JP4440726B2 - Bonding apparatus, bonding method, and bonding apparatus control program - Google Patents

Description

  The present invention relates to a technique for applying and bonding an adhesive on a substrate when manufacturing a flat recording medium such as an optical disk, for example, and in particular, improving a method for reducing bubbles in the adhesive. The present invention relates to a bonding apparatus, a bonding method, and a bonding apparatus control program.

  Optical reading type disk-shaped recording media such as an optical disk and a magneto-optical disk are widely used in various standards such as a reproduction-only medium and a medium in which recorded information can be rewritten. Such a recording medium is manufactured by bonding a pair of substrates via an adhesive layer in order to protect the recording surface formed on the substrate or to realize high-density recording by multilayering the recording surface. There are many cases.

  An example of the manufacturing procedure of such a bonded disk will be described with reference to FIGS. First, two polycarbonate substrates P are injection molded in advance, and a metal film (recording film) for laser reflection is formed by sputtering in a sputtering chamber. Then, as shown in FIG. 12A, an ultraviolet curable adhesive is applied to the bonding surface of the two substrates P, and the adhesive is spread by spin coating. In spin coating, a thin film (adhesive layer R) is formed on the substrate P by applying the adhesive around the center of the substrate P and then spinning the substrate P at a high speed. , Which is to disperse excess adhesive.

  As shown in FIG. 12B, the pair of substrates P on which the adhesive layer R is formed in this way are introduced into the decompression chamber S, and one of the substrates P is in a state where the adhesive layers R face each other in parallel. It is held by the holding unit T. Then, by exhausting from the decompression chamber S by the exhaust device, the pressure around the substrate P decreases from the atmospheric pressure 2a to the base pressure 2b close to vacuum, as shown in FIG. In the space thus reduced in pressure, the holding portion T holding one substrate P is lowered by a driving source such as a cylinder, so that the pair of substrates P are bonded together. The reason for making the state close to vacuum at the time of bonding is to eliminate as much as possible gas molecules between the surfaces to be bonded.

  After that, as shown in FIG. 12C, the periphery of the bonded substrate P is returned to atmospheric pressure by introducing the atmosphere, or after being pressurized to atmospheric pressure or higher (after 2c in FIG. 13). reference). By being released to atmospheric pressure in this way, the bubbles remaining in the adhesive layer R are gradually compressed by the pressure difference from the vacuum. As shown in FIG. 12D, the adhesive layer R is formed by irradiating the entire surface with ultraviolet light from the light source U as shown in FIG. 12D on the substrate P left in the atmosphere for several seconds to several tens of seconds until the bubbles are sufficiently compressed. Harden. As a result, the two substrates P are firmly bonded to complete the disc.

  By the way, an information recording medium such as a DVD has a single-layer disc in which a substrate having a recording film formed on either side is bonded to a substrate in which a recording film is formed on both discs to increase the storage capacity. There is a layer disc. Such recording, reproduction, and erasing on the disc are performed by a laser beam from a head equipped with an optical pickup or the like, and the light for the second layer of the two-layer disc is close to the substrate on the layer close to the head and the head. It passes through the recording film of the layer and the adhesive layer, and reaches the substrate of the layer far from the head and the recording film of the layer far from the head.

  For this reason, when there are scratches or dust at the site through which light passes, especially when bubbles or the like at the time of bonding remain in the adhesive layer, the recording or reproduction of information is hindered. Scratches and dust adhering to the substrate and the adhesive layer can be avoided by improving and managing the production process, but it is difficult to eliminate bubbles remaining in the adhesive layer, and countermeasures are required. This is the same for a single-sided single-layer disc, and it is not preferable that air bubbles that can be visually recognized remain.

The following factors can be cited as factors for remaining bubbles in the adhesive layer.
(a) Gas is trapped at the boundary between the substrate and the adhesive when the adhesive is applied to the substrate.
(b) Gas is confined between the substrate and the adhesive layer during bonding.
(c) Gas remains inside the adhesive.
Among these, as a method of eliminating (a) and (b), there is a conventional technique described in Patent Document 1. This is a technique for eliminating a bag path that is likely to occur at the time of bonding by blowing a gas. However, with such a conventional technique, bubbles existing inside the adhesive cannot be removed as shown in (c).

In order to cope with this, the following method can be considered.
(A) Method of prolonged vacuum standing
(1) For each bonding, lengthen the evacuation time for evacuation and secure the time for the bubbles in the adhesive to be removed.
(2) By vacuuming the entire production process after applying the adhesive and simultaneously vacuuming multiple sheets, the waiting time in vacuum of each substrate is lengthened, and the bubbles are defoamed in the adhesive. Secure.
(B) Method of prolonged exposure to air
(1) Compress the residual bubbles with the pressure difference between the atmosphere and the internal pressure by lengthening the process until the adhesive is cured after vacuum bonding and lengthening the time for leaving in the atmosphere.
(2) The remaining bubbles are compressed by the differential pressure between the atmosphere and the internal pressure by increasing the takt time for the required air exposure time.
JP 2004-70976 A

  However, the bubble suppression method as described above has the following problems. That is, in the method (A) (1), it is necessary to lengthen the exhaust time for evacuation, so that the tact time becomes long and the productivity is lowered. The same applies to the methods (B) and (2). In the methods (A) and (2), it is necessary to secure a large space for evacuation, resulting in an increase in equipment. The same applies to the methods (B) and (1) because it is necessary to secure a large space for leaving in the atmosphere.

  The present invention has been proposed to solve the above-described problems of the prior art, and its purpose is to reduce bubbles remaining in the adhesive layer even when the exhaust time and the air leaving time are short. It is providing the program for the bonding apparatus which can be improved, and can improve productivity, the bonding method, and the bonding apparatus control.

In order to achieve the above-mentioned object, the invention of claim 1 is a bonding apparatus for bonding a pair of substrates coated with an adhesive on one or both sides, an accommodating portion for accommodating the pair of substrates, by reducing the ambient pressure, so that air bubbles in the adhesive prior to bonding is inflated and burst, and an exhaust system for exhausting from the housing part, by increasing the ambient pressure of said substrate, before bonding And an air supply device that supplies gas to the housing portion so that bubbles in the adhesive are compressed.

Laminating method is a second aspect of the present invention, an adhesive is applied to one or both of the pair of substrates, by reducing the pressure around the pair of substrates, air bubbles in the adhesive before bonding expansion and ruptured by increasing the pressure near the pair of substrates, compresses the air bubbles in the adhesive before bonding, characterized in that bonding the pair of substrates.

According to a third aspect of the present invention, there is provided a bonding apparatus control program for causing a computer to control a bonding apparatus for bonding a pair of substrates coated with an adhesive on one or both sides. , by reducing the ambient pressure of said substrate, so that air bubbles in front of the adhesive bonding is inflated and burst, by the exhaust device is exhausted from the housing part, by increasing the ambient pressure of said substrate, as bubbles in the adhesive before bonding is compressed, characterized in that to supply the gas to the receiving portion by the air supply device.

  In the inventions of claims 1, 2, and 3 as described above, before bonding the pair of substrates, by reducing the pressure around the substrate to which the adhesive is applied, bubbles in the adhesive are changed to a differential pressure from the outside. After expanding and rupturing, the remaining bubbles can be compressed and reduced by further increasing the pressure around the substrate. Therefore, even if the exhaust time and the air leaving time are not ensured for a long time, bubbles having a size that affects the yield can be removed, and the productivity is improved.

  As described above, according to the present invention, even when the exhaust time and the air leaving time are short, the air bubbles remaining in the adhesive layer can be reduced, and the bonding apparatus and the bonding method capable of improving productivity. And it is providing the program for bonding apparatus control.

Next, embodiments of the present invention (hereinafter referred to as embodiments) will be specifically described with reference to the drawings.
[Device configuration]
First, the structure of the adhesive agent coating apparatus, the bonding apparatus, and the ultraviolet irradiation apparatus used for this embodiment is demonstrated with reference to FIGS. These apparatuses constitute a part of the disk manufacturing apparatus. A substrate molding apparatus, a metal film forming apparatus, and a substrate between each apparatus are disposed in the upstream process of these apparatuses. Any known technique can be applied to the delivery mechanism and the like, and a description thereof will be omitted.

  That is, as shown in FIGS. 1 and 2, the adhesive application device applies the adhesive onto the turntable 1 on which the disk substrate P1 (or P2) is placed and the substrate P1 (or P2). And an adhesive application part 2. The turntable 1 is a device in which a disk-shaped substrate P1 (or P2) is placed and mounted and rotated one by one. The adhesive application unit 2 is a nozzle that applies an ultraviolet curable adhesive supplied from an adhesive tank (not shown) to the inner peripheral side of the substrate P1 (or P2).

  As shown in FIGS. 3 to 6, the bonding apparatus includes a mounting table 3, a holding unit 4, and a storage unit 5. The mounting table 3 is a table on which one substrate P1 to be bonded is mounted. The holding unit 4 is a member that holds the other substrate P2 to be bonded to the substrate P1 at a predetermined distance D, and is provided so as to be moved up and down by an actuator such as a cylinder (not shown). The accommodating portion 5 is a member that can seal a space covering the substrate P1 on the mounting table 3 and the substrate P2 held by the holding portion 4, and is configured to be able to be depressurized to a state close to vacuum by being exhausted when sealed. . The accommodating portion 5 is provided with a supply / exhaust port 6 for supplying and discharging gas, and is connected to an exhaust device for reducing pressure and an air supply device for introducing gas, although not shown.

  Furthermore, as shown in FIG. 7, the ultraviolet irradiation apparatus includes a mounting table 7 on which the substrates P1 and P2 after bonding are mounted, and an ultraviolet irradiation unit 8 serving as an ultraviolet light source. In addition, from the lower part of the accommodating part 5 to the lower part of the ultraviolet irradiation part 8 in the state which mounted the board | substrate P1 and P2 which bonded together by using the mounting base 3 of the bonding apparatus and the mounting base 7 of the ultraviolet irradiation apparatus as a common base It is good also as a structure which moves, and it is good also as a structure where the accommodating part 5 and the ultraviolet irradiation part 8 change on a stand.

  The rotation and speed adjustment of the turntable 1, the adhesive dripping of the adhesive application unit 2, the operation of the exhaust device and the air supply device, the raising and lowering of the holding unit 4, the light emission of the ultraviolet irradiation unit 8, etc. The operation timing is controlled by a control device. This control device can be realized by, for example, a dedicated electronic circuit or a computer operating with a predetermined program. Therefore, a computer program for controlling the operation of the apparatus according to the procedure described below and a recording medium recording the computer program are also one aspect of the present invention.

The operation procedure of the present embodiment as described above will be described with reference to the configuration diagram of FIGS. 1 to 7, the flowchart of FIG. 8, and the explanatory diagrams of FIGS.
[Formation of adhesive layer]
First, the operation when two disc substrates P1 and P2 are bonded together will be described. That is, as shown in FIG. 1, the substrate P1 on which the recording film has been formed in the previous process is placed and mounted on the turntable 1 with the recording film facing up (step 801). Then, the adhesive application portion 2 spouts the adhesive R1 while rotating the turntable 1 at a low speed, whereby the adhesive R1 is applied concentrically with the substrate P1 to the inner peripheral portion of the substrate P1 (step 802). . Next, as shown in FIG. 2, when the turntable 1 is rotated at a high speed, the adhesive R1 is spread in the outer peripheral direction, and the excess adhesive R1 is shaken off, as shown in FIG. An adhesive layer R2 covering the film is formed (step 803). Similarly, the adhesive layer R2 is formed on the substrate P2.

  Thus, as shown in FIG. 4, a pair of board | substrate P1, P2 in which the contact bonding layer R2 was formed is carried in in the accommodating part 5 of a bonding apparatus (step 804), and predetermined spacing is carried out by the holding | maintenance part 4. Hold D and face each other in parallel (step 805). Then, by operating the exhaust device, the air is exhausted from the supply / exhaust port 6 to reduce the pressure around the held substrates P1 and P2 to a state close to vacuum (step 806). At this time, the pressure gradually decreases from 3a in FIG. 9 and decreases to a predetermined base pressure 3b. Thereby, as shown in FIG. 10, the bubbles in the adhesive layer R2 expand to 4a to 4c, When it becomes larger than the thickness L of the adhesive layer R2, as shown in 4d and 4e, it bursts and is filled with the surrounding adhesive.

  However, as shown to 5a-5c of FIG. 11, the bubble which remain | survives in the contact bonding layer R2 in the state just before bursting also exists. Therefore, in a state where the bubbles before bonding are easy to move, gas is introduced from the supply / exhaust port 6 as shown in FIG. 5, and as shown in 3 c of FIG. 9, the pressure does not remain on the bonding surface. Then, the pressure around the substrates P1 and P2 is increased (step 807). Then, as shown to 5c-5e of FIG. 11, the bubble which cannot burst is compressed by pressure difference (DELTA) P.

  In this state, one of the substrates P2 is lowered by the holding unit 4 and bonded together under a pressure that can avoid air entrapment (step 808). Further, as shown by 3d in FIG. 9, after the pressure increase due to the introduction of the gas is continued, the substrates P1, P2 are left in the atmosphere (step 809). From the expansion and burst of bubbles due to such pressure reduction to the reduction of residual bubbles and pressure release to the atmosphere by pressure increase (3a to 3d in FIG. 9), the time from pressure reduction of the prior art to air release (2a to 2c in FIG. 13) Realized in almost the same time. Then, after being left in the atmosphere for a short time, the substrates P1 and P2 are placed on the mounting table 7 of the ultraviolet irradiation device, and the adhesive layer R2 is cured by the ultraviolet light irradiated from the ultraviolet irradiation unit 8 (step 810).

[effect]
According to the present embodiment as described above, before the pair of substrates P1 and P2 are bonded together, by reducing the pressure around the substrates P1 and P2 on which the adhesive layer R2 is formed, the bubbles in the adhesive layer R2 are caused to have a differential pressure. After expanding and rupturing to reduce residual bubbles, the remaining bubbles can be compressed and reduced by increasing the pressure around the substrates P1 and P2. The expansion and rupture of bubbles, reduction of residual bubbles, and release to the atmosphere can be realized in almost the same time as the time from decompression to release to the atmosphere in the prior art. Bubbles having such a size as to affect the air quality can be removed, and productivity is improved. Further, by continuously exhausting and supplying gas before bonding the substrates P1 and P2, bubbles can be efficiently removed and reduced, so that the apparatus configuration is simplified and no extra cost is incurred.

[Other Embodiments]
The present invention is not limited to the embodiment as described above. For example, the gas supplied at the time of pressurization may be any gas as long as the pressure in the accommodating portion can be increased. Although the air may be used, the remaining bubbles can be further reduced if the gas is soluble in the adhesive. The gas that dissolves in the adhesive may be water vapor, hydrocarbon, organic solvent, or the like, but can be appropriately selected according to the material of the adhesive. The pressure around the substrate may be controlled according to the exhaust time or the air supply time, or may be controlled according to the exhaust amount or the air supply amount, or may be controlled according to a pressure measurement value by a sensor or the like. The pressure around the substrate is relatively changed from 3a (initial pressure: for example, atmospheric pressure) in FIG. 9 to 3b, 3c, 3d and the following (for example, released to atmospheric pressure). The value can be appropriately changed according to the type of adhesive, viscosity, layer thickness, area, volume of the accommodating portion, and the like.

  The accommodating portion may be of any shape, material, and size as long as the inside can be depressurized and pressurized, and the sealing structure for sealing is also free. A supply port and an exhaust port may be provided separately. The mounting table or the inner wall of the storage unit may be configured to move in a sealed state, and either or both of decompression and pressure increase may be performed by changing the volume of the storage unit. Moreover, the structure and number of holding | maintenance parts are also free. Therefore, it can be configured as an apparatus for bonding a plurality of substrates at the same time, or can be configured to be bonded by moving the lower or both substrates. An interval for holding the pair of substrates may be any distance that allows pressure reduction and pressure increase in a short time, and is not limited to a specific value. The interval may be changed between when the pressure is reduced and when the pressure is increased.

  In addition, the size, shape, material, number of recording layers, and the like of a disc to be manufactured according to the present invention are free, and are not limited to existing standards such as CD and DVD, but any standard that will be adopted in the future. It is applicable to. Furthermore, the present invention can be applied not only to an information recording disk but also to any substrate that is bonded using an adhesive. That is, the material and shape of the substrate and the type of adhesive are not limited to those exemplified in the above embodiment. For example, as a material of the substrate, resins such as acrylic and epoxy can be considered in addition to general polycarbonate, but the material is not limited thereto. Also, any material that can be used at present or in the future can be used as the adhesive. It is also possible to apply a material that is cured by irradiating a broad electromagnetic wave from the outside, such as a radiation curable resin, or by applying a temperature change, such as a thermosetting resin.

It is a perspective view which shows the adhesive agent application process in one Embodiment of this invention. It is a perspective view which shows the adhesive agent extending | stretching process in one Embodiment of this invention. It is a perspective view which shows the accommodation process to the accommodating part in one Embodiment of this invention. It is a perspective view which shows the exhaust process of the accommodating part in one Embodiment of this invention. It is a perspective view which shows the air supply process to the accommodating part in one Embodiment of this invention. It is a perspective view which shows the bonding process in one Embodiment of this invention. It is a perspective view which shows the ultraviolet irradiation process in one Embodiment of this invention. It is a flowchart which shows the bonding process procedure in one Embodiment of this invention. It is explanatory drawing which shows the pressure fluctuation in the accommodating part in one Embodiment of this invention. It is explanatory drawing which shows the change of the bubble which bursts and extinguishes inside the contact bonding layer at the time of pressure reduction in one Embodiment of this invention. It is explanatory drawing which shows the change of the bubble compressed within the contact bonding layer at the time of pressure | voltage rise in one Embodiment of this invention. It is explanatory drawing which shows the conventional board | substrate bonding procedure, (A) is spreading of an adhesive agent, (B) is bonding, (C) is left to air, (D) shows the process of adhesive hardening, respectively. It is explanatory drawing which shows the pressure fluctuation in the accommodating part in one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Turntable 2 ... Adhesive application part 2a, 3a ... Atmospheric pressure 2b, 3b ... Base pressure 3, 7 ... Mounting stand 4, T ... Holding part 5 ... Storage part 6 ... Supply / exhaust port 8 ... Ultraviolet irradiation part D ... Interval K ... coating device P, P1, P2 ... substrate R, R2 ... adhesive layer R1 ... adhesive S ... decompression chamber U ... light source

Claims (3)

In a bonding apparatus for bonding a pair of substrates coated with an adhesive on one or both sides,
An accommodating portion for accommodating the pair of substrates;
By lowering the ambient pressure of said substrate, so that air bubbles in front of the adhesive bonding is inflated and burst, and an exhaust system that exhausts from the accommodating portion,
By increasing the ambient pressure of said substrate, so as to prevent bubbles in the adhesive before bonding is compressed, the air supply device for supplying gas to the receiving portion,
It has a bonding apparatus characterized by having. Apply an adhesive to one or both of the pair of substrates,
By lowering the pressure around the pair of substrates, it is inflated and burst bubbles in front of the adhesive bonding,
By increasing the pressure near the pair of substrates, it compresses the air bubbles in the adhesive prior to bonding,
A bonding method comprising bonding the pair of substrates. In the pasting device control program for controlling the pasting device for pasting a pair of substrates coated with an adhesive on one or both sides, to a computer,
Accommodating the pair of substrates in an accommodating portion;
By lowering the ambient pressure of said substrate, so that air bubbles in front of the adhesive bonding is inflated and burst, is exhausted from the receiving portion by the exhaust system,
By increasing the ambient pressure of said substrate, so as to prevent bubbles in the adhesive before bonding is compressed, bonding apparatus control program, characterized in that to supply the gas to the receiving portion by the air supply device .

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