JP2017203094A - Method for producing semi-cured adhesive, method for producing composite body, resin adhesive, composite body, and electrostatic chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semi-cured adhesive having high stability of a shape while having adhesiveness.SOLUTION: A method for producing a semi-cured adhesive includes: a step of preparing a resin adhesive before semi-curing, which has a rate of change of log (|η|) to a temperature rise when a loss tangent tanδ (tanδ=η'/η", but η' is real part of complex viscosity η* (η=η'-iη", but i is an imaginary unit), and η" is imaginary part of complex viscosity η*) is 1 of 0.18 or less in dynamic viscoelasticity measurement conducted on conditions of distortion of 0.1 (%), a rate of temperature rise of 1 (°C/minute) and angular frequency of 6.28 (rad/second), and contains a thermosetting resin; and a step of heating the resin adhesive before semi-curing in a temperature range of ±15°C of a temperature when the loss tangent tanδ is 1 and thereby semi-curing the resin adhesive to form a semi-cured adhesive.SELECTED DRAWING: Figure 3

Description

  The technology disclosed in the present specification relates to a method for producing a semi-cured adhesive.

  For example, in a semiconductor manufacturing apparatus, an electrostatic chuck that attracts and holds a wafer by electrostatic attraction is used. The electrostatic chuck includes, for example, a base plate formed of metal, a ceramic plate formed of ceramics, and an adhesive layer that bonds the base plate and the ceramic plate. The electrostatic chuck has an internal electrode, and attracts and holds the wafer on the surface of the ceramic plate by using an electrostatic attractive force generated when a voltage is applied to the internal electrode.

  For the adhesive layer that bonds the base plate and the ceramic plate, for example, a sheet-like semi-cured adhesive that is semi-cured from a liquid or paste resin adhesive is placed between the base plate and the ceramic plate. The semi-cured adhesive is cured (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 2005-158962

  It is preferable that the semi-cured adhesive has high adhesiveness while having adhesiveness. However, in the process of semi-curing the resin adhesive before semi-curing, as the curing proceeds, the stability of the shape increases while the adhesiveness decreases. Further, the curing rate of the resin adhesive varies depending on the type and composition of the resin adhesive. For this reason, when using a resin adhesive with a relatively fast curing speed, even a slight difference in temperature when the resin adhesive before semi-curing is semi-cured greatly increases the adhesiveness and shape stability of the resin adhesive. Since it fluctuates, it is difficult to form a semi-cured adhesive having adhesiveness and high shape stability.

  Such a problem is not limited to the semi-curing adhesive for bonding the members constituting the electrostatic chuck, but the members constituting the semiconductor manufacturing apparatus parts such as a susceptor (heating device) and a shower head, for example. This is a common problem with semi-cured adhesives for bonding the adhesive. In addition, such problems are not limited to semiconductor manufacturing equipment components, but are, for example, semi-cured adhesives for bonding heat dissipation members and other members, and semi-curing agents for bonding optical system members and other members. This is a problem common to semi-cured adhesives for bonding members in a composite including a plurality of members such as a cured adhesive.

  The present specification discloses a technique capable of solving at least one of the above-described problems.

  The technology disclosed in the present specification can be realized as, for example, the following forms.

(1) In the method for producing a semi-cured adhesive, disclosed in this specification is a strain of 0.1 (%), a heating rate of 1 (° C./min), and an angular frequency of 6.28 (rad / sec). In dynamic viscoelasticity measurement performed under conditions, loss tangent tan δ (tan δ = η ′ / η ″, where η ′ is complex viscosity η ^* (η ^* = η′−iη ″, where i is an imaginary unit And η ″ is an imaginary part of the complex viscosity η ^* .) The change rate of log (| η ^* |) with respect to the temperature rise when 1 is 1 is 0.18 or less. Yes, a step of preparing a semi-cured resin adhesive containing a thermosetting resin, and a temperature of ± 15 (° C.) of the temperature when the loss tangent tan δ is 1 And semi-curing by heating within the range to form the semi-cured adhesive. The temperature at which the loss tangent tan δ is 1 means the temperature at which the resin adhesive begins to cure (hereinafter referred to as “curing start temperature T1”). The absolute value (| η ^* |) of the complex viscosity η ^* indicates the fluidity of the adhesive, and the larger | η ^* | means that the fluidity is lower. The change rate (slope) of | η ^* | with respect to temperature rise means the curing rate of the resin adhesive. From these, the inventors of the present application specify the curing rate at the curing start temperature T1 of the resin adhesive from the rate of change of log (| η ^* |) with respect to the temperature rise when the loss tangent tan δ is 1, From the specific results, it was found that a semi-cured adhesive having adhesiveness and high shape stability can be formed. Therefore, according to the method for producing the semi-cured adhesive, the rate of change of log (| η ^* |) with respect to the temperature rise when the loss tangent tan δ is 1 is 0.18 or less, and the half containing the thermosetting resin. A step of preparing a resin adhesive before curing, and a step of heating and semi-curing the resin adhesive before semi-curing within a temperature range of ± 15 (° C.) of the temperature when the loss tangent tan δ is 1 With. Thereby, a semi-cured adhesive having adhesiveness and high shape stability is produced by suppressing the fluctuation of the viscoelasticity of the resin adhesive with respect to the temperature difference when the resin adhesive is semi-cured. Can do.

(2) In the method for producing a semi-cured adhesive, in the step of preparing the resin adhesive before the semi-curing, a change rate of log (| η ^* |) with respect to the temperature rise is 0.05 or more. Also good. When a resin adhesive having a relatively slow curing rate is used, it takes time until the resin adhesive is semi-cured. As a result, the production efficiency of the semi-cured adhesive may be reduced. On the other hand, according to the method for producing a semi-cured adhesive, since the rate of change of log (| η ^* |) with respect to the temperature rise is 0.05 or more, a decrease in the production efficiency of the semi-cured adhesive is suppressed. be able to.

(3) In the method for producing the semi-cured adhesive, the thermosetting resin may be a thermosetting silicone resin. According to the method for producing the semi-cured adhesive, since the thermosetting silicone resin is a material that has high heat resistance and is relatively soft, adhesion and characteristics of members requiring particularly airtightness are different. A semi-cured adhesive suitable for bonding members can be manufactured.

(4) In the method for producing the semi-cured adhesive, the thermosetting silicone resin may be an addition-curable thermosetting silicone resin. According to the method for producing the semi-cured adhesive, the addition-curable thermosetting silicone resin is a material that hardly generates a by-product when cured, and therefore, particularly for bonding between members constituting the semiconductor manufacturing apparatus. A suitable semi-cured adhesive can be produced.

(5) A composite manufacturing method disclosed in this specification includes a first member, a second member, and an adhesive layer that bonds the first member and the second member. In the dynamic viscoelasticity measurement performed under the conditions of a strain of 0.1 (%), a heating rate of 1 (° C./min), and an angular frequency of 6.28 (rad / sec) in the body manufacturing method, the loss tangent tan δ ( tan δ = η ′ / η ″, where η ′ is the real part of the complex viscosity η ^* (η ^* = η′−iη ″, where i is an imaginary unit), and η ″ is the complex A resin adhesive before semi-curing containing a thermosetting resin and having a change rate of log (| η ^* |) of 0.18 or less with respect to a temperature rise when the viscosity is imaginary part of η ^* . The step of preparing and semi-curing the resin adhesive before semi-curing by heating within a temperature range of ± 15 (° C.) of the temperature when the loss tangent is 1 A step of forming an adhesive, a step of disposing the semi-cured adhesive between the first member and the second member, and between the first member and the second member. Forming the adhesive layer by curing the semi-cured adhesive disposed on the surface. According to the manufacturing method of this composite_body | complex, the fall of the manufacturing efficiency of a composite_body | complex can be suppressed.

(6) The resin adhesive disclosed in the present specification is a resin adhesive containing a thermosetting resin, with a strain of 0.1 (%), a temperature increase rate of 1 (° C./min), and an angular frequency of 6.28 ( In the dynamic viscoelasticity measurement performed under the condition of rad / sec), the loss tangent tan δ (tan δ = η ′ / η ″, where η ′ is the complex viscosity η ^* (η ^* = η′−iη ″, where , I is an imaginary unit), and η ″ is the imaginary part of the complex viscosity η ^* .) The change rate of log (| η ^* |) with respect to the temperature rise when 1 is 1) It is characterized by being 0.18 or less.

(7) In the composite disclosed in the present specification, the first member formed of ceramics and the second member formed of metal are bonded using the resin adhesive. Features.

(8) The electrostatic chuck disclosed in the present specification is characterized in that the first member and the second member are bonded using the resin adhesive.

  The technology disclosed in the present specification can be realized in various forms. For example, a semi-cured adhesive, for example, a holding device such as an electrostatic chuck or a vacuum chuck, a heating device such as a susceptor, It can be realized in the form of a semiconductor manufacturing apparatus component such as a shower head, a manufacturing method thereof, and the like.

1 is a perspective view schematically showing an external configuration of an electrostatic chuck 100 in the present embodiment. It is explanatory drawing which shows roughly the XZ cross-sectional structure of the electrostatic chuck 100 in this embodiment. It is a flowchart which shows the manufacturing method of the electrostatic chuck 100 in this embodiment. It is explanatory drawing which shows the relationship between viscosity term (eta) ', rigidity term (eta) ", loss tangent tan-delta, and temperature in the dynamic viscoelasticity measurement about a resin adhesive. It is explanatory drawing which shows the relationship between the logarithm (log (| (eta) ^* |)) of the absolute value of complex viscosity (eta) ^* about a resin adhesive, and temperature. It is explanatory drawing which shows the result of performance evaluation. It is explanatory drawing which shows the relationship between log (| (eta) ^* |) and normalized temperature.

A. Embodiment:
A-1. Configuration of the electrostatic chuck 100:
FIG. 1 is a perspective view schematically showing an external configuration of an electrostatic chuck 100 in the present embodiment, and FIG. 2 is an explanatory diagram schematically showing an XZ cross-sectional configuration of the electrostatic chuck 100 in the present embodiment. . In each figure, XYZ axes orthogonal to each other for specifying the direction are shown. In this specification, for convenience, the positive direction of the Z-axis is referred to as the upward direction, and the negative direction of the Z-axis is referred to as the downward direction. However, the electrostatic chuck 100 is actually installed in a direction different from such a direction. May be.

  The electrostatic chuck 100 is a device that attracts and holds an object (for example, a wafer W) by electrostatic attraction, and is used, for example, to fix the wafer W in a vacuum chamber of a semiconductor manufacturing apparatus. The electrostatic chuck 100 includes a ceramic plate 10 and a base plate 20 that are arranged in a predetermined arrangement direction (in this embodiment, the vertical direction (Z-axis direction)). The ceramic plate 10 and the base plate 20 are such that the lower surface of the ceramic plate 10 (hereinafter referred to as “ceramic side adhesive surface S2”) and the upper surface of the base plate 20 (hereinafter referred to as “base side adhesive surface S3”) are arranged in the above-described arrangement direction. It arrange | positions so that it may oppose. The electrostatic chuck 100 further includes an adhesive layer 30 disposed between the ceramic side adhesive surface S2 of the ceramic plate 10 and the base side adhesive surface S3 of the base plate 20. The electrostatic chuck 100 corresponds to the composite in the claims, and the ceramic plate 10 and the base plate 20 correspond to the first member and the second member in the claims.

  The ceramic plate 10 is, for example, a circular flat plate member, and is formed of ceramics. The diameter of the ceramic plate 10 is, for example, about 50 mm to 500 mm (usually about 200 mm to 350 mm), and the thickness of the ceramic plate 10 is, for example, about 2 mm to 10 mm.

Various ceramics can be used as the material for forming the ceramic plate 10. From the viewpoint of strength, wear resistance, plasma resistance, and the relationship with the material for forming the base plate 20 described later, for example, aluminum oxide (alumina , Al ₂ O ₃ ) or ceramics mainly composed of aluminum nitride (AlN) are preferably used. In addition, the main component here means a component having the largest content ratio (weight ratio).

  A pair of internal electrodes 40 formed of a conductive material (for example, tungsten or molybdenum) is provided inside the ceramic plate 10. When a voltage is applied to the pair of internal electrodes 40 from a power source (not shown), an electrostatic attractive force is generated, and the wafer W causes the upper surface of the ceramic plate 10 (hereinafter referred to as an “attracting surface S1”) by the electrostatic attractive force. It is fixed by adsorption.

  In addition, a heater 50 made of a resistance heating element formed of a conductive material (for example, tungsten or molybdenum) is provided inside the ceramic plate 10. When a voltage is applied to the heater 50 from a power source (not shown), the ceramic plate 10 is heated by the heat generated by the heater 50, and the wafer W held on the suction surface S1 of the ceramic plate 10 is heated. Thereby, the temperature control of the wafer W is realized. In addition, the heater 50 is arrange | positioned substantially concentrically by Z direction view, for example, in order to heat the adsorption surface S1 of the ceramic board 10 as uniformly as possible.

  The base plate 20 is, for example, a circular flat plate-like member having the same diameter as the ceramic plate 10 or a larger diameter than the ceramic plate 10 and is formed of a composite material composed of ceramics and an aluminum alloy. The diameter of the base plate 20 is, for example, about 220 mm to 550 mm (usually about 220 mm to 350 mm), and the thickness of the base plate 20 is, for example, about 20 mm to 40 mm.

  As a material for forming the base plate 20, a metal or various composite materials can be used. As the metal, Al (aluminum) or Ti (titanium) is preferably used. As the composite material, it is preferable to use a composite material in which an aluminum alloy containing aluminum as a main component is melted and pressed into porous ceramics containing silicon carbide (SiC) as a main component. The aluminum alloy contained in the composite material may contain Si (silicon) or Mg (magnesium), or may contain other elements as long as the properties are not affected.

  A coolant channel 21 is formed inside the base plate 20. When a coolant (for example, a fluorine-based inert liquid or water) flows through the coolant channel 21, the base plate 20 is cooled, and heat transfer between the base plate 20 and the ceramic plate 10 via the adhesive layer 30 is performed. The ceramic plate 10 is cooled, and the wafer W held on the suction surface S1 of the ceramic plate 10 is cooled. Thereby, the temperature control of the wafer W is realized.

  The adhesive layer 30 bonds the ceramic plate 10 and the base plate 20 together. The thickness of the adhesive layer 30 is, for example, about 0.03 mm to 1 mm. The constituent material of the adhesive layer 30 will be described later.

A-2. Method for manufacturing electrostatic chuck 100:
Next, a method for manufacturing the electrostatic chuck 100 in the present embodiment will be described. FIG. 3 is a flowchart showing a method for manufacturing the electrostatic chuck 100 according to this embodiment. First, the ceramic plate 10 and the base plate 20 are prepared (S110). As described above, the ceramic plate 10 is formed of ceramics, and the base plate 20 is formed of a composite material composed of ceramics and an aluminum alloy for composite materials. In addition, since the ceramic board 10 and the base board 20 can be manufactured with a well-known manufacturing method, description of a manufacturing method is abbreviate | omitted here.

  Next, an adhesive paste is prepared (S120). The adhesive paste is a paste-like resin adhesive before semi-curing (sheeting). In S120, a liquid resin adhesive may be prepared. The constituent material of the resin adhesive is preferably a thermosetting resin such as an epoxy resin or a silicone resin, and a commercially available material may be used, or a material prepared by blending raw materials may be used. The epoxy resin can be produced by blending a curing agent or a curing catalyst with various epoxy compounds. The addition-curable silicone resin can be produced by blending an organopolysiloxane having a double bond (vinylsilyl group), a hydrogenated organopolysiloxane (hydrosilyl group), and a platinum compound as a curing catalyst thereof. Further, the peroxide curable silicone resin may be prepared by curing an organopolysiloxane having a methylsilyl group or a vinylsilyl group with an organic peroxide. The curing rate of the adhesive paste varies depending on the contents of various raw materials and other additives such as a curing agent, a curing catalyst, and a filler.

  As a constituent material of the resin adhesive, a silicone resin is preferable. This is because the silicone resin has high heat resistance and flexibility. Among silicone resins, addition curable silicone resins are particularly preferable. Addition-curing silicone resins have no by-products associated with the curing reaction and do not leave low-molecular components such as peroxide residues. This is because it does not occur.

  Here, the adhesive paste is a resin adhesive before semi-curing the adhesive sheet used for bonding the ceramic plate 10 and the base plate 20 in S150 described later. The adhesive sheet is a sheet-like semi-cured adhesive (self-adhesive sheet). Since the adhesive sheet is a semi-cured sheet-like resin adhesive, there is an advantage that the thickness of the adhesive layer after the main curing is easily equalized compared to the liquid adhesive. For this reason, it is preferable that the adhesive sheet has high adhesiveness while having adhesiveness. That is, the adhesive sheet has sufficient adhesiveness to bond the ceramic plate 10 and the base plate 20 and has a stable shape that can maintain a flat shape so that the ceramic plate 10 and the base plate 20 can be bonded without gaps. Sex is required.

  However, in the process of semi-curing the adhesive paste, as the curing progresses, the stability of the shape increases while the adhesiveness decreases. Moreover, the curing rate of the adhesive paste varies depending on the content (composition) of each constituent material of the resin adhesive. For this reason, when an adhesive paste having a relatively high curing rate is used, the adhesiveness and shape stability of the adhesive paste vary greatly even with a slight difference in temperature when the adhesive paste is semi-cured. Conversely, when an adhesive paste having a relatively slow curing rate is used, it takes time until the adhesive paste is semi-cured. As a result, the manufacturing efficiency of the adhesive sheet or the electrostatic chuck 100 may be reduced. Accordingly, the adhesive paste prepared in S120 preferably has a curing rate (hereinafter referred to as “appropriate curing rate”) suitable for forming an adhesive sheet having adhesiveness and high shape stability.

Therefore, in this embodiment, an adhesive paste that satisfies the following viscoelasticity condition is prepared as an adhesive paste having an appropriate curing rate.
<Viscoelastic conditions>
In the dynamic viscoelasticity measurement, the rate of change of log (| η ^* |) with respect to the temperature rise when the loss tangent tan δ is 1 is 0.18 or less.
However,
Loss tangent tan δ = viscosity term η ′ / stiffness term η ″
・ Viscosity term η ′: Complex viscosity η ^* (η ^* = η′−iη ″, where i is an imaginary unit) ・ Rigid term η ″: Imaginary part of complex viscosity η ^* Dynamic viscosity The measurement conditions for the elasticity measurement are, for example, as follows.
・ Place the adhesive paste between two discs with a diameter of 15 (mm) ・ Strain 0.1 (%)
・ Temperature increase rate 1 (℃ / min)
-Angular frequency 6.28 (rad / sec)

  The viscoelastic conditions will be described in detail. First, the temperature when the loss tangent tan δ is 1 means the temperature at which the adhesive paste (resin adhesive) starts to cure (hereinafter referred to as “curing start temperature T1”). The reason is as follows. FIG. 4 is an explanatory diagram showing the relationship among the viscosity term η ′, the stiffness term η ″, the loss tangent tan δ, and the temperature in the dynamic viscoelasticity measurement for the resin adhesive. As shown in FIG. 4, since the resin adhesive (adhesive paste) before semi-curing has relatively high fluidity, the viscosity term η ′ is larger than the stiffness term η ″, and the loss tangent tan δ is larger than 1. . When the resin adhesive is cured by heating, the elasticity of the resin adhesive becomes relatively high, so that the rigidity term η ″ becomes larger than the viscosity term η ′ and the loss tangent tan δ becomes smaller than 1. Therefore, the temperature when the loss tangent tan δ is 1 (η ′ = η ″) can be said to be the temperature at which the resin adhesive moves from the liquid to the solid, that is, the curing start temperature T1. In FIG. 4, the curing start temperature T1 is 80 (° C.).

Then, from the rate of change (slope) of the absolute value (| η ^* |) of the complex viscosity η ^* with respect to the temperature rise when the curing start temperature T1 (when the loss tangent tan δ is 1), the resin adhesive is cured. Speed can be evaluated. The reason is as follows. FIG. 5 is an explanatory diagram showing the relationship between the logarithm of the absolute value of the complex viscosity η ^* (log (| η ^* |)) and the temperature of the resin adhesive. The absolute value of the complex viscosity η ^* indicates the fluidity of the resin adhesive, and the larger the absolute value of the complex viscosity η ^* , the lower the fluidity. Specifically, as shown in FIG. 5, since the resin adhesive before being semi-cured is soft and has high fluidity, the absolute value of the complex viscosity η ^* is small. When the resin adhesive is cured by heating, the fluidity of the resin adhesive is lowered, so that the absolute value of the complex viscosity η ^* is increased.

The steep change in the absolute value of the complex viscosity η ^* due to the temperature rise means that the resin adhesive has a property of rapid curing and rapid curing. On the contrary, the fact that the change in the absolute value of the complex viscosity η ^* due to the temperature rise is gentle means that the resin adhesive has a property of slowly curing and slowly curing. Therefore, the curing rate at which the resin adhesive begins to cure can be evaluated from the rate of change of the absolute value of the complex viscosity η ^* with respect to the temperature rise at the curing start temperature T1. In the example of FIG. 5, it can be evaluated that the curing rate of the adhesive paste is faster as the change rate of log (| η ^* |) at 80 (° C.) (the slope of the straight line L) is larger.

A change rate of log (| η ^* |) of 0.18 or less means that the curing rate at the start of curing is relatively moderate. Therefore, an adhesive paste having a change rate of log (| η ^* |) of 0.18 or less is prepared as an adhesive paste having an appropriate curing rate (S120).

  Next, the prepared adhesive paste is semi-cured by heating within a temperature range of ± 15 (° C.) of the temperature when the loss tangent tan δ is 1 to form an adhesive sheet (S130). Next, an adhesive sheet is disposed between the ceramic plate 10 and the base plate 20 (S140).

  Next, the laminated body of the ceramic plate 10 and the base plate 20 via the adhesive sheet is placed in a hot press furnace and heated while being pressurized in a vacuum (S150). As a result, the adhesive sheet is melted to form the adhesive layer 30, and the ceramic plate 10 and the base plate 20 are bonded to each other by the adhesive layer 30. After the heating and pressure bonding in S150, post-processing (polishing of the outer periphery and upper and lower surfaces, formation of terminals, etc.) is performed as necessary. With the above manufacturing method, the electrostatic chuck 100 having the above-described configuration is manufactured.

A-3. Performance evaluation:
The performance evaluation described below was performed for the resin adhesive (adhesive paste, adhesive sheet) used in the manufacturing method described above. FIG. 6 is an explanatory diagram showing the results of performance evaluation.

A-3-1. For each example and each comparative example:
As shown in FIG. 6, in the performance evaluation, the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 3 were prepared, adhesive pastes were prepared from the resin compositions, and the adhesive paste was semi-cured to form an adhesive sheet Then, the adhesive sheet is fully cured to form an adhesive layer.

(How to make adhesive paste)
The production method of the adhesive paste of each example and each comparative example is as follows. An organopolysiloxane having a vinylsilyl group and an organopolysiloxane having a hydrosilyl group are blended so that the respective functional groups are equivalent (1: 1), and a platinum catalyst is added as a catalyst by 20 ppm by weight of platinum. To do. Thereby, an adhesive paste is produced. The curing rate of the adhesive paste can also be adjusted by the type and amount of filler. When the same type of filler is used, the curing rate tends to be slower as the amount added is larger. Alumina (Al ₂ O ₃ ) particles are used as a filler for controlling thermal conductivity and strength, and silica particles are used as a filler for adjusting viscosity.

Specifically, Example 1 is an addition-curable silicone resin composition containing the following materials.
-Organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups in one molecule-Organohydrogenpolysiloxane having hydrogen atoms bonded to two or more silicon atoms (that is, SiH groups) in one molecule・ Platinum group metal catalyst ・ Silane coupling agent having an alkoxyl group (ie, Si—OR group) bonded to two or more silicon atoms in one molecule ・ 49 wt% of alumina particles
・ Silica particles 1wt%
By changing the content of the filler in the resin composition, the change in fluidity (temperature dependence of the complex viscosity) with respect to the temperature rise can be changed. For this reason, as shown in FIG. 6, the resin compositions of Examples 2 to 6 and Comparative Examples 1 to 3 are different from Example 1 in the content of filler (alumina particles, silica particles). .

(About the method of forming the adhesive sheet)
The method for forming the adhesive sheet of each example and each comparative example (semi-curing (sheeting) method of the adhesive paste) is as follows. The adhesive paste prepared as described above is spread on a polyethylene terephthalate (PET) film. A publicly known method can be used as a method of spreading, and a doctor blade is used in this performance evaluation. Next, the adhesive paste spread on the PET film is cut into a predetermined size, and then the cut adhesive paste with the PET film is heated at a predetermined temperature for a predetermined time with a dryer. Is cured. Thereby, an adhesive sheet with a PET film is formed. In addition, you may cover each adhesive paste with a cover film as needed, such as preventing adhesion of dust during heating.

A-3-2. Evaluation method:
In order to judge whether or not the formed adhesive sheets with PET films of Examples 1 to 6 and Comparative Examples 1 to 3 are resin adhesives having adhesiveness and high shape stability. Evaluation (semi-curing) and uniformity of curing.

(About evaluation of sheeting)
In evaluation of sheet formation, the peelability test and the adhesion test were performed on the adhesive sheets with PET films of Examples 1 to 6 and Comparative Examples 1 to 3.
In the peelability test of the adhesive sheet, for example, an aluminum plate is placed on the surface of the adhesive sheet that is not attached with the PET film, and the adhesive sheet is attached to the aluminum plate by pressing it with a rubber roll or the like. Thereafter, the PET film is peeled from the adhesive sheet. And when both the following sticking conditions and peeling conditions are satisfy | filled, it evaluates that peelability is favorable.
Adhering conditions: When adhering to an aluminum plate, the adhesive sheet hardly spreads.
Peeling condition: When peeling the PET film, the adhesive sheet can be evenly transferred and adhered to the aluminum plate without tearing over the entire surface and without remaining on the PET film.

  Conversely, if the adhesive sheet spreads when affixed to an aluminum plate, or if it cannot be transferred to the aluminum plate due to tearing of the adhesive sheet when peeling the PET film, the peelability is poor. It is evaluated that it is. The cause of the spread of the adhesive sheet is considered to be insufficient semi-curing of the adhesive sheet. The factors that could not be transferred to the aluminum plate may be that the semi-curing is insufficient and the strength of the adhesive sheet is insufficient, or that the semi-curing is excessive and the adhesive sheet is not sufficiently bonded to the aluminum plate.

  Next, among the adhesive sheets with PET films of Examples 1 to 6 and Comparative Examples 1 to 3, only those that were good in the above-described peelability test are tested. In the adhesion test of the adhesive sheet, the semi-cured adhesive sheet is transferred to each of the two aluminum plates as the adherend, and the adhesive sheets transferred to each of the two aluminum plates are bonded together, for example, 50 The adhesive sheet is fully cured by heating at 150 degrees for a time to form an adhesive layer.

  Thereafter, the two aluminum plates are pulled until they are broken in opposite directions, and the strength, strain, and fracture surface state at the time of breaking are confirmed. As a result of confirming the state of the fractured surface, if it is recognized that the adhesive sheet is coherently broken inside the adhesive sheet at all locations in the sheet surface, it is evaluated that the adhesiveness of the adhesive sheet is good. On the contrary, when it is recognized that at least a part of the sheet surface is broken at the interface between the adhesive sheet and the aluminum plate or the interface between the two adhesive sheets, the adhesiveness of the adhesive sheet is determined as interfacial peeling. Evaluate as bad. Interfacial peeling means that the adhesiveness of the adhesive sheet is lost.

  In the evaluation of sheeting, the sheeting with the semi-curing temperature and the semi-curing time (heating time from the start of heating until the adhesive paste is semi-cured) that both the evaluation of the peelability test and the evaluation of the adhesive test are good When the condition can be found, the evaluation of sheet formation is “◯”. FIG. 6 shows the half-curing temperature and the half-curing time under favorable sheeting conditions. On the other hand, although the semi-curing temperature and the semi-curing time were variously changed, when the sheet forming favorable condition could not be found, the sheet forming evaluation is “x”.

(Evaluation of curing uniformity)
In the evaluation of the uniformity of curing, the adhesive paste prepared above is placed in a petri dish having a diameter of 30 (mm) so that the thickness is about 5 (mm) to 10 (mm), and the surface of the adhesive paste is flattened. Leave until. Thereafter, the petri dish containing the adhesive paste is heated at 150 (° C.) with a dryer to cure the adhesive paste, and the cured body is observed. When the surface of the cured body is flat and there is no unevenness, distortion, cracking, hardness variation, etc., it is evaluated that the uniformity of curing is good. On the contrary, when the surface of the cured body is not flat and has some abnormality, it is evaluated that the uniformity of curing is poor. If the curing speed of the adhesive paste is too fast, the adhesive paste is not cured uniformly, and it is considered that the surface of the cured body has unevenness and distortion.

A-3-3. Evaluation results:
As shown in FIG. 6, in Comparative Examples 1 to 3, the content of the filler (alumina particles, silica particles) is almost zero, and the change rate of log (| η ^* |) at the curing start temperature T1 is 0. 20 to 0.28. Moreover, in Comparative Examples 1-3, both evaluation of sheet formation and evaluation of the uniformity of hardening are evaluated as "x". On the other hand, in Examples 1-6, content of a filler is 10% or more, and the rate of change of log (| η ^* |) in hardening start temperature T1 is 0.05-0.18. Smaller than Comparative Examples 1 to 3. Moreover, in Examples 1-6, both evaluation of sheet formation and evaluation of the uniformity of hardening are evaluated as "(circle)".

  From these things, in Comparative Examples 1-3, since the content of the filler is small, the curing speed is relatively fast and deviates from the appropriate curing speed. For this reason, it is considered that an adhesive sheet having adhesiveness and high shape stability cannot be formed. On the other hand, in Examples 1-6, since there is much content of a filler compared with Comparative Examples 1-3, a cure rate is comparatively slow and it is close to a proper cure rate. For this reason, it is considered that an adhesive sheet having adhesiveness and high shape stability can be formed.

FIG. 7 is an explanatory diagram showing the relationship between log (| η ^* |) and the normalized temperature. The normalization temperature is a temperature obtained by subtracting the curing start temperature T1 from the measurement temperature. In Comparative Examples 1 to 3, the change rate of log (| η ^* |) at the curing start temperature is steep compared to Examples 1 to 6. Therefore, as shown in FIG. 7, in Comparative Examples 1 to 3, even when the temperature at which the resin adhesive is semi-cured slightly deviates from the curing start temperature T1, the viscoelasticity (log (| η) ^{* It} can be seen that the variation of |)) is large, that is, the variation of adhesiveness and shape stability is large. As a result, in Comparative Examples 1 to 3, it can be said that it is difficult to form an adhesive sheet having adhesiveness and high shape stability. On the other hand, in Examples 1-6, even if the temperature at which the resin adhesive is semi-cured slightly deviates from the curing start temperature T1, the variation in the viscoelasticity (log (| η ^* |)) of the resin adhesive varies. It can be seen that the fluctuation is small, that is, the adhesiveness and the stability of the shape are small. As a result, in Examples 1-6, it can be said that it is easy to form an adhesive sheet having adhesiveness and high shape stability.

In Examples 1 and 2, since the rate of change of log (| η ^* |) at the curing start temperature is 0.05 or more, the half-curing time is within 6 hours, which is relatively short. Thereby, the manufacturing efficiency of an adhesive sheet and the electrostatic chuck 100 can be improved. Furthermore, in Examples 1 and 2, the change rate of log (| η ^* |) at the curing start temperature is 0.07, and the semi-curing time is 6 hours or more. On the other hand, in Examples 3 to 6, the change rate of log (| η ^* |) at the curing start temperature is 0.13 to 0.15, and the semi-curing time is within 3 hours. From these facts, it can be seen that if the rate of change of log (| η ^* |) at the curing start temperature is 0.13 to 0.18, the half-curing time can be further shortened.

A-4. Effects of this embodiment:
As described above, the inventor of the present application evaluates the curing rate of the resin adhesive based on the result of the dynamic viscoelasticity measurement of the resin adhesive, and efficiently uses the resin adhesive having an appropriate curing rate based on the evaluation result. I found out how to prepare. That is, the temperature when the loss tangent tan δ is 1 means the curing start temperature T1. The absolute value (| η ^* |) of the complex viscosity η ^* indicates the fluidity of the adhesive, and the larger | η ^* | means that the fluidity is lower. The change rate (slope) of | η ^* | with respect to temperature rise means the curing rate of the resin adhesive. From these, the inventors of the present application specify the curing rate at the curing start temperature T1 of the resin adhesive from the rate of change of log (| η ^* |) with respect to the temperature rise when the loss tangent tan δ is 1, From the specific results, it was found that an adhesive sheet having adhesiveness and high shape stability can be formed.

Therefore, according to the present embodiment, an adhesive paste before semi-curing is prepared in which the change rate of log (| η ^* |) with respect to the temperature rise when the loss tangent tan δ is 1 is 0.18 or less. This makes it possible to efficiently select a resin adhesive (adhesive paste) with a curing rate suitable for forming an adhesive sheet that has adhesiveness and high shape stability from resin adhesives of various compositions. Can be prepared. Next, the adhesive paste before semi-curing is heated and semi-cured within a temperature range of ± 15 (° C.) when the loss tangent tan δ is 1, thereby forming an adhesive sheet. Thereby, the adhesive sheet with high shape stability can be manufactured while having adhesiveness by suppressing the fluctuation of the viscoelasticity of the resin adhesive with respect to the temperature difference when the adhesive paste is semi-cured.

B. Variations:
The technology disclosed in the present specification is not limited to the above-described embodiment, and can be modified into various forms without departing from the gist thereof. For example, the following modifications are possible.

It may be a semi-cured adhesive as in the following invention.
Loss tangent tan δ (tan δ = η ′ / η) in dynamic viscoelasticity measurement performed under the conditions of strain 0.1 (%), heating rate 1 (° C./min), angular frequency 6.28 (rad / sec) ″, Where η ′ is the real part of the complex viscosity η ^* (η ^* = η′−iη ″, where i is an imaginary unit), and η ″ is the imaginary part of the complex viscosity η ^* . The change rate of log (| η ^* |) with respect to the temperature rise when 1) is 1 is formed by curing a resin adhesive before semi-curing which is 0.18 or less. A semi-cured adhesive.

  The material which forms each member in the said embodiment is an example to the last, and each member may be formed with another material.

  In the above embodiment, the refrigerant flow path 21 is formed inside the base plate 20, but the refrigerant flow path 21 is not inside the base plate 20 but on the surface of the base plate 20 (for example, the base plate 20 and It may be formed between the adhesive layer 30). Moreover, in the said embodiment, although the bipolar system with which a pair of internal electrode 40 was provided in the inside of the ceramic board 10 was employ | adopted, the monopolar system in which the one internal electrode 40 was provided in the inside of the ceramic board 10 is used. It may be adopted.

  Further, the method of manufacturing the electrostatic chuck 100 in the above embodiment is merely an example, and various modifications can be made.

  Further, the present invention is not limited to bonding of members constituting the electrostatic chuck 100, but can be applied to bonding of members constituting semiconductor manufacturing apparatus parts such as a susceptor (heating device) and a shower head. . Moreover, it is applicable also to the adhesive agent for thermal radiation members, thermal interface material, the sealing agent for semiconductors, the sealing agent for optical devices, an underfill material, etc.

10: Ceramic plate 20: Base plate 21: Refrigerant flow path 30: Adhesive layer 40: Internal electrode 50: Heater 100: Electrostatic chuck L: Straight line S1: Adsorption surface S2: Ceramic side adhesive surface S3: Base side adhesive surface W: Wafer

Claims (8)

In the method for producing a semi-cured adhesive,
Loss tangent tan δ (tan δ = η ′ / η) in dynamic viscoelasticity measurement performed under the conditions of strain 0.1 (%), heating rate 1 (° C./min), angular frequency 6.28 (rad / sec) ″, Where η ′ is the real part of the complex viscosity η ^* (η ^* = η′−iη ″, where i is an imaginary unit), and η ″ is the imaginary part of the complex viscosity η ^* . A ratio of change in log (| η ^* |) with respect to the temperature rise when temperature is 1 is 0.18 or less, and preparing a resin adhesive before semi-curing including a thermosetting resin;
Forming the semi-cured adhesive by semi-curing the resin adhesive before semi-curing by heating within a temperature range of ± 15 (° C.) of the temperature when the loss tangent tan δ is 1; A method for producing a semi-cured adhesive. In the manufacturing method of the semi-hardened adhesive agent of Claim 1,
The method for producing a semi-cured adhesive, characterized in that, in the step of preparing the resin adhesive before semi-curing, the rate of change of log (| η ^* |) with respect to the temperature rise is 0.05 or more. In the manufacturing method of the semi-hardened adhesive agent of Claim 1 or Claim 2,
The method for producing a semi-cured adhesive, wherein the thermosetting resin is a thermosetting silicone resin. In the manufacturing method of the semi-hardened adhesive agent of Claim 3,
The method for producing a semi-cured adhesive, wherein the thermosetting silicone resin is an addition-curable thermosetting silicone resin. In a method for manufacturing a composite body comprising a first member, a second member, and an adhesive layer that bonds the first member and the second member,
Loss tangent tan δ (tan δ = η ′ / η) in dynamic viscoelasticity measurement performed under the conditions of strain 0.1 (%), heating rate 1 (° C./min), angular frequency 6.28 (rad / sec) ″, Where η ′ is the real part of the complex viscosity η ^* (η ^* = η′−iη ″, where i is an imaginary unit), and η ″ is the imaginary part of the complex viscosity η ^* . A ratio of change in log (| η ^* |) with respect to the temperature rise when temperature is 1 is 0.18 or less, and preparing a resin adhesive before semi-curing including a thermosetting resin;
Heating the resin adhesive before semi-curing within a temperature range of ± 15 (° C.) when the loss tangent is 1 to form a semi-curing adhesive;
Disposing the semi-cured adhesive between the first member and the second member;
Forming the adhesive layer by curing the semi-cured adhesive disposed between the first member and the second member. . In a resin adhesive containing a thermosetting resin,
Loss tangent tan δ (tan δ = η ′ / η) in dynamic viscoelasticity measurement performed under the conditions of strain 0.1 (%), heating rate 1 (° C./min), angular frequency 6.28 (rad / sec) ″, Where η ′ is the real part of the complex viscosity η ^* (η ^* = η′−iη ″, where i is an imaginary unit), and η ″ is the imaginary part of the complex viscosity η ^* . The rate of change of log (| η ^* |) with respect to temperature rise when 1 is 1 is 0.18 or less.   The 1st member formed with the ceramics, and the 2nd member formed with the metal are adhere | attached using the said resin adhesive of Claim 6, The composite_body | complex characterized by the above-mentioned.   An electrostatic chuck, wherein the first member and the second member are bonded using the resin adhesive according to claim 6.

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