Method for processing an insulating layer, method for manufacturing a redistribution layer, and processing apparatus.

Abstract

The present invention provides a method for processing an insulating layer that makes it possible to reduce the thickness of the residual film at the bottom of a via hole in the insulating layer of a redistribution layer to a predetermined level or less. [Solution] This is a method for processing an insulating layer 20 using an imprint mold 50. The imprint mold 50 has a plurality of pillars 52. An insulating layer 20 is formed on the upper surface of a substrate 30. A hardened deposit 61 of the first material 60 is attached to the tip of each pillar 52. The imprint mold 50 with the deposit 61 attached to the tip of each pillar 52 is pressed against the insulating layer 20 and pressure is applied. Then, the imprint mold 50 is withdrawn from the insulating layer 20 to form via holes 22 in the insulating layer 20. The insulating layer 20 is hardened. The elastic modulus of the first material 60 and the deposit 61 is the same as or lower than the elastic modulus of the insulating layer 20.

Description

Technical Field

[0001] The present disclosure relates to a method for processing an insulating layer, particularly an insulating layer serving as a base for a rewiring layer, a method for manufacturing a rewiring layer, and a processing apparatus.

Background Art

[0002] In recent years, miniaturization, high functionality, and multifunctionality of electronic components and devices have advanced. In order to meet these needs, higher density of elements and narrower pitch of wirings in semiconductor chips mounted on electronic components and the like have been demanded.

[0003] For example, an interposer, which is a wiring board inserted between a semiconductor chip and a mounting substrate, plays a role of effectively connecting semiconductor devices and modules with different shapes and pitches. Therefore, by using an interposer in electronic components and the like, formation of a high-density circuit becomes possible. <L000013>

[0004] When forming wirings and vias in an interposer, for example, after forming groove portions and via holes inside an insulating layer formed on the upper surface of a base material by etching, photolithography, or the like, metal plating or the like is applied inside the groove portions and via holes to form wirings and vias. Vias connect wirings in different layers to each other or connect a wiring and a land electrode provided on the front surface and / or back surface of the interposer.

[0005] <0000U18>On the other hand, in recent years, an imprint method has been attracting attention as a wiring formation method to replace etching and photolithography. The imprint method is a method of forming groove portions and via holes by transferring a pattern to an insulating layer made of a resin material formed on the surface of a base material using an imprint mold having a fine pattern formed thereon and curing the insulating layer (see, for example, Patent Document 1). In this case, the cured insulating layer is not removed and becomes a part of the rewiring layer constituting the interposer.

[0006] According to the imprint method disclosed in Patent Document 1, via holes can be formed with high precision in a batch. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Special Publication No. 2022-508102 [Overview of the project] [Problems that the invention aims to solve]

[0008] When via holes are formed in a redistribution layer by photolithography and etching, after forming a mask pattern for the via holes and performing exposure and development, virtually no residual insulating layer remains at the bottom of the via holes, and any remaining residue can be removed by descam processing. Patent Document 1 also discloses that the insulating layer remaining at the bottom of the via holes after imprinting is removed by a similar descam process.

[0009] However, the surface of the substrate on which the insulating layer is formed may actually have warping or undulation. Also, the land electrodes provided on the substrate may have depressions due to dishing or other processes. Furthermore, the flatness of the imprint mold may not be sufficient, resulting in variations in the depth of the via holes formed in the insulating layer during imprinting.

[0010] When these conditions occur, during imprinting, the tips of the pillars provided on the imprint mold do not reach the surface of the substrate or land electrode, resulting in a certain thickness of insulating layer remaining on the surface of the substrate or land electrode.

[0011] If the insulating layer remains with a thickness exceeding the specified limit, it cannot be completely removed by the descam process. This can lead to the bottom of the via not being exposed during the subsequent metal plating process, potentially causing poor connection with the underlying substrate or rewiring layer.

[0012] This disclosure has been made in view of the foregoing, and its purpose is to provide a method for processing an insulating layer, a method for manufacturing a redistribution layer, and a processing apparatus that can reduce the thickness of the residual film at the bottom of via holes provided in the insulating layer of a redistribution layer to a predetermined level or less. [Means for solving the problem]

[0013] To achieve the above objective, a method for processing an insulating layer according to one aspect of the present disclosure is a method for processing an insulating layer using an imprint mold. The imprint mold has at least a main body and a plurality of pillars. At least the plurality of pillars protrude from the second surface of the main body. The method for processing an insulating layer comprises at least an insulating layer formation step, a first material attachment step, a pressurizing step, a demolding step, and a curing step. In the insulating layer formation step, an insulating layer is formed on the upper surface of the substrate. In the first material attachment step, a first material is attached to the tips of the pillars. In the pressurizing step, the imprint mold is pressed against the insulating layer and pressurized so that the first material reaches the upper surface of the substrate. In the demolding step, the imprint mold is withdrawn from the insulating layer to form via holes in the insulating layer where the pillars were inserted. In the curing step, the insulating layer is cured. The elastic modulus of the first material is the same as or lower than the elastic modulus of the insulating layer.

[0014] A method for manufacturing a redistribution layer according to one aspect of the present disclosure comprises at least a recess forming step, a pretreatment step, a plating step, and a planaring step. In the recess forming step, at least a plurality of via holes are formed in the insulating layer formed on the upper surface of the substrate using the insulating layer processing method. In the pretreatment step, a barrier layer and a seed layer are formed on the surface of the insulating layer, including the inner wall surfaces of each of the plurality of via holes. In the plating step, metal plating is performed on the surface of the seed layer to fill the via holes with metal. In the planaring step, the metal formed on the upper surface of the insulating layer is removed to process the metal embedded in the via holes into vias. The insulating layer and the plurality of vias constitute the redistribution layer.

[0015] A processing apparatus according to one aspect of the present disclosure is a processing apparatus for forming at least a plurality of via holes in an insulating layer formed on the upper surface of a substrate. The processing apparatus comprises at least a first unit, a second unit, and a mold holder. The first unit comprises at least a first stage and a first material supply mechanism for supplying a first material having the same or lower elastic modulus as the insulating layer so as to spread over a predetermined area on the upper surface of the first stage. The second unit comprises at least a second stage on which the substrate on which the insulating layer is formed is placed, and a heating mechanism for heating the second stage. The mold holder is fitted with a first moving mechanism for moving the mold holder at least between the first unit and the second unit, and a second moving mechanism for moving the mold holder toward the first stage and the second stage, respectively. An imprint mold is detachably attached to the lower end of the mold holder. The imprint mold comprises at least a main body and a plurality of pillars protruding from a second surface of the main body. In the first unit, the first material is attached to the tips of a plurality of pillars. In the second unit, the mold holder is used to press the imprint mold to which the first material is attached against the insulating layer and apply pressure to form a plurality of via holes in the insulating layer. [Effects of the Invention]

[0016] According to this disclosure, the thickness of the residual film at the bottom of the via holes provided in the insulating layer of the redistribution layer can be reduced to a predetermined level or less. Furthermore, electrical connection failures between the substrate provided in the layer below the redistribution layer and the redistribution layer can be reduced. [Brief explanation of the drawing]

[0017] [Figure 1A] This is a schematic cross-sectional view of the main part of the interposer. [Figure 1B] This is an enlarged view of the area enclosed by the dashed line in Figure 1A. [Figure 1C] It is an enlarged view of the portion surrounded by the dashed line in FIG. 1B. [Figure 2] It is a schematic configuration diagram of the processing apparatus according to Embodiment 1. [Figure 3] It is a schematic cross-sectional view of the imprint mold. [Figure 4] It is a schematic diagram for explaining the step of adhering and curing the first material to the tip of the pillar. [Figure 5A] It is a schematic diagram for explaining the method of processing the insulating layer according to Embodiment 1. [Figure 5B] It is a schematic diagram for explaining the subsequent steps of FIG. 5A. [Figure 6A] It is an enlarged view of the insulating layer in which the groove portion and the via hole are formed. [Figure 6B] It is a schematic diagram for explaining the conventional problem, and is a corresponding view of FIG. 6A. [Figure 6C] It is another schematic diagram for explaining the conventional problem, and is a corresponding view of FIG. 6A. [Figure 7] It is an enlarged view of the portion including the tip of the pillar in the pressing step according to Embodiment 1. [Figure 8] It is a schematic diagram showing the outline of the via hole forming step according to Embodiment 1. [Figure 9] It is a schematic diagram showing the outline of the via hole forming step according to Embodiment 1, and is a schematic diagram when the deformation amount of the deposit is large. [Figure 10A] It is a schematic diagram for explaining the manufacturing method of the rewiring layer according to Embodiment 1. [Figure 10B] It is a schematic diagram for explaining the subsequent steps of FIG. 10A. [Figure 11] It is a schematic diagram showing the outline of the via hole forming step according to the modification. [Figure 12] It is a schematic cross-sectional view of the tip of another pillar according to the modification. [Figure 13] It is a schematic diagram showing the outline of the via hole forming step according to Embodiment 2. [Figure 14]This is a schematic diagram showing an overview of another via hole formation process according to Embodiment 2. [Figure 15] This is a schematic diagram showing an overview of the via hole formation process according to Embodiment 3. [Figure 16] This is a schematic cross-sectional view of the via hole after the pretreatment process according to Embodiment 3. [Modes for carrying out the invention]

[0018] Embodiments of the present disclosure will be described below with reference to the drawings. The following description of preferred embodiments is illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0019] (Embodiment 1) [Interposer Configuration] Figure 1A is a schematic cross-sectional view of the main part of the interposer. Figure 1B is an enlarged view of the area enclosed by the dashed line in Figure 1A. Figure 1C is an enlarged view of the area enclosed by the dashed line in Figure 1B.

[0020] In the interposer 40, the side on which the rewiring layer 10A is provided is called the top or upper side, and the side on which the base material 30 is provided is called the bottom or lower side. Also, in the rewiring layer 10, the side on which the surface of the wiring 11 is exposed is called the top or upper side, and the opposite side is called the bottom or lower side. Furthermore, in the insulating layer, the side on which the surface of the groove portion 21 (see Figures 5B and 6A) is exposed is called the top or upper side, and the opposite side is called the bottom or lower side.

[0021] The interposer 40 shown in Figure 1A is a wiring structure in which five redistribution layers 10 are laminated on the upper surface of a core substrate 30 (hereinafter sometimes simply referred to as the substrate 30). The uppermost redistribution layer 10A has only pad electrodes 13 exposed on its upper surface for electrical connection to electrical elements, wiring boards, or circuit boards (none of which are shown). The number of redistribution layers 10 provided on the interposer 40 is not particularly limited to the example shown in Figure 1A. It may be fewer than five layers, for example, one layer. It may also be more than five layers. It can be appropriately changed depending on the number of elements connected to the interposer 40.

[0022] Furthermore, the core substrate 30 is a wiring structure in which multiple TGV (Through Glass Vias) electrodes 32 are provided penetrating the glass substrate 31. Multiple land electrodes (not shown) are arranged on the upper surface of the core substrate 30, covering the TGV electrodes 32, and the vias 12 of the bottommost rewiring layer 10 are electrically connected to the land electrodes. In addition, multiple other land electrodes (not shown) are arranged on the lower surface of the core substrate 30, covering the TGV electrodes 32. In many cases, each of the multiple land electrodes provided on the lower surface of the core substrate 30 is provided with a protruding electrode (not shown) for electrically connecting to an external substrate. Note that the upper and / or lower surfaces of the TGV electrodes 32 may also function as land electrodes.

[0023] As shown in Figure 1B, the redistribution layer 10 is arranged with multiple wires 11 and vias 12 embedded in the insulating layer 20. The upper surface of the wires 11 is flush with the upper surface of the insulating layer 20. The lower surface of the vias 12 is flush with the lower surface of the insulating layer 20. Although not shown in Figures 1A and 1B, vias 12 that penetrate the insulating layer 20 and have their upper and lower surfaces exposed may be provided in the redistribution layer 10. Vias 12 exposed on the lower surface of the redistribution layer 10 are connected to the wires 11 of the redistribution layer 10 that are in contact with the lower surface. In the redistribution layer 10 that is in contact with the core substrate 30, vias 12 exposed on the lower surface are connected to a land electrode or TGV electrode 32 provided on the upper surface of the core substrate 30.

[0024] Furthermore, as shown in Figure 1C, the wiring 11 is a conductor provided in the insulating layer 20, with a metal layer 11A made of copper (Cu) embedded in a groove 21 whose surface is covered with a laminated structure of a barrier layer 14 and a seed layer 15. In the wiring 11, the exposed upper surface is covered with a surface protection layer 16 instead of the aforementioned laminated structure. Although not shown, the via 12 has a similar structure. However, the via 12 is not provided with a surface protection layer 16.

[0025] The barrier layer 14 prevents the copper constituting the metal layer 11A from diffusing into the insulating layer 20 and causing short circuits within the rewiring layer 10. The barrier layer 14 also functions as an adhesion layer with the insulating layer 20. The barrier layer 14 may be made of a high-melting-point metal or compound such as TaN, TiN, or cobalt (Co), and may have a structure in which layers of different materials are stacked. The seed layer 15 functions as a growth base layer when performing copper electroplating, which will be explained later. Normally, when copper plating is performed, the seed layer 15 is also a thin film of copper. The surface protection layer 16 is provided to prevent oxidation and corrosion of the metal layer 11A, i.e., copper, during or after the manufacturing process. The surface protection layer 16 is an inorganic insulating film such as SiCN. However, it is not limited to this, and an inorganic conductive film such as TaN or TiN may be used as the surface protection layer 16. Also, if the width of the wiring 11 is wide, for example, 5 μm or more, the surface protection layer 16 may be omitted. Furthermore, to prevent corrosion of the metal layer 11A, a corrosion inhibitor may be applied to the upper surface of the wiring 11.

[0026] The interposer 40 is used to electrically connect a wiring board or circuit board to one or more semiconductor elements. The interposer 40 is particularly useful when the semiconductor elements have multiple pins and a narrow pad pitch. Examples of such semiconductor elements include high-performance LSIs such as CPUs (Central Processing Units) and GPUs (Graphics Processing Units), as well as large-scale memories such as HBM (High Bandwidth Memory).

[0027] On the other hand, in many cases, as shown in Figure 1A, the interposer 40 requires multiple rewiring layers 10, which results in a huge amount of manufacturing work, leading to a decrease in manufacturing yield and an increase in manufacturing costs.

[0028] Therefore, the inventors of the present invention investigated a method of simultaneously forming multiple grooves 21 and multiple via holes 22 (see Figures 5B and 6A) in the insulating layer 20 using a multi-stage imprint mold 50 (see Figure 3), and then embedding copper in them. By doing so, the manufacturing time for the redistribution layer 10 and, consequently, the interposer 40 can be reduced.

[0029] On the other hand, when forming via holes 22 using the imprint mold 50, the inventors of this application have found that the bottom of the via holes 22 may not open, leaving an insulating layer of a certain thickness. Below, we will explain in detail the equipment and construction methods for solving the problems of this disclosure, including a detailed explanation of this phenomenon.

[0030] [Overview of the processing equipment] Figure 2 is a schematic diagram of the processing apparatus according to Embodiment 1. Figure 3 is a schematic cross-sectional view of the imprint mold.

[0031] The processing apparatus 600 shown in Figure 2 comprises first to third units 100, 200, and 300, a mold holder 400, and a control unit 500. These are housed inside a housing (not shown). Alternatively, each of the first to third units 100, 200, and 300 may have its own housing, with the components described later housed inside each of these housings.

[0032] The first unit 100 comprises a flat first stage 110 and a first material supply mechanism 120. The first material supply mechanism 120 supplies the first material 60 (see Figure 4) so ​​that it spreads over a predetermined area on the upper surface of the first stage 110. The first material supply mechanism 120 also supplies the first material 60 to the upper surface of the first stage 110 so that the thickness of the first material 60 is uniform over the spread area.

[0033] The first material 60 consists of a resin-containing material and is supplied to the upper surface of the first stage 110 in a liquid or highly fluid state. Alternatively, the first material 60 processed into a sheet may be placed on the upper surface of the first stage 110. Furthermore, the configuration of the first material supply mechanism 120 is appropriately selected according to the supply method, supply form, and supply range of the first material 60. For example, when supplying liquid first material 60 over the entire upper surface of the first stage 110, the first material supply mechanism 120 may be a spin coater used in semiconductor manufacturing, etc. Also, when supplying first material 60 partially to the upper surface of the first stage 110, the first material supply mechanism 120 may be an inkjet type coater. The first material supply mechanism 120 may also be a spray coater. Furthermore, as mentioned above, when the first material 60 is a sheet material, the first material supply mechanism 120 may be a sheet transfer device.

[0034] Furthermore, the first unit 100 is equipped with a first material curing mechanism 130. The first material curing mechanism 130 is a mechanism for curing the first material 60 attached to the pillar 52. The curing method for the first material 60 in the first material curing mechanism 130 is appropriately selected according to the properties of the resin constituting the first material 60. For example, if the first material 60 is made of a photocurable resin material, the first material curing mechanism 130 is a light irradiation mechanism that irradiates the first material 60 attached to the pillar 52 with UV light. If the first material 60 is made of a thermosetting resin material, it is a heating mechanism that heats the first material 60 attached to the pillar 52. The first material curing mechanism 130 may also be a mechanism for drying and curing the first material attached to the pillar 52, for example, a hot air blowing mechanism.

[0035] The second unit 200 includes a flat second stage 210 on which a substrate 30 with an insulating layer 20 formed on it is placed, and a heating mechanism 220 for heating the second stage. The second unit 200 also includes a light irradiation mechanism 230 for irradiating the insulating layer 20 with light, in this case UV light. Furthermore, if the imprint process (pressure process) described later is thermal imprinting, the light irradiation mechanism 230 may be omitted.

[0036] Furthermore, the second unit 200 may have a mechanism (not shown; hereinafter sometimes referred to as a surface treatment mechanism) for performing surface treatment on the substrate 30 before forming the insulating layer 20. The surface treatment mechanism may be provided outside the second unit 200.

[0037] The third unit 300 has an etching chamber 310. In the etching chamber 310, after the insulating layer 20, which will be described later, has been processed, that is, after the insulating layer 20 has been formed with multiple grooves 21 and multiple via holes 22, any deposits 61 (see Figure 4) adhering to the imprint mold 50 are removed. The third unit 300 may be located outside the processing apparatus 600.

[0038] The mold holder 400 is a holding member to which an imprint mold 50 is detachably attached at its lower end. The mold holder 400 is fitted with a first moving mechanism 410 for moving the mold holder 400 between the first to third units 100, 200, and 300. The mold holder 400 is also fitted with a second moving mechanism 420 for moving the mold holder 400 toward the first stage 110 and the second stage 210, respectively. When the third unit 300 is outside the processing device 600, the first moving mechanism 410 moves the mold holder 400 between the first unit 100 and the second unit 200.

[0039] Furthermore, the mold holder 400 is fitted with a pressurizing mechanism 430 that pressurizes the mold holder 400, located directly above the second stage 210, toward the second stage 210 with a predetermined pressure. The pressurizing mechanism 430 incorporates, for example, a known load cell. The pressurizing mechanism 430 may also be incorporated into the second moving mechanism 420.

[0040] The control unit 500 includes at least one or more CPUs (Central Processing Units) and a storage unit consisting of semiconductor memory or the like (neither of which is shown). The control unit 500 controls the operation of the first material supply mechanism 120, the heating mechanism 220, the light irradiation mechanism 230, the first moving mechanism 410, the second moving mechanism 420, and the pressurizing mechanism 430, as described above. The control unit 500 also controls the operation of the drive mechanism and heating mechanism (neither of which is shown) inside the etching chamber 310. The control unit 500 may be provided for each unit or for each mechanism.

[0041] Next, we will describe the shape of the imprint mold 50.

[0042] As shown in Figure 3, the imprint mold 50 has a plate-shaped main body 51 having a first surface 51A and a second surface 51B, a plurality of steps 53, and a plurality of pillars 52. The first surface 51A and the second surface 51B face each other. The plurality of steps 53 protrude from the second surface 51B of the main body 51. In the example shown in Figure 3, the plurality of pillars 52 protrude from the bottom surfaces of the plurality of steps 53. Although not shown, the pillars 52 may also protrude from the second surface 51B of the main body 51. In that case, the tips of all pillars 52 are set to be in the same position with respect to the second surface 51B. Alternatively, in the imprint mold 50, the plurality of steps 53 may be omitted, and only the plurality of pillars 52 protrude from the second surface 51B.

[0043] As described above, by using the mold holder 400 and the pressurizing mechanism 430 to press the imprint mold 50 against the insulating layer 20 and apply pressure, grooves 21 are formed in the insulating layer 20 at locations corresponding to the steps 53, and via holes 22 are formed at locations corresponding to the pillars 52. When UV light is used in the imprint process, the material of the imprint mold 50 is limited to a light-transmitting material, but when only thermal imprinting is used, the material of the imprint mold 50 is not limited to this.

[0044] [Method for processing the insulating layer] Figure 4 is a schematic diagram illustrating the process of attaching and curing the first material to the tip of the pillar. Figure 5A is a schematic diagram illustrating the processing method for the insulating layer according to Embodiment 1. Figure 5B is a schematic diagram illustrating the process following Figure 5A. For the sake of clarity, in Figures 4, 5A, and 5B, only the first stage 110, the second stage 210, the heating mechanism 220, and the imprint mold 50 of the processing apparatus 600 are shown, and other parts are omitted from the illustration.

[0045] Furthermore, in the examples described below, a photosensitive polyimide resin that is thermoplastic in the B stage is used as the insulating layer 20. The B stage is an intermediate stage in the reaction of a thermosetting resin, in which it softens upon heating and becomes highly fluid.

[0046] First, we will explain the process of attaching and curing the first material 60 to the tip of the pillar 52.

[0047] As shown in Figure 4, the first material 60 is supplied to the upper surface of the first stage 110 provided in the first unit 100 of the processing apparatus 600 (first material supply step). The material of the first material 60 is one of those described above. The first material 60 is applied to the upper surface of the first stage 110 by a spin coating method. At this point, the first material 60 is in a liquid or highly fluid state. In this embodiment, the elastic modulus of the first material 60 after curing is 10 kPa or more and 10 MPa or less. It is more preferable that the elastic modulus is 500 kPa or more and 5 MPa or less.

[0048] Next, the first moving mechanism 410 and the second moving mechanism 420 move the mold holder 400 to the first unit 100 and lower it toward the first stage 110, thereby attaching the first material 60 to the tip of the pillar 52 of the imprint mold 50 attached to the mold holder 400 (first material attachment step).

[0049] The first material 60 is a resin-containing material, and its elastic modulus after curing is the same as or lower than that of the resin material constituting the insulating layer 20. In this embodiment, the first material 60 is composed solely of resin.

[0050] The resin in the first material 60 is appropriately set in combination with the resin constituting the insulating layer 20. The insulating layer 20 functions as an interlayer insulating layer that insulates the wiring 11 of the same layer or different layers in the rewiring layer 10 and the interposer 40. In order to suppress signal delay and attenuation inside the interposer 40, a low dielectric resin material is usually selected as the insulating layer 20. For example, polyimide resins and epoxy resins are selected, but as will be described later, considering deformation by imprinting, it is preferable that the insulating layer 20 be a polyimide resin material. Depending on the type of polyimide resin, its modulus of elasticity after complete curing is about 2000 MPa.

[0051] Furthermore, the resin included in the first material 60 can be general rubber (modulus of elasticity at room temperature: approximately 1 MPa) or replica mold resin with a modulus of elasticity of approximately 2 MPa to 6 MPa. However, it is not limited to these; thermoplastic resins used in thermal imprinting (modulus of elasticity during thermal imprinting: several tens of Pa to 10 kPa), which will be described later, may also be used. It is preferable that the modulus of elasticity of the first material 60 during the imprinting process, which will be described later, is between 100 kPa and 2 MPa.

[0052] After the first material 60 is attached to the tip of the pillar 52, the mold holder 400 and the imprint mold 50 are pulled upward by the second moving mechanism 420. Furthermore, the first material hardening mechanism 130 hardens the first material 60 to form an attached substance 61 (attached substance formation step).

[0053] Furthermore, as shown in Figure 5A, in the second unit 200, the upper surface of the substrate 30 is pre-treated by the surface treatment mechanism described above (substrate pre-treatment step). This pre-treatment is a process that cleans and hydrophilizes the upper surface of the substrate 30. Alternatively, as a cleaning or hydrophilization treatment, plasma irradiation may be performed on the upper surface of the substrate 30, as shown in Figure 5A.

[0054] Next, insulating resin 20A is applied to the upper surface of the pre-treated substrate 30 by a coating device (not shown) located outside the processing apparatus 600 (resin coating step). Subsequently, the second stage 210 is heated by the heating mechanism 220 to volatilize the solvent contained in the insulating resin 20A and pre-cur the insulating layer 20 (pre-curing step of insulating layer). Note that the steps shown in Figure 4 and the steps shown in Figure 5A may be performed simultaneously inside the processing apparatus 600, or at different timings.

[0055] After performing the steps shown in Figures 4 and 5A, the insulating layer 20 is softened while the substrate 30 is heated to a predetermined temperature, as shown in Figure 5B (insulating layer softening step). In other words, the insulating layer 20 is brought to the aforementioned B stage. During this time, the second moving mechanism 420 is operated to move the mold holder 400 and the imprint mold 50 attached thereto toward the insulating layer 20.

[0056] Next, the imprint mold 50 is moved, and the tip of the pillar 52 is pressed against the upper surface of the insulating layer 20 and pressurized downwards with a predetermined pressure (pressurization step). The pillar 52 and the step 53 are inserted into the softened insulating layer 20, and after the tip of the pillar 52 reaches the upper surface of the substrate 30, the insulating layer 20 is irradiated with UV light by the light irradiation mechanism 230 (photocuring step). The pressurization step until the tip of the pillar 52 reaches the upper surface of the substrate 30 is sometimes called the imprint step. In this embodiment, the imprint step is a type that uses both thermal imprinting and optical imprinting in combination.

[0057] After the UV light irradiation time reaches a predetermined time, the second moving mechanism 420 is operated to pull out the imprint mold 50 from the insulating layer 20 (demolition process). After the demolition process is completed, via holes 22 are formed in the insulating layer 20 where the pillars 52 were inserted, and grooves 21 are formed where the steps 53 were inserted.

[0058] Furthermore, the insulating layer of the substrate 30 is cured (main curing step). This main curing step is performed by heating the substrate 30, on which the insulating layer 20 having a plurality of grooves 21 and a plurality of via holes 22 is formed, at a predetermined temperature for a predetermined time using a heating device (not shown) provided outside the processing apparatus 600.

[0059] In this embodiment, the insulating layer 20 was photocured by irradiating it with UV light through the imprint mold 50 during the thermal imprinting process. However, the insulating layer 20 may also be photocured by irradiating it with UV light after demolding the imprint mold 50. In this case, it is not necessary to use a light-transmitting material for the imprint mold 50, and the range of materials that can be used to construct the imprint mold 50 is broadened. However, in the latter case, since the crosslinking reaction by UV light has not occurred, the substrate 30 will be cooled to reduce its fluidity before demolding the imprint mold 50.

[0060] Alternatively, only the photoimprint method may be used. The insulating layer 20 is made of a resin material that has photocuring and thermocuring properties. In this case, the pre-curing step can be omitted. However, if the insulating resin 20A is supplied in liquid form to the upper surface of the substrate 30, the insulating resin 20A may be heated using the heating mechanism 220 in order to reduce the fluidity of the insulating resin 20A.

[0061] Next, the challenges of forming via holes 22 in the insulating layer 20 using the imprint mold 50 will be explained with reference to Figures 6A to 6C.

[0062] Figure 6A is an enlarged view of the insulating layer in which grooves and via holes are formed. Figure 6B is a schematic diagram illustrating the conventional problem and is equivalent to Figure 6A. Figure 6C is another schematic diagram illustrating the conventional problem and is equivalent to Figure 6A.

[0063] In the insulating layer 20 after imprinting and subsequent curing, a groove 21 is formed with the same depth as the height of the step 53, relative to the upper surface of the insulating layer 20, as shown in Figure 6A. In addition, a via hole 22 with the same depth as the length of the pillar 52 is formed so as to reach the TGV electrode 32 or a land electrode (not shown) exposed on the upper surface of the substrate 30 from the bottom surface of the groove 21.

[0064] However, in reality, the via hole 22 may not reach the TGV electrode 32 or the land electrode, and a residual film 20B of about 0.something μm to several μm in thickness may remain at the bottom of the via hole 22 on the upper surface of the substrate 30.

[0065] For example, if the base material 30 is warped, the top surface of the base material 30 may tilt from its initial position, as shown in Figure 6B. Also, if there is variation in the thickness of the base material 30 or if the flatness of the top surface of the base material 30 is poor, the top surface of the base material 30 may tilt locally from its initial position.

[0066] When this happens, the relative distance between the tip of the pillar 52 and the upper surface of the substrate 30 varies, resulting in areas where the tip of the pillar 52 does not reach the surface of the substrate 30. As a result, in some via holes 22, the aforementioned residual film 20B remains at the bottom of the via hole 22.

[0067] Furthermore, when forming the TGV electrode 32, metal adhering to the upper surface of the glass substrate 31 may be removed by CMP (Chemical Mechanical Polishing) or other methods. In this case, if the width of the TGV electrode 32 becomes wider, a phenomenon called dishing may occur, causing the central part of the TGV electrode 32 to become concave.

[0068] When such a depression occurs, the thickness of the insulating layer 20 relative to the top surface becomes thicker than the design value in some areas, and as shown in Figure 6C, the tip of the pillar 52 can no longer reach the surface of the substrate 30. As a result, the aforementioned residual film 20B remains at the bottom of the via hole 22.

[0069] The inventors of this application have found that the aforementioned problem can be solved by performing imprinting with an adsorbent 61 having an elastic modulus less than or equal to that of the insulating layer 20 attached to the tip of the pillar 52. This will be explained further below.

[0070] Figure 7 is an enlarged view of the portion including the tip of the pillar in the pressurization process according to Embodiment 1. Figure 8 is a schematic diagram showing an overview of the via hole formation process according to Embodiment 1. Figure 9 is a schematic diagram showing an overview of the via hole formation process according to Embodiment 1, and is a schematic diagram showing the case when the amount of deformation of the attached material is large.

[0071] In the example shown in Figure 7, the upper surface of the substrate 30 is tilted from its initial position, similar to the example shown in Figure 6B. As a result, the relative distance between the tip of the pillar 52 and the upper surface of the substrate 30 varies in the direction along the upper surface of the insulating layer 20.

[0072] On the other hand, as shown in Figure 7, deposits 61 are attached to the tip of the pillar 52. The length of the deposits 61 along the length of the pillar 52 roughly corresponds to the thickness of the first material 60 supplied to the first stage 110. Therefore, if this length is set to about 1 μm to several μm, the tip position of the pillar 52 will appear to be about 1 μm to several μm closer to the upper surface of the substrate 30. In this state, if the pressure is appropriately set and the pillar 52 is inserted into the insulating layer 20, the aforementioned variation in relative distance can be absorbed and the deposits 61 can reach the upper surface of the substrate 30. In other words, the thickness of the residual film 20B at the bottom of the via hole 22 can be reduced to below a predetermined level.

[0073] Furthermore, since the elastic modulus of the deposit 61 is less than or equal to that of the insulating layer 20, in areas where the relative distance between the tip of the pillar 52 and the upper surface of the base material 30 is shorter than the thickness of the insulating layer 20 (see the enlarged view on the right side of Figure 7), the deposit 61 deforms significantly and pushes open the via hole 22. This allows the deposit 61 to reach the upper surface of the base material 30 while preventing damage to the pillar 52. Also, because the deposit 61 is a low-elasticity material, even if the deposit 61 deforms and pushes open the via hole 22, its shape returns to its original state when the pillar 52 is pulled out, and the deposit 61 is pulled out together with the pillar 52, so it does not remain at the bottom of the via hole 22.

[0074] Furthermore, as shown in Figure 8, if the deposit 61 adheres only to the lower surface of the tip of the pillar 52, the diameter D of the via hole 22 can be made the same as the diameter D of the pillar 52. In other words, the diameter of the via hole 22 can be easily controlled. On the other hand, as shown in Figure 9, if the deposit 61 deforms significantly at the bottom of the via hole 22, the diameter D1 of the bottom of the via hole 22 becomes larger than the diameter D of the via hole 22 above it (D1 > D). As the diameter D1 increases, when the via 12 is formed in the process described later, the contact area between the via 12 and the TGV electrode 32 can be increased, and the resistance of the via 12 can be reduced. However, in this case, the barrier layer 14 and seed layer 15 mentioned above will not adhere to the inner wall surface of the via hole 22 as easily as the bottom of the via hole 22, so care must be taken to control the range of the diameter D1, or in other words, the amount of deposit 61 that adheres.

[0075] [Manufacturing method for redistribution layer] After the steps shown in Figures 5A and 5B are taken to form multiple grooves 21 and multiple via holes 22 in the insulating layer 20 formed on the upper surface of the substrate 30, the steps shown in Figures 10A and 10B are taken to form the redistribution layer 10. Note that the steps shown in Figures 10A and 10B are performed in a processing apparatus separate from the processing apparatus 600.

[0076] Figure 10A is a schematic diagram illustrating the method for manufacturing a redistribution layer according to Embodiment 1. Figure 10B is a schematic diagram illustrating the subsequent steps following Figure 10A.

[0077] First, as shown in Figure 10A, the insulating layer 20, which has multiple grooves 21 and multiple via holes 22 formed on it, is subjected to plasma etching (etching process). By performing this process, as shown in Figure 10A, residual film 20B of a few tenths of a micrometer or less remaining at the bottom of the via holes 22 can be reliably removed, and the upper surface of the TGV electrode 32 can be exposed. Furthermore, even if there is no residual film 20B, depending on the size of the surface irregularities of the attached material 61, residue of the insulating layer 20 may remain on the upper surface of the TGV electrode 32 in the size of several tens of nanometers. Such residue can also be reliably removed by etching.

[0078] Next, the upper surface of the substrate 30 exposed at the bottom of the insulating layer 20 and via holes 22 is subjected to reverse sputtering. Reverse sputtering is a process in which inert gas ions, typically argon ions, are irradiated to remove the surface of the insulating layer 20 and substrate 30 and any substances adhering to that surface. After the reverse sputtering, a barrier layer 14 and a seed layer 15 are continuously formed on the upper surface of the substrate 30 exposed at the bottom of the insulating layer 20 and via holes 22 (pre-treatment step).

[0079] Typically, the process from reverse sputtering to the formation of the seed layer 15 is carried out continuously within the sputtering apparatus. In other words, the barrier layer 14 and the seed layer 15 are each formed by the sputtering method. Note that the barrier layer 14 and the seed layer 15 are formed in separate chambers. However, this is not particularly limited, and the barrier layer 14 and the seed layer 15 may also be formed by the CVD method. Alternatively, the process from reverse sputtering to the formation of the barrier layer 14 may be carried out continuously within the same vacuum apparatus, and the seed layer 15 may be formed in a separate apparatus.

[0080] After the pretreatment process, the substrate 30 with the insulating layer 20 formed on it is introduced into a plating tank (not shown), and a Cu plating layer 70, in this case a metal of the same type as the seed layer 15, is formed on the surface of the seed layer 15 by electroplating (Cu plating process). Plating is carried out until the Cu plating layer 70 is thick enough to sufficiently fill the grooves 21 and via holes 22. The metal to be plated is not particularly limited to copper. When plating with a metal other than copper, it is preferable to use the same type of metal for the seed layer 15 as the metal to be plated. Alternatively, the grooves 21 and via holes 22 may be filled with metal using electroless plating.

[0081] Next, the Cu plating layer 70 deposited on the upper surface of the insulating layer 20 is removed. In this embodiment, the Cu plating layer 70 deposited on the upper surface of the insulating layer 20 is polished and removed by the CMP method to flatten the upper surface of the insulating layer 20 (flattening step). However, this is not limited to this, and for example, the Cu plating layer 70 deposited on the upper surface of the insulating layer 20 may be cut and removed using a surface planer to flatten the upper surface of the insulating layer 20. By removing the Cu plating layer 70 deposited on the upper surface of the insulating layer 20, the copper (Gu) embedded in the groove 21 is processed into wiring 11, and the copper embedded in the via hole 22 is processed into via 12.

[0082] After planarization, a surface protection layer 16 is formed to cover the upper surface of the wiring 11 exposed on the upper surface of the insulating layer 20 (surface treatment step). Typically, an inorganic insulating film or inorganic conductive film that will become the surface protection layer 16 is formed over the entire upper surface of the insulating layer 20, and then the portion excluding the upper surface of the wiring 11 is removed by photolithography and etching using a photomask (not shown). As mentioned above, instead of the surface treatment step to form the surface protection layer 16, a treatment such as applying a corrosion inhibitor to the upper surface of the wiring 11 may be performed.

[0083] After performing the steps described above, a redistribution layer 10 is obtained. If necessary, the redistribution layer 10 is laminated by performing the processes shown in Figures 5A, 5B and 10A, 10B on the upper surface of the formed redistribution layer 10 (lamination process). After forming the required number of redistribution layers 10, an external connection electrode (not shown) is formed on the surface of the TGV electrode 32 or land electrode exposed on the lower surface of the substrate 30 to complete the interposer 40.

[0084] [Effects, etc.] As described above, the method for processing the insulating layer 20 according to this embodiment uses an imprint mold 50 having a main body 51, a plurality of steps 53, and a plurality of pillars 52. The plurality of steps 53 protrude from the second surface 51B of the main body 51, and the plurality of pillars 52 protrude from the bottom surfaces of the plurality of steps 53. Alternatively, the pillars 52 may protrude from the second surface 51B of the main body 51. Furthermore, in the imprint mold 50, the plurality of steps 53 may be omitted, and only the plurality of pillars 52 may protrude from the second surface 51B.

[0085] The method for processing the insulating layer 20 comprises at least the following steps.

[0086] In the insulating layer formation process, an insulating layer 20 is formed on the upper surface of the substrate 30.

[0087] In the first material attachment process, the first material 60 is attached to the tip of the pillar 52. The attached first material 60 is then hardened to become the attached material 61.

[0088] In the pressurizing process, the imprint mold 50 is pressed against the insulating layer 20 and pressurized so that the adhering material 61 reaches the upper surface of the substrate 30.

[0089] In the demolding process, the imprint mold 50 is pulled out from the insulating layer 20, forming via holes 22 in the insulating layer 20 where the pillars 52 were inserted, and grooves 21 in the areas where the steps 53 were inserted. If multiple steps 53 are omitted in the imprint mold 50, the grooves 21 are not formed in the demolding process, and only the via holes 22 are formed.

[0090] In the curing process, the insulating layer 20 is cured. This curing process includes a UV light curing process and the main curing process.

[0091] The elastic modulus of the first material 60 and its cured deposit 61 is the same as or lower than the elastic modulus of the insulating layer 20.

[0092] According to this embodiment, even if the relative distance between the tip of the pillar 52 and the upper surface of the substrate 30 varies due to warping of the substrate 30 or dishing of the TGV electrode 32, this variation in relative distance can be absorbed, and the thickness of the residual film 20B at the bottom of the via hole 22 can be kept below a predetermined level. This ensures that the bottom of the via hole 22 can be reliably opened in the subsequent etching process. Furthermore, in the redistribution layer 10 formed by embedding a metal such as copper in the groove 21 and the via hole 22, electrical connection problems with the substrate 30 or another redistribution layer 10 provided in the layer below can be reduced.

[0093] When the insulating layer 20 is a polyimide resin or an epoxy resin, it is preferable that the elastic modulus of the first material 60 and the adhering material 61 is sufficiently lower than their respective elastic moduli (approximately several hundred MPa to several thousand MPa). For example, in the imprint process, the elastic modulus of the first material 60 and the adhering material 61 is preferably 10 kPa or more and 10 MPa or less, and more preferably 100 kPa or more and 2 MPa or less.

[0094] In this way, the deposit 61 deforms significantly and pushes open the via hole 22, allowing the deposit 61 to reach the upper surface of the base material 30 while preventing damage to the pillar 52.

[0095] Furthermore, in the demolding process in this embodiment, the imprint mold 50 is pulled out from the insulating layer 20 while the deposit 61 remains attached to the tip of the pillar 52.

[0096] In this way, no deposits 61 remain at the bottom of the via hole 22, and the subsequent etching process ensures that the upper surface of the substrate 30 is reliably exposed at the bottom of the via hole 22.

[0097] Furthermore, if the insulating layer 20 is thermoplastic, in the pressurizing process, the elastic modulus of the material constituting the imprint mold 50, the deposit 61, and the insulating layer 20 increases in this order.

[0098] On the other hand, in the release process, the elastic modulus of the material constituting the imprint mold 50, the insulating layer 20, and the adhering material 61 increases in this order.

[0099] By defining the elastic modulus in this way, the imprint mold 50 can be reliably embedded in the insulating layer 20 during the pressurizing process. Furthermore, after the demolding process, the thickness of the residual film 20B at the bottom of the via hole 22 can be reduced to below a predetermined level.

[0100] The first material 60 and the attached substance 61 are preferably low water-repellent materials. This further suppresses the insulating layer 20 from wrapping around to the bottom of the via hole 22, preventing the formation of a residual film 20B or residue.

[0101] The first material 60 and the adhering material 61 are preferably made of materials with high release properties. This makes it easier to insert the imprint mold 50 into the insulating layer 20 during the pressurizing process. Furthermore, it makes it easier to remove the imprint mold 50 from the insulating layer 20 during the release process.

[0102] The method for manufacturing the redistribution layer 10 according to this embodiment comprises at least the following steps.

[0103] In the recess formation step, a plurality of grooves 21 and a plurality of via holes 22 are formed in the insulating layer 20 formed on the upper surface of the substrate 30 using the aforementioned processing method for the insulating layer 20.

[0104] In the pretreatment step, a barrier layer 14 and a seed layer 15 are formed on the surface of the insulating layer 20, which includes the inner wall surfaces of the multiple grooves 21 and the multiple via holes 22.

[0105] In the plating process, metal plating is applied to the surface of the seed layer 15 to fill the grooves 21 and via holes 22 with metal.

[0106] In the planarization process, the metal formed on the upper surface of the insulating layer 20 is removed, thereby processing the metal embedded in the grooves 21 into wiring 11 and the metal embedded in the via holes 22 into vias 12.

[0107] In the imprint mold 50, if multiple steps 53 are omitted, the grooves 21 are not formed in the recess formation process, and only the via holes 22 are formed. In the pretreatment process, a barrier layer 14 and a seed layer 15 are formed on the surface of the insulating layer 20, including the inner wall surfaces of each of the multiple via holes 22. In the plating process, metal plating is performed on the surface of the seed layer 15 to fill the via holes 22 with metal. In the planarization process, the metal formed on the upper surface of the insulating layer 20 is removed, thereby processing the metal embedded in the via holes 22 into vias 12.

[0108] According to this embodiment, the vias 12 can be reliably exposed on the lower surface of the insulating layer 20 in the redistribution layer 10. This reduces electrical connection problems between the redistribution layer 10 and the substrate 30 or another redistribution layer 10 provided in the layer below it.

[0109] Furthermore, the process may include a lamination step in which multiple redistribution layers are stacked in the thickness direction by repeatedly performing a series of processes from the recess formation step to the planarization step. In this way, an interposer 40 having a multilayer redistribution layer 10 can be easily manufactured.

[0110] The processing apparatus 600 according to this embodiment is an apparatus for forming a plurality of grooves 21 and a plurality of via holes 22 in an insulating layer 20 formed on the upper surface of a substrate 30. The processing apparatus 600 comprises at least a first unit 100, a second unit 200, and a mold holder 400.

[0111] The first unit 100 includes at least a first stage 110 and a first material supply mechanism 120. The first material supply mechanism 120 supplies the first material 60 so as to spread over a predetermined area on the upper surface of the first stage 110.

[0112] The second unit 200 includes at least a second stage 210 on which a substrate 30 with an insulating layer 20 formed on it is placed, and a heating mechanism 220 for heating the second stage 210.

[0113] The mold holder 400 is fitted with a first moving mechanism 410 and a second moving mechanism 420. The first moving mechanism 410 moves the mold holder 400 at least between the first unit 100 and the second unit 200. The second moving mechanism 420 moves the mold holder 400 toward the first stage 110 and the second stage 210, respectively.

[0114] An imprint mold 50 is detachably attached to the lower end of the mold holder 400.

[0115] In the first unit 100, the first material 60 is attached to the tips of multiple pillars 52 provided on the imprint mold 50.

[0116] In the second unit 200, the mold holder 400 presses the imprint mold 50, to which the hardened deposit 61 of the first material 60 is attached, against the insulating layer 20 and applies pressure, thereby forming multiple grooves 21 and multiple via holes 22 in the insulating layer 20. If multiple steps 53 are omitted in the imprint mold 50, multiple via holes 22 are formed in the insulating layer 20 in the second unit 200.

[0117] By configuring the processing apparatus 600 in this way, the thickness of the residual film 20B at the bottom of the via hole 22 can be reduced to below a predetermined level. This ensures that the bottom of the via hole 22 can be reliably opened in the subsequent etching process. Furthermore, in the redistribution layer 10 formed by embedding a metal such as copper in the groove 21 and the via hole 22, electrical connection problems with the substrate 30 or another redistribution layer 10 provided in the layer below can be reduced.

[0118] Preferably, the first unit 100 further includes a first material hardening mechanism 130 that hardens the first material 60 attached to the pillar 52 to form an adhering substance 61. In this way, the adhering substance 61, which is a low-elasticity material, can be securely fixed and attached to the tip of the pillar 52.

[0119] If the imprint mold 50 is made of a light-transmitting material and the insulating layer 20 is made of a photocurable material, the second unit 200 preferably further comprises a light irradiation mechanism 230. The light irradiation mechanism 230 irradiates the insulating layer 20 with light that passes through the imprint mold 50.

[0120] By providing the light irradiation mechanism 230, the insulating layer 20 can be cured by irradiating it with light during or immediately after the pressurizing process. This suppresses deformation of the grooves 21 and via holes 22.

[0121] The processing apparatus 600 may further include a third unit 300. In the third unit 300, after forming a plurality of grooves 21 and a plurality of via holes 22 in the insulating layer 20, the adhering material 61 attached to the imprint mold 50 is removed. If the plurality of steps 53 in the imprint mold 50 are omitted, the third unit 300 removes the adhering material 61 attached to the imprint mold 50 after forming the plurality of via holes 22 in the insulating layer 20.

[0122] By providing the third unit 300, the imprint mold 50 can be used continuously without being removed from the mold holder 400. This reduces the downtime of the processing device 600. In addition, since the deposits 61 adhering to the imprint mold 50 can be removed at the appropriate timing, the amount of deposits 61 at the tip of the pillar 52 can be kept constant, and variations in the amount of extrusion of the insulating layer 20 during the pressurizing process can be suppressed. This suppresses variations in the shape of the via holes 22.

[0123] <Variation> Figure 11 is a schematic diagram showing an overview of the via hole formation process according to a modified example. Figure 12 is a schematic cross-sectional view of the tip of another pillar according to a modified example. For the sake of clarity, in Figure 11 and the subsequent drawings, the same reference numerals are used for parts that are the same as in Embodiment 1, and detailed explanations are omitted.

[0124] In the via hole formation process shown in Figure 11, the extent of the deposit 61 covering the tip of the pillar 52 differs from that of the via hole formation process shown in Figure 8. As shown in the leftmost diagram of Figure 11, the deposit 61 is attached to the tip of the pillar 52 so as to cover not only the bottom surface but also the outer surface.

[0125] Therefore, during the pressurization process, when the pillar 52 is inserted into the insulating layer 20, the adhering material 61 pushes out an area of ​​the insulating layer 20 that is larger than the diameter D of the pillar 52. Furthermore, after the demolding process, the diameter of the via holes 22 formed in the insulating layer 20 becomes larger than the diameter D of the pillar 52.

[0126] According to this modified example, by attaching the deposit 61 to the tip of the pillar 52 so as to cover the outer surface, and by appropriately adjusting the amount of deposit, specifically the width of the deposit 61, the diameter of the via hole 22 can be increased relative to the diameter D of the pillar 52. This makes it possible to change the resistance of the via 12 according to the design specifications of the rewiring layer 10 and, consequently, the interposer 40. The amount of deposit 61 can be adjusted, for example, by repeating the process shown in Figure 4 multiple times.

[0127] As shown in Figure 11, if the length of the deposit 61 along the longitudinal direction of the pillar 52 is shorter than the thickness of the insulating layer 20, and the deformation of the deposit 61 in contact with the upper surface of the substrate 30 is large, the diameter D3 at the bottom of the via hole 22 may become larger than the diameter D2 at the top. For this reason, the amount of deposit 61 must be set according to the desired diameter of the via hole 22 and the allowable amount of change in diameter.

[0128] Furthermore, when the deposit 61 is attached to the tip of the pillar 52 so as to cover the outer surface, the first material 60 may unintentionally crawl upwards, making it impossible to properly set the amount and width of the deposit 61. To control such crawling, for example, the tip of the pillar 52 may be shaped as shown in Figure 12.

[0129] The tip of the pillar 52 shown in Figure 12 has a first portion 52a and a second portion 52b. The second portion 52b is located above the first portion 52a, that is, closer to the main body 51. Furthermore, the diameter Db of the second portion 52b is larger than the diameter Da of the first portion 52a.

[0130] By shaping the tip of the pillar 52 as shown in Figure 12, in the first material adhesion process, the upward movement of the first material 60 is blocked by the step created by the difference in diameter between the first portion 52a and the second portion 52b. In other words, the adhering material 61 covers the outer surface of the first portion 52a and adheres to the pillar 52, while not adhering to the second portion 52b. Therefore, by appropriately setting the first portion 52a along the longitudinal direction of the pillar 52 and the diameters Da and Db, it is possible to prevent the first material 60 from unintentionally crawling up and to set the amount and width of the adhering material 61 to desired values.

[0131] (Embodiment 2) Figure 13 is a schematic diagram showing an overview of the via hole formation process according to Embodiment 2. Figure 14 is a schematic diagram showing an overview of another via hole formation process according to Embodiment 2.

[0132] Embodiment 1 and its modifications describe a method in which the imprint mold 50 is pulled out from the insulating layer 20 while the adhering material 61 remains attached to the pillar 52 during the release process.

[0133] However, the processing method for the insulating layer 20 of this disclosure is not limited thereto. As shown in Figures 13 and 14, the imprint mold 50 may be withdrawn from the insulating layer 20 while the deposits 61 remain at the bottom of the via holes 22. In this case, the deposits 61 remaining at the bottom of the via holes 22 are removed in the etching step following the demolding step.

[0134] Furthermore, even if the deposit 61 deforms and pushes out the insulating layer 20 at the bottom of the via hole 22, anisotropic dry etching can leave the deposit 61 embedded in the inner wall surface at the bottom of the via hole 22. This reduces the difference between the diameter at the bottom and the diameter at the top of the via hole 22. Also, when forming the barrier layer 14 and the seed layer 15, it is possible to improve insufficient coverage at the bottom of the via hole 22. Consequently, defects in metal embedding into the via hole 22 during the plating process can be reduced, preventing connection defects between the via 12 and the TGV electrode 32, land electrode, and underlying wiring 11, and preventing a decrease in connection reliability.

[0135] Furthermore, in order to suppress the expansion of the diameter of the via holes 22 during the etching process, it is preferable that the deposit 61 be made of a material with a higher etching rate than the insulating layer 20. For example, it is preferable that the first material 60 and the deposit 61 be resin materials with lower molecular weight than the insulating layer 20. Alternatively, it is preferable that the first material 60 and the deposit 61 be resin materials with a lower glass transition temperature than the insulating layer 20.

[0136] Furthermore, it is preferable that the first material 60 and the attached material 61 are resin materials that experience greater film loss due to heating than the insulating layer 20. For example, the amount of film loss can be increased by increasing the solvent content in the first material 60 and the attached material 61. In this case, the solvent content in the first material 60 and the curing conditions for the first material 60 are set so that a certain proportion of the solvent remains in the attached material 61.

[0137] Furthermore, as shown in Figure 14, a heating step is provided between the demolding step and the etching step to heat the insulating layer 20 on which the deposits 61 remain. By reducing the amount of deposits 61 during the heating step, the amount of etching of the deposits 61 and the insulating layer 20 in the etching step can be reduced, thereby suppressing the expansion of the diameter of the via holes 22.

[0138] In the example shown in Figure 14, a heating step is provided separately from the main curing step of the insulating layer 20. However, if the deposits 61 have been sufficiently reduced by heating during the pressurizing step or by heating during the curing step when using the optical imprint method, the aforementioned heating step can be omitted.

[0139] (Embodiment 3) Figure 15 is a schematic diagram showing an overview of the via hole formation process according to Embodiment 3. Figure 16 is a schematic cross-sectional view of the via hole after the pretreatment process according to Embodiment 3.

[0140] The via hole formation process shown in Figure 15 differs from the via hole formation process of Embodiment 2 shown in Figure 13 in that the deposit 61A is a conductive material. In this embodiment, the deposit 61A is made conductive by using a resin material in which fine particles of a conductive substance, such as nanoconductive material, are dispersed as the first material 60. The content ratio of the nanoconductive material can be appropriately changed according to the conductivity required for the deposit 61A.

[0141] In this embodiment, as shown in Figure 15, the via hole formation process uses a conductive material for the deposit 61A, and leaves the deposit 61A at the bottom of the via hole 22 after the demolding process. In this case, heating during the pressurizing process causes the nano-conductive material in the deposit 61A to bond with the TGV electrode 32. Furthermore, the bond between the insulating layer 20 and the deposit 61A is strengthened via the nano-conductive material. For this reason, the deposit 61A remains at the bottom of the via hole 22 after the demolding process. In this case, as shown in Figure 16, the barrier layer 14 and seed layer 15 are formed while the deposit 61A remains at the bottom of the via hole 22.

[0142] According to this embodiment, the etching process to remove the deposits 61A can be omitted. In other words, the number of steps in the processing method for the insulating layer 20 and the manufacturing method for the redistribution layer 10 can be reduced. Furthermore, since the deposits 61A are made of a conductive material, even if the deposits 61A are left at the bottom of the via hole 22, electrical connection between the via 12 and the underlying wiring 11, TGV electrode 32, or land electrode can be ensured.

[0143] Furthermore, as shown in the right-hand diagram of Figure 16, defects may occur in the barrier layer 14 or seed layer 15 inside the via hole 22. In particular, when the aspect ratio of the via hole 22, that is, the ratio of depth to diameter, increases, the amount of metal adhering to the inner wall surface at the bottom of the via hole 22 decreases in physical vapor deposition methods such as sputtering, making it prone to defects. When such defects occur, metal will not deposit in the defective area during the subsequent electroplating process, resulting in poor metal filling of the via hole 22. As a result, the resistance of the via 12 may increase, and poor connections between the via 12 and the underlying wiring 11 may occur. In addition, the reliability of the connection between the via 12 and the underlying wiring 11 may decrease.

[0144] On the other hand, according to this embodiment, even if there are defects in the barrier layer 14 or seed layer 15, the deposits 61A in the layer below are conductive, making it less likely for metal deposition defects to occur. As a result, metal embedding defects in the via holes 22 can be suppressed, and the occurrence of increased resistance in the via 12 and connection defects between the via 12 and the wiring 11 etc. below it can be suppressed. In addition, a decrease in connection reliability between the via 12 and the wiring 11 etc. below it can be suppressed.

[0145] (Other embodiments) The processing apparatus 600 may also be further equipped with an insulating layer forming mechanism (not shown) for forming an insulating layer 20 on the upper surface of the substrate 30. In this way, the insulating layer forming process and subsequent processes can be carried out continuously, and the manufacturing turnaround time (TAT) for the rewiring layer 10 and, consequently, the interposer 40 can be shortened. The insulating layer forming mechanism is provided, for example, inside the second unit 200.

[0146] This insulating layer formation mechanism is, for example, a spin coater. However, it is not particularly limited to this, and the insulating layer formation mechanism may also be a spray coater. The insulating layer formation mechanism applies an insulating resin 20A, such as the polyimide resin mentioned above, to the entire upper surface of the substrate 30 to a uniform thickness. [Industrial applicability]

[0147] The insulating layer processing method of this disclosure is useful because it can reduce the thickness of the residual film at the bottom of the via holes provided in the insulating layer of the redistribution layer to below a predetermined level, and can also reduce electrical connection failures between the redistribution layer and the substrate provided in the layer below it, as well as the redistribution layer itself. [Explanation of Symbols]

[0148] 10 Redistribution layer 11 Wiring 11A metal layer 12 Beers 13 Pad electrodes 14 Barrier layer 15 Seed Layer 16 Surface protective layer 20 Insulating layer 20A insulating resin 20B Residual film 21 Groove 22 Beer Hall 30 Substrate (Core Substrate) 31 Glass substrate 32 TGV electrode 40 Interposer 50 Imprint molds 51 Main body 51A 1st page 51B 2nd side 52 Pillars 53 steps 60 1st material 61, 61A Adhered substances 70 Cu plating layer 100 Unit 1 110 Stage 1 120 1st material supply mechanism 130 First material hardening mechanism 200 Unit 2 210 Stage 2 220 Heating mechanism 230 Light irradiation mechanism 300 Unit 3 310 Etching Room 400 Mold Holder 410 1st movement mechanism 420 Second movement mechanism 430 Pressurization mechanism 500 Control Unit 600 Processing equipment

Claims

1. A method for processing an insulating layer using an imprint mold, The aforementioned imprint mold comprises at least a main body and a plurality of pillars, At least multiple pillars protrude from the second surface of the main body, An insulating layer formation step in which an insulating layer is formed on the upper surface of the substrate, A first material attachment step involves attaching a first material to the tip of the pillar, A pressing step of pressing the imprinting mold against the insulating layer and applying pressure so that the first material reaches the upper surface of the substrate, A release step is to remove the imprint mold from the insulating layer to form via holes in the insulating layer where the pillars were inserted, The process includes at least a curing step for curing the insulating layer, A method for processing an insulating layer, characterized in that the elastic modulus of the first material is the same as or lower than the elastic modulus of the insulating layer.

2. In the method for processing an insulating layer according to claim 1, The imprint mold further has a plurality of steps protruding from the second surface of the main body, Multiple pillars protrude from the bottom surface of multiple steps, The method for processing an insulating layer is characterized in that, in the release step, the imprint mold is pulled out from the insulating layer to form a groove at the location where the step was inserted.

3. In the method for processing an insulating layer according to claim 1, A method for processing an insulating layer, characterized in that the elastic modulus of the first material is 10 kPa or more and 10 MPa or less.

4. In the method for processing an insulating layer according to claim 3, A method for processing an insulating layer, characterized in that the elastic modulus of the first material is 100 kPa or more and 2 MPa or less.

5. In the method for processing an insulating layer according to claim 1, A method for processing an insulating layer, characterized in that, in the demolding step, the first material is removed from the insulating layer while the imprint mold remains attached to the tip of the pillar.

6. In the method for processing an insulating layer according to claim 5, In the pressing step, the material constituting the imprint mold, the first material, and the insulating layer have increasing elastic moduli in this order. In the demolding step, the material constituting the imprint mold, the insulating layer, and the first material are arranged in such an order that the elastic modulus is highest, and this is the method for processing an insulating layer.

7. In the method for processing an insulating layer according to claim 1, A method for processing an insulating layer, characterized in that, in the demolding step, the first material is left in place at the bottom of the via hole, and the imprint mold is withdrawn from the insulating layer.

8. In the method for processing an insulating layer according to claim 7, A method for processing an insulating layer, further comprising an etching step of removing the first material remaining at the bottom of the via hole by etching after the demolding step has been performed.

9. In the method for processing an insulating layer according to claim 8, A method for processing an insulating layer, further comprising a heating step of heating the insulating layer before performing the etching step.

10. In the method for processing an insulating layer according to claim 7, A method for processing an insulating layer, characterized in that the first material is a conductive material.

11. A recess forming step of forming at least a plurality of via holes in the insulating layer formed on the upper surface of the substrate using the insulating layer processing method according to any one of claims 1 to 10, A pretreatment step of forming a barrier layer and a seed layer on the surface of the insulating layer, including the inner wall surface of each of the multiple via holes, A plating step in which metal plating is performed on the surface of the seed layer to fill the via holes with metal, The system comprises at least a planarization step of processing the metal embedded in the via hole into a via by removing the metal formed on the upper surface of the insulating layer, A method for manufacturing a redistribution layer, characterized in that the redistribution layer is composed of the insulating layer and a plurality of vias.

12. In the method for manufacturing a redistribution layer according to claim 11, The imprint mold further has a plurality of steps protruding from the second surface of the main body, In the recess formation step, a plurality of grooves are further formed in the insulating layer, In the pretreatment step, the barrier layer and the seed layer are formed on the surface of the insulating layer, which includes the inner wall surfaces of each of the plurality of grooves and the plurality of via holes. In the plating process, the metal plating is performed on the surface of the seed layer to fill the grooves and via holes with the metal. In the planarization step, the metal formed on the upper surface of the insulating layer is removed, thereby processing the metal embedded in the groove into wiring, and the metal embedded in the via hole into vias. A method for manufacturing a redistribution layer, characterized in that the redistribution layer is composed of the insulating layer, a plurality of the wirings, and a plurality of the vias.

13. In the method for manufacturing a redistribution layer according to claim 11, A method for manufacturing a redistribution layer, further comprising a lamination step of stacking a plurality of the redistribution layers in the thickness direction by repeatedly performing the series of processes from the recess formation step to the planarization step.

14. A processing apparatus for forming at least a plurality of via holes in an insulating layer formed on the upper surface of a substrate, It comprises at least a first unit, a second unit, and a mold holder, The first unit is, Stage 1 and The first stage comprises at least a first material supply mechanism that supplies a first material having the same or lower elastic modulus as the insulating layer so as to spread over a predetermined area on the upper surface of the first stage, The second unit is, A second stage on which the substrate on which the insulating layer is formed is placed, The device comprises at least a heating mechanism for heating the second stage, The mold holder includes: A first moving mechanism for moving the mold holder at least between the first unit and the second unit, A second moving mechanism is attached to move the mold holder toward the first stage and the second stage, respectively. An imprint mold is detachably attached to the lower end of the mold holder. The aforementioned imprint mold is The main body and It has at least a plurality of pillars protruding from the second surface of the main body, In the first unit, the first material is attached to the tips of a plurality of the pillars. The processing apparatus is characterized in that the second unit uses the mold holder to press the imprint mold to which the first material is attached against the insulating layer and apply pressure to form a plurality of via holes in the insulating layer.

15. In the processing apparatus according to claim 14, The imprint mold further has a plurality of steps protruding from the second surface of the main body, Multiple pillars protrude from the bottom surface of multiple steps, The processing apparatus is characterized in that the second unit presses the imprint mold to which the first material is attached against the insulating layer using the mold holder and applies pressure to form a plurality of grooves and a plurality of via holes in the insulating layer.

16. In the processing apparatus according to claim 14, The processing apparatus is characterized in that the first unit further comprises a first material hardening mechanism for hardening the first material adhering to the pillar.

17. In the processing apparatus according to claim 14, The aforementioned imprint mold is made of a light-transmitting material. The insulating layer is a photocurable material, The processing apparatus is characterized in that the second unit further comprises a light irradiation mechanism that irradiates the insulating layer with light through the imprint mold.

18. In the processing apparatus according to claim 14, A processing apparatus further comprising a third unit for removing the first material adhering to the imprint mold after a plurality of via holes have been formed in the insulating layer.

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