Solid-state imaging device, method for manufacturing the same, and electronic apparatus
The present technology relates to a solid-state imaging device compatible with miniaturization of pixels, a method for manufacturing the solid-state imaging device, and an electronic apparatus. The solid-state imaging device is formed by joining a front surface side as the wiring layer formation surface of the first semiconductor substrate to a back surface side of the second semiconductor substrate. The first semiconductor substrate includes a photodiode and a transfer transistor. The second semiconductor substrate includes a charge/voltage retention portion that retains the electric charge transferred by the transfer transistor or the voltage corresponding to the electric charge. The solid-state imaging device includes a through electrode that penetrates the second semiconductor substrate, and transmits the electric charge or the voltage to the charge/voltage retention portion. The present technology can be applied to solid-state imaging devices and the like, for example.
1 . A solid-state imaging apparatus, comprising:
a first semiconductor substrate;
a second semiconductor substrate,
wherein a front surface side of the first semiconductor substrate forms a wiring layer formation surface of the first semiconductor substrate and joins to a back surface side of the second semiconductor substrate which is an opposite side of a wiring layer formation surface of the second semiconductor substrate,
wherein the first semiconductor substrate includes:
a photoelectric conversion portion that photoelectrically converts incident light;
a transfer transistor that transfers electric charges of the photoelectric conversion portion; and
a voltage conversion transistor that converts the electric charges transferred by the transfer transistor into a corresponding voltage, and
wherein the second semiconductor substrate includes a charge voltage retention portion that retains the corresponding voltage converted by the voltage conversion transistor; and
a through electrode that penetrates through the second semiconductor substrate and transmits the corresponding voltage converted by the transfer transistor to the charge voltage retention portion,
wherein the transfer transistor and the voltage conversion transistor are formed on a surface of the second semiconductor substrate, opposite a light incident side of the first semiconductor substrate and
wherein the through electrode does not penetrate through the first semiconductor substrate.
2 . The solid-state imaging apparatus according to claim 1 , further comprising a photomask arranged between the first semiconductor substrate and the second semiconductor substrate, wherein the photomask is formed by a portion of a metal wiring provided within a wiring layer.
3 . The solid-state imaging apparatus according to claim 1 , wherein a cross-sectional diameter of the through electrode penetrating both the first semiconductor substrate and the second semiconductor substrate is less than or equal to the cross-sectional diameter of the through electrode penetrating only the second semiconductor substrate.
4 . The solid-state imaging apparatus according to claim 1 , wherein the charge voltage retention portion of the second semiconductor substrate includes a capacitor.
5 . The solid-state imaging apparatus according to claim 1 , wherein the first semiconductor substrate and the second semiconductor substrate are electrically coupled only via a plurality of the through electrodes provided within a pixel region of the solid-state imaging apparatus.
6 . The solid-state imaging apparatus according to claim 1 , wherein the transfer transistor and the voltage conversion transistor are provided between the wiring layer formation surface of the first semiconductor substrate and the wiring layer formation surface of the second semiconductor substrate.
7 . The solid-state imaging apparatus according to claim 1 , further comprising a light blocking film positioned below the photoelectric conversion portion and above the through electrode throughout a length of the through electrode in a cross-sectional view.
8 . The solid-state imaging apparatus according to claim 7 , wherein the light blocking film includes tungsten.
9 . A manufacturing method for a solid-state imaging apparatus, the method comprising:
forming a photoelectric conversion portion, a transfer transistor, and a voltage conversion transistor in a first semiconductor substrate,
wherein the photoelectric conversion portion photoelectrically converts incident light, wherein the transfer transistor transfers electric charges of the photoelectric conversion portion and
wherein the voltage conversion transistor converts the electric charges transferred by the transfer transistor into a corresponding voltage;
bonding a front surface side of the first semiconductor substrate which is a wiring layer formation surface of the first semiconductor substrate to a back surface side of a second semiconductor substrate which is an opposite side of a wiring layer formation surface of the second semiconductor substrate;
forming a charge voltage retention portion in the second semiconductor substrate after the bonding,
wherein the charge voltage retention portion retains the corresponding voltage converted by the voltage conversion transistor;
forming a through electrode that penetrates the second semiconductor substrate and transmits the corresponding voltage converted by the transfer transistor to the charge voltage retention portion;
forming the transfer transistor and the voltage conversion transistor on a surface of the second semiconductor substrate, opposite a light incident side of the first semiconductor substrate; and
not penetrating the first semiconductor substrate with the through electrode.
10 . The manufacturing method for a solid-state imaging apparatus according to claim 9 , wherein the method further comprises:
arranging a photomask between the first semiconductor substrate and the second semiconductor substrate; and
forming the photomask by a portion of a metal wiring provided within a wiring layer.
11 . The manufacturing method for a solid-state imaging apparatus according to claim 9 , wherein a cross-sectional diameter of the through electrode penetrating both the first semiconductor substrate and the second semiconductor substrate is less than or equal to the cross-sectional diameter of the through electrode penetrating only the second semiconductor substrate.
12 . The manufacturing method for a solid-state imaging apparatus according to claim 9 , wherein the charge voltage retention portion of the second semiconductor substrate includes a capacitor.
13 . The manufacturing method for a solid-state imaging apparatus according to claim 9 , wherein the method further comprises electrically coupling the first semiconductor substrate and the second semiconductor substrate only via a plurality of the through electrodes provided within a pixel region of the solid-state imaging apparatus.
14 . An electronic apparatus including a solid-state imaging apparatus, the electronic apparatus comprising:
an optical system;
a solid-state imaging apparatus that receives light from the optical system, the solid-state imaging apparatus comprising:
a first semiconductor substrate;
a second semiconductor substrate,
wherein a front surface side of the first semiconductor substrate forms a wiring layer formation surface of the first semiconductor substrate and joins to a back surface side of the second semiconductor substrate which is an opposite side of a wiring layer formation surface of the second semiconductor substrate,
wherein the first semiconductor substrate includes:
a photoelectric conversion portion that photoelectrically converts incident light;
a transfer transistor that transfers electric charges of the photoelectric conversion portion; and
a voltage conversion transistor that converts the electric charges transferred by the transfer transistor into a corresponding voltage, and
wherein the second semiconductor substrate includes a charge voltage retention portion that retains the corresponding voltage converted by the voltage conversion transistor; and
a through electrode that penetrates through the second semiconductor substrate and transmits the corresponding voltage converted by the transfer transistor to the charge voltage retention portion,
wherein the transfer transistor and the voltage conversion transistor are formed on a surface of the second semiconductor substrate, opposite a light incident side of the first semiconductor substrate and
wherein the through electrode does not penetrate through the first semiconductor substrate; and
a digital signal processor that processes signals received from the solid-state imaging apparatus.
15 . The electronic apparatus according to claim 14 , further comprising a photomask arranged between the first semiconductor substrate and the second semiconductor substrate, wherein the photomask is formed by a portion of a metal wiring provided within a wiring layer.
16 . The electronic apparatus according to claim 14 , wherein a cross-sectional diameter of the through electrode penetrating both the first semiconductor substrate and the second semiconductor substrate is less than or equal to the cross-sectional diameter of the through electrode penetrating only the second semiconductor substrate.
17 . The electronic apparatus according to claim 14 , wherein the charge voltage retention portion of the second semiconductor substrate includes a capacitor.
18 . The electronic apparatus according to claim 14 , wherein the first semiconductor substrate and the second semiconductor substrate are electrically coupled only via a plurality of the through electrodes provided within a pixel region of the solid-state imaging apparatus.
19 . The electronic apparatus according to claim 14 , further comprising a light blocking film positioned below the photoelectric conversion portion and above the through electrode throughout a length of the through electrode in a cross-sectional view.
20 . The electronic apparatus according to claim 19 , wherein the light blocking film includes tungsten.