Substrate processing method and substrate processing apparatus

Abstract

Provided are a substrate processing method and a substrate processing apparatus for applying stress to a substrate.　This substrate processing method involves: forming a metal film, in which the volume changes upon oxidation, on the reverse surface of a substrate; forming an oxide film, through which oxygen passes, on the obverse surface of the metal film; and oxidizing the metal film and applying stress to the substrate.

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus. [Background technology]

[0002] It is known to provide a film on the back surface of a semiconductor substrate that applies stress to the semiconductor substrate. Patent Document 1 discloses a method for manufacturing a semiconductor device that reduces warpage of the substrate by depositing an insulating film having tensile stress on the back surface of the semiconductor substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-45680 Summary of the Invention [Problem to be solved by the invention]

[0004] In one aspect, the present disclosure provides a substrate processing method and a substrate processing apparatus for applying stress to a substrate. [Means for solving the problem]

[0005] In order to solve the above problem, according to one aspect, a back surface of a substrate is provided with a 、 When oxidized expansion changes Made of metal materials Metal film deposition and On the surface of the metal film 、 oxygen of transparent Possible Deposits an oxide film a step of supplying oxygen to the substrate; and a step of oxidizing the substrate with oxygen that has permeated the oxide film. The metal film is oxidized. The volume of the metal film is expanded by On the substrate compression Apply stress and A method for processing a substrate is provided. [Effects of the Invention]

[0006] According to one aspect, the present disclosure can provide a substrate processing method and a substrate processing apparatus for applying stress to a substrate. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a configuration diagram showing an example of a substrate processing apparatus according to an embodiment; [Figure 2] FIG. 1 is a cross-sectional view of a film forming apparatus. [Figure 3] FIG. 2 is a cross-sectional view of an example of an oxidation treatment device. [Figure 4] 5 is an example of a flowchart showing the operation of the substrate processing apparatus according to the first embodiment. [Figure 5] 2 is a schematic cross-sectional view of an example of a semiconductor substrate processed by the substrate processing apparatus of the first embodiment. [Figure 6A] 1 is an example of a graph showing the density of states of Ru. [Figure 6B] An example of a graph showing the density of states of Co. [Figure 7] 10 is an example of a flowchart showing the operation of the substrate processing apparatus according to the second embodiment. [Figure 8] FIG. 10 is a schematic cross-sectional view of a semiconductor substrate processed by the substrate processing apparatus according to the second embodiment. [Figure 9] FIG. 11 is a schematic cross-sectional view of a semiconductor substrate processed by the substrate processing apparatus according to the third embodiment. [Figure 10] FIG. 11 is a schematic cross-sectional view of a semiconductor substrate processed by the substrate processing apparatus according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] <Substrate processing apparatus 10> A substrate processing apparatus 10 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a structural diagram showing an example of the substrate processing apparatus 10 according to an embodiment.

[0010] The substrate processing apparatus 10 includes a vacuum transfer chamber 1 that is maintained under vacuum and that transfers a substrate W, which is an example of a semiconductor substrate, and a plurality of processing modules that are airtightly connected to the periphery of the vacuum transfer chamber 1 and perform predetermined processing on the substrate W. In this example, for example, four processing modules are provided, but it is sufficient that one or more processing modules are provided. Hereinafter, the four processing modules are referred to as processing chambers PM1, PM2, PM3, and PM4, and are collectively referred to as processing chamber PM. The four processing chambers PM1 to PM4 and the two load lock chambers 2 are connected to each side of the hexagonal vacuum transfer chamber 1.

[0011] In the processing chambers PM1 to PM4, predetermined processing is performed on the substrate W. For example, the processing performed in the processing chambers PM1 to PM4 may be a film formation process or an oxidation-reduction process. The processing chamber PM will be described later with reference to FIGS. 2 and 3.

[0012] A substrate transfer mechanism 7 for transferring the substrate W is provided inside the vacuum transfer chamber 1. The substrate transfer mechanism 7 transfers the substrate W to and from the processing chambers PM1 to PM4 and the load lock chamber 2.

[0013] The load lock chamber 2 is airtightly connected to the vacuum transfer chamber 1 and switches the internal atmosphere between a vacuum atmosphere and an air atmosphere. In this embodiment, two load lock chambers 2 are provided, but the number is not limited to this.

[0014] The two load lock chambers 2 are airtightly connected to a common atmospheric transfer chamber 3 for transferring substrates W in an atmospheric atmosphere. The atmospheric transfer chamber 3 is provided with loading ports 4 with loading tables at multiple locations for loading FOUPs 5, each containing, for example, 25 substrates W. In this embodiment, loading tables are provided at four locations, but this is not limited to this. A pressing mechanism 41 functions to press the FOUPs 5 on the loading tables toward the atmospheric transfer chamber 3.

[0015] Between the two load lock chambers 2, an alignment mechanism 8 for aligning the substrate W is installed.

[0016] A substrate transfer mechanism 9 for transferring the substrate W is provided inside the atmospheric transfer chamber 3. The substrate transfer mechanism 9 transfers the substrate W to the load lock chamber 2, the FOUP 5 of the load port 4, and the alignment mechanism 8.

[0017] Gate valves G are provided between the vacuum transfer chamber 1 and the processing chambers PM1 to PM4, between the vacuum transfer chamber 1 and the load lock chamber 2, and between the load lock chamber 2 and the atmospheric transfer chamber 3, and the substrate W is transferred airtight by opening and closing the gate valves G.

[0018] The substrate processing apparatus 10 having such a configuration has a control unit 6 that is configured, for example, by a computer. The control unit 6 controls the entire substrate processing apparatus 10. The control unit 6 has a memory and a CPU, and the memory stores programs and recipes used to perform processing in each processing chamber PM. The programs include programs related to input operations and display of processing parameters. The recipes set process conditions such as the temperature to which the processing chamber PM is heated, processing procedures, and transport paths for substrates W.

[0019] The CPU transports the substrate W removed from the FOUP 5 to the plurality of processing chambers PM along a predetermined route using the substrate transport mechanism 9 and the substrate transport mechanism 7 in accordance with the program and recipe stored in the memory. The CPU then executes a predetermined process in each processing chamber PM based on the process conditions set in the recipe. The program may be stored in a storage unit such as a computer storage medium, such as a flexible disk, compact disk, hard disk, or MO (magneto-optical disk), and installed in the control unit 6, or may be downloaded using the communication function.

[0020] The unprocessed substrate W unloaded from the FOUP 5 is transported to the load lock chamber 2 by the substrate transport mechanism 9. Next, the unprocessed substrate W is transported to the processing chamber PM by the substrate transport mechanism 7. In the processing chamber PM, the substrate W is subjected to a desired process (for example, a film formation process, etc.). After being processed in the processing chamber PM, the substrate W may be transported by the substrate transport mechanism 7 to another processing chamber PM where it may be further processed. After being processed, the substrate W is returned to the FOUP 5 via the load lock chamber 2.

[0021] Next, a film forming apparatus 100 will be described as an example of the processing chamber PM. Here, a plasma sputtering apparatus will be described as an example of the film forming apparatus 100. FIG. 2 is an example of a cross-sectional view of the film forming apparatus 100.

[0022] The film forming apparatus 100 has a grounded processing vessel 101 made of a metal such as aluminum. A bottom 102 of the processing vessel 101 is provided with an exhaust port 103 and a gas inlet 107. An exhaust pipe 104 is connected to the exhaust port 103. A throttle valve 105 for adjusting pressure and a vacuum pump 106 are connected to the exhaust pipe 104. A gas supply pipe 108 is connected to the gas supply pipe 108. A gas supply source 109 is connected to the gas supply pipe 108 for supplying a plasma excitation gas such as Ar gas and other necessary gases such as N2 gas. A gas control unit 110 including a gas flow rate controller, a valve, etc. is installed in the gas supply pipe 108.

[0023] A mounting mechanism 111 is provided within the processing vessel 101 for mounting a substrate W to be processed. The mounting mechanism 111 includes a disk-shaped mounting table 112 and a hollow cylindrical support 113 that supports the mounting table 112. The mounting table 112 is made of a conductive material such as an aluminum alloy and is grounded via the support 113. A cooling jacket 114 is provided within the mounting table 112, and a coolant is supplied into the cooling jacket 114 to cool the mounting table 112. A resistance heater 115 coated with an insulating material is embedded on the cooling jacket 114 within the mounting table 112. The substrate temperature is controlled to a predetermined temperature by controlling the supply of coolant to the cooling jacket 114 and the power supply to the resistance heater 115.

[0024] An electrostatic chuck 116, which is configured by an electrode 116b embedded in a dielectric member 116a, is provided on the upper surface side of the mounting table 112 for electrostatically attracting the substrate W. The lower part of the support pillar 113 extends downward through an insertion hole 117 formed in the center of the bottom 102 of the processing vessel 101. The support pillar 113 can be raised and lowered by an elevating mechanism (not shown), thereby raising and lowering the entire mounting mechanism 111.

[0025] An expandable metal bellows 118 is provided to surround the support 113. The upper end of the metal bellows 118 is joined to the lower surface of the mounting table 112. The lower end of the metal bellows 118 is joined to the upper surface of the bottom 102 of the processing vessel 101, and allows the mounting mechanism 111 to move up and down while maintaining the airtightness inside the processing vessel 101.

[0026] For example, three support pins 119 (only two are shown) are vertically provided on the bottom 102 facing upward. Furthermore, pin insertion holes 120 are formed in the mounting table 112 corresponding to the support pins 119. When the mounting table 112 is lowered, the upper ends of the support pins 119 that pass through the pin insertion holes 120 receive the substrate W, and the substrate W can be transferred between the support pins 119 and a transfer arm (not shown) that enters from the outside. A transfer port 121 is provided in the lower sidewall of the processing vessel 101 to allow the transfer arm to enter, and this transfer port 121 is provided with an openable and closable gate valve G.

[0027] A chuck power supply 123 is connected to the electrode 116b of the electrostatic chuck 116 via a power supply line 122. A DC voltage is applied from the chuck power supply 123 to the electrode 116b, thereby attracting and holding the substrate W by electrostatic force. A bias high-frequency power supply 124 is also connected to the power supply line 122, and high-frequency bias power is supplied to the electrode 116b of the electrostatic chuck 116 via the power supply line 122, thereby applying the bias power to the substrate W. The frequency of this high-frequency power is preferably 400 kHz to 60 MHz, and for example, 13.56 MHz is adopted.

[0028] Meanwhile, a dielectric transmission plate 131 is airtightly installed on the ceiling of the processing vessel 101 via a seal member 132. A plasma generation source 133 is installed above the transmission plate 131 to generate plasma in the processing space S within the processing vessel 101 by converting a plasma excitation gas into plasma.

[0029] The plasma generation source 133 has an induction coil 134 provided corresponding to the transmission plate 131. A high frequency power supply 135 for generating plasma, for example, 13.56 MHz, is connected to the induction coil 134, and high frequency power is introduced into the processing space S via the transmission plate 131 to form an induced electric field.

[0030] A metal baffle plate 136 that diffuses the introduced high-frequency power is provided directly below the transmission plate 131. A target 137 made of Cu or a Cu alloy and having, for example, a ring-shaped (truncated conical shell) cross section that slopes inward is provided below the baffle plate 136 so as to surround the upper lateral side of the processing space S. A variable voltage DC power supply 138 for the target that applies DC power to attract Ar ions is connected to the target 137. Note that an AC power supply may be used instead of the DC power supply.

[0031] In addition, a magnet 139 is provided on the outer periphery of the target 137. The target 137 is sputtered by Ar ions in the plasma, releasing sputtered particles, many of which are ionized as they pass through the plasma.

[0032] A cylindrical protective cover member 140 made of, for example, aluminum or copper is provided below the target 137 so as to surround the processing space S. The protective cover member 140 is grounded. The inner end of the protective cover member 140 is provided so as to surround the outer periphery of the mounting table 112.

[0033] In the film formation apparatus configured as described above, the substrate W is carried into the processing chamber 101, placed on the mounting table 112 so that the surface of the substrate W to be subjected to film formation (the back surface of the substrate, which will be described later) faces the processing space S, and is attracted by the electrostatic chuck 116, and the following operations are performed under the control of the control unit 6. At this time, the temperature of the mounting table 112 is controlled by controlling the supply of refrigerant to the cooling jacket 114 and the power supply to the resistance heater 115 based on the temperature detected by a thermocouple (not shown).

[0034] First, the vacuum pump 106 is operated to create a predetermined vacuum state in the processing vessel 101, and the gas control unit 110 is operated to flow Ar gas at a predetermined flow rate while controlling the throttle valve 105 to maintain the predetermined vacuum level inside the processing vessel 101. Thereafter, DC power is applied to the target 137 from the DC power supply 138, and further, RF power (plasma power) is supplied from the RF power supply 135 of the plasma generation source 133 to the induction coil 134. Meanwhile, the bias RF power supply 124 supplies a predetermined bias RF power to the electrode 116b of the electrostatic chuck 116.

[0035] As a result, in the processing vessel 101, argon plasma is formed by the high frequency power supplied to the induction coil 134, generating argon ions, which are attracted by the DC voltage applied to the target 137 and collide with the target 137, sputtering the target 137 and releasing particles. At this time, the amount of released particles is optimally controlled by the DC voltage applied to the target 137.

[0036] Furthermore, most of the particles from the sputtered target 137 are ionized as they pass through the plasma, and the ionized particles and electrically neutral atoms are scattered downward as a mixture. At this time, the pressure inside the processing vessel 101 can be increased to a certain degree, thereby increasing the plasma density, thereby enabling the particles to be ionized with high efficiency. The ionization rate at this time is controlled by the high-frequency power supplied from the high-frequency power supply 135.

[0037] When the ions enter an ion sheath region having a thickness of about several mm, which is formed on the surface of the substrate W by the bias high-frequency power applied from the bias high-frequency power supply 124 to the electrode 116b of the electrostatic chuck 116, they are attracted and accelerated toward the substrate W with strong directionality, and are deposited on the substrate W. This causes the sputtered particles to form a film.

[0038] Next, an oxidation treatment device 200 will be described as an example of the treatment chamber PM. Fig. 3 is a cross-sectional view of an example of the oxidation treatment device.

[0039] 3 is a cross-sectional view showing an example of an oxidation treatment apparatus. This oxidation treatment apparatus has a processing vessel 201 formed into a cylindrical shape from, for example, aluminum or the like. Inside the processing vessel 201, a mounting table 202 made of, for example, a ceramic material such as AlN is arranged on which a substrate W is placed, and a heater 203 is provided within this mounting table 202. This heater 203 generates heat when power is supplied from a heater power supply (not shown). Three substrate support pins (not shown) for transporting the substrate are provided on the mounting table 202 so that they can be protruded and retracted from the surface of the mounting table 202.

[0040] An exhaust port 211 is provided at the bottom of the processing vessel 201, and an exhaust pipe 212 is connected to the exhaust port 211. A throttle valve 213 for adjusting the pressure and a vacuum pump 214 are connected to the exhaust pipe 212, so that the inside of the processing vessel 201 can be evacuated. Meanwhile, a substrate loading / unloading port 221 is formed in the sidewall of the processing vessel 201, and the substrate loading / unloading port 221 can be opened and closed by a gate valve G. Then, the substrate W is loaded and unloaded with the gate valve G open.

[0041] A gas inlet 231 is formed in the center of the ceiling wall of the processing vessel 201. A gas supply pipe 232 is connected to the gas inlet 231, and a gas supply source 233 is connected to the gas supply pipe 232 to supply a processing gas used in the oxidation process. In addition, a gas control unit 234 including a gas flow rate controller, a valve, etc. is installed in the gas supply pipe 232.

[0042] In the oxidation treatment apparatus configured as described above, the gate valve G is opened, and the substrate W is placed on the mounting table 202 with the surface to be oxidized (the back surface of the substrate, which will be described later) facing the processing space S. Then, the gate valve G is closed, and the processing vessel 201 is evacuated by the vacuum pump 214, and the pressure inside the processing vessel 201 is adjusted to a predetermined level by the throttle valve 213. The substrate W on the mounting table 202 is heated to a predetermined temperature by the heater 203. Then, a processing gas is supplied from the gas supply source 233 into the processing vessel 201 via the gas supply pipe 232 and the gas inlet 231, and a process of oxidizing a metal film, which will be described later, is performed.

[0043] Next, an example of a process for applying stress to a substrate W by the substrate processing apparatus 10 will be described with reference to Figures 4 and 5. Figure 4 is an example of a flowchart showing the operation of the substrate processing apparatus 10 of the first embodiment. Figure 5 is an example of a cross-sectional schematic view of a semiconductor substrate 510 processed by the substrate processing apparatus 10 of the first embodiment.

[0044] In step S101, a semiconductor substrate 500 (substrate W) is prepared. Here, the semiconductor substrate 500 is accommodated in the FOUP 5.

[0045] Here, metal wiring is formed on one surface of the semiconductor substrate 500. In the following description, the surface on which the metal wiring is formed will be referred to as the front surface of the semiconductor substrate 500, and the surface opposite to the surface on which the metal wiring is formed will be referred to as the back surface of the semiconductor substrate 500. The metal wiring is formed of a metal material such as copper (Cu), ruthenium (Ru), or cobalt (Co).

[0046] In step S102, a metal film 511 is formed on the rear surface of the semiconductor substrate 500. Here, the processing chamber PM1 of the substrate processing apparatus 10 is the film formation apparatus 100 (see FIG. 2). The control unit 6 controls the substrate transfer mechanisms 7 and 9 to transfer the semiconductor substrate 500 to the processing chamber PM1. The control unit 6 controls the processing chamber PM1 (film formation apparatus 100) to form the metal film 511 on the rear surface of the semiconductor substrate 500.

[0047] Here, a film of a metal material whose volume expands when oxidized is deposited as the metal film 511. Examples of metal materials that expand when oxidized include vanadium (V) and tungsten (W).

[0048] In step S103, an oxide film (protective film) 512 is formed on the rear surface of the semiconductor substrate 500. Here, the processing chamber PM2 of the substrate processing apparatus 10 is the film forming apparatus 100 (see FIG. 2). The control unit 6 controls the substrate transfer mechanism 7 to transfer the semiconductor substrate 500 to the processing chamber PM2. The control unit 6 controls the processing chamber PM2 (film forming apparatus 100) to form an oxide film 512 that covers the surface of the metal film 511 formed on the rear surface of the semiconductor substrate 500.

[0049] Here, the oxide film 512 functions as a protective film that covers the metal film 511. The oxide film 512 is also permeable to oxygen (O). The oxide film 512 is made of, for example, zirconia ( ZrO 2) It is formed from hafnia (HfO2) or its complex compounds.

[0050] In step S104, the metal film 511 is oxidized. Here, the processing chamber PM3 of the substrate processing apparatus 10 is the oxidation processing apparatus 200 (see FIG. 3). The control unit 6 controls the substrate transfer mechanism 7 to transfer the semiconductor substrate 500 to the processing chamber PM3. The control unit 6 controls the processing chamber PM3 (oxidation processing apparatus 200) to oxidize the metal film 511.

[0051] Thereafter, the control unit 6 controls the substrate transport mechanisms 7 and 9 to accommodate the processed semiconductor substrate 510 in the FOUP 5.

[0052] 5, the metal film 511 formed on the back surface of the semiconductor substrate 500 is oxidized and expands in volume, in other words, an outward stress is generated (see the open arrow). As a result, a compressive stress can be applied to the semiconductor substrate 500 (see the open arrow).

[0053] For example, if the semiconductor substrate 500 is warped so as to be convex, the warpage of the semiconductor substrate 500 can be reduced by applying a compressive stress to the semiconductor substrate 500 .

[0054] Metal wiring is also formed on the semiconductor substrate 500. As the miniaturization of metal wiring advances, the line width becomes thinner than the mean free path of electrons in the metal, and the wiring resistance increases. In addition, as the pitch between wirings becomes narrower, it is necessary to suppress the migration of metal atoms.

[0055] Fig. 6A is an example of a graph showing the density of states of Ru. Fig. 6B is an example of a graph showing the density of states of Co. The vertical axis shows the density of states (DOS), and the horizontal axis shows the energy (E-Ef) with the Fermi level at 0. The dashed line shows the density of states when no stress is applied, the dashed-dotted line shows the density of states when a uniaxial pressure of 10 GPa is applied, and the solid line shows the density of states when an isotropic pressure of 10 GPa is applied.

[0056] Here, the electrical conductivity σ is expressed by the following formula: where e is the elementary charge, μ is the mobility, n is the carrier density, and ρ is the resistivity.

[0057] σ=eμn=1 / ρ

[0058] As shown in Figure 6A, when Ru is subjected to uniaxial pressure (dashed line) and isotropic pressure (solid line) at the Fermi level (E-Ef=0), the density of states increases compared to when no stress is applied. In other words, the carrier density n of electrons that contribute to electrical conduction increases. This increases the electrical conductivity σ.

[0059] As shown in Figure 6B, when Co is subjected to isostatic pressure (solid line) at the Fermi level (E - E = 0), the density of states increases compared to when no stress is applied. In other words, the carrier density n of electrons that contribute to electrical conduction increases. This increases the electrical conductivity σ.

[0060] By applying a compressive stress to the semiconductor substrate 500 in this manner, the resistance of the metal wiring formed on the semiconductor substrate 500 can be reduced.

[0061] Furthermore, by applying compressive stress to the semiconductor substrate 500, internal stress is generated as a resistance force within the metal crystals of the metal wiring. This resistance force suppresses the movement of metal atoms, thereby making it possible to suppress migration of metal atoms.

[0062] Next, another example of a process for applying stress to a substrate W by the substrate processing apparatus 10 will be described with reference to Figures 7 and 8. Figure 7 is an example of a flowchart showing the operation of the substrate processing apparatus 10 of the second embodiment. Figure 8 is an example of a cross-sectional schematic view of a semiconductor substrate 520 processed by the substrate processing apparatus 10 of the second embodiment.

[0063] In step S201, a semiconductor substrate 500 (substrate W) is prepared. Here, the semiconductor substrate 500 is accommodated in the FOUP 5.

[0064] Here, metal wiring is formed on one surface of the semiconductor substrate 500. In the following description, the surface on which the metal wiring is formed will be referred to as the front surface of the semiconductor substrate 500, and the surface opposite to the surface on which the metal wiring is formed will be referred to as the back surface of the semiconductor substrate 500.

[0065] In step S202, a first metal film 521 is formed on the rear surface of the semiconductor substrate 500. Here, the processing chamber PM4 of the substrate processing apparatus 10 is the film formation apparatus 100 (see FIG. 2). The control unit 6 controls the substrate transfer mechanisms 7 and 9 to transfer the semiconductor substrate 500 to the processing chamber PM4. The control unit 6 controls the processing chamber PM4 (film formation apparatus 100) to form the first metal film 521 on the rear surface of the semiconductor substrate 500.

[0066] Here, a film of a metal material whose volume shrinks when oxidized is formed as the first metal film 521. For example, magnesium (Mg) or strontium (Sr) can be used as the metal material whose deposition shrinks when oxidized.

[0067] In step S203, a first oxide film (protective film) 522 is formed on the back surface of the semiconductor substrate 500. Here, the processing chamber PM2 of the substrate processing apparatus 10 is the film forming apparatus 100 (see FIG. 2). The control unit 6 controls the substrate transfer mechanism 7 to transfer the semiconductor substrate 500 to the processing chamber PM2. The control unit 6 controls the processing chamber PM2 (film forming apparatus 100) to form a first oxide film 522 that covers the surface of the first metal film 521 formed on the back surface of the semiconductor substrate 500.

[0068] Here, the first oxide film 522 functions as a protective film that covers the first metal film 521. The first oxide film 522 is also permeable to oxygen. The first oxide film 522 is made of, for example, zirconia ( ZrO 2) It is formed from hafnia (HfO2) or its complex compounds.

[0069] In step S204, a second metal film 523 is formed on the rear surface of the semiconductor substrate 500. Here, the processing chamber PM1 of the substrate processing apparatus 10 is the film formation apparatus 100 (see FIG. 2). The control unit 6 controls the substrate transfer mechanism 7 to transfer the semiconductor substrate 500 to the processing chamber PM1. The control unit 6 controls the processing chamber PM1 (film formation apparatus 100) to form the second metal film 523 on the rear surface of the semiconductor substrate 500.

[0070] Here, a film of a metal material whose volume expands when oxidized is deposited as the second metal film 523. Examples of metal materials that expand when oxidized include vanadium (V) and tungsten (W).

[0071] In step S205, a second oxide film (protective film) 524 is formed on the back surface of the semiconductor substrate 500. Here, the processing chamber PM2 of the substrate processing apparatus 10 is the film forming apparatus 100 (see FIG. 2). The control unit 6 controls the substrate transfer mechanism 7 to transfer the semiconductor substrate 500 to the processing chamber PM2. The control unit 6 controls the processing chamber PM2 (film forming apparatus 100) to form the second oxide film 524 that covers the surface of the second metal film 523 formed on the back surface of the semiconductor substrate 500.

[0072] Here, the second oxide film 524 functions as a protective film that covers the second metal film 523. The second oxide film 524 is also permeable to oxygen. The second oxide film 524 is made of, for example, zirconia ( ZrO 2) It is formed from hafnia (HfO2) or its complex compounds.

[0073] In step S206, the first metal film 521 and the second metal film 523 are oxidized. Here, the processing chamber PM3 of the substrate processing apparatus 10 is the oxidation processing apparatus 200 (see FIG. 3). The control unit 6 controls the substrate transfer mechanism 7 to transfer the semiconductor substrate 500 to the processing chamber PM3. The control unit 6 controls the processing chamber PM3 (oxidation processing apparatus 200) to oxidize the first metal film 521 and the second metal film 523.

[0074] Thereafter, the control unit 6 controls the substrate transport mechanisms 7 and 9 to accommodate the processed semiconductor substrate 510 in the FOUP 5.

[0075] 8, the first metal film 521 formed on the back surface of the semiconductor substrate 500 is oxidized and its volume shrinks, in other words, an inward stress is generated (see the outline arrow). Also, the second metal film 523 is oxidized and its volume expands, in other words, an outward stress is generated (see the outline arrow). This allows the compressive stress applied to the semiconductor substrate 500 to be increased (see the outline arrow).

[0076] For example, if the semiconductor substrate 500 is warped so as to be convex, the warpage of the semiconductor substrate 500 can be reduced by applying a compressive stress to the semiconductor substrate 500 .

[0077] Furthermore, by applying compressive stress to the semiconductor substrate 500, the resistance of the metal wiring formed in the semiconductor substrate 500 can be reduced. Furthermore, by applying compressive stress to the semiconductor substrate 500, internal stress is generated as a resistance force within the metal crystals of the metal wiring. This resistance force suppresses the movement of metal atoms. Therefore, migration of metal atoms can be suppressed.

[0078] Next, another example of processing for applying stress to the substrate W by the substrate processing apparatus 10 will be described with reference to FIGS.

[0079] FIG. 9 is an example of a schematic cross-sectional view of a semiconductor substrate 530 processed by the substrate processing apparatus 10 of the third embodiment.

[0080] The processed semiconductor substrate 530 has the semiconductor substrate 500, a metal film 531, and an oxide film 532. Here, the metal film 531 is formed as a film of a metal material whose volume shrinks when the metal film 531 is oxidized. The rest is the same as the flow shown in FIG. 4, and therefore, redundant explanations will be omitted.

[0081] 9, the metal film 511 formed on the back surface of the semiconductor substrate 500 is oxidized and its volume shrinks, in other words, an inward stress is generated (see the white arrow). As a result, a tensile stress can be applied to the semiconductor substrate 500 (see the white arrow).

[0082] For example, if the semiconductor substrate 500 is warped so as to be concave, the warpage of the semiconductor substrate 500 can be reduced by applying a tensile stress to the semiconductor substrate 500.

[0083] FIG. 10 is an example of a schematic cross-sectional view of a semiconductor substrate 540 processed by the substrate processing apparatus 10 of the fourth embodiment.

[0084] The processed semiconductor substrate 540 has the semiconductor substrate 500, a first metal film 541, a first oxide film 542, a second metal film 543, and a second oxide film 544. Here, a film of a metal material whose volume expands when the first metal film 541 is oxidized is formed as the first metal film 541. A film of a metal material whose volume contracts when the second metal film 543 is oxidized is formed as the second metal film 543. The rest is the same as the flow shown in FIG. 7, so repeated explanations will be omitted.

[0085] 10, the first metal film 541 formed on the back surface of the semiconductor substrate 500 is oxidized and expands in volume, in other words, generates outward stress (see the outline arrow). Also, the second metal film 543 is oxidized and contracts in volume, in other words, generates inward stress (see the outline arrow). This allows the tensile stress applied to the semiconductor substrate 500 to be increased (see the outline arrow).

[0086] For example, if the semiconductor substrate 500 is warped so as to be concave, the warpage of the semiconductor substrate 500 can be reduced by applying a tensile stress to the semiconductor substrate 500.

[0087] The above describes one embodiment of the substrate processing apparatus 10, but the present disclosure is not limited to the above embodiment, and various modifications and improvements are possible within the scope of the gist of the present disclosure as set forth in the claims.

[0088] The oxidation treatment device 200 (treatment chamber PM3) that performs the oxidation treatment has been described using the oxidation treatment device 200 shown in Fig. 3 as an example, but is not limited to this. The oxidation treatment device may be a device that oxidizes a metal film using any of oxygen plasma, active oxygen, and thermal oxidation.

[0089] Furthermore, the substrate processing apparatus 10 may include a reduction processing apparatus (not shown) that reduces the metal film in addition to an oxidation processing apparatus that oxidizes the metal film. The reduction processing apparatus may be an apparatus that reduces the metal film using any of hydrogen plasma, active hydrogen, and heated hydrogen. This makes it possible to adjust the oxidation state of the metal film. That is, by adjusting the oxidation state of the metal film, it is possible to adjust the stress applied to the semiconductor substrate 500. The oxidation processing apparatus and the reduction processing apparatus may be different apparatuses or may be one oxidation-reduction processing apparatus.

[0090] The oxidation treatment apparatus (reduction treatment apparatus, redox treatment apparatus) may also include a spectrometer (not shown) that irradiates a metal film with dispersed light, a detector (not shown) that detects reflected light from the metal film, and a stress estimation unit (not shown) that estimates the stress distribution of the stress applied by the metal film to the substrate based on the optical absorption spectrum of the reflected light detected by the detector. Here, if tungsten (W) or vanadium (V) is used as the metal film, for example, its oxides, WO3 and W2O5, have electrochromic properties and change their light absorption depending on the oxidation / reduction state. Therefore, by utilizing the electrochromic properties, the oxidation / reduction state of the metal film can be monitored across the entire surface of the substrate W from the absorption spectrum of the reflected light detected by the detector, and this can be used as an indicator of the in-plane stress distribution.

[0091] This application claims priority based on Japanese Patent Application No. 2021-7405, filed on January 20, 2021, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0092] 500 semiconductor substrates 510,520,530,540 Semiconductor substrate 511 Metal Film 512 Oxide film 521 First metal film 522 First oxide film 523 Second metal film 524 Second oxide film 531 Metal Film 532 Oxide film 541 First metal film 542 First oxide film 543 Second metal film 544 Second oxide film

Claims

1. forming a metal film on the rear surface of the substrate, the metal film being made of a metal material whose expansion changes when oxidized; forming an oxygen-permeable oxide film on the surface of the metal film; supplying oxygen to the substrate; and a step of oxidizing the metal film with oxygen that has permeated the oxide film to expand the volume of the metal film and apply a compressive stress to the substrate. Substrate processing method.

2. forming a metal film on a rear surface of the substrate, the metal film being made of a metal material that shrinks in volume when oxidized; forming an oxygen-permeable oxide film on the surface of the metal film; supplying oxygen to the substrate; and a step of oxidizing the metal film with oxygen that has permeated the oxide film to shrink the volume of the metal film and apply tensile stress to the substrate. Substrate processing method.

3. forming a first metal film on a rear surface of the substrate, the first metal film being made of a metal material that shrinks in volume when oxidized; forming a first oxide film on a surface of the first metal film, the first oxide film being permeable to oxygen; forming a second metal film on a surface of the first oxide film, the second metal film being made of a metal material that expands in volume when oxidized; forming a second oxide film on a surface of the second metal film, the second oxide film being permeable to oxygen; supplying oxygen to the substrate; and oxidizing the first metal film and the second metal film with oxygen that has permeated the first oxide film and the second oxide film, thereby contracting a volume of the first metal film and expanding a volume of the second metal film, thereby applying a compressive stress to the substrate. Substrate processing method.

4. forming a first metal film on a rear surface of the substrate, the first metal film being made of a metal material that expands in volume when oxidized; forming a first oxide film on a surface of the first metal film, the first oxide film being permeable to oxygen; forming a second metal film on a surface of the first oxide film, the second metal film being made of a metal material whose volume shrinks when oxidized; forming a second oxide film on a surface of the second metal film, the second oxide film being permeable to oxygen; supplying oxygen to the substrate; and oxidizing the first metal film and the second metal film with oxygen that has permeated the first oxide film and the second oxide film, thereby expanding the volume of the first metal film and contracting the volume of the second metal film, thereby applying a tensile stress to the substrate. Substrate processing method.

5. the metal film formed of a metal material that expands in volume when oxidized is tungsten or vanadium, The oxide film is made of zirconia, hafnia, or a composite compound thereof. The substrate processing method according to claim 1 .

6. the metal film formed of a metal material whose volume shrinks when oxidized is magnesium or strontium, The oxide film is made of zirconia, hafnia, or a composite compound thereof. The substrate processing method according to claim 2 .

7. The first metal film is magnesium or strontium, the second metal film is tungsten or vanadium, the first oxide film and the second oxide film are made of zirconia, hafnia, or a composite compound thereof; The substrate processing method according to claim 3 .

8. The first metal film is tungsten or vanadium, the second metal film is magnesium or strontium; the first oxide film and the second oxide film are made of zirconia, hafnia, or a composite compound thereof; The substrate processing method according to claim 4 .

9. The substrate has metal wiring on its surface.

4. The substrate processing method according to claim 1.

10. An oxidation treatment device that supplies oxygen to a substrate having a metal film formed of a metal material that expands or contracts in volume when oxidized, and oxidizes the metal film; a spectroscope for irradiating the metal film with dispersed light; a detector for detecting reflected light from the metal film; a stress estimation unit that estimates a stress distribution of the stress applied to the substrate by the metal film based on the optical absorption spectrum of the reflected light detected by the detector. Substrate processing equipment.

11. the oxidation treatment device oxidizes the metal film using any one of oxygen plasma, active oxygen, and thermal oxidation; The substrate processing apparatus according to claim 10 .

12. Further comprising a reduction device for reducing the metal oxide film on the back surface of the semiconductor substrate. The substrate processing apparatus according to claim 10 or 11.

13. the reduction device reduces the metal film using any one of hydrogen plasma, active hydrogen, and heated hydrogen. The substrate processing apparatus according to claim 12 .

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