Solid-state imaging device, method of manufacturing the same, and electronic device

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.

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.

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.