Interposer wafer, method for manufacturing an interposer wafer, interposer, and method for manufacturing an interposer

Abstract

To provide an interposer wafer that can reduce contamination by heavy metals. [Solution] The interposer wafer according to the present invention comprises a silicon wafer (bulk silicon wafer) 11 and a solid solution region 13 formed on the surface of the silicon wafer 11 in which elements contributing to gettering are solid-dissolved, and when heat treatment is performed in a hydrogen or nitrogen atmosphere at a temperature of 800°C to 1150°C for 1 minute to 5 minutes, the solid solution region 13 has a solid solution of 1.0 nm 2 More than 10nm 2 The following sizes and 1.0×10 15 / cm 3 The above 1.0 × 10 17 / cm 3 Interposer wafers in which black spot-like defects of the following density are formed.

Description

[Technical Field]

[0001] The present invention relates to a wafer for an interposer, a method for manufacturing an interposer wafer, an interposer, and a method for manufacturing an interposer. [Background technology]

[0002] In recent years, as semiconductor devices have improved in performance, miniaturization has progressed, and high density has been achieved by mounting semiconductor devices in three dimensions. In this high-density technology, it is necessary to electrically connect the stacked semiconductor devices. For this reason, an intermediate substrate called an interposer is placed between the semiconductor devices, and through-silicon vias (TSVs) made of Cu or other materials are provided on the interposer to achieve electrical connection between the semiconductor devices (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Osamu Shimada, "Prospects for Interposer Technology Contributing to High-Density Integration of Devices," Journal of the Japan Society for Electronics Packaging, Vol. 22, No. 5, 361-366 (2019) [Overview of the project] [Problems that the invention aims to solve]

[0004] In miniaturization for high-density technology, wafers for interposers are susceptible to contamination by heavy metals during processing processes such as grinding and polishing, as well as during TSV (Total Slip Vegetable) manufacturing. Reducing the effects of such contamination is therefore crucial. However, conventional interposers, including the one described in Non-Patent Literature 1, do not incorporate any measures to reduce heavy metal contamination.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a wafer for an interposer capable of reducing contamination by heavy metals during the manufacture of the interposer.

Means for Solving the Problems

[0006] The present invention for solving the above problems is as follows.

[0007] 1. A silicon wafer and a solid solution region formed in the surface layer portion of the silicon wafer, in which elements contributing to gettering are dissolved. When heat treatment is performed at a temperature of 800 °C or higher and 1150 °C or lower for 1 minute or longer and 5 minutes or shorter in an atmosphere of hydrogen or nitrogen, black dot-like defects having a size of 1.0 nm or more and 10 nm or less and a density of 1.0×10 / cm or more and 1.0×10 / cm or less are formed in the solid solution region. A wafer for an interposer. In the case of heat treatment at a temperature of 800 °C or higher and 1150 °C or lower for 1 minute or longer and 5 minutes or shorter in an atmosphere of hydrogen or nitrogen, in the solid solution region, 1.0 nm 2 or more and 10 nm 2 or less in size and 1.0×10 15 / cm 3 or more and 1.0×10 17 / cm 3 or less in density of black dot-like defects are formed. A wafer for an interposer.

[0008] 2. A silicon wafer and a solid solution region formed in the surface layer portion of the silicon wafer, in which elements contributing to gettering are dissolved. The solid solution region contains black dot-like defects having a size of 1.0 nm or more and 10 nm or less and a density of 1.0×10 / cm or more and 1.0×10 / cm or less. A wafer for an interposer. The solid solution region has a size of 1.0 nm 2 or more and 10 nm 2 or less and 1.0×10 15 / cm 3 or more and 1.0×10 17 / cm 3 or less in density. A wafer for an interposer.

[0009] 3. The element contains carbon and hydrogen, and the peak concentration of carbon in the solid solution region is 1.0×10 20 atoms / cm 3 or less, and the hydrogen concentration is 5.0×10 20 atoms / cm 3 or less. The wafer for an interposer according to the above 1 or 2.

[0010] 4. The interposer wafer according to any one of items 1 to 3, wherein the silicon wafer is an epitaxial silicon wafer in which a silicon epitaxial layer is formed on the surface of the silicon wafer, and the solid solution region is formed in the surface layer of the silicon epitaxial layer.

[0011] 5. Ions of elements that contribute to gettering are added to the surface of the silicon wafer in a quantity of 1.0 × 10⁻¹⁶. 15 atoms / cm 2 An ion implantation step is performed by implanting the following doses to form a solid solution region in the surface layer of the silicon wafer where the elements of the ions are solidly dissolved, A heat treatment step in which the silicon wafer into which the ions have been implanted is subjected to a heat treatment in a hydrogen or nitrogen atmosphere at a temperature of 800°C to 1150°C for 1 minute to 5 minutes to form black spot-like defects within the solid solution region, A method for manufacturing wafers for interposers.

[0012] 6. The method for manufacturing an interposer wafer according to 5, wherein the ions are cluster ions containing carbon and hydrogen.

[0013] 7. The process further includes an epitaxial layer formation step, in which a silicon epitaxial layer is formed on the surface of the silicon wafer prior to the ion implantation step, A method for manufacturing an interposer wafer according to 5 or 6, wherein in the ion implantation step, the ions are implanted into the surface layer of the silicon epitaxial layer to form the solid solution region on the surface of the silicon epitaxial layer.

[0014] 8. A silicon wafer, a solid solution region formed on the surface of the silicon wafer in which elements contributing to gettering are solidly dissolved, a through hole penetrating the silicon wafer, an oxide film covering the surface of the silicon wafer including the inside of the through hole, and a through electrode provided in the through hole covered by the oxide film, The solid solution region is 1.0 nm2 More than 10nm 2 The following sizes and 1.0×10 15 / cm 3 The above 1.0 × 10 17 / cm 3 An interposer containing black spot-like defects of the following density.

[0015] 9. The element comprises carbon and hydrogen, and the peak concentration of carbon in the solid solution region is 1.0 × 10⁻⁶ 20 atoms / cm 3 The following is true, and the hydrogen concentration is 5.0 × 10⁻⁶ 20 atoms / cm 3 The interposer described in item 8 above is as follows:

[0016] 10. The interposer according to 8 or 9, wherein the silicon wafer is an epitaxial silicon wafer in which a silicon epitaxial layer is formed on the surface of the silicon wafer, and the solid solution region is formed on the surface of the silicon epitaxial layer.

[0017] 11. A polishing step to adjust the thickness of an interposer wafer by polishing the back surface of an interposer wafer manufactured by the interposer wafer manufacturing method described in any one of items 5 to 7 above, A through-hole forming step of forming through holes in the wafer for the interposer, An oxide film formation step in which an oxide film is formed on the surface of the interposer wafer, including the inside of the through hole, An electrode formation step of forming through electrodes in the through holes of the interposer wafer on which the oxide film is formed, A method for manufacturing an interposer, including the method described above. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide an interposer wafer that can reduce contamination by heavy metals during the manufacturing of interposers. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic cross-sectional view of a first example of an interposer wafer according to the present invention. [Figure 2] This is a schematic cross-sectional view of a second example of an interposer wafer according to the present invention. [Figure 3] This is a schematic cross-sectional view of a third example of an interposer wafer according to the present invention. [Figure 4] This is a schematic cross-sectional view of a fourth example of an interposer wafer according to the present invention. [Figure 5] This is a flowchart of a first example of a method for manufacturing an interposer wafer according to the present invention. [Figure 6] This is a flowchart of a second example of a method for manufacturing an interposer wafer according to the present invention. [Figure 7] This is a flowchart of a third example of a method for manufacturing an interposer wafer according to the present invention. [Figure 8] This is a flowchart of a fourth example of a method for manufacturing an interposer wafer according to the present invention. [Figure 9] This is a schematic cross-sectional view of a first example of an interposer according to the present invention. [Figure 10] This is a schematic cross-sectional view of a second example of an interposer according to the present invention. [Figure 11] This figure shows an example of the configuration of a through-electrode in an interposer according to the present invention. [Figure 12] This is a flowchart of a first example of a method for manufacturing an interposer according to the present invention. [Figure 13] This is a flowchart of a second example of the method for manufacturing an interposer according to the present invention. [Figure 14] (a) A diagram showing the distribution of black spot defects in the solid solution region, and (b) A diagram showing the relationship between the area and number of detected black spot defects. [Modes for carrying out the invention]

[0020] Embodiments of the present invention will be described below. The interposer wafer according to the present invention comprises a silicon wafer and a solid solution region formed on the surface of the silicon wafer in which elements contributing to gettering are solidly dissolved, and when heat treatment is performed in a hydrogen or nitrogen atmosphere at a temperature of 800°C to 1150°C for 1 minute to 5 minutes, the solid solution region has a thickness of 1.0 nm. 2 More than 10nm 2 The following sizes and 1.0×10 15 / cm 3 The above 1.0 × 10 17 / cm 3 The following densities of black spot-like defects are formed.

[0021] Figure 1 is a schematic cross-sectional view of a first example of an interposer wafer according to the present invention. The interposer wafer (hereinafter also simply referred to as "wafer") 1 shown in Figure 1 comprises a bulk silicon wafer 11 and a solid solution region 13 formed on the surface of the bulk silicon wafer 11 in which elements contributing to gettering are solid-dissolved. When heat treatment is performed in a hydrogen or nitrogen atmosphere at a temperature of 800°C to 1150°C for 1 minute to 5 minutes, the solid solution region 13 has a thickness of 1.0 nm. 2 More than 10nm 2 The following sizes and 1.0×10 15 / cm 3 The above 1.0 × 10 17 / cm 3 The wafer is configured to form black spot-like defects of the following density. These black spot-like defects are presumed to be defects in which amorphous regions formed by implantation of ions of elements contributing to gettering recrystallize due to heat treatment, and the recrystallized regions form composite clusters. The formation of these black spot-like defects can impart excellent gettering capability for heavy metals to the interposer manufactured using wafer 1.

[0022] In this specification, "black spot defects" refer to black spot-like defects detected in the solid solution region 13 when the cleavage plane of the interposer wafer 1 is observed in bright mode using a transmission electron microscope (TEM). "Size of black spot defects" refers to the area of ​​the defect in the cross-sectional TEM image. If the black spot defects are not circular or cannot be considered circular, the area is approximated as a circle using the circumscribed circle with the smallest diameter encompassing the black spot defects. Furthermore, "density of black spot defects" is defined by the number of defects per predetermined area in the region where black spot defects exist in the cross-sectional TEM image, multiplied by the final thickness of the sample used for the TEM observation at that time. Black spot defects can be detected and their size and density measured using, for example, image analysis software (Pigman, Wafermasters).

[0023] The size of the black spot-like defects is 10 nm 2 The following conditions can prevent black spot defects from causing leakage current. On the other hand, in terms of leakage current, there is no particular lower limit to the size of black spot defects, but 1.0 nm is preferable. 2 Since black spot-like defects smaller than 1.0 nm cannot be detected, the size of the black spot-like defects is 1.0 nm. 2 That concludes this section.

[0024] Furthermore, the density of black spot-like defects is 1.0 × 10⁻⁶ 15 / cm 3 If the above conditions are met, the interposer manufactured using wafer 1 can be given sufficient gettering capability against heavy metals. On the other hand, if the density of black spot defects is 1.0 × 10⁻⁶ 17 / cm 3 By doing the following, it is possible to prevent the occurrence of crystal defects caused by ion implantation, such as stacking faults other than black spot defects.

[0025] As the bulk silicon wafer 11, a silicon wafer made of single-crystal silicon can be suitably used.

[0026] The bulk silicon wafer 11 can be made by slicing a single crystal ingot grown by the Czochralski method (CZ method) or the Floating Zone method (FZ method) with a wire saw or the like. Furthermore, carbon and / or nitrogen may be added to the bulk silicon wafer 11 to impart higher gettering capability. Additionally, an arbitrary dopant may be added to the bulk silicon wafer 11 at a predetermined concentration to create a so-called n + type or p + type, or n - type or p - A bulk silicon wafer 11 of a specific type may also be used.

[0027] The oxygen concentration of bulk silicon wafer 11 is 10 × 10 17 atoms / cm 3 The following is preferable. This makes it possible to suppress the formation of oxygen precipitates (Bulk Micro Defects, BMDs) in the bulk silicon wafer 11 due to the heat treatment during the manufacture of the interposer. On the other hand, the lower limit of the oxygen concentration of the bulk silicon wafer 11 is not limited in terms of BMD formation, but if the oxygen concentration is too low, the strength of the bulk silicon wafer 11 will decrease, so 1 × 10 16 atoms / cm 3 It is preferable to keep the above in place.

[0028] The solid solution region 13 is a region within the bulk silicon wafer 11 in which elements contributing to heavy metal gettering are solid-dissolved. In this specification, the "solid solution region" is defined as a region in which elements contributing to heavy metal gettering are present in a solid solution of 1.0 × 10⁻⁶. 17 atoms / cm 3 This refers to a region where solid solution is present. The solid solution region 13 can be formed, for example, by implanting ions of elements that contribute to heavy metal gettering into the surface layer of the bulk silicon wafer 11.

[0029] The elements that contribute to heavy metal gettering are not particularly limited as long as they are elements capable of gettering heavy metals, and carbon, boron, phosphorus, arsenic, etc., can be used. Among these, it is preferable that the above elements include carbon from the viewpoint of obtaining excellent gettering ability.

[0030] If the elements contributing to heavy metal gettering include carbon, the peak concentration of carbon will be 1.0 × 10⁻⁶. 20 atoms / cm 3 The following is preferable. This makes it possible to prevent the occurrence of crystal defects caused by ion implantation, such as stacking faults other than black spot defects.

[0031] Furthermore, the elements contributing to heavy metal gettering more preferably include two or more elements, including carbon, and in particular, it is preferable to include one or more dopant elements selected from the group consisting of boron, phosphorus, arsenic, and antimony, in addition to carbon. Since the types of metals that can be efficiently gettered differ depending on the type of element dissolved in the solid solution region 13, a wider range of metal contamination can be addressed by dissolving two or more elements. For example, in the case of carbon, nickel can be efficiently gettered, and in the case of boron, copper and iron can be efficiently gettered.

[0032] Furthermore, elements contributing to heavy metal gettering may include, in addition to carbon, hydrogen, oxygen, fluorine, etc., and it is preferable that they include at least carbon and hydrogen. When the above elements include hydrogen, hydrogen remains in the interposer manufactured using the bulk silicon wafer 11, and during the device formation process, it can deactivate interface state defects in the device, thereby improving device characteristics such as reducing leakage current. In this specification, the above effect of hydrogen is referred to as the "hydrogen passivation effect".

[0033] If the elements contributing to heavy metal gettering include hydrogen, the hydrogen concentration is 5.0 × 10⁻⁶. 20 atoms / cm 3The following is preferable. This prevents the occurrence of crystal defects such as cavities caused by hydrogen.

[0034] When manufacturing an interposer using the interposer wafer 1 according to the present invention described above, in the interposer manufacturing process, the above heat treatment is applied to the wafer 1 shown in Figure 1, resulting in a solid solution region of 1.0 nm within the solid solution region 13. 2 More than 10nm 2 The following sizes and 1.0×10 15 / cm 3 The above 1.0 × 10 17 / cm 3 Black spot-like defects 13a of the following density are formed.

[0035] Figure 2 is a schematic cross-sectional view of a second example of an interposer wafer according to the present invention. The difference between wafer 2 shown in Figure 2 and wafer 1 shown in Figure 1 is that in wafer 2 shown in Figure 2, the silicon wafer is composed of a silicon epitaxial wafer in which a silicon epitaxial layer 12 is formed on the surface of a bulk silicon wafer 11. In this case, the solid solution region 13 is provided in the surface layer of the silicon epitaxial layer 12. The silicon epitaxial layer 12 can be formed on the bulk silicon wafer 11 under general conditions by the CVD method.

[0036] By using a silicon epitaxial wafer with a low oxygen concentration and free of grown-in defects as the silicon wafer constituting the interposer, the influence of crystal defects and oxygen in the bulk silicon wafer 11 can be significantly reduced.

[0037] Among these silicon epitaxial wafers, an epitaxial silicon wafer in which a silicon epitaxial layer is formed on the surface of a bulk single-crystal silicon wafer can be suitably used.

[0038] The thickness of the silicon epitaxial layer 12 is preferably between 100 μm and 300 μm. Since the thickness of a typical interposer is about 100 μm to 300 μm, by setting the thickness of the silicon epitaxial layer 12 to between 100 μm and 300 μm, the entire area of ​​the silicon wafer used as an interposer can be composed of the silicon epitaxial layer 12, thereby eliminating the effects of crystal defects and oxygen in the bulk silicon wafer 11.

[0039] Figure 3 is a schematic cross-sectional view of a third example of an interposer wafer according to the present invention. The wafer 3 shown in Figure 3 comprises a bulk silicon wafer 11 as a silicon wafer and a solid solution region 13 formed on the surface of the bulk silicon wafer 11 in which elements contributing to gettering are solid-dissolved, wherein the solid solution region 13 is 1.0 nm 2 More than 10nm 2 The following sizes and 1.0×10 15 / cm 3 The above 1.0 × 10 17 / cm 3 Includes black spot-like defects 13a of the following density.

[0040] The wafer 3 shown in Figure 3 is a wafer obtained by heat-treating the wafer 1 shown in Figure 1 at a temperature of 800°C to 1150°C for 1 to 5 minutes in a hydrogen or nitrogen atmosphere to form black spot-like defects 13a within the solid solution region 13. In the interposer manufacturing process, the above heat treatment is applied to the wafer 1 shown in Figure 1 to form black spot-like defects 13a within the solid solution region 13. The above heat treatment may also be performed before the interposer manufacturing process.

[0041] Figure 4 is a schematic cross-sectional view of a fourth example of an interposer wafer according to the present invention. The difference between wafer 4 shown in Figure 4 and wafer 3 shown in Figure 3 is that in wafer 4 shown in Figure 4, the silicon wafer is composed of a silicon epitaxial wafer in which a silicon epitaxial layer 12 is formed on the surface of a bulk silicon wafer 11. In this case, the solid solution region 13 is provided in the surface layer of the silicon epitaxial layer 12. By using this wafer 4, an interposer with excellent gettering ability against heavy metals can also be manufactured.

[0042] (Method for manufacturing wafers for interposers) The method for manufacturing an interposer wafer according to the present invention involves adding ions containing elements that contribute to gettering to the surface layer of a silicon wafer, in a manner of 1.0 × 10⁻⁶ 15 atoms / cm 2 The method is characterized by including an ion implantation step in which the above-mentioned elements are implanted in the following dose amounts to form a solid solution region in the surface layer of the silicon wafer. By setting the dose amount low, it is possible to prevent the occurrence of crystal defects such as stacking faults caused by ion implantation other than black spot defects.

[0043] <Ion implantation process> Figure 5 is a flow chart of a first example of a method for manufacturing an interposer wafer according to the present invention. As shown in Figure 5(a), in the ion implantation step, ions containing elements that contribute to gettering are implanted into the surface layer of the bulk silicon wafer 11, which is a silicon wafer, at a rate of 1.0 × 10⁻¹⁶ 15 atoms / cm 2 The following doses are injected to form a solid solution region 13 in which the above elements are solidly dissolved in the surface layer of the bulk silicon wafer 11. The requirements for the silicon wafer and the elements contributing to gettering in the ion implantation process are the same as those for the silicon wafer and the elements contributing to gettering in the interposer wafer according to the present invention described above, so an explanation is omitted.

[0044] The ions implanted into the bulk silicon wafer 11 (hereinafter also referred to as "implanted ions") can be monomer ions, which are ions of a single atom. Alternatively, the implanted ions can be cluster ions, which are formed by giving a positive or negative charge to clusters of multiple atoms or molecules (usually around 2 to 2000). From the viewpoint of obtaining higher gettering ability, it is preferable that the implanted ions be cluster ions. Conventional devices can be used as monomer ion generators or cluster ion generators.

[0045] When the implanted ions are cluster ions, the compounds to be ionized are not particularly limited, but ethane, methane, carbon dioxide (CO2), etc. can be used as carbon source compounds that can be ionized. Diborane, decaborane (B) can be used as boron source compounds that can be ionized. 10 H 14 ) and the like can be used. For example, when a gas mixture of dibenzyl and decaborane is used as the material gas, a hydrogen compound cluster in which carbon, boron, and hydrogen are aggregated can be produced. Also, cyclohexane (C6H 12 If ) is used as the material gas, cluster ions consisting of carbon and hydrogen can be generated. In particular, pyrene (C) is a suitable carbon source compound. 16 H 10 ), dibenzyl (C 14 H 14 Cluster C generated from ) etc. n H m It is preferable to use (1≦n≦16, 3≦m≦10) because it is easier to control the small-sized cluster ion beam. Suitable carbon source compounds for generating such small-sized cluster ions include CH3, C2H3, C3H5, and C5H5.

[0046] It is also preferable to use a compound containing both carbon and the dopant element as the compound to be ionized. By implanting such a compound as a cluster ion, both carbon and the dopant element can be dissolved in a single implantation.

[0047] When injecting cluster ions, the cluster size can be appropriately set to be 2 to 100, preferably 60 or less, more preferably 50 or less.

[0048] As the ion implantation conditions, in addition to the above-mentioned ion species, implantation energy, dose amount, dose rate (parameter corresponding to the beam current value), irradiation angle, temperature of the silicon wafer during ion implantation, and thickness of the protective oxide film can be mentioned.

[0049] In the present invention, the dose amount of the implanted ions is 1.0×10 15 atoms / cm 2 or less. Thereby, when the silicon wafer 11 after the ion implantation process is heat-treated at a temperature of 800°C or higher and 1150°C or lower for 1 minute or longer and 5 minutes or shorter in an atmosphere of hydrogen or nitrogen, within the solid solution region 13, black dot-like defects 13a with a size of 1.0 nm 2 or more and 10 nm 2 or less and a density of 1.0×10 15 / cm 3 or more and 1.0×10 17 / cm 3 or less can be formed. The dose amount of the implanted ions is preferably 1.0×10 13 atoms / cm 2 or more. Thereby, sufficient gettering ability for heavy metals can be imparted to the interposer manufactured using the manufactured wafer for interposer.

[0050] Regarding the six parameters other than the dose amount of the above-mentioned ions, ion implantation is performed under the condition that a solid solution region 13 in which elements contributing to gettering are solid-dissolved is formed in the surface layer portion of the bulk silicon wafer 11 by appropriately setting them.

[0051] The implantation energy is generally in the range of 5 to 200 keV both when injecting monomer ions and when injecting cluster ions.

[0052] The beam current value can be, for example, within the range of 100 μA to 3000 μA. The dose rate corresponding to this range is 1.0×10 12 ~5.0×10 14 . Also, the irradiation angle of the ions with respect to the surface layer of the wafer can be, for example, within the range of -7.0 degrees to +7.0 degrees.

[0053] The temperature of the bulk silicon wafer 11 during ion implantation can be room temperature. Also, by making the temperature of the bulk silicon wafer 11 during ion implantation lower than 25°C, more preferably 0°C or lower, a higher gettering ability can be obtained. The temperature of the bulk silicon wafer 11 during ion implantation is preferably -200°C or higher, more preferably -120°C or higher.

[0054] Thus, the interposer wafer 1 shown in FIG. 1 can be manufactured.

[0055] <Epitaxial layer formation step> Note that, before the ion implantation step, an epitaxial layer formation step of forming a silicon epitaxial layer 12 on the surface of the bulk silicon wafer 11 is further included, and elements contributing to gettering can be implanted into the surface layer of the silicon epitaxial layer 12 in the ion implantation step. Thereby, the interposer wafer 2 shown in FIG. 2 can be manufactured.

[0056] FIG. 6 is a flow chart of a second example of a method for manufacturing an interposer wafer according to the present invention. As shown in FIG. 6(b), before the ion implantation step, a silicon epitaxial layer 12 is formed on the surface of the bulk silicon wafer 11. Then, as shown in FIG. 6(c), ions are implanted into the surface layer of the silicon epitaxial layer 12. Thereby, a solid solution region 13 in which elements contributing to gettering are solid-dissolved is formed in the silicon epitaxial layer 12.

[0057] <Heat treatment step> Furthermore, after the ion implantation process, the process may further include a heat treatment step in which the ion-implanted silicon wafer is subjected to a heat treatment in a hydrogen or nitrogen atmosphere at a temperature of 800°C to 1150°C for 1 to 5 minutes to form black spot-like defects 13a within the solid solution region 13. This makes it possible to manufacture the interposer wafer 3 shown in Figure 3.

[0058] Figure 7 shows a flow chart of a third example of a method for manufacturing an interposer wafer according to the present invention. After the ion implantation step shown in Figure 7(b), the ion-implanted bulk silicon wafer 11 is subjected to heat treatment in a hydrogen or nitrogen atmosphere at a temperature of 800°C to 1150°C for 1 to 5 minutes. As a result, black spot-like defects 13a are formed in the solid solution region 13, as shown in Figure 7(c).

[0059] In Figure 7, the interposer wafer is made of a bulk silicon wafer 11, but it can be made of a silicon epitaxial wafer. This makes it possible to manufacture an interposer wafer 4 in which black spot-like defects 13a are formed within the solid-liquid region 13 of the silicon epitaxial layer 12, as shown in Figure 4.

[0060] Figure 8 shows a flow chart of a fourth example of the method for manufacturing an interposer wafer according to the present invention. After the epitaxial layer formation step shown in Figure 8(b) and the ion implantation step shown in Figure 8(c), the ion-implanted silicon epitaxial wafer is subjected to a heat treatment in a hydrogen or nitrogen atmosphere at a temperature of 800°C to 1150°C for 1 to 5 minutes. As a result, black spot-like defects 13a are formed in the solid solution region 13 of the silicon epitaxial layer 12, as shown in Figure 8(d).

[0061] (Interposer) The interposer according to the present invention comprises a silicon wafer, a solid solution region formed on the surface of the silicon wafer in which elements contributing to gettering are solidly dissolved, a through hole penetrating the silicon wafer, an oxide film covering the surface of the silicon wafer including the inside of the through hole, and a through electrode provided in the through hole covered by the oxide film, wherein the solid solution region is 1.0 nm 2 More than 10nm 2 The following sizes and 1.0×10 15 / cm 3 The above 1.0 × 10 17 / cm 3 It is characterized by containing black spot-like defects of the following density.

[0062] Figure 9 is a schematic cross-sectional view showing a first example of an interposer according to the present invention. The interposer 100 shown in Figure 9 comprises a bulk silicon wafer 11 as a silicon wafer, a solid solution region 13 formed on the surface of the bulk silicon wafer 11 in which elements contributing to gettering are solid-dissolved, a through hole 14 penetrating the bulk silicon wafer 11, an oxide film 15 covering the surface of the bulk silicon wafer 11 including the inside of the through hole 14, and a through electrode 16 provided in the through hole 14 covered by the oxide film 15. The solid solution region 13 is 1.0 nm 2 More than 10nm 2 The following sizes and 1.0×10 15 / cm 3 The above 1.0 × 10 17 / cm 3 It includes black spot-like defects of the following density.

[0063] In the interposer 100, a solid solution region 13 is provided on the surface of the bulk silicon wafer 11 in which elements contributing to gettering are solid-dissolved, and since the solid solution region 13a contains black spot-like defects, it has excellent gettering ability for heavy metals.

[0064] Figure 10 is a schematic cross-sectional view showing a second example of an interposer according to the present invention. The difference between the interposer 200 shown in Figure 10 and the interposer 100 shown in Figure 9 is that in the interposer 200 shown in Figure 10, the silicon wafer is composed of a silicon epitaxial wafer in which a silicon epitaxial layer 12 is formed on the surface of a bulk silicon wafer 11. This makes it possible to significantly reduce the effects of crystal defects and oxygen in the bulk silicon wafer 11.

[0065] Figure 11 shows an example of the configuration of a through electrode 16 in an interposer according to the present invention. As shown in Figure 11, the through electrode 16 can be composed of, for example, a barrier layer 16a provided on an oxide film 15, a seed layer 16b provided on the barrier layer 16a, and a packing layer 16c filled in a through hole 14 in which the seed layer 16b is provided. Specifically, the barrier layer 16a can be made of TiN, the seed layer 16b of Cu, and the packing layer 16c of Cu.

[0066] (Manufacturing method for interposers) The method for manufacturing an interposer according to the present invention is characterized by comprising: a polishing step of adjusting the thickness of an interposer wafer manufactured by the interposer wafer manufacturing method according to the present invention described above by polishing the back surface of the interposer wafer; a through-hole forming step of forming through holes in the interposer wafer; an oxide film forming step of forming an oxide film on the surface of the interposer wafer, including the inside of the through holes; and an electrode forming step of forming through electrodes in the through holes of the interposer wafer on which the oxide film has been formed.

[0067] <Polishing process> Figure 12 shows a flow chart of a first example of the interposer manufacturing method according to the present invention. First, in the polishing step, the back surface of the interposer wafer 1 or 2 (Figure 12(a)) manufactured by the interposer wafer manufacturing method according to the present invention described above is polished to adjust the thickness of the interposer wafer 1 or 2 (Figure 12(b)).

[0068] As mentioned above, the polishing process described above is preferable so that the thickness of wafer 1 or 2 after polishing is between 100 μm and 300 μm.

[0069] <Through hole formation process> Next, in the through-hole formation process, a through-hole 14 is formed in wafer 1 or 2 (Figure 12(c)).

[0070] The through-holes 14 can be formed, for example, by ion etching. Furthermore, the size and number of the through-holes 14 can be appropriately set according to the design of the semiconductor devices to be placed above and below the interposer being manufactured.

[0071] <Oxide film formation process> Next, in the oxide film formation process, an oxide film 15 is formed on the surface of wafer 1 or 2, including the inside of the through hole 14 (Figure 12(d)).

[0072] The oxide film 15 can be formed by heat-treating wafer 1 or 2 in an oxidizing atmosphere at a temperature of 800°C to 1000°C. The thickness of the formed oxide film can be, for example, 0.5 μm to 1.0 μm.

[0073] <Electrode formation process> Then, in the electrode formation process, through electrodes 16 are formed in through holes 14 of wafer 1 or 2 on which the oxide film 15 has been formed (Figure 12(e)).

[0074] Furthermore, if the through electrode 16 has the configuration shown in Figure 11, the barrier layer 16a made of TiN can be formed by MOCVD or PVD (sputtering). Similarly, the seed layer 16b made of Cu can also be formed by MOCVD or PVD (sputtering). In addition, the filling layer 16c made of Cu can be formed by filling the through hole 14 with Cu or by conformal plating.

[0075] In this way, the interposer 100 shown in Figure 9 can be manufactured.

[0076] Figure 13 shows a flow chart of a second example of the method for manufacturing an interposer according to the present invention. The difference between the flow chart shown in Figure 13 and the flow chart shown in Figure 12 is that in the flow chart shown in Figure 13, an interposer wafer 2 or 4, which is an epitaxial silicon wafer obtained according to the flow chart shown in Figure 6 or 8, is used as the silicon wafer to be subjected to the polishing process (Figure 13(a)). This makes it possible to manufacture the interposer 200 shown in Figure 10. [Examples]

[0077] The following describes examples of the present invention, but the present invention is not limited to these examples.

[0078] A wafer 1 for an interposer was manufactured according to the method for manufacturing an interposer wafer according to the present invention. First, a silicon wafer (diameter: 300 mm, thickness: 775 μm, dopant: boron) was prepared. Next, a cluster ion generator (manufactured by Nisshin Ion Equipment Co., Ltd., model number: CLARIS) was used to generate C2H3 clusters from cyclohexane, and the carbon dose was set to 1.0 × 10⁻⁶. 15 Carbonates / cm 2 As a result, ions were implanted into the surface layer of a silicon wafer, forming a solid solution region 13 in which carbon was solidly dissolved in the surface layer of the silicon wafer (ion implantation process). At that time, the ion implantation energy was 80 keV, the beam current value was 850 μA, the irradiation angle was 0 degrees, and the wafer temperature during irradiation was 25°C.

[0079] A silicon wafer with ions implanted was heat-treated at 1150°C for 5 minutes in a hydrogen atmosphere. The cleavage plane of the heat-treated silicon wafer was observed in bright mode using a cross-sectional TEM. The distribution of black spot-like defects 13a in the solid solution region 13 is shown in Figure 14(a). The observed results showed that the density of black spot-like defects 13a was 3.0 × 10⁻⁶. 16 / cm 3 That was the case.

[0080] Furthermore, black spot-like defects 13a were detected using image analysis software (Pigman, Wafermasters), and the area and size of each black spot-like defect 13a were measured. The relationship between the area and number of black spot-like defects is shown in Figure 14(b). As is clear from Figure 14(b), the size of the black spot-like defects 13a in the solid solution region 13 is approximately 10 nm. 2 The results were as follows:

[0081] When the carbon and hydrogen concentrations were measured in the silicon wafer after ion implantation as described above, the peak carbon concentration was 6.85 × 10⁻⁶. 19 atoms / cm 3 This revealed that it possesses high gettering ability. Furthermore, the hydrogen concentration was 9.62 × 10⁻⁶. 17 atoms / cm 3 This indicates that a high hydrogen passivation effect can be expected. Therefore, interposers manufactured from these interposer wafers can also be expected to have high gettering capability against heavy metals and a high hydrogen passivation effect. [Industrial applicability]

[0082] According to the present invention, it is possible to provide an interposer wafer that can reduce contamination by heavy metals. [Explanation of symbols]

[0083] 1,2,3,4 Interposer wafers 11. Bulk silicon wafers 12 Silicone epitaxial layer 13 Solid solution region 13a Black spot-like defects 14 Through holes 15 Oxide film 16 Through electrode 16a Barrier layer 16b Seed layer 16c packed bed 100,200 Interposers

Claims

1. The device comprises a silicon wafer and a solid solution region formed on the surface of the silicon wafer in which elements contributing to gettering are solidly dissolved. When heat treatment is performed in a hydrogen or nitrogen atmosphere at a temperature of 800°C to 1150°C for 1 minute to 5 minutes, the solid solution region is 1.0 nm ２ 10nm or more ２ The following sizes and 1.0 x 10 １５ / cm ３ The above 1.0 x 10 １７ / cm ３ Interposer wafers in which black spot-like defects of the following density are formed.

2. The device comprises a silicon wafer and a solid solution region formed on the surface of the silicon wafer in which elements contributing to gettering are solidly dissolved. The solid solution region is 1.0 nm ２ or more and 10 nm ２ or less in size and 1.0×10 １５ / cm ３ or more and 1.0×10 １７ / cm ３ or less in density, and contains black dot defects. A wafer for an interposer

3. The element comprises carbon and hydrogen, and the peak concentration of carbon in the solid solution region is 1.0 × 10⁻⁶. ２０ atoms / cm ３ The following is true, and the hydrogen concentration is 5.0 × 10⁻⁶. ２０ atoms / cm ３ The wafer for an interposer according to claim 1 or 2, which is as follows:

4. The interposer wafer according to claim 1 or 2, wherein the silicon wafer is an epitaxial silicon wafer in which a silicon epitaxial layer is formed on the surface of the silicon wafer, and the solid solution region is formed in the surface layer of the silicon epitaxial layer.

5. Ions of elements that contribute to gettering are added to the surface of the silicon wafer in a quantity of 1.0 × 10⁻¹⁰ units. １５ atoms / cm ２ An ion implantation step is performed by implanting the following doses to form a solid solution region in the surface layer of the silicon wafer in which the elements of the ions are solidly dissolved, A heat treatment step in which the silicon wafer into which the ions have been implanted is subjected to a heat treatment in a hydrogen or nitrogen atmosphere at a temperature of 800°C to 1150°C for 1 minute to 5 minutes to form black spot-like defects in the solid solution region, A method for manufacturing wafers for interposers.

6. The method for manufacturing an interposer wafer according to claim 5, wherein the ions are cluster ions containing carbon and hydrogen.

7. The process further includes an epitaxial layer formation step, which involves forming a silicon epitaxial layer on the surface of the silicon wafer prior to the ion implantation step, A method for manufacturing an interposer wafer according to claim 5 or 6, wherein in the ion implantation step, the ions are implanted into the surface layer of the silicon epitaxial layer to form the solid solution region on the surface of the silicon epitaxial layer.

8. The device comprises a silicon wafer, a solid solution region formed on the surface of the silicon wafer in which elements contributing to gettering are solidly dissolved, a through hole penetrating the silicon wafer, an oxide film covering the surface of the silicon wafer including the inside of the through hole, and a through electrode provided within the through hole covered by the oxide film. The solid solution region is 1.0 nm ２ 10nm or more ２ The following sizes and 1.0 x 10 １５ / cm ３ The above 1.0 x 10 １７ / cm ３ An interposer containing black spot-like defects of the following density.

9. The element comprises carbon and hydrogen, and the peak concentration of carbon in the solid solution region is 1.0 × 10⁻⁶. ２０ atoms / cm ３ The following is true, and the hydrogen concentration is 5.0 × 10⁻⁶. ２０ atoms / cm ３ The interposer according to claim 8, which is as follows:

10. The interposer according to claim 8 or 9, wherein the silicon wafer is an epitaxial silicon wafer in which a silicon epitaxial layer is formed on the surface of the silicon wafer, and the solid solution region is formed on the surface of the silicon epitaxial layer.

11. A polishing step to adjust the thickness of an interposer wafer by polishing the back surface of an interposer wafer manufactured by the method for manufacturing an interposer wafer according to claim 5 or 6, A through-hole forming step of forming through holes in the wafer for the interposer, An oxide film formation step in which an oxide film is formed on the surface of the interposer wafer, including the inside of the through hole, An electrode formation step of forming through electrodes in the through holes of the interposer wafer on which the oxide film is formed, A method for manufacturing an interposer, including the method described above.

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