer and the second insulating layer, wherein the second contact electrode is configured to electrically connect the second photoelectric conversion element and the element-side second metal pad.