JP6433532B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device including a plurality of element portions.

  In a photoelectric conversion device such as a CMOS image sensor which is a kind of semiconductor device, a photoelectric conversion unit having a plurality of photoelectric conversion elements and a signal processing unit for processing an electric signal from the photoelectric conversion unit are monolithically formed on one semiconductor substrate. I made it. It has been studied that the photoelectric conversion unit and the signal processing unit are separately formed into separate parts (chips), these parts are stacked, and the parts are electrically connected by a conductive member. By doing in this way, the occupation area (footprint) of the photoelectric conversion apparatus in the electronic device in which the photoelectric conversion apparatus is mounted can be efficiently utilized. In order to obtain an electrical connection between the parts, a conductive member is provided. Such a structure can be applied to various semiconductor devices that realize a so-called system-in-package.

  Patent Document 1 describes that inter-substrate wiring (68) is provided as a conductive member for obtaining electrical connection between semiconductor substrates (31, 45) corresponding to components.

JP 2011-096851 A

  When the inter-substrate wiring of Patent Document 1 is formed of copper, copper contained in the inter-substrate wiring may diffuse into the semiconductor well region (32) and the interlayer insulating film (39) surrounding the inter-substrate wiring. As a result, the semiconductor device may not operate normally, or the desired performance may not be obtained due to contamination with copper, and there is a problem that sufficient reliability cannot be obtained. An object of the present invention is to provide a highly reliable semiconductor device.

  Means for solving the problems include a first element portion including a first semiconductor layer, a first conductor layer, and a first insulator layer positioned between the first semiconductor layer and the first conductor layer. A second wiring layer, a second element portion including a second semiconductor layer, a second conductor layer, and a second insulator layer positioned between the second semiconductor layer and the second conductor layer. And the second wiring part is located between the first element part and the second element part and between the first wiring part and the second element part. The semiconductor device further includes a conductive member that penetrates the first semiconductor layer and the first insulator layer and connects the first conductor layer and the second conductor layer, and the conductive member includes: A first region containing a metal having a diffusion coefficient with respect to the first semiconductor layer greater than a diffusion coefficient of oxygen with respect to the first semiconductor layer; And a second region containing a material different from the metal is located at least between the first region and the first semiconductor layer and between the first region and the first insulator layer. The diffusion coefficient of the metal with respect to the material is lower than the diffusion coefficient of the metal with respect to the first semiconductor layer and the diffusion coefficient of the metal with respect to the first insulator layer.

  According to the present invention, a highly reliable semiconductor device can be provided.

1 is a schematic diagram of an example of a semiconductor device. 1 is a schematic diagram of an example of a semiconductor device. The schematic diagram of an example of the manufacturing method of a semiconductor device. The schematic diagram of an example of the manufacturing method of a semiconductor device. The schematic diagram of an example of the manufacturing method of a semiconductor device. The schematic diagram of another example of the manufacturing method of a semiconductor device. The schematic diagram of another example of the manufacturing method of a semiconductor device.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the following description, a plurality of drawings may be referred to each other. The same or similar components are denoted by common reference numerals, and the description of the components denoted by the common reference numerals is omitted as appropriate.

<First Embodiment>
A photoelectric conversion device as an example of the semiconductor device of this embodiment will be described with reference to FIG. FIG. 1A is a perspective view of a semiconductor device 1 which is a main part of the semiconductor device. FIGS. 1B and 1C are exploded perspective views of an example of the semiconductor device 1. FIG. 1D is a schematic diagram of an electronic apparatus 5 including a semiconductor device 3 including the semiconductor device 1.

  In the semiconductor device 1 shown in FIG. 1A, as shown in FIG. 1B or FIG. 1C, the first portion 10 and the second portion 20 overlap. The present embodiment mainly relates to a conductive member for obtaining an electrical connection between the first portion 10 and the second portion 20. As shown in FIG. 1A, the first portion 10 includes a first element portion 30 and a first wiring portion 31. The second portion 20 includes a second element unit 50 and a second wiring unit 51. The second wiring part 51 is located between the first part 10 and the second element part 50. That is, the second wiring part 51 is located between the first element part 30 and the second element part 50, and the second wiring part 51 is located between the first wiring part 31 and the second element part 50. In the present embodiment, the first wiring part 31 is located between the first element part 30 and the second part 20, but the first element part 30 is located between the first wiring part 31 and the second part 20. May be.

  In the present embodiment, the first portion 10 includes a photoelectric conversion unit 11. The photoelectric conversion unit 11 includes a photoelectric conversion element that generates signal charges in response to incident light. The photoelectric conversion unit 11 may include a signal generation circuit that generates an electric signal based on signal charges generated by the photoelectric conversion element. The signal generation circuit includes, for example, an amplification transistor, a transfer transistor, a reset transistor, and a selection transistor. The photoelectric conversion unit 11 of another example may include a CCD (Charge Coupled Device) for transferring signal charges with the photoelectric conversion element.

  In the present embodiment, the second portion 20 includes a signal processing unit 22. The signal processing unit 22 processes an electrical signal based on the signal charge generated by the photoelectric conversion unit 11. The signal processing unit 22 can include a noise removal circuit, an amplification circuit, a conversion circuit, and an image processing circuit. The noise removal circuit is, for example, a CDS (Correlated Double Sampling) circuit. The amplifier circuit is, for example, a column amplifier circuit. The conversion circuit is, for example, an ADC (Analog Digital Converter) circuit including a comparator and a counter. The image processing circuit includes, for example, a memory and a processor, and generates image data from a digital signal subjected to analog-digital conversion, and performs image processing on the image data.

  In FIG. 1A, the position of the photoelectric conversion unit 11 is surrounded by a one-dot chain line, and the position of the signal processing unit 22 is surrounded by a two-dot chain line. The signal processing unit 22 is located in the orthogonal projection region of the photoelectric conversion unit 11 onto the second portion 20. The signal processing unit 22 can be arranged regardless of the inside or outside of the orthogonal projection region of the photoelectric conversion unit 11. A part of the signal processing unit 22 may be provided in the first portion 10. For example, a signal processing unit for analog signals such as a noise removal circuit and an amplifier circuit may be provided in the first portion 10, and a signal processing unit for digital signals such as a conversion circuit and an image processing circuit may be provided in the second portion 20.

  As shown in FIGS. 1B and 1C, the semiconductor device 1 can further include a control unit 12 that controls the photoelectric conversion unit 11 and / or a control unit 21 that controls the signal processing unit 22. . These control units can be provided in at least one of the first portion 10 and the second portion 20. In the example shown in FIG. 1B, the control unit 12 is provided in the first portion 10, and in the example shown in FIG. 1C, the control unit 21 is provided in the second portion 20. The control unit for the photoelectric conversion unit 11 can be provided in the first part 10 and the control unit for the signal processing unit 22 can be provided in the second part 20 separately. The control unit 12 may include a vertical driving circuit that supplies a driving signal to the pixel circuit via a vertical scanning line, and a power supply circuit. The control unit 21 may include a timing generation circuit for driving the signal processing unit 22, a reference signal supply circuit for supplying a reference signal to the conversion circuit, an amplifying circuit, or a horizontal scanning circuit for sequentially reading signals from the conversion circuit.

  As shown in FIG. 1D, the semiconductor device 3 can include a package 2 as a mounting member for primary mounting of the semiconductor device 1. The semiconductor device 1 can be die-bonded and accommodated in this package. The package 2 may include external terminals such as PGA (Pin Grid Array), LGA (Land Grid Array), BGA (Ball Grid Array), and lead frame. As shown in FIG. 1D, the semiconductor device 3 can include a circuit board 4 as a mounting member for secondary mounting. The package 2 can be mounted on the circuit board 4. The circuit board 4 may be a printed board such as a rigid board, a flexible board, or a rigid flexible board. The semiconductor device 3 as a photoelectric conversion device can be a camera module including an optical system for guiding light to the semiconductor device 1.

  The semiconductor device 3 can be mounted on various electronic devices. In addition to the semiconductor device 3, the electronic device 5 includes a peripheral device 6 such as an arithmetic device, a storage device, a recording device, a communication device, or a display device. These peripheral devices are connected to the semiconductor device 3 and exchange signals directly or indirectly. Examples of the electronic device 5 include information terminals such as mobile phones and personal computers, and video devices such as cameras and displays. Of course, an information terminal with a camera is also included.

  Details of an example of the semiconductor device 1 will be described with reference to FIG. FIG. 2 is a cross-sectional view of the semiconductor device 1 in a plane including the points P and Q shown in FIG. 2 is an example having a control unit 12 as shown in FIG.

  In the following description, it is assumed that the conductor layer is made of a material having higher conductivity than the semiconductor layer, and the insulator layer is made of a material having lower conductivity than the semiconductor layer.

  In the following description of semiconductor compounds and metal compounds, carbonitrides and oxynitrides are included in nitrides, and nitrided carbides and oxycarbides are included in carbides.

  First, regarding the first portion 10, the configurations of the first element unit 30 and the first wiring unit 31 will be described.

  The first element unit 30 includes a first semiconductor layer 33. The first semiconductor layer 33 is, for example, a silicon layer. The first element unit 30 includes a photodiode PD, which is a photoelectric conversion element, provided in the first semiconductor layer 33 as a semiconductor element constituting the photoelectric conversion unit 11 in FIG. In the photodiode PD, the first semiconductor layer 33 includes an n-type semiconductor region 34 and a p-type semiconductor region 35. In addition, the first semiconductor layer 33 has a p-type semiconductor region 32. The photoelectric conversion element may be a photogate. The signal generation circuit that can be included in the photoelectric conversion unit 11 can be configured by a semiconductor element such as a MOS transistor. FIG. 2 shows the transfer transistor Tr1 and the reset transistor Tr2 of the photoelectric conversion unit 11. Also, transistors Tr3 and Tr4 are shown as semiconductor elements of the control unit 12 in FIG.

  In this example, a part of the surface 103 of the first semiconductor layer 33 constituting the first element unit 30 forms an interface with the gate insulating films of the MOS transistors Tr1, Tr2, Tr3, Tr4. The first element unit 30 is provided with an element isolation 38 such as STI (Shallow Trench Isolation) or LOCOS (LOCal Oxidation of Silicon). The first element unit 30 is provided with a first protective film (not shown) made of an insulating layer such as silicon nitride or silicon oxide that protects the surface 103 of the first semiconductor layer 33. As described above, the first element unit 30 may include the element isolation 38, the gate insulating film, the gate electrode, and the first protective film in addition to the first semiconductor layer 33.

  The first wiring part 31 includes a conductor layer and an insulator layer. The first wiring unit 31 can have a plurality of wiring levels. One wiring level can have a wiring pattern and a plug. A typical conductor layer constitutes a wiring pattern. Furthermore, a typical conductor layer constitutes a main conductive layer having a large current density in the wiring pattern, but the conductor layer constitutes a sub conductive layer having a current density lower than that of the main conductive layer in the wiring pattern. There is also. The conductor layer may constitute a via plug for obtaining conduction with the lower wiring level (wiring level on the semiconductor layer side) or a contact plug for obtaining conduction with the first element unit 30 in some cases.

  Via plugs and contact plugs can also be composed of a main conductive layer and a sub conductive layer. These sub-conductive layers can typically be barrier metals. The barrier function of the barrier metal includes a barrier against diffusion between the main conductive layer and the insulator layer, or a barrier against reaction between the main conductive layer and the insulator layer. However, “barrier metal” is a convenient name given to the sub-conductive layer and does not necessarily have any barrier function. Even when these barrier functions are not required, the barrier metal can be used simply as a base for forming the main conductive layer or for the purpose of mitigating electromigration or stress migration.

  The insulator layer can function as an inter-wiring insulating layer that insulates wiring patterns at the same wiring level and / or an interlayer insulating layer that insulates wiring patterns at different wiring levels. The first wiring unit 31 has a large number of electrical paths (wirings) configured at two or more wiring levels. One wiring can be composed of a contact plug, a via plug, and a wiring pattern.

  A detailed configuration of the first wiring unit 31 will be described. The first wiring part 31 is provided with contact plugs 44a, wiring patterns 40a, 40b, 40c and via plugs 44b, 44c. These contact plugs, wiring patterns, and via plugs formed of a conductor layer constitute a large number of electrical paths. The contact plug 44a is mainly made of a tungsten layer, and has a barrier metal including a titanium layer and / or a titanium nitride layer in addition to the tungsten layer. The wiring patterns 40a, 40b, 40c and the via plugs 44b, 44c are mainly made of a copper layer, and have a barrier metal including a tantalum nitride layer and / or a tantalum layer in addition to the copper layer. The wiring pattern 40a is composed of one copper layer, and the wiring pattern 40b and the via plug 44b, and the wiring pattern 40c and the via plug 44c are integrally composed of one copper layer. The first wiring 311 of this example includes a wiring pattern 40c, and the contact plug 44a, the wiring patterns 40a and 40b, and the via plugs 44b and 44c are connected to the semiconductor element Tr4 provided in the first element unit 30. Connected through.

  The first wiring portion 31 is provided with insulator layers 39a, 39b, 39c, 39d, and 39e made of silicon oxide as an interlayer insulating layer or an inter-wiring insulating layer. The insulator layer 39b is an inter-wiring insulating layer for the wiring pattern 40a. The insulator layers 39a, 39b, 39c, and 39d are located between the wiring pattern 40c and the first semiconductor layer 33. The wiring pattern 40 c is located between the insulator layer 39 e and the first semiconductor layer 33. The first wiring portion 31 can further include an insulator layer (not shown) made of silicon nitride, silicon carbide, or the like as a copper diffusion prevention layer contained in the wiring patterns 40a, 40b, and 40c. These can be arranged between the interlayer insulating layer and the wiring pattern. The diffusion prevention layer may be thinner than the interlayer insulating layer or the inter-wiring insulating layer.

  Next, regarding the second portion 20, the configurations of the second element unit 50 and the second wiring unit 51 will be described.

  The second element unit 50 includes a second semiconductor layer 55 and includes MOS transistors Tr5, Tr6, Tr7, Tr8 as semiconductor elements constituting the signal processing unit 22. In this example, a part of the surface 203 of the second semiconductor layer 55 forms an interface with the gate insulating films of the MOS transistors Tr5, Tr6, Tr7, Tr8. The second element unit 50 is provided with an element isolation 58 such as STI or LOCOS. The second element unit 50 is provided with a second protective film (not shown) made of an insulator such as silicon nitride or silicon oxide that protects the surface 203 of the second semiconductor layer 55. In addition to the second semiconductor layer 55, the second element unit 50 may include an element isolation 58, a gate insulating film, a gate electrode, and a second protective film.

  The second wiring part 51 includes a conductor layer and an insulator layer. The conductor layer and the insulator layer of the second wiring part 51 also have the same functions as the conductor layer and the insulator layer of the first wiring part 31.

  A detailed configuration of the second wiring unit 51 will be described. The second wiring portion 51 is provided with a contact plug 54a, a plurality of wiring patterns 53a, 53b, 53c and via plugs 54b, 54c. These contact plugs, wiring patterns, and via plugs formed of a conductor layer constitute a large number of electrical paths. The contact plug 54a and the via plug 54c are mainly made of a tungsten layer, and have a barrier metal including a titanium layer and / or a titanium nitride layer in addition to the tungsten layer. The wiring patterns 53a and 53b and the via plug 54b are mainly made of a copper layer, and have a barrier metal including a tantalum nitride layer and / or a tantalum layer in addition to the copper layer. The wiring pattern 53a includes one copper layer. The wiring pattern 53b and the via plug 54b are integrally formed of one copper layer. The wiring pattern 53c is mainly made of an aluminum layer, and has a barrier metal including a titanium layer and / or a titanium nitride layer in addition to the aluminum layer. The second wiring 512 of this example includes a wiring pattern 53c, and the contact plug 54a, the wiring patterns 53a and 53b, and the via plugs 54b and 54c are connected to the semiconductor element Tr5 provided in the second element unit 50. Connected through.

  The second wiring portion 51 is provided with insulator layers 49a, 49b, 49c, 49d, and 49e made of silicon oxide as an interlayer insulating layer and an inter-wiring insulating layer. The insulator layer 49b is an inter-wiring insulating layer for the wiring pattern 53a. The insulator layers 49a, 49b, 49c, and 49d are located between the wiring pattern 53c and the second semiconductor layer 55. The wiring pattern 53 c is located between the insulator layer 49 e and the second semiconductor layer 55. The second wiring portion 51 can further include an insulator layer (not shown) made of silicon nitride or silicon carbide as a copper diffusion prevention layer contained in the wiring patterns 53a and 53b. These can be arranged between the interlayer insulating layer and the wiring pattern.

  In the wiring patterns 40a, 40b, 40c, 53a, 53b and the plugs 44a, 44b, 44c, 54a, 54b, 54c, the copper layer, the tungsten layer, and the aluminum layer function as a main conductive layer having high conductivity in the wiring. The main conductive layer is made of a material having higher conductivity than a sub-conductive layer such as a tantalum layer, a tantalum nitride layer, a titanium layer, or a titanium nitride layer used for the barrier metal, and has a larger cross-sectional area in the direction in which a current flows.

  Although the wiring pattern 40a, 40b, 40c, 53a, 53b has shown the example which mainly consists of a copper layer, the wiring pattern which mainly consists of an aluminum layer like the wiring pattern 53c can also be employ | adopted for these. The copper layer and the aluminum layer may be not only single copper or aluminum but also an alloy to which other metals are added. For example, the copper layer may contain less aluminum, silicon, or the like than copper, and the aluminum layer may contain less copper, silicon, or the like than aluminum. Insulator layers 39a, 39b, 39c, 39d1, 39d2, 39e, 49a, 49b, 49c, 49d, and 49e are examples made of silicon oxide. However, silicate glasses such as BSG, PSG, and BPSG may be used. it can. Alternatively, a material having a lower dielectric constant than silicon oxide (low-k material) can be used.

  The example in which the wiring pattern of the first wiring part 31 is three levels of wiring patterns 40a, 40b, and 40c and the wiring pattern of the second wiring part 51 is three levels of 53a, 53b, and 53c is shown. However, the number of levels of the wiring pattern can be set as appropriate, and may be different between the first wiring part 31 and the second wiring part 51. For example, the number of levels of the wiring pattern of the second wiring unit 51 may be larger than the number of levels of the wiring pattern of the first wiring unit 31.

  Subsequently, another structure of the electronic device 1 will be described.

  The first portion 10 and the second portion 20 are joined by the first wiring portion 31 and the second wiring portion 51. The insulator layer 39e of the first wiring part 31 and the insulator layer 49e of the second wiring part 51 are joined via the joint surface 60. Thereby, the insulator layer 39e and the insulator layer 49e are located between the first wiring 311 and the second wiring 512 (between the wiring pattern 40c and the wiring pattern 53c).

  The semiconductor device 1 of this example is a back-illuminated photoelectric conversion device in which a surface (back surface 104) opposite to the surface (front surface 103) on which the transistors Tr1 to 4 of the first semiconductor layer 33 are provided is a light receiving surface. Configure. In the back-illuminated photoelectric conversion device, the thickness of the first semiconductor layer 33 of the first portion 10 is less than 10 μm, for example, 2 to 5 μm. The second semiconductor layer 55 is thicker than the first semiconductor layer 33, and the second semiconductor layer 55 functions as a support for the first semiconductor layer 33. The thickness of the second semiconductor layer 55 is 10 μm or more, for example, 20 to 500 μm.

  An optical member 41 is provided on the back surface 104 side of the first semiconductor layer 33.

  The optical member 41 can include an antireflection layer 61, an insulator layer 62, a light shielding layer 63, an insulator layer 69, a planarizing layer 71, a color filter array 73, and a microlens array 74. The optical member 41 is in contact with the back surface 104 of the first semiconductor layer 33 constituting the light receiving surface of the first element unit 30. The surface 401 of the optical member 41 opposite to the surface on the first element unit 30 side is the light incident surface of the optical member 41. In this example, the light incident surface is constituted by a microlens array 74.

  The electrode pads 78 are arranged on the same level as the wiring pattern 53c. On the electrode pad 78, an opening 77 that penetrates the plurality of insulator layers, the first semiconductor layer 33, and the optical member 41 is provided. A bonding wire 79 connected to the electrode pad 78 is provided in the opening 77. Wire bonding is connected to the internal terminals of the package. Note that the connection between the semiconductor device 1 and the package is not limited to wire bonding, and flip-chip connection can also be used.

  The semiconductor device 1 is provided with a conductive member 68 that connects the first wiring 311 and the second wiring 512 to each other. The conductive member 68 of the present embodiment includes a first through part 65, a second through part 66, and a connecting part 67 that connects them.

  The first penetration part 65 penetrates the first element part 30 and is connected to the first wiring 311 of the first wiring part 31. The second penetration part 66 penetrates the first element part 30 and the first wiring part 31 and is connected to the second wiring part 51 of the second part 20. Although the first penetrating portion 65 penetrates the first element portion 30, the first wiring portion 31 does not penetrate, and therefore does not penetrate the first portion 10. On the other hand, the second penetrating portion 66 penetrates the first portion 10 because it penetrates the first element portion 30 and the first wiring portion 31. In order to achieve electrical connection between the first wiring 311 and the second wiring 512, the first through portion 65, the second through portion 66, and the connecting portion 67 are made of a conductive material. It may be configured.

  As another form of the conductive member 68, a form in which the first through part 65 and the second through part 66 are integrated may be mentioned. For such a configuration, refer to the through-connection conductor (84) described in FIG. 15 of Japanese Patent Application Laid-Open No. 2010-245506 and the inter-substrate wiring (80) described in FIG. 21 of Japanese Patent Application Laid-Open No. 2011-96851. can do.

  Further, in this example, the first through portion 65 is in contact with the wiring pattern 40c, and the second through portion 66 is in contact with the wiring pattern 53c. However, the present invention is not limited thereto, and the first through portion 65 may be in contact with any one or a plurality of wiring patterns 40a, 40b, and 40c, and the second through portion 66 may be any one of the wiring patterns 53a, 53b, and 53c. Or you may contact several. Further, the first through portion 65 and the second through portion 66 may be in contact with the conductive layer (copper layer or aluminum layer) of the wiring pattern, or the barrier metal layer (titanium layer or titanium nitride layer, etc.) of the wiring pattern. In some cases, it may contact the tantalum layer. In some cases, the conductor layer may be in contact with the conductor layer of the barrier metal of the wiring pattern.

  The conductive member 68 is surrounded by an insulating region 42 provided in the first semiconductor layer 33. The insulating region 42 may be a gas or vacuum region. The photoelectric conversion unit 11 and the signal processing unit 22, the photoelectric conversion unit 11 and the control unit 21, and the control unit 12 and the signal processing unit 22 are electrically connected by the conductive member 68. A block 90 shown in FIG. 2 shows a region including the conductive member 68, the first wiring 311, the second wiring 512, and the insulating region 42 related to the connection between the parts. A plurality of the blocks 90 are preferably arranged in parallel. By arranging a plurality of blocks 90 in parallel, a signal for each column or row of the photoelectric conversion unit 11 is transferred to the signal processing unit 22, and the signal processing unit 22 is based on signal charges generated by the photoelectric conversion unit 11. The signal can be processed. Further, the blocks 90 may be arranged in columns, or the columns and parallel may be used in combination.

  A cap layer 70 made of silicon nitride, silicon carbide, or the like is provided on the conductive member 68. The cap layer 70 can function as a protective layer that prevents corrosion of the conductive member 68 from moisture from the outside.

  The above is an example of the configuration of the semiconductor device 1. These configurations can be changed as appropriate.

  Hereinafter, the conductive member 68 will be described in detail.

  The conductive member 68 of the present embodiment contains a metal having a diffusion coefficient of the first semiconductor layer 33 with respect to the semiconductor (silicon) larger than that of oxygen with respect to the semiconductor (silicon). Hereinafter, such a metal is defined as an “easy diffusible metal”. This easily diffusible metal can function as a conductive material for achieving electrical connection between the first wiring 311 and the second wiring 512. A region containing a readily diffusible metal in the conductive member 68 will be referred to as a readily diffusible metal region 681 (first region).

  The larger the diffusion coefficient, the easier it is to diffuse into the material of interest. Although the diffusion coefficient may have temperature dependence, the temperature at which the diffusion coefficient should be compared is within the temperature range at which the conductive member 68 is exposed when the semiconductor device 1 is manufactured or used. Comparison of the diffusion coefficient with oxygen at a temperature at which the conductive member 68 cannot be exposed does not make sense. Since the first semiconductor layer 33 in this example is a silicon layer, the relative relationship of the diffusion coefficient of a general material with respect to silicon will be exemplified. Gold, silver, copper, nickel, iron, and zinc are mentioned as a metal whose diffusion coefficient with respect to silicon is larger than the diffusion coefficient of oxygen with respect to silicon. Aluminum, tungsten, bismuth, and tin are mentioned as a metal whose diffusion coefficient with respect to silicon is smaller than the diffusion coefficient of oxygen with respect to silicon. In addition, hydrogen and sulfur are mentioned as a nonmetal and a semimetal whose diffusion coefficient with respect to silicon is larger than the diffusion coefficient of oxygen with respect to silicon. Nonmetals and metalloids having a diffusion coefficient for silicon smaller than that of oxygen for silicon include carbon, boron, arsenic, antimony, and phosphorus.

  A diffusion barrier region 682 (second region) that suppresses diffusion of the easily diffusible metal from the easily diffusible metal region 681 to the nearby region located in the vicinity thereof is formed between the easily diffusible metal region 681 and the nearby region. It is provided in between. The layer as the vicinity region located in the vicinity of the easily diffusible metal region 681 can be the first semiconductor layer 33 through which the first through portion 65 and the second through portion 66 of the conductive member 68 penetrate. Further, the layer as the vicinity region can be an insulator layer 39a, 39b, 39c, 39d (first insulator layer) provided as an interlayer insulating layer in the first wiring portion 31. Further, the layer as the vicinity region is provided in the insulator layer 39e (third insulator layer) provided in the first wiring part 31 or the second wiring part 51 through which the second penetration part 65 of the conductive member 68 passes. The insulating layer 49e (third insulating layer) may be formed. Alternatively, the layer as the neighborhood region may be the first semiconductor layer 33 with the back surface 104 facing the connecting portion 67. In addition, the layer as the vicinity region can be a conductor layer (first conductor layer) of the wiring pattern 40 c of the first wiring 311 with which the first through portion 65 of the conductive member 68 contacts. In addition, the layer as the vicinity region may be a conductor layer (second conductor layer) of the wiring pattern 53c of the second wiring 512 with which the second through portion 65 of the conductive member 68 contacts. Alternatively, it may be an insulator layer 49a, 49b, 49c, 49d (second insulator layer) provided between the wiring pattern 53c and the second semiconductor layer 55.

  When these first penetration part 65 and second penetration part 66 have the easily diffusible metal region 681, the diffusion barrier region 682 is located between the easily diffusible metal region 681 and the nearby region. The diffusion barrier region 682 contains one or more types of diffusion barrier materials. The diffusion barrier material is a material different from the easily diffusible metal.

  The diffusion coefficient of the easily diffusible metal with respect to the diffusion barrier material is lower than the diffusion coefficient of the easily diffusible metal with respect to the semiconductor (silicon). The diffusion coefficient of the easily diffusible metal with respect to the diffusion barrier material is lower than the diffusion coefficient of the easily diffusible metal with respect to the insulator (silicon oxide) of the first insulator layer. Simply put, diffusible metals are less diffusible to diffusion barrier materials than semiconductors and insulators in the vicinity. When the easily diffusible metal is gold, silver or copper, the semiconductor in the neighboring region is silicon, and the insulator is silicon oxide, the diffusion barrier material is tantalum, tantalum nitride, tantalum carbide, titanium, titanium nitride, titanium carbide, tungsten , Tungsten nitride, tungsten carbide, manganese, silicon nitride, and silicon carbide. Thus, the diffusion barrier material is preferably a metal, metal nitride, metal carbide, semiconductor nitride, or semiconductor carbide.

  As described above, the first wiring portion 31 can have an insulator layer as a diffusion prevention layer for wiring materials such as a silicon nitride layer and a silicon carbide layer, in addition to the silicon oxide layer. The diffusion coefficient of the easily diffusible metal with respect to the diffusion barrier material is preferably less than or equal to the diffusion coefficient of the easily diffusible metal with respect to the insulator (silicon nitride or silicon carbide) of these diffusion prevention layers, but this need not be the case. The material of the diffusion preventing layer and the diffusion barrier material of the diffusion barrier region 681 may be the same. If the thickness of the diffusion preventing layer is smaller than that of the interlayer insulating layer, the influence of diffusion of the easily diffusible metal in the conductive member 68 on the diffusion preventing layer may not be considered.

  In this example, the conductive member 68 includes a diffusion barrier region 682 that suppresses diffusion of copper, which is a readily diffusible metal contained in the conductive member 68, into the first portion 10. In this example, the easily diffusible metal whose diffusion is prevented by the diffusion barrier region 682 is copper. The easily diffusible metal is silicon that is the material of the first semiconductor layer 33 that constitutes most of the first element portion 30, and silicon oxide that is the material of the insulator layers 39 a to 39 e that constitute most of the first wiring portion 31. It is easy to diffuse in. The diffusion coefficient of the easily diffusible metal with respect to the diffusion barrier region 682 is smaller than the diffusion coefficient of the easily diffusible metal with respect to the material (silicon) of the first semiconductor layer 33 and its oxide (silicon oxide).

  The arrangement of the diffusion barrier region 682 will be described in detail. A part (first part) of the diffusion barrier region 682 is located between the part including the easily diffusible metal of the first penetrating part 65 and the first part 10, and the diffusible metal of the first penetrating part 65 is removed. The diffusion of the included portion to the first portion 10 is suppressed. A part (second portion) of the diffusion barrier region 682 is located between the region including the easily diffusible metal of the second through portion 66 and the first portion 10, so that the easily diffusible metal of the second through portion 66 is removed. The diffusion of the metal in the included region to the first portion 10 is suppressed. A part (third portion) of the diffusion barrier region 682 is located between the region including the easily diffusible metal of the connecting portion 67 and the first portion 10 to diffuse the metal of the connecting portion 67 into the first portion 10. Suppress. The first part, the second part, and the third part of the diffusion barrier region 682 constitute a part of the first through part 65, the second through part 66, and the connecting part 67, respectively.

  The diffusion barrier material is an insulating material and / or a conductive material. In the case where the diffusion barrier material is a conductive material, the conductive material can serve as a part of the conduction between the first wiring 311 and the second wiring 512 as a part of the conductive member 68. When the diffusion barrier material is an insulating material, the insulating material is located between the conductive member 68 and the first portion 10 or the second portion 20. The diffusion barrier material may be composed of both an insulating material and / or a conductive material.

The diffusion barrier region 682 may have a single layer structure or a multilayer structure. The single layer structure may be an insulating layer or a conductive layer. The multilayer structure may be a multilayer structure including only a conductive layer, a multilayer structure including only an insulating layer, or a multilayer structure including both an insulating layer and a conductive layer. Good. The diffusion barrier region 682 of this embodiment is a part of the conductive member 68 made of a conductive material and has a single layer structure of a tantalum layer. In the present embodiment, a part of the diffusion barrier region 682 is located between the easily diffusible metal region 681 of the first penetrating portion 65 and the first wiring 311 and is in contact with the wiring pattern 40c. Further, a part of the diffusion barrier region 682 is located between the easily diffusible metal region 681 of the second through portion 66 and the second wiring 512 and is in contact with the wiring pattern 40 c. When the diffusion barrier region 682 has a multilayer structure of a conductive layer and an insulating layer, at least the insulating layer should not be positioned between the easily diffusible metal region 681 of the first penetrating portion 65 and the first wiring 311. To. Similarly, the insulating layer of the diffusion barrier region 682 is not positioned between the easily diffusible metal region 681 of the second through portion 66 and the second wiring 512. An insulating layer may be disposed between the conductive layer in the diffusion barrier region 682 and the conductive member 68. The first wiring portion 31 includes a via plug 44 having a barrier metal (tantalum film) that prevents diffusion of the metal (copper) included in the second through portion 66 and having the same atomic number as the metal (copper) in the first portion 10. A and 44c are provided. For example, assuming that the thickness of the barrier metal of the via plug 44b is T ₁ and the thickness of the conductive layer of the diffusion barrier region 682 at the same height as the via plug 44b is T ₀ , the conductive layer of the diffusion barrier region 682 satisfies T ₁ <T _0. Can be determined. Similarly, the thickness of the conductive layer of the diffusion barrier region 682 at the same height as the via plug 44c can be made thicker than the barrier metal of the via plug 44c. The thickness of the conductive layer of the easily diffusible metal region 681 formed in the first through portion 65 and the second through portion 66 is larger than the barrier metal formed in the via plugs 44b and 54b of the first wiring portion 31 and the second wiring portion 51. Describe why When the barrier metal formed on the via plugs 44b and 54b is thickened, the EM resistance is deteriorated and the via resistance is increased. On the other hand, since the dimensions of the first through portion 65 and the second through portion 66 are several times larger, the current density is lowered and the EM resistance is improved, and the resistance is also lowered because the cross-sectional area is large. Therefore, it is possible to increase the thickness of the conductive layer of the easily diffusible metal region 681 formed in the first through portion 65 and the second through portion 66.

Further, the first wiring portion 31 has a via plug having a barrier metal (tantalum film) that prevents diffusion in the first portion 10 of the metal (Cu) having the same atomic number as the metal (Cu) included in the second through portion 66. including. For example, the via plug 44b. The width of the via plug 44b is D ₁ , the thickness of the barrier metal (tantalum film) of the via plug 44b is T ₁ , and the width of the conductive member 68 (the first through portion 65 or the second through portion 66) at the same height as the via plug 44b. D _0, a and _{T 0} thickness of the conductive layer of the diffusion barrier region 682 at the same height as the via plug 44b. In this example, the width of the first through portion 65 or the second through portion 66 and the thickness of the conductive layer in the diffusion barrier region 682 can be determined so that T ₀ / D ₀ <T ₁ / D ₁ is satisfied. By selecting the diffusion barrier material according to the above-described guidelines, the ratio of the thickness of the conductive layer in the diffusion barrier region 682 in the conductive member 68 may be smaller than the ratio of the thickness of the barrier metal in the via plug.

The width of the _{D 1C} of the contact plug 44a provided in the first wiring portion 31, the thickness of the conductive layer of the diffusion barrier region 682 as _{T C} at the same height as the contact plug _44a, can be a T C _{<D 1C} . Even if the conductive layer Tc in the diffusion barrier region 682 is not so large, the easily diffusible metal region 681 can ensure conductivity.

Width _{D 1C} of the contact plug 44a provided in the first wiring portion 31, the width of the contact plug 54a provided in the second wiring portion 51 as _{D 2,} can be a _D 2C _{<D 1C.} This is because the first portion 10 and the second portion 10 can be formed separately, and the second portion 20 can be formed with a finer process rule than the first portion 10. It is good also as _D1C <= _D2C as needed. T _C <D _2C may be satisfied, and T _C <D _2C <D _1C may be satisfied.

  The diffusion barrier region 682 suppresses diffusion of the easily diffusible metal in the easily diffusible metal region 681 to the first semiconductor layer 33. As a result, it is possible to reduce a leakage current that can be generated in the semiconductor elements Tr1 to Tr4 of the first element unit 30 or a dark current that can be generated in the photoelectric conversion element PD of the first element unit 30. Further, the diffusion barrier region 682 suppresses diffusion of the easily diffusible metal in the easily diffusible metal region 681 to the insulator layers 39a to 39e. Generation of voids in the easily diffusible metal region 681 due to diffusion of the easily diffusible metal from the easily diffusible metal region 681 is suppressed. Moreover, the resistance reduction of the insulator layers 39a to 39e due to the diffusion of the easily diffusible metal into the insulator layers 39a to 39e is suppressed. Thereby, the reliability of the wiring structure of the 1st wiring part 31 is ensured.

  A method for manufacturing the photoelectric conversion device of this embodiment will be described with reference to FIGS. 3, 4, and 5. 3, 4, and 5 are cross-sectional views showing the same part (plane including points P and Q in FIG. 1) as in FIG. 2.

  The manufacturing process of the first portion 10a will be described with reference to FIG.

  First, the first element unit 30 is formed. This will be specifically described below. A first semiconductor substrate 33a to be the first semiconductor layer 33 is prepared. The first semiconductor substrate 33a is, for example, a silicon substrate. An insulating region 42 that isolates a desired region of the first semiconductor substrate 33a is formed. The insulating region 42 is formed at a position surrounding the conductive member 68 in FIG. The insulating region 42 is formed to a depth exceeding the lower surface (back surface) 104 of the first semiconductor layer 33 in FIG. The insulating region 42 is formed by opening a desired position from the back surface side from the upper surface (front surface) 103 of the first semiconductor substrate 33a and filling the opening with an insulating material. The insulating region 42 forms a groove from the back surface side at a desired position from the upper surface (front surface) 103 of the first element portion 30a, covers this groove, and at least a part of the groove becomes a gas or a void. It is also possible to form.

  Next, the element isolation 38 is formed on the upper surface (front surface) 103 of the first semiconductor substrate, and the wells of Tr3 and Tr4 are formed on the first semiconductor substrate. Thereafter, the n-type semiconductor region 34 and the p-type semiconductor region 35 of the photoelectric conversion unit, and the n-type semiconductor region and the p-type semiconductor region of Tr1, Tr2, Tr3, Tr4 are formed. A gate electrode is formed on the first semiconductor substrate via a gate oxide film. Next, a first protective film (not shown) for protecting the surface 103 of the first semiconductor substrate is formed so as to cover the gate electrode. As described above, the first element portion 30a is formed.

  Next, the first wiring part 31 is formed on the first element part 30a. This will be specifically described below. First, the insulator layer 39a is formed on the first semiconductor substrate 33a via the first protective film, and contact holes are formed in the first protective layer and the insulating layer 39a. A contact plug 44a is formed by forming a titanium layer and a titanium nitride layer as sub-conductive layers and a tungsten layer as a main conductive layer in the contact holes. The contact plug 44a has, for example, a width of 130 nm and a length (contact hole depth) of 200 nm.

  Thereafter, the insulator layer 39b is formed, and a single damascene groove (trench) is formed in the insulator layer 39b. Then, using a single damascene method, a tantalum layer as a sub conductive layer and a copper layer as a main conductive layer are formed to form a wiring pattern 40a. Then, a diffusion prevention layer (not shown) made of, for example, silicon nitride or silicon carbide is deposited with a thickness of 50 nm.

  Next, an insulating layer 39c is formed as an interlayer insulating layer, and patterned to form a dual damascene hole (via) in the insulating layer 39c. The dimensions of the groove (via) are, for example, a width of 150 nm and a depth of 300 nm. Thereafter, patterning is performed to form a dual damascene trench in the insulator layer 39c. Thereafter, for example, a tantalum film of 10 nm and a copper seed film of 100 nm are deposited to form a copper plating film of 900 nm, for example. Then, excess portions of the film outside the trench are removed by CMP. In this way, the via plug 44b and the wiring pattern 40b are integrally formed using the dual damascene method. Then, a diffusion preventing layer (not shown) 50 nm is deposited. Similarly, the insulator layer 39d is formed, and the via plug 44b and the wiring pattern 40b are integrally formed by a dual damascene method. Thereafter, an insulator layer 39e made of silicon oxide is formed.

  As described above, the first portion 10 a having the first element portion 30 and the first wiring portion 31 is obtained.

  The manufacturing process of the second part will be described with reference to FIG.

  First, the second element unit 50 is formed. This will be specifically described below. First, a second semiconductor substrate 55a to be the second semiconductor layer 55 is prepared. The second semiconductor substrate 55a is, for example, a silicon substrate. An element isolation 58 is formed on the upper surface (surface) 203 of the second semiconductor substrate. Next, Tr5, Tr6, Tr7, Tr8 wells are formed in the second semiconductor substrate. Thereafter, the n-type semiconductor region and the p-type semiconductor region of Tr5, Tr6, Tr7, Tr8 are formed. A gate electrode is formed on the second semiconductor substrate via a gate oxide film. Next, a second protective film (not shown) for protecting the surface 203 of the second semiconductor substrate is formed so as to cover the gate electrode. As described above, the second element portion 50a is formed.

  Next, the second wiring part 51 is formed on the upper surface (front surface) 203 of the second element part 50. The contact plug 54a and the via plug 54c can be formed in the same manner as the contact plug 44a. The contact plug 54a has, for example, a width of 65 nm and a height (contact hole depth) of 100 nm. The wiring pattern 53a can be formed in the same manner as the wiring pattern 40a. The wiring pattern 53b and the contact plug 54b can be formed in the same manner as the wiring pattern 40b and the via plug 44b. Although the wiring level is 3 here, the number of wiring levels of the second wiring part 51 may be larger than that of the first wiring part 31. The wiring pattern 53c can be formed by patterning a laminate of a titanium layer and / or a titanium nitride layer and an aluminum layer, and further a titanium layer and / or a titanium nitride layer.

  Thus, the second portion 20a having the second element unit 50 and the second wiring unit is obtained. Either the first part 10a or the second part 20a may be produced in any order, and these may be performed in parallel.

  The description will be continued with reference to FIG. The first wiring part 31 side of the first part 10a and the second wiring part 51 side of the second part 20a are joined by the joining surface 60. The surface of the first portion 10a on the first wiring portion 31 side (surface of the insulator layer 39e) and the surface of the second portion 20a on the second wiring portion 51 side (surface of the insulator layer 49e) are composed of insulating layers. The planarization is performed by a CMP method, an etch back method, or the like. The joining of the first portion 10a and the second portion 20a is preferably performed in a vacuum or in an inert gas atmosphere. Further, before bonding, the surface of the first portion 10a on the first wiring portion 31 side (surface of the insulator layer 39e) and the surface of the second portion 20a on the second wiring portion 51 side (surface of the insulator layer 49e). Therefore, it is desirable to perform plasma irradiation. By performing this plasma irradiation, the bonding between the silicon oxide film and the silicon nitride film becomes stronger as compared with the case where the plasma irradiation is not performed. In addition to plasma irradiation, a method of activating the bonding surface by chemical treatment is also applicable.

  In this embodiment, the example which directly joined the 1st wiring part 31 and the 2nd wiring part 51 using plasma joining etc. was shown. However, the insulator layer of the first wiring part 31 and the insulator layer of the second wiring part 51 can also be joined via an adhesive layer. Alternatively, the conductor layers of the first wiring part 31 and the conductor layer of the second wiring part 51 can be directly joined to each other using metal joining. Copper can be suitably used as a material for the conductor layer to be metal-bonded.

  Further, the first semiconductor substrate of the first element portion 30a of the first portion 10a after bonding is thinned from the lower surface (back surface). Thinning can be performed by a method such as grinding, CMP, or etching. By thinning to the surface 104, the 1st part 10 provided with the 1st element part 30 containing the 1st semiconductor layer 33 which is the structure of FIG.3 (d) is obtained. Incident light efficiently reaches the photoelectric conversion unit 11 by thinning the first semiconductor layer 33. This contributes to an improvement in sensitivity.

  As described above, a laminate of the first portion 10 and the second portion 20 is obtained.

  The description will be continued with reference to FIG. An antireflection layer 61 and an insulator layer 62 are formed on the surface 104 of the thinned first semiconductor layer 33. Thereafter, the light shielding layer 63 is formed. The antireflection layer 61 preferably has a refractive index between the silicon layer and the silicon oxide layer. The antireflection layer 61 can be made of, for example, silicon nitride. There may be a plurality of antireflection layers 61. The insulator layer 62 is made of, for example, silicon oxide. The light shielding layer 63 can be formed by depositing and patterning aluminum or tungsten. The light shielding layer 63 is preferably disposed between the pixels, on the optical black pixel, and on the element affected by the incidence of light. It is also possible to conduct the light shielding layer 63 and the first element part 30 by depositing the light shielding layer 63 after the antireflection layer 61 and the insulator layer 62 are patterned before the light shielding layer 63 is deposited.

  Further, the insulator layer 69 is formed on the insulator layer 62 and the light shielding layer 63. The insulator layer 69 is a silicon oxide film, for example. Thereafter, the insulator layer 69 in a desired region inside the insulating region 42 is patterned to form a connection groove 67a. The connecting groove 67a is formed to a depth that does not reach the first element portion 30, for example. A first through hole 65a reaching the first wiring 311 and a second through hole 66a reaching the second wiring 512 are formed on the bottom surface of the connecting groove 67a. The first through-hole 65a includes the insulator layer 69, the insulator layer 62, the antireflection layer 61, the first element portion 30, the element isolation 38, the first protective film of the first wiring portion 31, and the insulator layers 39a, 39b, and 39c. , 39d are etched. And it is formed so as to reach the wiring pattern 40 c of the first wiring part 31. The second through-hole 66a is formed of the insulator layers 69a and 39b of the insulator layer 69, the insulator layer 62, the antireflection layer 61, the first element portion 30, the element isolation 38, the first protective film, and the first wiring portion 31. , 39c, 39d, and the insulator layer 49e are etched. And it is formed so as to reach the conductor layer 53 c of the second wiring part 51. The dimensions of the first through hole 65a and the second through hole 66a are, for example, a width of 1 to 3 μm and a depth of 3 to 8 μm. The depth is several times larger than the via plugs 44b and 54b formed in the first wiring part 31 and the second wiring part 51 described above. The first through hole 65a and the second through hole 66a may be formed at the same time, or may be separately patterned and etched. The distance between the first through hole 65a and the second through hole 66a is preferably 1 to 10 μm. If the distance between the first through-hole 65a and the second through-hole 66a is small, it becomes difficult to form a groove, and if it is large, the chip area becomes large.

  The description will be continued with reference to FIG. A diffusion barrier region 682 is deposited in the first through hole 65a, the second through hole 66a, and the connecting groove 67a. The diffusion barrier region 682 is made of a single layer film of tantalum. The diffusion barrier region 682 can be formed by depositing a tantalum film having a thickness of 30 nm, for example. The dimensions of the first through hole 65 a and the second through hole 66 a are larger than the holes for plugs of the first wiring 311 and the second wiring 512. Therefore, the diffusion barrier region 682 formed in the first through hole 65a and the second through hole 66a is preferably deposited thicker than the tantalum film formed in the via plugs 44b and 54b.

  Next, a conductive material is embedded in the first through hole 65a, the second through hole 66a, and the connecting groove 67a. A first through part 65, a second through part 66, and a connecting part 67 are formed. For example, a copper seed layer having a thickness of 300 nm is deposited in the first through hole 65a, the second through hole 66a, and the connecting groove 67a on which the diffusion barrier region 682 is deposited, thereby forming a copper plating layer having a thickness of 3 μm.

  The description will be continued with reference to FIG. By removing the excess portions of the diffusion barrier region 682 and the copper film, the first through portion 65, the second through portion 66, and the connecting portion 67 can be formed. In addition, a conductive member 68 is formed by the first through portion 65, the second through portion 66, and the connecting portion 67. As a result, the conductor layer 40c of the first wiring portion 31 of the first portion 10 and the conductor layer 53c of the second wiring portion 51 of the second portion 20 are electrically connected. In the present embodiment, since the conductive member 68 is formed in the region of the insulating region 42 formed in the first element part 30, the conductive member 68 and the first element part 30 are electrically connected. Is prevented.

  In the formation process of the conductive member 68 of the present embodiment, the dual damascene method in which copper is embedded in the first through hole 65a, the second through hole 66a, and the connecting groove 67a at once is used, but is not limited thereto. For example, a single damascene method may be used. For example, the first through-hole 65a and the second through-hole 66a are first formed, the conductive material is filled in the first through-hole 65a and the second through-hole 66a at once, and then the connection groove 67a is formed to form the connection groove 67a. A conductive material can be embedded in the substrate. Further, in the dual damascene method, the trench first in which the connecting groove 67a is formed before the first through hole 65a and the second through hole 66a is taken as an example. However, a via first in which the connection groove 67a is formed after the first through hole 65a and the second through hole 66a are formed may be used. Further, the connection portion 67 may be formed by patterning a conductive film such as aluminum without embedding a conductive material. For example, a via plug mainly composed of tungsten is formed in an insulating layer formed on the first through portion 65 and the second through portion 66, and an aluminum film covering the insulating layer and the via plug is patterned by etching. Thereby, the connection part 67 which consists of a via plug and an aluminum layer can be formed. At this time, a barrier metal made of a titanium layer and / or a titanium nitride layer can be provided between tungsten as the via plug and the insulating layer. Moreover, the barrier metal which consists of a titanium layer and / or a titanium nitride layer can also be provided in the upper layer and / or lower layer of an aluminum layer.

  In this example, a conductive member 68 is formed in which the conductive layer 40c of the first wiring part 31 of the first portion 10 and the conductive layer 53c of the second wiring part 51 of the second portion 20 are electrically connected. Various modifications are possible.

  The description will be continued with reference to FIG. An insulating cap layer 70 and a planarization layer 71 are formed so as to cover the conductive member 68. When the connecting portion 67 is formed of copper as in the present embodiment, it is preferable to use a silicon nitride film as the cap layer 70. In this embodiment, the cap layer 70 is formed only in the region covering the conductive member 68, but may be formed in the region covering the photoelectric conversion element. In the case of a photoelectric conversion device as in this embodiment, it is preferable to remove at least the cap layer in the region where the photodiode is arranged. Further, the planarization layer 71 can be composed of a plurality of films such as an inorganic insulator film and an organic insulator film. Further, the planarization layer 71 can be planarized as appropriate. The main material of the conductive member 68 composed of the first through portion 65, the second through portion 66, and the connecting portion 67 in this example is copper, and this copper is surrounded by the diffusion barrier region 682 and the cap layer 70. The diffusion barrier region 682 and the cap layer 70 can prevent metal diffusion of the first through portion 65, the second through portion 66, the connecting portion 67, and the conductive member 68. Next, a color filter 73 made of resin and an on-chip lens 74 are appropriately formed on the planarizing layer 71 in this order.

  Thereafter, an opening 77 is formed in the electrode pad 78. Thereby, the configuration shown in FIG. 2 is obtained. In the present embodiment, the example in which the formation process of the opening 77 is performed after the formation of the color filter 73 and the on-chip lens 74 is shown, but it can be performed before the formation of the color filter 73 and the on-chip lens 74. After the color filter 73 and the on-chip lens 74 are formed, heat treatment at a high temperature (about 400 ° C.) cannot be performed to protect the color filter 73 and the on-chip lens 74 that are resins. When the semiconductor device 1 is damaged by the processing of the opening 77, a heat treatment for recovering the damage may be required, and the order of the steps can be changed as appropriate.

  Thereafter, the semiconductor device 1 is bonded to the package using a die bond. Then, a bonding wire 79 connected to the electrode pad 78 is formed in the opening 77. The package is sealed with a transparent plate. An LGA (Land Grid Array) which is an external terminal of the package is fixed to the circuit board by reflow soldering.

Second Embodiment
In the present embodiment, the diffusion barrier region 682 includes a conductive layer and an insulating layer. A manufacturing method in such a case will be described.

  As shown in FIG. 6A, a connecting groove 67a, a first connection hole 65b, and a second connection hole 66b are formed. At this time, portions of the diffusion preventing layers 83 and 84 provided in advance in the first wiring part 31 in which the second connection holes 66a are provided have been removed in advance by patterning. The formation of the first connection hole 65b and the formation of the second connection hole 66b can be performed in parallel. At this time, etching is performed by an etching method in which the etching rate for the insulator layers 39a, 39b, 39c, 39d, 39e, and 49e, which are silicon oxide layers, is higher than the etching rate for the diffusion prevention layers 83 and 84. By doing so, even if the first connection hole 65b and the second connection hole 66b are simultaneously formed using the diffusion prevention layer 84 as an etching stopper, the first connection hole 65b is prevented from reaching the wiring first. It is done.

  As shown in FIG. 6B, a first diffusion barrier film 751 made of a diffusion barrier material made of an insulating material such as silicon nitride is formed.

  As shown in FIG. 6C, the diffusion barrier film 751 is etched back to form a silicon nitride layer 750 having an opening at the bottom. The silicon nitride layer 750 becomes an insulating layer of the diffusion barrier region 682 that functions as an insulating region between the conductive member 68 and the first semiconductor layer 33.

  As shown in FIG. 6D, the diffusion preventing layer 84 and the insulator layer 39d are etched to form a first through hole 65a reaching the tantalum layer 81 of the barrier metal. Further, the insulator layer 49e and the barrier metal titanium nitride layer 87 are etched to form a second through hole 66a reaching the aluminum layer 86.

  As shown in FIG. 6E, a second diffusion barrier film 1682 made of a diffusion barrier material made of a conductive material such as tantalum is formed. The second diffusion barrier film 1682 will later become a conductive layer of the diffusion barrier region 682 that is a part of the diffusion barrier region 682 and also a part of the conductive member 68. A tantalum layer 81 is located between the second diffusion barrier film 1682 and the copper layer 82. By doing in this way, the metal contamination by the etching of the copper layer 82 can be avoided.

  As shown in FIG. 6F, a copper film 1681 is embedded in the first through hole 65a, the second through hole 66a, and the connecting groove. A second diffusion barrier film 1682 is located between the copper film 1681 and the aluminum layer 86. By doing in this way, even if the aluminum layer 86 is exposed, it is possible to avoid the copper in the second through hole 66a from diffusing into the aluminum layer 86. Thereafter, the excess tantalum film 1682 and the copper film 1681 outside the connection groove are removed by the CMP method, and the conductive member 68 is obtained.

<Third Embodiment>
In the present embodiment, the first element unit 30 is located between the first wiring unit 31 and the second wiring unit 51. The second penetration part 66 penetrates the first semiconductor layer 33 and the insulator layer 39e, and the first penetration part 65 penetrates the insulator layer 39e but does not penetrate the first semiconductor layer 33.

  The diffusion barrier region 682 of this embodiment is made of an insulating material such as silicon nitride. The easily diffusible metal region 681 includes copper, and the first through portion 65 and the second through portion 66 penetrate through the diffusion preventing layers 83 and 87 and are in contact with the copper layers 82 and 86. The connecting portion 67 includes an aluminum layer and a barrier metal, and connects the first through portion 65 and the second through portion 66 via a via plug 87 made of tungsten.

DESCRIPTION OF SYMBOLS 10 1st part 30 1st element part 31 1st wiring part 20 2nd part 50 2nd element part 51 2nd wiring part 681 Easy diffusible metal area | region 682 Diffusion barrier area | region 65 1st penetration part 66 2nd penetration part 67 Connection Part 68 Conductive member

Claims (37)

A first semiconductor layer provided with a photoelectric conversion unit and a first transistor;
A second semiconductor layer provided with a second transistor;
A first conductor layer disposed between the first semiconductor layer and the second semiconductor layer;
Between the first semiconductor layer and the second semiconductor layer, the distance to the second semiconductor layer is smaller than the distance between the second semiconductor layer and the first conductor layer. A second conductor layer;
A first insulator layer disposed between the first semiconductor layer and the first conductor layer in a direction in which the first semiconductor layer and the second semiconductor layer are stacked;
A second insulator layer disposed between the second semiconductor layer and the second conductor layer;
A third insulator layer disposed between the first conductor layer and the second conductor layer;
A through portion disposed in a through-hole penetrating the first semiconductor layer, the first insulator layer, and the third insulator layer, the first conductor layer and the second conductor layer; A conductive member to be connected,
The penetrating portion has a region mainly containing a first conductive material and a conductive layer mainly containing a second conductive material different from the first conductive material,
The conductive layer prevents diffusion of the first conductive material, is disposed between the region and the first insulator layer, and is in contact with the first insulator layer;
The conductive layer continuously extends from one to the other of the first conductor layer and the second conductor layer so as to be in contact with the first conductor layer and the second conductor layer. A semiconductor device.   The semiconductor device according to claim 1, wherein the conductive layer is disposed between the region and the first semiconductor layer. An interlayer insulating layer disposed between the first insulator layer and the first semiconductor layer in the direction;
A wiring pattern disposed between the first insulator layer and the interlayer insulating layer,
The semiconductor device according to claim 1, wherein the conductive layer is in contact with the interlayer insulating layer.   4. The semiconductor device according to claim 1, wherein the conductive layer is disposed between the region and the third insulator layer and is in contact with the third insulator layer. 5. .   The semiconductor device according to claim 1, wherein the second conductor layer contains copper. The second conductive material is either metal nitride or metal carbide;
The semiconductor device according to claim 1, wherein the conductive layer is in contact with the third insulator layer.   7. The device according to claim 1, wherein the second conductive material includes at least one of tantalum, tantalum nitride, tantalum carbide, titanium, titanium nitride, titanium carbide, tungsten, tungsten nitride, tungsten carbide, and manganese. The semiconductor device described. The semiconductor device according to claim 1, wherein the first conductive material includes at least one of gold, silver, copper , nickel, iron, and zinc.   9. The device according to claim 1, wherein at least one of the first insulator layer, the second insulator layer, and the third insulator layer has a dielectric constant lower than that of silicon oxide. The semiconductor device described.   The conductive member includes a first part that contacts the first conductor layer, a second part that contacts the second conductor layer, and a third part that couples the first part and the second part. The semiconductor device of any one of Claims 1 thru | or 9 containing.   The semiconductor device according to claim 1, wherein the first semiconductor layer has an opening for performing wire bonding connection or flip chip connection.   The semiconductor device according to claim 3, wherein the wiring pattern includes a copper wiring. Including a barrier metal provided on a wiring disposed between the first semiconductor layer and the second semiconductor layer;
The semiconductor device according to claim 1, wherein a thickness of the conductive layer is larger than a thickness of the barrier metal.   The semiconductor device according to claim 1, wherein the conductive layer surrounds the region in the through hole.   The semiconductor according to claim 1, wherein the conductive layer reduces diffusion of the first conductive material into the first semiconductor layer, the first insulating layer, and the third insulating layer. apparatus. A first semiconductor layer provided with a photoelectric conversion unit and a first transistor;
A second semiconductor layer provided with a second transistor;
A first conductor layer disposed between the first semiconductor layer and the second semiconductor layer;
In the direction in which the first semiconductor layer and the second semiconductor layer are stacked, the second semiconductor layer and the first conductor are disposed between the first semiconductor layer and the second semiconductor layer. A second conductor layer disposed at a position where the distance to the second semiconductor layer is smaller than the distance to the layer;
A conductive member connecting the first conductor layer and the second conductor layer,
The conductive member is disposed between a first conductive material and the first conductive material and the first semiconductor layer, and includes tantalum, tantalum nitride, tantalum carbide, titanium, titanium nitride, titanium carbide, tungsten, tungsten nitride, At least one of the material of the tungsten carbide and manganese mainly has a conductive layer containing,
A diffusion coefficient of the first conductive material relative to the first semiconductor layer is greater than a diffusion coefficient of the first conductive material relative to the conductive layer;
The conductive layer is in contact with the first conductor layer, the second conductor layer, and the first semiconductor layer;
The semiconductor device, wherein the conductive layer continuously extends from one of the first conductor layer and the second conductor layer to the other. The first semiconductor layer includes a trench disposed between the first portion and the second portion of the first semiconductor layer, and separating the first portion and the second portion;
The semiconductor device according to claim 16, wherein the second portion is disposed between the trench and the conductive member and is in contact with the conductive layer.   The semiconductor device according to claim 17, wherein the first semiconductor layer includes an element isolation portion configured by STI or LOCOS that contacts an insulating material provided in the trench. A first insulator layer disposed between the first semiconductor layer and the first conductor layer;
A second insulator layer disposed between the second semiconductor layer and the second conductor layer;
A third insulator layer disposed between the first conductor layer and the second conductor layer;
The semiconductor device according to claim 16, wherein the conductive layer is in contact with at least one of the first insulator layer and the third insulator layer. An interlayer insulating layer disposed between the first insulator layer and the first semiconductor layer in the direction;
A wiring pattern disposed between the first insulator layer and the interlayer insulating layer,
The semiconductor device according to claim 19, wherein the conductive layer is in contact with the interlayer insulating layer. The conductive member includes a penetrating portion disposed in a through hole penetrating the first semiconductor layer and the first insulator layer,
21. The semiconductor device according to claim 19, wherein the conductive layer is in contact with an inner side of the first semiconductor layer and an inner side of the first insulator layer in the through hole.   The semiconductor device according to claim 16, wherein the conductive layer contains titanium nitride.   The semiconductor device according to claim 16, wherein the second conductor layer contains copper. A plurality of blocks each including the conductive member and a first trench and a second trench provided in the first semiconductor layer;
The semiconductor device according to claim 16, wherein the conductive layer is disposed between the first trench and the second trench. A first semiconductor layer provided with a photoelectric conversion unit and a first transistor;
A second semiconductor layer provided with a second transistor;
A first conductor layer disposed between the first semiconductor layer and the second semiconductor layer;
In the direction in which the first semiconductor layer and the second semiconductor layer are stacked, the second semiconductor layer and the first conductor are disposed between the first semiconductor layer and the second semiconductor layer. A second conductor layer disposed at a position where the distance to the second semiconductor layer is smaller than the distance to the layer;
A first insulator layer disposed between the first semiconductor layer and the first conductor layer;
A conductive member connecting the first conductor layer and the second conductor layer,
The conductive member is disposed between the first conductive material and the first conductive material and the first insulator layer, and includes tantalum, tantalum nitride, tantalum carbide, titanium, titanium nitride, titanium carbide, tungsten, and tungsten nitride. includes a conductive layer which mainly contains at least one material of tungsten carbide and manganese, and
A diffusion coefficient of the first conductive material relative to the first insulator layer is greater than a diffusion coefficient of the first conductive material relative to the conductive layer;
The conductive layer is in contact with the first conductor layer, the second conductor layer, and the first insulator layer;
The semiconductor device, wherein the conductive layer continuously extends from one of the first conductor layer and the second conductor layer to the other. The first semiconductor layer includes a trench disposed between the first portion and the second portion of the first semiconductor layer, and separating the first portion and the second portion;
26. The semiconductor device according to claim 25, wherein the second portion is disposed between the trench and the conductive member and is in contact with the conductive layer.   27. The semiconductor device according to claim 26, wherein the first semiconductor layer includes an element isolation portion made of STI or LOCOS that contacts an insulating material provided in the trench. A second insulator layer disposed between the second semiconductor layer and the second conductor layer;
A third insulator layer disposed between the first conductor layer and the second conductor layer;
28. The semiconductor device according to claim 25, wherein the conductive layer is in contact with the third insulator layer. An interlayer insulating layer disposed between the first insulator layer and the first semiconductor layer in the direction;
A wiring pattern disposed between the first insulator layer and the interlayer insulating layer,
30. The semiconductor device according to claim 28, wherein the conductive layer is in contact with the interlayer insulating layer. The conductive member includes a penetrating portion disposed in a through hole penetrating the first semiconductor layer and the first insulator layer,
30. The semiconductor device according to claim 28 or 29, wherein the conductive layer is in contact with an inner side of the first semiconductor layer and an inner side of the first insulator layer in the through hole.   31. The semiconductor device according to claim 25, wherein the conductive layer contains titanium nitride.   32. The semiconductor device according to claim 25, wherein the second conductor layer contains copper. A plurality of blocks each including the conductive member and a first trench and a second trench provided in the first semiconductor layer;
The semiconductor device according to claim 16, wherein the conductive layer is disposed between the first trench and the second trench. The first conductor layer is included in a first wiring pattern;
The first wiring pattern has a first barrier metal between the first semiconductor layer and the first conductor layer,
The second conductor layer is included in a second wiring pattern,
34. The semiconductor device according to claim 1, wherein the second wiring pattern includes a second barrier metal. The semiconductor device according to claim 1, wherein the first conductive material is embedded inside the conductive layer. An electrode pad;
A bonding wire connected to the electrode pad,
36. The semiconductor device according to claim 1, wherein an insulating material is disposed between the second conductor layer and the electrode pad. A semiconductor device according to any one of claims 1 to 36 ;
A peripheral device connected to the semiconductor device,
An electronic apparatus, wherein the peripheral device is an arithmetic device, a storage device, a recording device, a communication device, or a display device.

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