Substrate, laminated structure, and method of making laminated structure

Abstract

To realize a substrate and a laminated structure that can maintain a surface active state even in the air and that allow fine chip mounting.SOLUTION: A substrate 10 includes an electrode portion 3 formed on the surface of a base material 1, an insulating material 4 filled in the base material 1 surface region other than the electrode part 3 on the surface of the base material 1, and a self-assembled film 5 formed on the electrode exposed surface formed by the electrode portion 3 and the insulating material 4. As a result, it is possible to bond substrates that can maintain a surface active state even in the air, and to realize a laminated structure that enables fine chip mounting.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a substrate having a self-assembled film, a laminated structure, and a method for manufacturing the laminated structure. [Background technology]

[0002] In mounting chips on printed circuit boards, joining chips together, and mounting, the pitch between circuit patterns or electrodes has become narrower, down to around 10 μm, making the conventional methods of joining electrodes to the circuit pattern of the board using solder, or pouring in an insulating material after joining the electrodes, no longer viable.

[0003] Patent document 1 describes cleaning the bonding surfaces by plasma irradiation or the like in order to bond the chip and substrate using direct bonding (also called "hybrid bonding"), in which the bonding surfaces of the chip and substrate are made of insulating material that is a metal region and a dielectric region. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-509578 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the method described in Patent Document 1, after cleaning by plasma irradiation or the like, the bonding surfaces are exposed to a non-vacuum environment such as a mounting machine, so it is difficult to maintain the activated state due to cleaning for a long period of time, and the activated state may be lost due to oxidation, etc., making hybrid bonding difficult. In addition, if mounting is to be performed in a vacuum, the mounting machine itself must be housed in a chamber, which increases the size of the device and increases the cost.

[0006] An object of the present invention is to solve the above problems and to provide a substrate and a laminated structure capable of maintaining a surface active state even in the atmosphere and enabling mounting of narrow electrode pitches. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a substrate having an electrode portion formed on a surface of the substrate, an insulating material filled in a surface area of ​​the base material other than the electrode portion on the surface of the base material; The present invention provides a substrate comprising the electrode portion and a self-assembled film formed on an exposed surface of the electrode formed of the insulating material.

[0008] This configuration allows the surface activation state to be maintained even in the atmosphere by the self-assembled film, making it possible to mount electrodes with a narrow pitch.

[0009] The substrate may be configured such that the functional group at the tip of the surface of the self-assembled film includes a vinyl group, a hydroxy group, an acrylic group, an epoxy group, an amino group, or an isocyanate group.

[0010] This configuration enables bonding between electrode parts and bonding between insulating materials, and enables electrical conduction between the electrode parts via the self-assembled film.

[0011] In order to solve the above problems, the present invention provides a laminated structure in which substrates are bonded together, comprising: a first electrode portion formed on a surface of a first base material; a first insulating material filled in a surface region of the first base material other than the first electrode portion on the surface of the first base material; and a first self-assembled film formed on an electrode exposed surface formed by the first electrode portion and the first insulating material, a second electrode portion formed on a surface of a second base material, a second insulating material filled in a surface region of the second base material other than the second electrode portion on the surface of the second base material, and a second self-assembled film formed on an electrode exposed surface formed by the second electrode portion and the second insulating material, the second self-assembled film on the second substrate facing each other; The present invention provides a laminated structure in which at least a part of the first electrode portion and at least a part of the second electrode portion are aligned and laminated.

[0012] With this configuration, a laminated structure can be realized in which electrical conductivity is established between the first electrode portion and the opposing second electrode portion via the first self-assembled film and the second self-assembled film, but no electrical conductivity is established via the first insulating material or the second insulating material.

[0013] In the laminate structure, the first self-assembled film and the second self-assembled film may have a configuration in which the functional group at the tip of the surface includes a vinyl group, a hydroxy group, an acrylic group, an epoxy group, an amino group, or an isocyanate group.

[0014] With this configuration, a laminated structure can be realized in which the vinyl groups, hydroxy groups, acrylic groups, epoxy groups, amino groups, or isocyanate groups of the self-assembled film on the first substrate and the vinyl groups, hydroxy groups, acrylic groups, epoxy groups, amino groups, or isocyanate groups of the self-assembled film on the second substrate are polymerized to maintain a strong bond.

[0015] In order to solve the above problems, the present invention provides a method for producing a laminated structure having a self-assembled film, comprising the steps of: an alignment step of aligning in the atmosphere at least a part of the electrode part on the first substrate and at least a part of the electrode part on the second substrate by placing the self-assembled films of a first substrate and a second substrate opposite each other, the first substrate including an electrode part formed on a surface of the substrate, an insulating material filled in a surface region of the substrate other than the electrode part on the surface of the substrate, and a self-assembled film formed on an electrode exposed surface formed by the electrode part and the insulating material; and a bonding step of bonding the aligned first substrate and second substrate in the atmosphere.

[0016] This configuration makes it possible to bond substrates that can maintain a surface active state even in the atmosphere, and realizes a laminated structure that allows for the mounting of fine chips.

[0017] In the method for manufacturing a laminated structure, the bonding step may be configured to heat or irradiate the self-assembled films of the first substrate and the second substrate with ultraviolet light.

[0018] With this configuration, a laminated structure can be realized in which the vinyl groups, hydroxy groups, acrylic groups, epoxy groups, amino groups, or isocyanate groups in the first substrate and the vinyl groups, hydroxy groups, acrylic groups, epoxy groups, amino groups, or isocyanate groups in the second substrate are polymerized by heating or exposure to ultraviolet light, thereby maintaining a strong bond. Effect of the Invention

[0019] According to the present invention, it is possible to realize a substrate and a laminated structure capable of maintaining a surface active state even in the atmosphere and capable of mounting fine chips. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a diagram illustrating a substrate in the first embodiment of the present invention. [Diagram 2] 3A to 3C are diagrams illustrating a method for manufacturing a substrate in accordance with the first embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram illustrating a self-assembled film on a substrate in Example 1 of the present invention. [Figure 4] FIG. 11 is a diagram illustrating a laminated structure in Example 2 of the present invention. [Diagram 5] 11A to 11C are diagrams illustrating a method for manufacturing a laminated structure in Example 2 of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLES

[0021] (substrate) The configuration of the substrate in the first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a diagram for explaining the substrate in the first embodiment of the present invention.

[0022] The substrate 10 in the first embodiment has an electrode portion 3 such as a bump formed thereon so as to be electrically conductive with the circuit pattern 2 on the surface of the substrate 1. The surface area of ​​the substrate 1 other than the electrode portion 3 on the surface of the substrate 1 is filled with an insulating material 4. The electrode exposed surface formed by the electrode portion 3 and the insulating material 4 is configured to be substantially flush. The substrate 1 in the first embodiment is a chip made of silicon, but is not necessarily limited thereto and can be appropriately changed. For example, it may be a glass substrate, a ceramic substrate, a glass epoxy substrate, or a wafer substrate. The electrode portion 3 is formed of copper, but this may also be another material. For example, gold, silver, etc. can be adopted. The thickness of the electrode portion 3 may be any thickness, but is about 1 μm in the first embodiment. The pitch of the electrode portion 3 is 10 μm or less at the narrowest point. The insulating material 4 is made of SiO2 in the first embodiment, but is not particularly limited thereto and may be any insulator.

[0023] In addition, a self-assembled film 5 is formed on the entire surface of the electrode exposed surface formed by the base material 1 of the electrode part 3 and the insulating material 4. The self-assembled film 5 is made of a metal alkoxide film containing a silane coupling agent, and is also called a SAM film (Self-Assembled Monolayer). It is extremely thin with a molecular level thickness (nm order), and allows light to pass through, allowing the electrode part 3 to be visually recognized. In addition, the tip part (the part opposite the electrode part 3 and the insulating material 4) contains a vinyl group, a hydroxyl group, an acrylic group, an epoxy group, an amino group, or an isocyanate group (see FIG. 3(b)), and when a laminated structure is formed between the substrates 10 as described later, these are polymerized to realize a strong bond.

[0024] Conventionally, even if the chip surface is activated by plasma cleaning in a vacuum chamber, the activated state cannot be maintained when it is returned to the atmosphere, so that direct mounting such as hybrid bonding is difficult. Since the substrate 10 in Example 1 has a self-assembled film 5 on its surface, the surface activation state can be maintained even in the atmosphere, so that the bonding of the electrode parts 3 to each other and the bonding of the insulating materials 4 to each other in the atmosphere can be performed by a conventional mounting machine. In addition, since the surface is covered with the self-assembled film 5, it has strong peel resistance against strongly penetrating substances such as acidic substances, alkaline substances, and surfactants. Furthermore, since the thickness of the self-assembled film 5 is on the order of nm, a current flows only between the opposing electrode parts 3 in the laminated structure described later, and even if the pitch of the electrode parts 3 is 10 μm or less, a narrow electrode pitch can be realized without current leaking to adjacent electrodes.

[0025] (Substrate manufacturing method) A method for manufacturing a substrate in Example 1 of the present invention will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a diagram for explaining the method for manufacturing a substrate in Example 1 of the present invention. Fig. 3 is a diagram for explaining a self-assembled film on the substrate in Example 1 of the present invention.

[0026] First, an electrode part forming step is carried out to form electrode parts 3 on the circuit pattern 2 of the substrate 1. The electrode parts 3 may be formed by any method, such as by forming a film in a vacuum, or by plating or printing. Next, an insulating material filling step is carried out to fill the areas on the surface of the substrate 1 other than the electrode parts 3 with an insulating material. Any method may be used as the filling method.

[0027] Next, a self-assembled film formation process is performed. Prior to this self-assembled film formation process, the surface formed by the electrode part 3 and the insulating material 4 is subjected to surface polishing (for example, CMP method, etc.) and a cleaning process to form an electrode exposed surface. In the self-assembled film formation process, the substrate 1 on which the electrode part 3 and the insulating material 4 are formed is first placed in a vacuum chamber C, and the surface (electrode exposed surface) is plasma cleaned by irradiating plasma in a vacuum (see FIG. 2(a)). Next, an evaporation source that imparts hydrophilic groups is supplied to the vacuum chamber C, and the surface (electrode exposed surface) of the electrode part 3 and the insulating material 4 on the substrate 1 is modified and hydrophilized by the plasma atmosphere formed by plasma generation, thereby performing a surface hydrophilization mode (see FIG. 2(b)). Next, in the same vacuum chamber C, an evaporation source that promotes hydrolysis of the precursor material of the self-assembled film is supplied to the vacuum chamber C for the substrate 1 whose surface has been hydrophilized, and a self-assembled mode is performed to form a SAM film on the hydrophilized surface (electrode exposed surface) (see FIG. 2(c)).

[0028] At this time, the Y portion of the precursor material of the self-assembled film contains a vinyl group, a hydroxyl group, an acrylic group, an epoxy group, an amino group, or an isocyanate group at the tip as a functional group, and as described later, when forming a laminate structure between substrates 10, these vinyl groups, hydroxyl groups, acrylic groups, epoxy groups, amino groups, or isocyanate groups polymerize with each other to realize strong bonding. Note that the above-mentioned vinyl groups, hydroxyl groups, acrylic groups, epoxy groups, amino groups, or isocyanate groups are not functional groups in the middle of the self-assembled film.

[0029] Next, in the same vacuum chamber C, hydrolysis is carried out using water vapor (see FIG. 2(d)). As a result, the molecular arrangement shown in FIG. 3(a) in the self-organization mode of FIG. 2(e) becomes the molecular arrangement after dehydration and condensation shown in FIG. 3(b), resulting in a structure that extends long from the surface but is difficult to collapse. Note that the example in FIG. 3 shows a case where the end of the self-organized film 5 has an acrylic group.

[0030] Through the above-mentioned electrode portion forming step, insulating material forming step, and self-assembled film forming step, the substrate 10 can be obtained. The substrate 10 on which the self-assembled film 5 is formed can maintain an active state without inactivating the surface even in the atmosphere, and the bonding of the chip can be performed in the atmosphere.

[0031] Thus, in Example 1, the electrode portion formed on the surface of the substrate, an insulating material filled in a surface area of ​​the base material other than the electrode portion on the surface of the base material; The self-assembled film is formed on the electrode exposed surface formed by the electrode portion and the insulating material, and the self-assembled film is formed on the substrate, so that the surface activity can be maintained even in the atmosphere, making it possible to mount fine chips. EXAMPLES

[0032] (Laminated structure) Example 2 of the present invention differs from Example 1 in that it relates to a laminated structure in which substrates are bonded together. The laminated structure in Example 2 will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a diagram for explaining the laminated structure in Example 2 of the present invention. Fig. 5 is a diagram for explaining a manufacturing method of the laminated structure in Example 2 of the present invention.

[0033] In the laminated structure 100 of Example 2, a first self-assembled film 5 on a first substrate 10 having a first electrode portion 3 formed on the surface of the first substrate 1, a first insulating material 4 filled in the surface area of ​​the first substrate 1 other than the first electrode portion 3 on the surface of the first substrate 1, and a first self-assembled film 5 formed on the electrode exposed surface formed by the first electrode portion 3 and the first insulating material 4 is bonded opposite a second self-assembled film 5 on a second substrate 10' having a second electrode portion 3' formed on the surface of the second substrate 1', a second insulating material 4' filled in the surface area of ​​the second substrate 1' other than the second electrode portion 3' on the surface of the second substrate 1', and a second self-assembled film 5' formed on the electrode exposed surface formed by the second electrode portion 3' and the second insulating material 4'.

[0034] At this time, the first electrode portion 3 and the second electrode portion 3' are opposed to each other, aligned, and bonded. Therefore, electrical conduction is possible between the first electrode portion 3 and the second electrode portion 3' via the first self-assembled film 5 and the second self-assembled film 5' on the nm order. However, it is not necessary to align all the first electrode portions 3 and the second electrode portions 3', and it is sufficient to have a laminated structure in which at least a part of the multiple first electrode portions 3 and at least a part of the multiple second electrode portions 3' are opposed to each other, aligned, and bonded according to the convenience of the electronic circuit.

[0035] 4, the distance between the opposing tips of the first electrode portion 3 and the second electrode portion 3' is on the order of nm, which is the length of the first self-assembled film 5 and the second self-assembled film 5', and therefore electricity can easily pass through. In contrast, the distance between the electrodes is about 10 μm, so there is no risk of current leaking, and an electric circuit can be normally configured.

[0036] (Method of manufacturing laminated structure) The method for manufacturing the laminated structure will be described with reference to Fig. 5. Fig. 5 is a diagram for explaining the method for manufacturing the laminated structure in Example 2 of the present invention.

[0037] First, in a known mounting machine, the first self-assembled film 5 of the first substrate 10 and the second self-assembled film 5' of the second substrate 10' are opposed to each other. Then, after the first substrate 10 and the second substrate 10' are aligned in parallel, an alignment step is carried out in which at least some of the electrode portions 3 on the first substrate 10 and at least some of the electrode portions 3' on the second substrate 10' are two-dimensionally aligned in the atmosphere.

[0038] At this time, since the self-assembled film 5 on the first substrate 10 and the self-assembled film 5' on the second substrate 10' are both thin films on the order of nm, the positions of the electrode portion 3 and the electrode portion 3' underneath can be visually confirmed. Then, alignment can be performed by a known method while checking the positions of the electrode portion 3 and the electrode portion 3' while checking the alignment marks with a camera of the mounting machine.

[0039] After the alignment process is completed, a bonding process is performed in which the first substrate 10 and the second substrate 10' are bonded in the atmosphere. A mounting machine is used to bring the first substrate 10 and the second substrate 10' into contact with each other while eliminating the distance in the height direction. After that, the substrate is heated to about 50°C to 500°C. The heating time varies depending on the electrode material, but may be from a few minutes to a few tens of minutes.

[0040] In the second embodiment, the bonding step is heated, but the present invention is not limited to this and can be modified as appropriate. For example, ultraviolet light may be irradiated after mounting.

[0041] In this way, in Example 2, the laminated structure in which the substrates are bonded to each other is a first electrode portion formed on a surface of a first base material; a first insulating material filled in a surface region of the first base material other than the first electrode portion on the surface of the first base material; and a first self-assembled film formed on an electrode exposed surface formed by the first electrode portion and the first insulating material, a second electrode portion formed on a surface of a second base material, a second insulating material filled in a surface region of the second base material other than the second electrode portion on the surface of the second base material, and a second self-assembled film formed on an electrode exposed surface formed by the second electrode portion and the second insulating material, the second self-assembled film on the second substrate facing each other; The laminate structure is characterized in that at least a portion of the first electrode portion and at least a portion of the second electrode portion are aligned and laminated, thereby realizing a laminate structure in which electrical conductivity is established between the first electrode portion and the opposing second electrode portion via the first self-assembled film and the second self-assembled film, but no electrical conductivity is established via the first insulating material or the second insulating material.

[0042] Also, there is provided a method for producing a laminated structure having a self-assembled film, comprising the steps of: an alignment step of aligning in the atmosphere at least a part of the electrode part on the first substrate and at least a part of the electrode part on the second substrate by placing the self-assembled films of a first substrate and a second substrate opposite each other, the first substrate including an electrode part formed on a surface of the substrate, an insulating material filled in a surface region of the substrate other than the electrode part on the surface of the substrate, and a self-assembled film formed on an electrode exposed surface formed by the electrode part and the insulating material; By using this method for manufacturing a laminated structure, which is characterized by including a bonding process in which the aligned first substrate and second substrate are bonded in the atmosphere, it is possible to bond substrates that can maintain a surface active state even in the atmosphere, and to produce a laminated structure that allows for the mounting of fine chips. [Industrial Applicability]

[0043] INDUSTRIAL APPLICABILITY The substrate, the laminated structure, and the method for manufacturing the laminated structure of the present invention can be widely used in the field of mounting fine chips. [Explanation of symbols]

[0044] 1, 1´ Base material 2, 2´ Circuit Pattern 3, 3´ electrode part 4, 4´ Insulation 5, 5´ Self-assembled membrane 10, 10´ Board 100 laminated structure C Chamber

Claims

A substrate capable of having a laminated structure in which substrates are polymer-bonded to each other, a plurality of electrode portions formed on the surface of a base material, an insulating material filled in the surface region of the base material between the electrode portions on the surface of the base material, and a self-assembled monolayer formed on the entire electrode exposed surface formed by the electrode portion and the insulating material, and the self-assembled monolayer enables polymer bonding with the self-assembled monolayer on the counter substrate, while the electrode portion is electrically conductive between the electrode portions facing each other on the counter substrate through the self-assembled monolayer, and between the adjacent electrode portions, there is no electrical conduction through the self-assembled monolayer. A substrate characterized by this.

2. A laminated structure in which substrates are polymer-bonded to each other, a plurality of first electrode portions formed on the surface of a first base material, a first insulating material filled in the surface region of the first base material between the first electrode portions on the surface of the first base material, and a first self-assembled monolayer formed on the entire electrode exposed surface formed by the first electrode portion and the first insulating material, with respect to the first self-assembled monolayer in the first substrate having a plurality of second electrode portions formed on the surface of a second base material, a second insulating material filled in the surface region of the second base material between the second electrode portions on the surface of the second base material, and a second self-assembled monolayer formed on the entire electrode exposed surface formed by the second electrode portion and the second insulating material, the second self-assembled monolayer in the second substrate faces at least a part of the first electrode portion and at least a part of the second electrode portion are aligned and laminated, the first self-assembled monolayer and the second self-assembled monolayer are polymer-bonded to each other, while the first electrode portion and the second electrode portion facing each other through the first self-assembled monolayer and the second self-assembled monolayer are electrically conductive, and between the adjacent first electrode portions and between the adjacent second electrode portions, there is no electrical conduction through the first self-assembled monolayer and the second self-assembled monolayer. A laminated structure characterized by this.

3. A method for manufacturing a laminated structure having a self-assembled monolayer, A first substrate including a plurality of electrode portions formed on a substrate surface, an insulating material filled in a substrate surface region between the electrode portions on the substrate surface, and a self-assembled monolayer formed on the entire electrode exposed surface formed by the electrode portions and the insulating material, and an alignment step of aligning at least some of the electrode portions on the first substrate and at least some of the electrode portions on the second substrate by facing the self-assembled monolayers of the first substrate and the second substrate to each other in the air, A bonding step of bonding the aligned first substrate and second substrate in the air, In the bonding step, the self-assembled monolayers on the first substrate and the second substrate enable polymerization bonding between the self-assembled monolayers on the first substrate and the second substrate, A method for manufacturing a laminated structure, characterized in that the electrode portions on the first substrate and the second substrate facing each other through the self-assembled monolayers on the first substrate and the second substrate after bonding are electrically conductive, and between adjacent electrode portions on the first substrate and the second substrate, there is no electrical conduction through the self-assembled monolayers on the first substrate and the second substrate.

4. The method for manufacturing a laminated structure according to claim 3, characterized in that in the bonding step, heating or ultraviolet irradiation is performed on the self-assembled monolayers of the first substrate and the second substrate.

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