Method of manufacturing semiconductor device and laminate

Abstract

To provide a method of manufacturing a semiconductor device capable of stacking a plurality of substrates without complicating a process.SOLUTION: A method of manufacturing a semiconductor device includes steps of: bonding a substrate and a temporary fixing substrate via an adhesive layer; thinning the substrate in a state in which the temporary fixing substrate is bonded; removing the temporary fixing substrate from the thinned substrate while leaving the adhesive layer; and bonding the substrate from which the temporary fixing substrate has been removed and a main fixing substrate via the adhesive layer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a semiconductor device and a stacked structure. [Background technology]

[0002] As electronic devices become smaller, lighter, and more powerful, there is a demand for higher integration of substrates such as semiconductor wafers and chips. In recent years, the integration of substrates has shifted from two-dimensional (which improves in-plane integration) to three-dimensional (which stacks multiple substrates vertically).

[0003] In order to stack multiple substrates, the substrates are required to be as thin as possible. Such substrates are usually obtained through a process of thinning by grinding the backside. The thinning process of the substrates is performed in a state where the substrates are temporarily fixed to a temporary fixing substrate using a temporary fixing material (see, for example, Patent Document 1). Furthermore, stacking of multiple substrates is performed using, for example, an adhesive (see, for example, Patent Document 2).

[0004] 1A to 1H are schematic partial cross-sectional views showing a conventional method for manufacturing a semiconductor device. Specifically, a substrate 1 and a temporary fixing substrate 2 are stacked and bonded together via a temporary fixing material 3 (FIGS. 1A and 1B). Next, while the substrate 1 is fixed with the temporary fixing substrate 2, the substrate 1 is thinned and electrodes 4 and the like are formed (FIGS. 1C and 1D). Next, the temporary fixing substrate 2 is removed from the thinned substrate 1 (FIG. 1E), and then the temporary fixing material 3 is further removed (FIG. 1F). The substrate 1 from which the temporary fixing substrate 2 and temporary fixing material 3 have been removed is bonded to another substrate 5 via another adhesive 6 (FIGS. 1G and 1H). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-219511 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-226060 Summary of the Invention [Problem to be solved by the invention]

[0006] To remove the temporary fixing material from the thinned substrate, it was necessary to dissolve the temporary fixing material in a solvent or dry etch it. Furthermore, to stack and bond the thinned substrates, a new adhesive had to be used separately. Thus, the stacking of thinned substrates required many steps, making it complicated.

[0007] Furthermore, there is concern that the solvents and dry etching used to remove the temporary fixing material may cause damage to the devices placed on the substrate, and it is desirable to be able to reduce such damage to the devices.

[0008] The present invention has been made in view of the above-mentioned problems, and aims to provide a method for manufacturing a semiconductor device and a stacked body that can stack multiple substrates without complicating the process. [Means for solving the problem]

[0009] The above problem can be solved by the following configuration.

[0010] The method for manufacturing a semiconductor device of the present invention includes the steps of: bonding a substrate and a temporary fixing substrate via an adhesive layer; thinning the substrate with the temporary fixing substrate adhered thereto; removing the temporary fixing substrate from the thinned substrate while leaving the adhesive layer; and bonding the substrate from which the temporary fixing substrate has been removed to a permanent fixing substrate via the adhesive layer.

[0011] The laminate of the present invention is a laminate having a substrate with devices and an adhesive layer disposed on the substrate with devices, and is used to carry out the steps of adhering the substrate with devices to a temporary fixing substrate via the adhesive layer, thinning the substrate with devices with the temporary fixing substrate adhered to it, removing the temporary fixing substrate from the thinned substrate with devices while leaving the adhesive layer behind, and adhering the thinned substrate with devices to the fixing substrate via the adhesive layer.

[0012] The laminate of the present invention is a laminate having a substrate with a device, a temporary fixing substrate, and an adhesive layer disposed between the substrate with the device and the temporary fixing substrate, and after the temporary fixing substrate is removed, the laminate is adhered to the permanent fixing substrate via the adhesive layer. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a method for manufacturing a semiconductor device and a stacked body that can stack a plurality of substrates without complicating the process. [Brief explanation of the drawings]

[0014] [Figure 1] 1A to 1H are schematic partial cross-sectional views showing a conventional method for manufacturing a semiconductor device. [Figure 2] 2A to 2H are schematic partial cross-sectional views illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention. [Figure 3] FIG. 3 is a schematic partial cross-sectional view showing the configuration of the device-equipped substrate of FIG. 2A. [Figure 4] 4A to 4E are schematic partial cross-sectional views showing a method for manufacturing a semiconductor device according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] As a result of extensive research, the inventors have discovered a method for stacking multiple substrates without complicating the process, by removing the temporary fixing substrate from a thinned substrate while leaving the adhesive layer, and then bonding the substrate to the permanent fixing substrate via the remaining adhesive layer.

[0016] Furthermore, in the above-mentioned method, it is desirable that good adhesion to the main fixing substrate can be achieved even after the temporary fixing substrate is removed from the adhesive layer. In response to this, the present inventors have found that by using, as the adhesive layer, preferably an adhesive layer having silanol groups on its surface, more preferably an adhesive layer containing a resin containing a siloxane bond and at least one of an imide bond and an amide bond, good adhesion to the main fixing substrate can be achieved even after the temporary fixing substrate is removed.

[0017] The mechanism behind this is not clear, but is thought to be as follows. The silanol groups on the surface of the adhesive layer readily form hydrogen bonds with functional groups, such as hydroxyl groups and silanol groups, on the surface of the fixing substrate, and when heated, readily aggregate with these functional groups to form chemical bonds, such as siloxane bonds. This allows for stronger adhesion between the fixing substrate and the adhesive layer placed on the thinned substrate simply by pressing them together. After removing the temporary fixing substrate, the adhesion to the permanent fixing substrate via the remaining adhesive layer can be further adjusted by surface treatment or polishing of the adhesive layer, etc. For example, by polishing the surface of the adhesive layer, the surface roughness can be reduced to a predetermined level or less, thereby further increasing the contact area with the permanent fixing substrate.

[0018] A method for manufacturing a semiconductor device according to an embodiment of the present invention will now be described.

[0019] 2A to 2G are schematic partial cross-sectional views showing a method for manufacturing a semiconductor device according to an embodiment of the present invention. Fig. 3 is a schematic partial cross-sectional view showing the configuration of the periphery of device-mounted substrate 11 of Fig. 2A.

[0020] A method for manufacturing a semiconductor device according to one embodiment of the present invention includes: 1) a step of bonding a device-attached substrate 11 and a temporary fixing substrate 12 via an adhesive layer 13 (temporary fixing step, Figures 2A and 2B); 2) a step of thinning the device-attached substrate 11 while the temporary fixing substrate 12 is attached (thinning step, Figure 2C); 3) a step of forming a rewiring layer 14 on the surface of the thinned device-attached substrate 11 opposite to the surface on which the adhesive layer 13 is arranged (rewiring step, Figure 2D); 4) a step of removing the temporary fixing substrate 12 from the thinned substrate 11 while leaving the adhesive layer 13 (peeling step, Figures 2E and 2F); and 5) a step of bonding the device-attached substrate 11 from which the temporary fixing substrate has been removed to a permanent fixing substrate 15 via the remaining adhesive layer 13 (permanent fixing step, Figures 2G and 2H). In this embodiment, an example will be described in which the substrate to be thinned is a device-equipped substrate 11. In addition, the devices on the device-equipped substrate 11 and their peripheral structure are not shown in FIG.

[0021] (1) Temporary fixing process In this step, the device-mounted substrate 11 and the temporary fixing substrate 12 are bonded together via an adhesive layer 13 (see FIGS. 2A and 2B).

[0022] (Device-mounted substrate 11) The device-equipped substrate 11 includes a substrate 11A and a device 11B disposed on the surface of the substrate (see FIG. 3). The device 11B can be a memory such as NAND, DRAM, SRAM, or MRAM, an LSI, a CMOS image sensor, a MEMS, an LED, a SAW device, or an optical device. The device 11B is preferably disposed on the surface of the substrate 11A on which the adhesive layer 13 is disposed (see FIG. 3).

[0023] Materials for the device-equipped substrate 11 include semiconductors (e.g., Si, InP, GaN, GaAs, InGaAs, InGaAlAs, SiC), borosilicate glass (Pyrex (registered trademark)), quartz glass (SiO2), sapphire, ZrO2, Si3N4, AlN, piezoelectric materials, dielectric materials (e.g., BaTiO3, LiNbO3, SrTiO3), diamond, metals (e.g., Al, Ti, Fe, Cu, Ag, Au, Pt, Pd, Ta, Nb), and resins (e.g., polydimethylsiloxane (PDMS), epoxy resin, phenolic resin, polyimide, benzocyclobutene resin, polybenzoxazole, etc.).

[0024] The device-equipped substrate 11 may have a multilayer structure, for example, an inorganic layer such as silicon oxide, silicon nitride, or SiCN (silicon carbonitride), an organic layer such as polyimide resin, polybenzoxazole resin, epoxy resin, or cyclotene (Dow, Chem), or a composite of these may be disposed on the surface of a silicon substrate or the like.

[0025] (Temporary fixing substrate 12) The temporary fixing substrate 12 is not particularly limited as long as it has a strength and a smooth surface sufficient to stably support the device-mounted substrate 11 when the substrate is thinned. Examples of the temporary fixing substrate 12 include Si substrates; glass substrates such as borosilicate glass (Pyrex (registered trademark)) and quartz glass (SiO2); metal substrates such as Al, Ti, Fe, Cu, and Ag; and resin substrates such as polydimethylsiloxane (PDMS), epoxy resin, phenol resin, polyimide, benzocyclobutene resin, and polybenzoxazole. In particular, from the viewpoint of enabling the temporary fixing substrate to be peeled off by laser lift-off or the like, as described below, the temporary fixing substrate 12 is preferably transparent, and is preferably a glass substrate or a transparent resin substrate.

[0026] The thickness of the temporary fixing substrate 12 need only be thick enough to stably support the device-mounted substrate 11 when the substrate 11 is thinned. The thickness of the temporary fixing substrate 12 may be thicker than the thickness of the permanent fixing substrate 15, for example, and may be 0.1 mm or more and 2 mm or less.

[0027] The temporary fixing substrate 12 is removed in a peeling step described later. Therefore, a peeling layer 16 for facilitating peeling may be provided on the surface of the temporary fixing substrate 12 on which the adhesive layer 13 is provided (see FIG. 4 described later).

[0028] (adhesive layer 13) The adhesive layer 13 is disposed between the device-equipped substrate 11 and the temporary fixing substrate 12, and temporarily bonds and fixes them together. In this embodiment, the adhesive layer 13 is disposed on the device-equipped substrate 11 side (see FIG. 2A).

[0029] From the viewpoint of more stable adhesion between the substrate 11 and the temporary fixing substrate 12, the adhesive layer 13 preferably has a functional group capable of forming a chemical bond on its surface. Examples of such functional groups include amino groups, epoxy groups, vinyl groups, and silanol groups (Si-OH groups). Among these, silanol groups are preferred from the viewpoint of adhesiveness and heat resistance. These functional groups may be formed by surface treatment after the formation of the adhesive layer, or by treatment with a silane coupling agent, or the adhesive layer may be formed using a compound containing these functional groups.

[0030] Whether or not the adhesive layer 13 has silanol groups on its surface can be confirmed by surface analysis using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Specifically, using a TOF-SIMS PHI nanoTOFII (ULVAC-PHI, Inc.), it is possible to confirm whether or not the adhesive layer has silanol groups on its surface based on the presence or absence of a peak at a mass-to-charge ratio (m / Z) of 45.

[0031] The adhesive layer 13 is not particularly limited as long as it contains a material that can be re-adhered even after peeling. Among these, materials having the above-described functional groups or materials capable of generating the above-described functional groups through surface treatment are preferred. From this perspective, the adhesive layer 13 preferably contains at least one selected from the group consisting of an imide bond, an amide bond, a siloxane bond, an epoxy group, and a benzocyclobutene structure as a partial structure. That is, the adhesive layer 13 preferably contains a resin containing at least one selected from the group consisting of a siloxane bond, an epoxy group, and a benzocyclobutene structure as a partial structure.

[0032] Examples of resins containing at least one selected from the group consisting of an imide bond, an amide bond, a siloxane bond, an epoxy group, and a benzocyclobutene structure include polyimide, polyamide, polyamideimide, maleimide resin, parylene, polyarylene ether, polybenzoxazole, benzocyclobutene resin, epoxy resin, resins containing a siloxane bond, etc. Among these, from the viewpoint of facilitating good adhesion to the main fixing substrate after peeling off the temporary fixing substrate, resins containing a siloxane bond are preferred.

[0033] Examples of resins containing a siloxane bond include divinylsiloxane benzocyclobutene polymer, siloxane imide polymer, siloxane amide polymer, siloxane amide imide polymer, epoxy-modified siloxane polymer, etc. Among these, from the viewpoint of more stably bonding the substrate 11 and the temporary fixing substrate 12 and also having better heat resistance, a resin containing a siloxane bond and at least one of an amide bond and an imide bond is preferred, and a siloxane imide polymer is more preferred.

[0034] The resin containing a siloxane bond and at least one of an amide bond and an imide bond may contain a structure represented by any one of formulas (1) to (3).

[0035] [ka]

[0036] In a resin containing a siloxane bond and at least one of an amide bond and an imide bond, the group bonded to Si may be substituted with a divalent group such as an alkylene group or a phenylene group. For example, the structure containing a siloxane bond may have a structure having (-O-)x(R1)ySi-R2-Si(R1)y(-O-)x (R1 is a monovalent group such as a methyl group, R2 is a divalent group such as an alkylene group or a phenylene group, x and y are each an integer of 0 or more, and x + y is 3).

[0037] The thickness of the adhesive layer 13 is not particularly limited, but is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 5 μm or less, and particularly preferably 2 μm or less. When the thickness of the adhesive layer 13 is 10 μm or less, for example, misalignment when bonding the device-mounted substrate 11 and the temporary fixing substrate 12 can be more effectively suppressed. Also, deformation of the device-mounted substrate 11 due to uneven thickness of the adhesive layer 13 can be suppressed. The lower limit of the thickness of the adhesive layer 13 is not particularly limited as long as it is sufficient to stably temporarily fix the substrate 11, and can be, for example, 0.1 μm or more, preferably 0.3 μm or more, and more preferably 0.5 μm or more.

[0038] Such an adhesive layer 13 can be formed, for example, by applying an adhesive composition to the device-mounted substrate 11 and / or the temporary fixing substrate 12, and then curing it by heating or the like.

[0039] For example, an adhesive layer containing a resin containing a siloxane bond and at least one of an amide bond and an imide bond can be obtained by heating and reacting (curing) an adhesive composition containing a compound containing three or more silanol groups, an amide group, and a carboxy group in one molecule. For example, a resin having a structure represented by formula (1) can be obtained by heating and reacting a compound represented by formula (4). Similarly, a resin having a structure represented by formula (2) can be obtained by heating and reacting a compound represented by formula (5). [ka]

[0040] In addition, an adhesive layer containing a resin containing a siloxane bond and at least one of an amide bond and an imide bond can also be obtained by heating and reacting (curing) an adhesive composition containing a compound (A) having an Si-O bond and an amino group and a crosslinking agent (B) having three or more -C(=O)OX groups (X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), at least one of which is a carboxy group.

[0041] Examples of the compound (A) include siloxane diamine, a silane coupling agent having an amino group, or a polymer (siloxane polymer) formed from these silane coupling agents via a siloxane bond (Si—O—Si). The crosslinking agent (B) includes a trivalent or tetravalent carboxylic acid compound or carboxylic acid ester compound. Examples of the carboxylic acid compound include alicyclic carboxylic acids such as 1,3,5-cyclohexanetricarboxylic acid; aromatic carboxylic acids such as pyromellitic acid, 1,4,5,8-naphthalenetetracarboxylic acid, biphenyl-3,3',4,4'-tetracarboxylic acid, benzophenone-3,3',4,4'-tetracarboxylic acid, and 4,4'-oxydiphthalic acid; and fluorinated aromatic carboxylic acids such as 1,4-ditrifluoromethylpyromellitic acid. Examples of the carboxylic acid ester compound include compounds in which some of the carboxy groups of the above carboxylic acid compounds have been substituted with ester groups.

[0042] The adhesive composition may further contain a polar solvent. Examples of polar solvents include protic inorganic compounds such as water and heavy water; alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, ethylene glycol, and propylene glycol; ethers such as tetrahydrofuran and dimethoxyethane; aldehydes and ketones such as acetone, ethyl methyl ketone, and cyclohexane; acid derivatives such as ethyl acetate, butyl acetate, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; and sulfur compounds such as dimethyl sulfoxide.

[0043] The method for applying the adhesive composition is not particularly limited, and may be, for example, a method such as spin coating, slit coating, spray coating, screen printing, squeegeeing, or inkjet printing.

[0044] The heating temperature of the adhesive composition may be set so that the solvent in the adhesive composition can be removed and the curing rate of the resulting adhesive layer 13 falls within the range described below. For example, when the adhesive composition contains the compounds described above, the temperature is preferably equal to or higher than the curing temperature, and can be, for example, 100°C or higher and 450°C or lower, and preferably 150°C or higher and 300°C or lower. The heating temperature means the surface temperature of the coating film of the adhesive composition. Heating can be carried out by a conventional method using a furnace or a hot plate.

[0045] By heating the adhesive composition in this way, the solvent contained in the adhesive composition is removed, and the components in the adhesive composition react to obtain a cured product, and an adhesive layer 13 containing the cured product is formed.

[0046] (Adhesion method) As described above, the adhesive composition may be applied to either the device-attached substrate 11 or the temporary fixing substrate 12. However, from the viewpoint of adhering the device-attached substrate 11 with less gaps or adhering the device-attached substrate 11 with the temporary fixing substrate 15 (described later) more stably, it is preferably applied to the device-attached substrate 11 (see FIG. 2A). That is, it is preferable to prepare a laminate L1 including the device-attached substrate 11 and an adhesive layer 13 disposed thereon (see FIG. 2A), and then adhere the device-attached substrate 11 and the temporary fixing substrate 12 via the adhesive layer 13 formed on the device-attached substrate 11 (see FIG. 2B). The device-attached substrate 11 and the temporary fixing substrate 12 can be adhered by pressing, for example, using a vacuum laminator or the like.

[0047] The device-mounted substrate 11 and the temporary fixing substrate 12 are preferably bonded together under the conditions that the cure rate of the adhesive layer 13 is 70% or more and the temperature is 150° C. or less.

[0048] If the cure rate of the adhesive layer 13 is 70% or more, it is possible to further reduce misalignment when bonding the device-mounted substrate 11 and the temporary fixing substrate 12. From the same viewpoint, the cure rate of the adhesive layer 13 is more preferably 80% or more, and even more preferably 90% or more. Furthermore, the upper limit of the cure rate of the adhesive layer 13 may be 100%, but from the viewpoint of further improving the adhesion between the device-mounted substrate 11 and the temporary fixing substrate 12, it may be 95% or less, or 90% or less.

[0049] The cure rate of the adhesive layer 13 can be confirmed by measuring the peak intensity of specific bonds and structures (the sum of the peak intensities when there are multiple peaks such as imide, amide, etc.) for the adhesive layer 13 using FT-IR (Fourier transform infrared spectroscopy) and determining the rate of increase or decrease in the peak intensity. Note that when there are band-like peaks that are difficult to separate, such as siloxane bonds, the maximum peak intensity can be used.

[0050] Furthermore, when specific bonds and structures are formed by the curing reaction, the rate of increase in peak intensity may be calculated using the following formula, and the calculated value may be used as the curing rate of the adhesive layer. Increase rate of peak strength (%)=[(peak strength of the specific bond and structure of the adhesive layer 13 before heating) / (peak strength of the specific bond and structure of the adhesive layer 13 after heating at 300° C. for 1 hour)]×100 The background signal can be removed by a conventional method. If necessary, the FT-IR measurement can be performed by the transmission method or the reflection method.

[0051] In the above-mentioned rate of increase in peak intensity, when there are a plurality of bonds and structures that cause an increase in peak intensity, the peak intensity may be interpreted as the total intensity of the plurality of peak intensities.

[0052] Furthermore, if the bonding temperature is 150°C or less, it is possible to further reduce, for example, thermal damage to the devices on the device-mounted substrate 11. From the same viewpoint, the bonding temperature may be 0°C or higher and 100°C or lower, 0°C or higher and 50°C or lower, or may be room temperature (for example, 25°C).

[0053] Furthermore, as will be described later, from the viewpoint of further increasing the adhesive strength with the temporary fixing substrate 12, it is preferable that the surface roughness Ra of the adhesive layer 13 when it is adhered to the temporary fixing substrate 12 is small, preferably 2 nm or less. The surface roughness Ra of the adhesive layer 13 can be measured by the method described later.

[0054] As a result, a laminate L2 is obtained which has the device-mounted substrate 11, the temporary fixing substrate 12, and the adhesive layer 13 disposed therebetween (see FIG. 2B).

[0055] (Laminated body L2) The adhesive strength between the device-equipped substrate 11 and the temporary fixing substrate 12 in the resulting laminate L2 is not particularly limited, but from the viewpoint of making it easier to more stably support the device-equipped substrate 11 when thinning the substrate, it is preferable to use a strength of 0.01 J / m 2 It is preferable that the concentration is 0.5 J / m or more. 2 On the other hand, from the viewpoint of facilitating peeling when peeling and removing the temporary fixing substrate 12, the adhesive strength of the laminate L2 is preferably 2.0 J / m or more (see FIG. 2B). 2 Preferably, it is 1.5 J / m or less. 2 More preferably, it is:

[0056] The adhesive strength can be determined by measuring the surface energy (adhesion strength) of the adhesive interface between the temporary fixing substrate 12 and the adhesive layer 13 in the laminate L2 using a blade insertion test, in accordance with the method described in M.P. Maszara, G. Goetz, A. Cavigila, and J.B.M. McKitterick, Journal of Applied Physics, 64 (1988) 4943-4950. Specifically, the adhesive strength can be determined by the following procedure. 1) A blade having a thickness of 0.1 mm to 0.3 mm is inserted into the adhesive interface between the temporary fixing substrate 12 and the adhesive layer 13 of the laminate L2. 2) Next, an infrared light source and an infrared camera are used to measure the distance from the blade tip to the tip of the crack in the blade insertion direction (crack length). 3) Then, the surface energy is measured based on the following formula: γ=3×10 9 ×t b 2 ×E 2 ×t 6 / (32×L 4 ×E×t 3 ) where: γ: Surface energy (J / m 2 ), t b : Blade thickness (m), E: Young's modulus (GPa) of the substrate 11 with the device and the temporary fixing substrate 12, t: thickness of the substrate and temporary fixing substrate (m), L: length of the crack (m) Represents.

[0057] The adhesive strength can be adjusted by, for example, the thickness and curing rate of adhesive layer 13, the presence or absence of surface treatment (plasma treatment), the presence or absence of release layer 16 (see FIG. 4), etc. For example, reducing the thickness of adhesive layer 13, increasing the curing rate, or providing release layer 16 tends to appropriately decrease the adhesive strength. On the other hand, applying plasma treatment to the surface of adhesive layer 13 tends to appropriately increase the adhesive strength.

[0058] In the laminate L2, the adhesive layer 13 and the device-equipped substrate 11 and / or the adhesive layer 13 and the temporary fixing substrate 12 are preferably bonded by Si-OM bonds (where M is a semiconductor atom such as Si or a metal atom such as Al), which allows the device-equipped substrate 11 to be supported more stably, thereby enabling the device-equipped substrate 11 to be thinned with higher precision.

[0059] (2) Thinning process Next, with the temporary fixing substrate 12 adhered, the device-equipped substrate 11 is thinned (see FIG. 2C).

[0060] Specifically, the back surface (the surface opposite to the surface on which the adhesive layer 13 is disposed) of the device-equipped substrate 11 is ground (backgrid) until the thickness becomes equal to or less than a predetermined value. Grinding is preferably performed until the thickness of the device-equipped substrate 11 becomes equal to or less than 100 μm, for example.

[0061] The back surface of the device-mounted substrate 11 can be ground by a known method.

[0062] (3) Rewiring process Next, a rewiring layer 14 is formed on the back surface of the thinned device-equipped substrate 11 (see FIG. 2D).

[0063] The redistribution layer 14 includes an insulating layer and wiring disposed therein. The substrate 11 with devices and the wiring in the redistribution layer 14 are electrically connected. For a specific example of the redistribution layer 14, see the description of element 310 chip-level BEOL in U.S. Patent Publication No. 2022 / 0013504.

[0064] (4) Peeling process Next, the temporary fixing substrate 12 is removed from the thinned substrate 11, leaving the adhesive layer 13 (see FIGS. 2E and 2F).

[0065] The method for removing the temporary fixing substrate 12 is not particularly limited, and may be any of a method for removing the temporary fixing substrate 12 by grinding, a method for placing a release layer 16 between the temporary fixing substrate 12 and the adhesive layer 13 and peeling at the interface between the release layer 16 and the adhesive layer 13 (see Figure 4), and a laser lift-off method.

[0066] When the temporary fixing substrate 12 is removed by the laser lift-off method, the temporary fixing substrate 12 is preferably a substrate that transmits laser light, and more preferably a transparent substrate.

[0067] (5) Main fixing process Then, the device-mounted substrate 11 from which the temporary fixing substrate 12 has been removed is bonded to the permanent fixing substrate 15 via the adhesive layer 13 (see FIGS. 2G and 2H).

[0068] The fixing substrate 15 is not particularly limited, and may be similar to the laminate obtained after the peeling step, which includes the thinned device-equipped substrate 11 and the adhesive layer 13 (in FIGS. 2F and 2G, the laminate includes the redistribution layer 14, the thinned device-equipped substrate 11, and the adhesive layer 13). However, the fixing substrate 15 is not limited to this, and may be the device-equipped substrate 11, or a substrate on which no devices are arranged (for example, a silicon substrate or a glass substrate).

[0069] The bonding method and conditions are not particularly limited. For example, the thinned device-equipped substrate 11 and the fixing substrate 15 may be pressure-bonded together via the remaining adhesive layer 13. From the viewpoint of more firmly bonding the thinned device-equipped substrate 11 and the fixing substrate 15 via the adhesive layer 13, it is preferable to pressure-bond the thinned device-equipped substrate 11 and the fixing substrate 15 under heating.

[0070] That is, the bonding temperature is set so that the adhesive strength between the device-mounted substrate 11 and the main fixing substrate 15 is 2.0 J / m 2 Any temperature may be used so long as the temperature is equal to or higher than the temperature above, and for example, the temperature is preferably 100°C or higher and 400°C or lower, and more preferably 150°C or higher and 300°C or lower.

[0071] The surface roughness Ra of the adhesive layer 13 when the fixing substrate 15 is adhered is not particularly limited, but from the viewpoint of further increasing the adhesive strength with the fixing substrate 15, the smaller the better, and preferably 2 nm or less. If the surface roughness Ra of the adhesive layer 13 is 2 nm or less, the contact area with the fixing substrate 15 can be further increased, thereby further increasing the adhesive strength. From the same viewpoint, the surface roughness Ra of the adhesive layer 13 when the fixing substrate 15 is adhered is more preferably 1.5 nm or less. The lower limit of the surface roughness Ra of the adhesive layer 13 is not particularly limited, but may be, for example, 0.01 nm or more.

[0072] The surface roughness Ra of the adhesive layer 13 can be measured by morphological observation using a scanning probe microscope (SPM). Specifically, the surface roughness can be determined by measuring a 3 μm × 3 μm square area using an SPM SPA400 (manufactured by Hitachi High-Technologies Corporation) in dynamic force microscope mode.

[0073] The surface roughness Ra of the adhesive layer 13 can be adjusted, for example, by carrying out a step of polishing the surface of the adhesive layer 13, as will be described later.

[0074] The curing rate of the adhesive layer 13 may be the same as the curing rate of the adhesive layer 13 in the temporary fixing step, thereby enabling the thinned device-mounted substrate 11 and the main fixing substrate 15 to be well bonded together while further suppressing misalignment.

[0075] In the laminate L3 obtained by the above bonding, the adhesive strength between the fixing substrate 15 and the device-mounted substrate 11 is 2.0 J / m 2 It is preferable that the value is 2.0 J / m or more. 2 More than 20J / m 2 It is more preferable that the adhesive strength is not more than 100%. When the adhesive strength is within the above range, the adhesive strength becomes more sufficient, and a semiconductor device with higher reliability can be obtained. The adhesive strength can be measured by the same method as described above.

[0076] The resulting laminate L3 is further laminated with other semiconductor elements as required, and then electrically connected to a semiconductor element mounting substrate (wiring board), thereby obtaining a semiconductor device.

[0077] (6) Other processes The method for manufacturing a semiconductor device may further include other steps in addition to those described above, as necessary.

[0078] For example, before the temporary fixing step or the main fixing step, a step of plasma treating the surface of the adhesive layer 13 may be further carried out. By plasma treating the surface of the adhesive layer 13, the surface of the adhesive layer 13 is further activated, so that the adhesion between the adhesive layer 13 and the temporary fixing substrate 12 (adhesion step) or the main fixing substrate (main fixing step) can be further improved even at low temperatures and low pressures.

[0079] Furthermore, after the peeling step, a step of polishing the adhesive layer 13 may be further carried out. This makes it possible to smooth the surface of the adhesive layer 13 when it is bonded to the main fixing substrate 15 in the main fixing step, thereby reducing the surface roughness Ra. This increases the contact area between the adhesive layer 13 and the main fixing substrate 15, allowing the thinned substrate 11 and the main fixing substrate 15 to be more firmly bonded via the adhesive layer 13. The polishing method is not particularly limited, and examples include fly cutting and chemical mechanical polishing (CMP).

[0080] Furthermore, before the main fixing step, a step of dicing the laminate including the thinned device-equipped substrate 11 and the adhesive layer 13 may be further carried out. In this way, in the main fixing step, the thinned device-equipped substrate 11, which has been separated by dicing, can be bonded to the main fixing substrate 15 via the remaining adhesive layer 13.

[0081] In the above embodiment, when the device of the device-mounted substrate 11 is arranged on the surface of the substrate on which the adhesive layer 13 is arranged (see Figure 3), further steps may be carried out, such as partially removing the adhesive layer 13 on the surface of the device 11B to expose the surface of the device 11B outside the adhesive layer 13, or forming electrodes or the like to electrically connect the device 11B to the fixing substrate 15.

[0082] Methods for partially removing adhesive layer 13 include fly cutting, chemical mechanical polishing (CMP), plasma dry etching, etc. The step of partially removing adhesive layer 13 on the surface of device 11B may also serve as the polishing step described above. The step of forming electrodes, etc. may involve forming holes by dry etching or the like, and then filling them with a metal material to form electrodes.

[0083] In the above embodiment, the substrate to be thinned is the device-equipped substrate 11, but the present invention is not limited to this, and a substrate without a device may also be used. Examples of the substrate without a device include a silicon wafer and a glass substrate.

[0084] In the above embodiment, a release layer 16 may be provided between the temporary fixing substrate 12 and the adhesive layer 13 in order to further improve the releasability of the temporary fixing substrate 12 .

[0085] 4A to 4E are schematic partial cross-sectional views showing a method for manufacturing a semiconductor device according to another embodiment of the present invention. 4A to 4E, a release layer 16 may be formed on the surface of the temporary fixing substrate 12 facing the adhesive layer 13 (see FIG. 4A). Examples of the release layer 16 include a metal layer such as Cu or Ti, and an easily removable sacrificial material layer. Examples of the sacrificial material layer include a layer of an adhesive material such as silicone resin, acrylic resin, epoxy resin, or polyimide, and a multilayer structure material including a layer of such an adhesive material and a laser ablation layer such as black carbon. This makes it easier to peel the temporary fixing substrate 12 from the adhesive layer 13 on the device-mounted substrate 11 in the peeling step (see FIG. 4E).

[0086] The thickness of the release layer 16 is not particularly limited, but from the viewpoint of making it easier to obtain adhesion after peeling, it is preferably equal to or thicker than the thickness of the adhesive layer 13. The thickness ratio of the release layer 16 / adhesive layer 13 can be, for example, 100 / 1 to 1 / 1.

[0087] Furthermore, in the above embodiment, an example was shown in which the step of forming the rewiring layer 14 was performed, but this may be performed as needed, and the step of forming the rewiring layer 14 may also be omitted.

[0088] In the above embodiment, the laminate L2 obtained in the bonding step is used by thinning the device-equipped substrate 11, removing the temporary fixing substrate 12 while leaving the adhesive layer 13, and then bonding it to the permanent fixing substrate 15 via the adhesive layer 13, but this is not limiting. For example, the laminate L2 may be used by removing the temporary fixing substrate 12 without thinning the device-equipped substrate 11, and then bonding it to the permanent fixing substrate 15 via the remaining adhesive layer 13. [Industrial Applicability]

[0089] According to the present invention, it is possible to provide a method for manufacturing a semiconductor device that allows a plurality of substrates to be stacked without complicating the process. [Explanation of symbols]

[0090] 11 Device-mounted substrate 11A board 11B devices 12 Temporary fixing board 13 Adhesive layer 14 Redistribution layer 15 fixing board 16 Peeling layer L1, L2, L3 laminate

Claims

1. a step of bonding the substrate and the temporary fixing substrate via an adhesive layer; a step of thinning the substrate while the temporary fixing substrate is adhered; removing the temporary fixing substrate from the thinned substrate while leaving the adhesive layer; a step of bonding the substrate from which the temporary fixing substrate has been removed and a permanent fixing substrate via the adhesive layer; A method for manufacturing a semiconductor device, comprising:

2. The substrate is a device-equipped substrate. The method for manufacturing a semiconductor device according to claim 1 .

3. In the step of adhering the temporary fixing substrate, a release layer is formed on a surface of the temporary fixing substrate facing the adhesive layer; The method for manufacturing a semiconductor device according to claim 1 or 2.

4. The thickness of the adhesive layer is 10 μm or less. The method for manufacturing a semiconductor device according to claim 1 or 2.

5. In the step of adhering the temporary fixing substrate, The substrate and the temporary fixing substrate are bonded to each other via the adhesive layer formed on the substrate. The method for manufacturing a semiconductor device according to claim 1 or 2.

6. In the step of adhering the temporary fixing substrate, The temporary fixing substrate and the substrate are bonded together at a temperature of 150°C or less and a cure rate of the adhesive layer is 70% or more. The method for manufacturing a semiconductor device according to claim 5 .

7. The adhesive layer has a silanol group on the surface. The method for manufacturing a semiconductor device according to claim 1 or 2.

8. the adhesive layer contains a resin containing at least one selected from the group consisting of an imide bond, an amide bond, a siloxane bond, an epoxy group, and a benzocyclobutene structure; The method for manufacturing a semiconductor device according to claim 1 or 2.

9. the adhesive layer contains a resin containing a siloxane bond and at least one of an amide bond and an imide bond; The method for manufacturing a semiconductor device according to claim 8 .

10. The method further comprises a step of plasma-treating the surface of the adhesive layer before the step of adhering the temporary fixing substrate or the step of adhering the permanent fixing substrate. The method for manufacturing a semiconductor device according to claim 1 or 2.

11. In the step of adhering the temporary fixing substrate, The adhesive strength between the substrate and the temporary fixing substrate is 0.01 J / m ２ 2.0J / m or more ２ Below is the The method for manufacturing a semiconductor device according to claim 1 or 2.

12. Further comprising forming a redistribution layer on a surface of the thinned substrate opposite to the surface on which the adhesive layer is disposed. The method for manufacturing a semiconductor device according to claim 1 or 2.

13. The method further includes a step of polishing the adhesive layer after the step of removing the temporary fixing substrate. The method for manufacturing a semiconductor device according to claim 1 or 2.

14. In the step of adhering the permanent fixing substrate or the step of adhering the temporary fixing substrate, The surface roughness Ra of the adhesive layer when bonded is 2 nm or less. The method for manufacturing a semiconductor device according to claim 1 or 2.

15. In the step of adhering the main fixing substrate, The adhesive strength between the substrate and the main fixing substrate is 2.0 J / m ２ 20J / m or more ２ Below is the The method for manufacturing a semiconductor device according to claim 1 or 2.

16. The device-equipped substrate includes a substrate and a device disposed between the substrate and the adhesive layer. The method for manufacturing a semiconductor device according to claim 2 .

17. The method further includes a step of dicing a laminate having the thinned substrate and the adhesive layer obtained by the step of removing the temporary fixing substrate, In the step of adhering the main fixing substrate, the diced thinned substrate and the main fixing substrate are adhered via the adhesive layer. The method for manufacturing a semiconductor device according to claim 1 or 2.

18. The fixing substrate is a laminate having a thinned substrate and an adhesive layer. The method for manufacturing a semiconductor device according to claim 1 or 2.

19. A laminate having a substrate with a device and an adhesive layer disposed on the substrate with a device, The adhesive is used to carry out the steps of: adhering the device-equipped substrate and a temporary fixing substrate via the adhesive layer; thinning the device-equipped substrate with the temporary fixing substrate adhered thereto; removing the temporary fixing substrate from the thinned device-equipped substrate while leaving the adhesive layer; and adhering the thinned device-equipped substrate and the fixing substrate via the adhesive layer. Laminate.

20. A laminate including a substrate with a device, a temporary fixing substrate, and an adhesive layer disposed between the substrate with a device and the temporary fixing substrate, After removing the temporary fixing substrate, the substrate is bonded to a permanent fixing substrate via the adhesive layer. Laminate.

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