Manufacturing method for solid-state imaging device and solid-state imaging device
10825730 ยท 2020-11-03
Assignee
Inventors
- Yasuhito Yoneta (Hamamatsu, JP)
- Ryoto Takisawa (Hamamatsu, JP)
- Shingo Ishihara (Hamamatsu, JP)
- Hisanori Suzuki (Hamamatsu, JP)
- Masaharu Muramatsu (Hamamatsu, JP)
Cpc classification
Y10T29/49124
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H01L21/77
ELECTRICITY
International classification
H01L21/77
ELECTRICITY
Abstract
A method for manufacturing a solid-state imaging device comprises a first step of preparing an imaging element having a second principal surface having an electrode arranged thereon, and a photoelectric converter part configured to photoelectrically convert the incident energy line so as to generate a signal charge; a second step of preparing a support substrate, provided with a through hole extending in a thickness direction thereof, having a third principal surface; a third step of aligning the imaging element and the support substrate with each other so that the electrode is exposed out of the through hole while the second and third principal surfaces oppose each other and joining the imaging element and the support substrate to each other; and a fourth step of arranging a conductive ball-shaped member in the through hole and electrically connecting the ball-shaped member to the electrode after the third step.
Claims
1. A method for manufacturing a solid-state imaging device, the method comprising: a first step of preparing an imaging element including a first principal surface configured to receive an energy line incident thereon, a second principal surface located on an opposite side of the imaging element from the first principal surface and having an electrode arranged thereon, and a photoelectric converter part configured to photoelectrically convert the incident energy line so as to generate a signal charge; a second step of preparing a support substrate, provided with a through hole extending in a thickness direction thereof, and having a third principal surface and a fourth principal surface located on opposite sides of the support substrate from each other, the support substrate including the through hole constituted by Si and an insulating film covering a surface of the substrate; a third step of aligning the imaging element and the support substrate with each other so that the electrode is exposed out of the through hole while the second principal surface and the third principal surface oppose each other and joining the imaging element and the support substrate to each other; and a fourth step of arranging a conductive ball-shaped member in the through hole, the conductive ball-shaped member having a diameter greater than a thickness of the support substrate as measured between the third principal surface and the fourth principal surface, and electrically connecting the conductive ball-shaped member to the electrode so that a part of the conductive ball-shaped member projects outside the fourth principal surface of the support substrate after the third step.
2. The method according to claim 1, wherein the electrode is formed with a plating film after the third step but before the fourth step.
3. The method according to claim 1, wherein the through hole is formed such that the diameter thereof increases as the through hole extends from the third principal surface to the fourth principal surface.
4. The method according to claim 1, wherein the imaging element is provided with an additional electrode; wherein, in the third step, the imaging element and the support substrate are aligned with each other so that the electrode and the additional electrode are exposed out of the through hole; and wherein the fourth step further includes arranging an additional conductive ball-shaped member in the through hole, the additional conductive ball-shaped member having a diameter greater than the thickness of the support substrate, and electrically connecting the additional conductive ball-shaped member to the additional electrode so that a part of the additional conductive ball-shaped member projects outside the fourth principal surface of the support substrate.
5. The method according to claim 1, wherein the imaging element is provided with an additional electrode; wherein the support substrate is provided with an additional through hole extending in the thickness direction of the support structure; wherein, in the third step, the imaging element and the support substrate are aligned with each other so that the electrode is exposed out of the through hole and the additional electrode is exposed out of the additional through hole; and wherein the fourth step further includes arranging an additional conductive ball-shaped member in the additional through hole, the additional conductive ball-shaped member having a diameter greater than the thickness of the support substrate, and electrically connecting the additional conductive ball-shaped member to the additional electrode so that a part of the additional conductive ball-shaped member projects outside the fourth principal surface of the support substrate.
6. The method according to claim 1, further comprising a fifth step of filling a space between the conductive ball-shaped member and the through hole with a resin material after the fourth step.
7. A method for manufacturing a solid-state imaging device, the method comprising: a first step of preparing an imaging element including a first principal surface configured to receive an energy line incident thereon, a second principal surface located on an opposite side of the imaging element from the first principal surface and having an electrode arranged thereon, and a photoelectric converter part configured to photoelectrically convert the incident energy line so as to generate a signal charge; a second step of preparing a support substrate, provided with a through hole extending in a thickness direction thereof, and having a third principal surface and a fourth principal surface located on opposite sides of the support substrate from each other; a third step of aligning the imaging element and the support substrate with each other so that the electrode is exposed out of the through hole while the second principal surface and the third principal surface oppose each other and joining the imaging element and the support substrate to each other; and a fourth step of arranging a conductive ball-shaped member in the through hole, the conductive ball-shaped member having a diameter greater than a thickness of the support substrate as measured between the third principal surface and the fourth principal surface, and electrically connecting the conductive ball-shaped member to the electrode so that a part of the conductive ball-shaped member projects outside the fourth principal surface of the support substrate after the third step, wherein the electrode and the second principal surface of the imaging element prepared by the first step are covered with a flattening film; and wherein the flattening film is partly removed after the third step but before the fourth step so as to expose at least a part of a surface of the electrode.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1) (a) of
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DESCRIPTION OF EMBODIMENTS
(22) In the following, embodiments of the present invention will be explained in detail with reference to the drawings. In the explanation, the same constituents or those having the same functions will be referred to with the same signs while omitting their overlapping descriptions.
First Embodiment
(23) With reference to
(24) As illustrated in
(25) The p-type semiconductor layer 11a has a protruded part thicker than the remaining part. The n-type semiconductor layer 11b is formed with a predetermined thickness on the protruded part. A p-n junction is formed at an interface between the p-type semiconductor layer 11a and the n-type semiconductor layer 11b. The vicinity of the interface functions as a photoelectric converter part, so as to photoelectrically convert various energy lines (e.g., light, UV rays, electron beams, radiations, charged particle beams, and the like) enter the interface, thereby generating signal charges.
(26) The p.sup.+-type semiconductor layer 11c is arranged so as not to cover principal surfaces of the n-type semiconductor layer 11b but side faces of the n-type semiconductor layer 11b and a surface of the p-type semiconductor layer 11a. The insulating layer 11d is arranged so as to cover a principal surface of the n-type semiconductor layer 11b and a surface of the p.sup.+-type semiconductor layer 11c. The insulating layer 11d is constituted by SiO.sub.2 or the like, for example. In the insulating layer 11d, the part covering the principal surface of the n-type semiconductor layer 11b is thinner than the part covering the surface of the p.sup.+-type semiconductor layer 11c.
(27) As illustrated in
(28) The AR coat 12 functions to prevent light in a predetermined wavelength band from being reflected. The AR coat 12 is constituted by SiO.sub.2, SiN or the like, for example. The AR coat 12 is formed on a surface of the p-type semiconductor layer 11a. The wiring 13 and electrodes 14 are patterned on a surface of the interlayer insulating layer 11f (a principal surface S2 of the photoelectric converter part 11). The wiring 13 and electrodes 14 are constituted by Al or the like, for example. The wiring 13 and electrodes 14 have their thicknesses set on the order of 0.1 m to 1 m, for example.
(29) As illustrated in (b) of
(30) In thus constructed imaging element 10, a region where the p-type semiconductor layer 11a, n-type semiconductor layer 11b, insulating layer 11d, and electrode films 11e are stacked functions as the light detection area A1, while the other region functions as a wiring area A2. The surface on the AR coat 12 side of the imaging element 10 functions as the principal surface S1 on which the energy line enters. The surface on the interlayer insulating layer 11f side of the imaging element 10 functions as the principal surface S2 opposing the support substrate 20.
(31) As illustrated in
(32) As illustrated in
(33) The support substrate 20 is formed with two through holes 23 extending in its thickness direction in this embodiment. As illustrated in (a) of
(34) As illustrated in (b) of
(35) The ball-shaped members 30 are conductive balls of solder, whose diameter can be set on the order of 100 m to 1000 m. The ball-shaped members 30 are arranged in the through holes 23 as illustrated in
(36) As illustrated in (b) of
(37) The electrodes 2c are patterned on the chip body 2a. The electrodes 2c are constituted by Al or the like, for example. In this embodiment, the plating films 2d are arranged on a part of principal surfaces of the electrodes 2c. The plating films 2d are constituted by Au, Ni or the like, for example. The insulating film 2e is formed so as to expose principal surfaces of the plating films 2d but cover the chip body 2a and electrodes 2c. The insulating film 2e is constituted by SiO.sub.2 or the like, for example.
(38) For securely fixing the ball-shaped members 30 into the through holes 23 and reliably securing the solid-state imaging device 1A and the IC chip to each other, a resin material 40 fills the through holes 23 and the interstices between the solid-state imaging device 1A and the IC chip 2. As the resin material, an epoxy resin or the like can be used, for example.
(39) With reference to
(40) Next, by so-called LOCOS process, p-type impurities are added onto the epi-wafer (p-type semiconductor layer 11a) by ion implantation using an Si.sub.3N.sub.4 film (not depicted) as a mask, so as to form the p.sup.+-type semiconductor layer 11c. Subsequently, using the same Si.sub.3N.sub.4 film as a mask, the insulating layer 11d is formed by oxidation. After removing the Si.sub.3N.sub.4 film, the n-type semiconductor layer 11b is formed by adding n-type impurities by ion implantation, and the electrode films 11e and the interlayer insulating layer 11f are layered thereon in this order. At this time, a plurality of belt-like electrode films 11e are formed so that end parts of the electrode films 11e adjacent to each other overlap as seen in the thickness direction of the imaging element 10 (see
(41) Subsequently, as illustrated in
(42) Next, as illustrated in (c) of
(43) Subsequently, the substrate 11g in the precursor 1Aa is removed by etching, polishing, or the like, so as to expose the p-type semiconductor layer 11a. Here, the thickness from the p-type semiconductor layer 11a to the flattening film 16 is set on the order of 10 m to 30 m, for example. This forms a precursor 1Ab for the solid-state imaging device 1A illustrated in (f) of
(44) Next, the plating films 15 are formed so as to cover the exposed electrodes 14. This forms a precursor 1Ad for the solid-state imaging device 1A illustrated in
(45) Subsequently, the solid-state imaging device 1A is mounted on the IC chip 2. Specifically, the ball-shaped members 30 and the electrodes 2c of the IC chip 2 are aligned with each other and joined to each other by flip-chip bonding. As a consequence, the solid-state imaging device 1A and the IC chip 2 are electrically connected to each other through the ball-shaped members 30. Then, the resin material 40 is caused to fill the through holes 23 and the interstices between the solid-state imaging device 1A and the IC chip 2. This completes the electronic component 3 illustrated in
(46) In thus configured first embodiment, the ball-shaped members 30 are arranged in the through holes 23 of the support substrate 20 joined to the imaging element 10, and the ball-shaped members 30 and the electrodes 14 are electrically connected to each other. Therefore, the electrical connection step is easy when manufacturing the solid-state imaging device 1A. Hence, the solid-state imaging device 1A can be manufactured easily, and the yield can be improved.
(47) Meanwhile, the conventional method for manufacturing a solid-state imaging device includes the steps of joining a sensor to a support substrate, forming a resist pattern on the other principal surface of the support substrate, forming a through hole by etching the support substrate from the other principal surface side, and forming a through electrode by filling the through hole with a metal. For securing insulation between the support substrate (the inner wall surface of the through hole) and the electrode when forming the electrode in the through hole, it is necessary for a high-quality oxide film having a uniform thickness to be formed on the inner wall surface of the through hole by a method such as CVD (Chemical Vapor Deposition) or the like, for example. In this case, however, it takes a high degree of difficulty to obtain an insulating film with a sufficient quality, whereby reliability is hard to secure.
(48) By contrast, the first embodiment can prepare a high-quality oxide film having a uniform thickness beforehand on the inner wall surfaces of the through holes 23 of the support substrate 20 by thermal oxidation or the like. Therefore, sufficient insulation can be secured between the support substrate 20 (the inner wall surfaces of the through holes 23) and the electrodes, whereby the highly reliable solid-state imaging device 1A can be obtained.
(49) The first embodiment forms the electrodes 14 with the plating films 15. Therefore, the ball-shaped members 30 can be connected to the electrodes 14 more securely through the plating films 15.
(50) In the first embodiment, the through holes 23 is formed such that the diameter thereof increases as the through hole 23 extends from the principal surface S3 to the principal surface S4. This makes it easier to arrange the ball-shaped members 30 in the through holes 23.
(51) In the first embodiment, the resin material 40 is arranged in the through holes 23. Therefore, the ball-shaped members 30 can securely be fixed into the through holes 23 by the resin material 40.
(52) In the first embodiment, the solid-state imaging device 1A further comprises the flattening film 16 for covering the surface of the interlayer insulating layer 11f and the wiring 13. Hence, the surface of the imaging element 10 is flattened by the flattening film 16, whereby the joint between the imaging element 10 and the support substrate 20 becomes more secure.
Second Embodiment
(53) With reference to
(54) As illustrated in
(55) As illustrated in (b) of
(56) A method for manufacturing the electronic component 3 equipped with the solid-state imaging device 1B in accordance with the second embodiment will now be explained with reference to
(57) Next, as illustrated in (c) of
(58) Subsequently, the substrate 11g in the precursor 1Ba is removed by etching, polishing, or the like, so as to expose the p-type semiconductor layer 11a. This forms a precursor 1Bb for the solid-state imaging device 1B illustrated in (f) of
(59) Next, the plating films 15 are formed so as to cover the exposed electrodes 14. This forms a precursor 1Bd for the solid-state imaging device LB illustrated in
(60) Subsequently, the solid-state imaging device 1B is mounted on the IC chip 2. Specifically, the ball-shaped members 30 and the electrodes 2c of the IC chip 2 are aligned with each other and joined to each other by flip-chip bonding. As a consequence, the solid-state imaging device 1B and the IC chip 2 are electrically connected to each other through the ball-shaped members 30. Then, the resin material 40 fills the through holes 23 and the interstices between the solid-state imaging device 1B and the IC chip 2. This completes the electronic component 3 illustrated in
(61) Thus configured solid-state imaging device 1B in accordance with the second embodiment exhibits the same operations and effects as with the solid-state imaging device 1A in accordance with the first embodiment.
(62) In the second embodiment, the through holes 23 is formed such that the diameter thereof increases as the through hole 23 extends from the principal surface S3 to the principal surface S4. This makes it easier to arrange the ball-shaped members 30 in the through holes 23. In the second embodiment, the ball-shaped member 30 abuts against each inner wall surface of the through hole 23 and thus is stabilized in the through hole 23. The step of aligning the ball-shaped member 30 with the electrode 2c also becomes easier.
(63) In the second embodiment, the support substrate 20 is provided with a plurality of through holes 23, while the electrodes 14 (plating films 15) correspond to the through holes 23 individually. Therefore, simply arranging the ball-shaped members 30 individually in the through holes 23 can easily make the ball-shaped members 30 and the electrodes 14 correspond to each other.
(64) While embodiments of the present invention are explained in detail in the foregoing, the present invention is not limited to the above-mentioned embodiments. For example, the flattening film 16, which is flattened by CMP in the above-mentioned embodiments, is not required to be flattened by CMP when the imaging element 10 and the support substrate 20 are bonded to each other by an adhesive or the like, since the flatness required for the bonding surfaces in this case is not so high as that in the ambient temperature bonding.
(65) The flattening film 16 disposed on the principal surface S2 of the photoelectric converter part 11 in the above-mentioned embodiments may be omitted.
(66) The through holes 23, which is formed such that the diameter thereof increases as the through hole 23 extends from the principal surface S3 to the principal surface S4 in the above-mentioned embodiments, may have a fixed size of openings in their extending direction. The through holes 23 may narrow from the principal surface S3 to the principal surface S4.
(67) While the above-mentioned embodiments fill the through holes 23 and the interstices between the solid-state imaging device 1A, 1B and the IC chip 2 with the resin material 40 after electrically connecting the solid-state imaging device 1A, 1B and the IC chip 2 to each other, the interstices between the solid-state imaging device 1A, 1B and the IC chip 2 may be filled with the resin material 40 after electrically connecting the solid-state imaging device 1A, 1B having the through holes 23 filled beforehand with the resin material 40 to the IC chip.
(68) The through holes 23 and the interstices between the solid-state imaging device 1A, 1B and the IC chip 2, which are filled with the resin material 40 in the above-mentioned embodiments, may be free of the resin material 40.
(69) The ball-shaped member 30, which is spherical in the above-mentioned embodiments, may partly have a spherical surface.
(70) While the above-mentioned embodiments are explained in terms of a CCD-type solid-state imaging device as a solid-state imaging device by way of example, it is needless to mention that the present invention is employable in various back-illuminated light-receiving element arrays such as CMOS-type solid-state imaging devices without being limited to CCD-type solid-state imaging devices.
REFERENCE SIGNS LIST
(71) 1A, 1B . . . solid-state imaging device; 2 . . . IC chip; 3 . . . electronic component; 10 . . . imaging element; 11 . . . photoelectric converter part; 14 . . . electrode; 15 . . . plating film; 16 . . . flattening film; 20 . . . support substrate; 23 . . . through hole; 30 . . . ball-shaped member; 40 . . . resin material; S1, S2, S3, S4 . . . principal surface.