JP2002319189A - Method and device for sticking substrate for optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the distribution of film thickness uniform, when two substrates for an optical disk are stuck. SOLUTION: An adhesive 8 is applied on one surface of one substrate 2 of two substrates 2 and 3, while the substrate 2 is rotated at a first rotary speed. A film 65 of the uncured adhesive is formed on the one surface of the one substrate 2 by rotating the one substrate 2 at a second speed higher than the first speed to diffuse the adhesive 8. The other substrate 3 is joined to the one surface of the one substrate 2 in the vacuum atmosphere. The adhesive 8 is cured to fix the two substrates 2 and 3 to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for bonding substrates for an optical disk for bonding and fixing two substrates.

[0002]

2. Description of the Related Art As shown in FIGS. 9 and 10, a recording / reproducing type optical disc 1 has first and second disc-shaped substrates 2 and 3 made of a resin such as polycarbonate, which are bonded and fixed. Adhesive layer 4. Also, the first substrate 2
Is formed with a recording layer 7 composed of a dye film 5 and a reflection film 6.

Conventionally, a method shown in FIG. 11 has been known as a method of bonding the first substrate 2 and the second substrate 3 together.
Hereinafter, this bonding method will be described.

[0004] First, as shown in FIG. 11 (A), while the first substrate 2 is rotated as shown by the arrow A, an ultraviolet-ray reactive curable adhesive 8 is supplied from the nozzle 11, and the first substrate 2 is placed on the first substrate 2. Apply in a ring. Next, as shown in FIG. 11B, the second substrate 3 is lowered with respect to the first substrate 2 as shown by an arrow B, and the second substrate 3 is placed on the first substrate 2 with an adhesive 8. Place on. Further, as shown in FIG. 11C, the first substrate 2 and the second substrate 3 are rotated at a high speed as indicated by an arrow C. Due to this rotation, the adhesive 8 is diffused between the first and second substrates 2 and 3, and the optical disc 1 composed of the first and second substrates 2 and 3 and the uncured adhesive layer 4 as an intermediate layer is formed. Is done. Finally, as shown in FIG. 11D, the optical disc 1 is irradiated with ultraviolet light 13 by the ultraviolet ray generator 11. The irradiation of the ultraviolet light 13 cures the adhesive layer 4, and the first substrate 2 and the second substrate 3 are fixed. Note that an adhesive may be applied to the second substrate 3. The ultraviolet light 13 may be irradiated from both sides of the optical disc 1 or from one side.

[0005]

The above-mentioned conventional method of bonding substrates has the following problems. First, as shown in FIGS. 9 and 10, the recording / reproducing type optical disc 1 can write and read information accurately and stably by a laser beam 14 irradiating irradiation from one side in a substantially thickness direction. Needs to be In order to realize this accurate and stable writing and reading, the inclination amount θ of the disk surface 15 is secured with high accuracy to prevent the incidence and reflection of the laser beam 14 in the information recording / reproducing range 16 and to reduce the intensity. Need to be prevented. And
In order to secure the inclination amount θ with high accuracy, the film thickness distribution of the adhesive layer 4 is made uniform to suppress the inclination of the first substrate 2 and the second substrate 3, and the conditions at the time of curing the adhesive layer 4 It is extremely important to suppress the warp of the optical disc 1 due to the above-mentioned factors.

However, in the conventional method in which the adhesive 8 flows and diffuses only by the centrifugal force, the thickness of the adhesive layer 4 becomes extremely thin especially near the center of the optical disc 1, and a uniform film thickness distribution cannot be obtained. The phenomenon in which the thickness of the adhesive layer 4 is reduced near the center of the optical disc 1 will be described with reference to FIG. In a state where the first substrate 2 and the second substrate 3 are bonded via the adhesive 8 and before the rotation indicated by an arrow C is started, the adhesive 8
7 and Newtonian flow, central direction 18 and outer peripheral direction 1
It gradually diffuses to 9. It is considered that the speed of this diffusion is proportional to the third power of the average value of the gap 21a in the central portion of the first and second substrates 2 and 3 and the gap 21b in the outer peripheral portion. From this state, as shown by the arrow C, the optical disk 1
When is rotated at a high speed, the adhesive 8 flows rapidly in the diameter direction due to the centrifugal force 22. The velocity of this flow is considered to be proportional to the angular velocity (Rω ² ). However, the adhesive having a certain volume applied near the center of the optical disc 1 increases the flow resistance as the diameter of the adhesive spreads, and the diffusion rate decreases. I do. That is, the diffusion area increases in a certain time,
It is considered that the approach of the second substrate 3 to the first substrate 2 due to the diffusion accelerates the fluctuation of the thickness of the adhesive 8 in the diameter direction. As a result, when the rotation in the direction of arrow C is stopped, the film thickness of the adhesive layer 4 near the center of the optical disk 1 decreases to be smaller than the film thickness of the adhesive layer 4 at the outer peripheral portion.

In the above-mentioned conventional method, the adhesive layer 4 is only cured by irradiating ultraviolet light in a state where the optical disk 1 on which the uncured adhesive layer 4 is formed is positioned and arranged. As shown in (1), a warp 25 occurs in the radial direction 23 and the circumferential direction 24 of the bonded optical disks 1, and it is difficult to reduce the amount of the warp 25 in the information recording / reproducing range 16.

Second, as shown in FIG. 10, a pinhole 27 due to peeling exists in the recording layer 7 or the recording layer 7
If bubbles 28 are present in the adhesive layer 4 in the vicinity, the quality of the optical disc 1 is degraded. If the quality degrades significantly, the optical disc 1 may not function as an optical disc. However, in the above-described conventional method, the adhesive 8 flows and diffuses between the first and second substrates 2 and 3 by centrifugal force. It's easy to do. Further, in the above-mentioned conventional method, the first and second substrates 2 and 3 are bonded together at atmospheric pressure.
8 tends to remain.

Accordingly, the present invention provides a method of bonding two substrates for an optical disk, wherein the uniformity of the film thickness distribution and the prevention of warpage ensure the amount of tilt of the disk surface with high accuracy, and the use of pinholes and bubbles It is an object of the present invention to improve the accuracy and stability of writing and reading of information by preventing occurrence of the information.

[0010]

According to a first aspect of the present invention, there is provided a method of bonding two substrates for an optical disk, each having at least one of them having a recording layer, with an adhesive. While rotating one of the substrates at a first rotation speed, an adhesive is applied to one surface thereof, and the one substrate is rotated at a second rotation speed higher than the first rotation speed. The adhesive is diffused, an uncured adhesive film is formed on one surface of the one substrate, the other substrate is joined to one surface of the one substrate, and the adhesive is cured to form the two substrates. To provide a method for attaching an optical disk substrate to which a substrate is fixed.

In the method for bonding substrates according to the present invention, after applying an adhesive while rotating one of the substrates at a first rotational speed, the substrate is rotated at a second rotational speed higher than the first rotational speed. Then, a film of the adhesive is formed. Therefore, compared to the conventional method in which the two substrates are bonded and then rotated to rotate the adhesive, the thinning of the adhesive near the center of the substrate is suppressed, and the thickness of the adhesive is reduced. The distribution can be made uniform. In addition, since the adhesive is diffused before joining the two substrates, the load acting on the recording layer can be reduced, and the occurrence of pinholes due to the separation of the recording layer can be prevented.

After the application of the adhesive at the first rotation speed is completed, the first rotation speed is maintained for a predetermined first time, and then the rotation speed of the one substrate is reduced to the second rotation speed. It is preferred to accelerate to speed.

By controlling the rotation speed of the substrate in this way, the diffusion of the adhesive at the beginning of the rotation at the second rotation speed becomes more uniform, so that the film thickness distribution of the adhesive is made more uniform. Can be.

After the lapse of the first time, the first time
The rotation speed of the one substrate is accelerated to a third speed that is higher than the rotation speed of the first substrate and lower than the second rotation speed, and the third substrate is accelerated for a second predetermined time.
It is preferable that the rotation speed of the one substrate is maintained and the rotation speed of the one substrate is accelerated to the second rotation speed after the lapse of the second predetermined time.

By gradually increasing the rotation speed of the substrate after supplying the adhesive, the diffusion of the adhesive becomes more uniform,
The film thickness distribution of the adhesive can be made more uniform.

[0016] The first rotation speed is not less than 30 rpm and not more than 60 rpm.
rpm or less, and the second rotation speed is 3000 rpm
m or more and 4000 rpm or less, and the third rotation speed is preferably 1000 rpm or more and 2000 rpm or less.

According to a second aspect of the present invention, there is provided a method of bonding at least one of two substrates for an optical disk having a recording layer with an adhesive, wherein an uncured adhesive film is formed on one surface of one of the substrates. A method of bonding a substrate for an optical disk, comprising bonding one substrate to one surface of the one substrate in a vacuum atmosphere, and curing the adhesive to fix the two substrates.

In the method for bonding substrates according to the second invention,
Since the other substrate is bonded to the one substrate on which the adhesive film is formed in advance in a vacuum atmosphere, it is possible to effectively prevent air bubbles from remaining in the adhesive. Further, after the two substrates are bonded, the adhesive is cured without rotating them, so that the load acting on the recording layer can be reduced and the occurrence of pinholes can be prevented.

When the other substrate is joined to one surface of the one substrate, it is preferable that a portion corresponding to the stamper groove of the one substrate is pressed against the other substrate by an elastic body.

In many cases, burrs generated during the molding of the substrate remain in the vicinity of the stamper groove. However, since the portion corresponding to the stamper groove of one substrate is pressed against the other substrate by the elastic body, the burrs are pressed, so that the occurrence of the warpage of the substrate can be prevented.

The hardness of the elastic body is 3 ° to 8 in Shore hardness.
°, particularly preferably 5 °.

According to a third aspect of the present invention, there is provided a method of bonding two substrates for an optical disk, at least one of which has a recording layer, with an adhesive, wherein one of the two substrates has a first rotational speed. While rotating in, the adhesive is applied to one surface, the one substrate is rotated at a second rotation speed that is higher than the first rotation speed to diffuse the adhesive,
Forming an uncured adhesive film on one surface of the one substrate,
Provided is a method of bonding substrates for an optical disk, in which one substrate is bonded to one surface of the one substrate in a vacuum atmosphere, and an adhesive is cured to fix the two substrates.

More specifically, the adhesive is a UV-curable adhesive. After bonding the other substrate to one surface of the one substrate, the adhesive is cured by irradiating ultraviolet light. The two substrates are fixed.

According to a fourth aspect of the present invention, there is provided an adhesive film forming apparatus for forming an adhesive film on a substrate for an optical disk, comprising: a holding mechanism for holding the substrate on an upper surface thereof; A rotation driving mechanism for rotating the substrate in a horizontal plane, and an adhesive supply mechanism for supplying an adhesive to the substrate held by the holding mechanism, wherein the rotation driving mechanism rotates the holding mechanism at a first rotation speed. While applying the adhesive to one surface of the substrate by the adhesive supply mechanism, the holding mechanism is rotated by the rotation drive mechanism at a second rotation speed higher than the first rotation speed to diffuse the adhesive. And an adhesive film forming apparatus for forming an uncured adhesive film on one surface of the one substrate.

According to a fifth aspect of the present invention, there is provided a bonding apparatus for bonding two substrates for an optical disk, comprising a sealable container, a vacuum suction mechanism for evacuating the container, and a vacuum suction mechanism disposed in the container. A holding unit for holding one of the two substrates, on each of which an uncured adhesive film is formed, so that they face each other; and an atmospheric pressure operating unit disposed outside the container. A first substrate and a second substrate, wherein two substrates in the container are movable toward and away from each other, respectively.
And a first and a second fixing mechanism for fixing the first and second holding mechanisms to the container, respectively. The first and second fixing mechanisms are evacuated by the evacuation mechanism in the container. The first and second holding mechanisms are released from each other by the atmospheric pressure acting on the above-mentioned atmospheric pressure acting part, and the holding by the first and second holding mechanisms is released. Provided is a joining device for joining two substrates that have been made.

According to a sixth aspect of the present invention, there is provided a bonding apparatus for bonding at least one of two substrates for an optical disk having a recording layer with an ultraviolet-curable adhesive, and a holding mechanism for holding the substrate on an upper surface thereof. A rotation drive mechanism for rotating the holding mechanism and rotating the substrate in a horizontal plane; and an adhesive supply mechanism for supplying an adhesive to one surface of the substrate held by the holding mechanism. After the adhesive is applied to one surface of the substrate by the adhesive supply mechanism while rotating the holding mechanism at the first rotation speed, the rotation driving mechanism drives the holding mechanism to rotate the holding mechanism at a speed higher than the first rotation speed. An adhesive film forming device that forms an adhesive film on one surface of the substrate by rotating at a rotational speed of, a sealable container, a vacuum suction mechanism for evacuating the container, and And a holding unit for holding one of the two substrates, on each of which an uncured adhesive film is formed, so that they face each other, and an atmospheric pressure operating unit disposed outside the container. A first and a second holding mechanism, wherein the two substrates in the container are movable toward and away from each other, and the first and second holding mechanisms are fixed to the container, respectively. A first and a second fixing mechanism, and after the inside of the container is evacuated by a vacuum evacuation mechanism, the fixing by the first and second fixing mechanisms is released,
The holding of the first and second holding mechanisms is brought close to each other by the atmospheric pressure acting on the atmospheric pressure action section, and the two substrates held by the holding sections of the first and second holding mechanisms are bonded with an adhesive. Provided is an apparatus for bonding substrates for optical discs, comprising: a substrate bonding apparatus for bonding; and an ultraviolet light generator for irradiating ultraviolet light to two substrates bonded by the substrate bonding apparatus to cure an adhesive.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention shown in the drawings will be described in detail. Note that the first and second substrates 2 and 3 constituting the optical disc 1 and the ultraviolet light reaction-curable adhesive 8 (adhesive layer 4) are the same as the conventional one shown in FIG. 9 and FIG.

First, a method for bonding a substrate for an optical disk will be schematically described with reference to FIG. This bonding method includes an adhesive film forming step 31, a bonding step 32, and an adhesive curing step 33. In addition, a substrate transfer step 34a from the adhesive film forming step 31 to the bonding step 32 and a substrate transfer step 34b from the bonding step 32 to the adhesive curing step 33 are provided.

In the adhesive film forming step 31, the adhesive 4 is applied and diffused while rotating the first substrate 2 about the axis L in a horizontal plane, and the uncured adhesive is applied to one surface of the first substrate 2. Form a film. This adhesive film forming step 31 includes:
This is performed by the adhesive film forming apparatus 35 shown in FIG.

In the bonding step 32, the second substrate 3 is bonded to one surface of the first substrate 2 on which the uncured adhesive film is formed in the vacuum vessel 69. This joining step 32 is shown in FIG.
Is performed by the joining device 36 shown in FIG.

In the adhesive curing step 33, ultraviolet light 101 is irradiated from one surface side of the optical disk 1 by the ultraviolet ray generator 100 to cure the adhesive between the first and second substrates 2 and 3, The first and second substrates 2 and 3 are fixed. In the figure, ultraviolet light may be irradiated from the lower surface side of the optical disk 1 or ultraviolet light may be irradiated from both upper and lower sides of the optical disk 1.

Next, the adhesive film forming apparatus 35 shown in FIG. 2 will be described. The adhesive film forming device 35 is a spin plate (holding mechanism) made of high-tensile aluminum having a disk-shaped mounting portion 41a on which a substrate is mounted and a shaft portion 41b extending downward from the mounting portion 41a. 41 are provided. The mounting portion 41a is provided with a positioning projection 42 that is inserted into the center hole of the substrate. The mounting portion 41a is provided with a plurality of suction holes 43 opened on the upper surface thereof, and each suction hole 43 communicates with one end of an air flow path 44 formed in the shaft portion 41b. The other end of the air flow path 44 is connected to the atmosphere and a vacuum suction pump 4 through a three-port two-position solenoid valve 45.
7 is communicated. If the solenoid valve 45 is at the first position 45A, the suction hole 43 will be in the air flow path 44 and the solenoid valve 4
The suction hole 43 is connected to the vacuum suction pump 47 via the air flow path 44 and the electromagnetic valve 45 if the suction hole 43 is located at the second position 45B. Therefore, the mounting portion 41a
The substrate placed on the substrate is positioned by the positioning protrusion 42 and is suction-held by suction of the vacuum suction pump 47.

A gear 48A is fixed to the shaft portion 41b of the spin plate 41, and the gear 48A
Is engaged with a gear 48B fixed to the output shaft 49a. Therefore, when the motor 49 operates, the spin plate 4
1 rotates, and the substrate sucked and held by the mounting portion 41a rotates around its axis L in a horizontal plane as shown by an arrow D.
The gears 48A and 48B and the motor 49 constitute a rotation drive mechanism in the present invention.

The adhesive 8 is applied to the substrate held by the mounting portion 41a.
An adhesive supply mechanism 50 for supplying the adhesive is provided. The adhesive supply mechanism 50 supplies a gas (nitrogen gas in the present embodiment) to the nozzle 52 disposed above the mounting portion 41a, a closed tank 53 storing the adhesive 8, and the tank 53. A gas supply source 54 is provided. When gas is supplied from the gas supply source 54 into the tank 53 via the pipe 55a, an amount of the adhesive 8 corresponding to the amount of the supplied gas is supplied to the nozzle 52 via the pipe 55b. Is discharged onto the substrate on the mounting portion 41a. The nozzle 52 is attached to the distal end of a rod 57a of an air cylinder 57 that can advance and retreat in the radial direction of the mounting portion 41a (substrate). Therefore, the nozzle 5 is controlled by the air-air cylinder 57.
The radial position of the second mounting portion 41a can be adjusted.

The mounting portion 41a of the spin plate 41 is surrounded by a hood 58 for preventing scattering of the adhesive. The nozzle 52 is placed above the hood 58 with the mounting portion 41a.
A large-diameter opening 58a for facing the upper substrate is provided,
Below the hood 58, a small-diameter opening 58b for inserting the shaft portion 41b is provided. The position of the hood 58 in the vertical direction can be adjusted by an air cylinder 59.

Controller 60 of adhesive supply mechanism 50
Controls the operations of the air cylinders 57 and 59, the solenoid valve 45, the vacuum suction pump 47, the motor 49, and the gas supply source.

Next, the operation of the adhesive film forming apparatus 35 (adhesive film forming step 33) will be described. First, the first substrate 2 is mounted on the mounting portion 41a, and is suction-held on the mounting portion 41a by the suction force of the vacuum suction pump 47 acting through the suction hole 43. At this time, the first substrate 2 is mounted on the mounting portion 41a such that the surface on the recording layer 7 side faces upward. Next, the spin plate 41 is moved from 30 to 60 by the motor 49.
The adhesive 8 is discharged from the nozzle 52 while being rotated at a low speed of about rpm, and while the spin plate 41 makes one rotation, the adhesive 8 is annularly formed around the stamper groove 62 as shown by reference numeral 61 in FIG. Apply.

After the application of the adhesive 8 is completed, as shown at time t0 to time t1 in FIG. 5, for a predetermined time (first time) of, for example, about 2 to 3 seconds, the time of the adhesive application is reduced. Maintain the rotation speed. Next, in FIG.
As shown at 1 to time t2, for example, the rotation speed of the spin plate 41 is increased from about 30 to 60 rpm to about 1000 to 2000 rpm in about 0.5 seconds (in this example, 1500 to 1500 rpm).
(rpm) (a third rotation speed). Due to the increase in the rotation speed of the spin plate 41, the adhesive 8 applied in a ring shape diffuses in the center direction of the first substrate 2 indicated by an arrow 63 in FIG.

As shown from time t2 to time t3, the rotation speed of about 1000 to 2000 rpm is maintained for a predetermined time (second time). Next, at time t3
From time t4 to time t4, the spin plate 41 is moved from the above-mentioned about 1000 to 2000 rpm to 3000 to 4000 rpm (3500 rpm in this example).
m) to the rotation speed (second rotation speed). Due to the re-acceleration of the spin plate 41, the arrows 63, 6
The diffusion of the adhesive 8 on the first substrate 2 indicated by 4 further proceeds. From time t4 to time t5, the above 300
The rotation speed of about 0 to 4000 rpm is maintained for, for example, about one second. Thereafter, as shown from time t5 to time t6, the rotation speed of the spin plate 41 is reduced,
For example, the rotation is stopped in about one second. At the end of the rotation, the uncured adhesive 8 is applied to the surface of the first substrate 2 on the recording layer 7 side.
Is formed (see FIG. 3).

As described above, in the adhesive film forming apparatus 35,
The adhesive 8 is applied while rotating the first substrate 2 at a rotation speed of about 30 to 60 rpm, and after maintaining the rotation speed for a predetermined time, the first substrate 2 is rotated at a high speed to rotate the film 6 of the adhesive 8.
5 is formed. Therefore, compared to the conventional method in which the two substrates are bonded and then rotated to rotate the adhesive, the thinning of the adhesive near the center of the substrate is suppressed, and the thickness of the adhesive is reduced. The distribution can be made uniform.
Further, since the adhesive is diffused before joining the two substrates, the load acting on the recording layer 7 can be reduced, and the occurrence of pinholes due to the separation of the recording layer 7 can be prevented. .

The rotation speed (30 to 6) at the time of applying the adhesive is used.
0rpm) to the maximum rotation speed (3000-4000r)
pm), the intermediate rotation speed (100
0 to 2000 rpm), and the rotation speed of the first substrate 2 is controlled so as to maintain the intermediate rotation speed for a predetermined time. Therefore, the diffusion of the adhesive at the start of rotation at the maximum rotation speed is more uniform. Thus, the film thickness distribution of the adhesive 8 can be made more uniform.

The control of the rotation speed of the spin plate 41 is not limited to the above, and any method may be used as long as the rotation speed is maintained after maintaining the rotation speed for a certain time after the application of the adhesive. For example, the rotation speed of the spin plate 41 may be controlled as shown in FIGS. 5B and 5C.

In FIG. 5B, after the rotation speed (30 to 60 rpm) at the time of applying the adhesive is maintained for about 2 to 3 seconds (from time t0 to time 1), 3000 to 4000 rpm is obtained for about 1 second.
m (time t1 to time t2). After the rotation speed is maintained for about 1 second (from time t2 to time t2).
3), 1000 to 2000 rpm in about 0.5 seconds
(From time t3 to time t4). Then, after maintaining this rotation speed for about 1 second (from time t4 to time t4).
5) The rotation is stopped by decelerating in about 0.5 seconds.

In FIG. 5C, after the rotation speed (30 to 60 rpm) at the time of applying the adhesive is maintained for about 2 to 3 seconds (from time t0 to time t1), 3000 to 4000 rpm is obtained for about 1 second.
pm (from time t1 to time t2). And
After maintaining this rotation speed for about one second (from time t2 to time t3), the rotation is reduced and stopped in about one second.

Next, the joining device 36 shown in FIG. 3 will be described. The joining device 36 includes an upper container 67 and a lower container 68.
Is provided. A rod 72a of an air cylinder 72 is connected to the upper container 67 via a drive shaft 70 and a drive plate 71, and can be moved up and down to a raised position shown in FIG. 3 and a lowered position shown in FIG. It is. Upper container 6 in the lowered position
The closed space 73 is formed by the container 7 and the lower container 68.
A seal rubber 74 for sealing the closed space 73 is attached to the upper surface of the lower container 68.

The lower container 68 is provided with a port 75 for evacuating the closed space 73. This port 75 is connected to either the atmosphere or a vacuum suction pump 77 via a three-port two-position solenoid valve 76. When the solenoid valve 76 is at the first position 76A, the inside of the sealed space 73 is communicated with the atmosphere via the port 75 and the solenoid valve 76, but when at the second position 76B, vacuum suction is performed through the port 75 and the solenoid valve 76. It is connected to a pump 77. Further, a vacuum gauge 78 for measuring the degree of vacuum in the closed space 73 is provided.

A holding portion 81 of an upper suction block (holding mechanism) 81 made of high-strength aluminum is provided inside the upper container 67.
a is arranged. A shaft portion 81b extending upward is connected to the holding portion 81a, and the shaft portion 81b projects outside the upper container 67 through an insertion hole 67a formed in the upper container 67. A seal rubber 83A for sealing the sealed space 73 is attached to the insertion hole 67a. One end of a horizontally extending link plate 84A is connected to an end of the shaft portion 81b protruding from the upper container 67.
The other end of the link plate 84A is connected to a rod 86a of an air cylinder (fixing mechanism) 86 fixed to the upper container 67. Upper container 67 of the upper suction block 81
And the link plate 84A constitute the atmospheric pressure acting portion in the present invention. The holding portion 81a is provided with a comb-like projection 87A for positioning the substrate.

As shown in FIG. 8A, an annular elastic body 89 made of urethane rubber is mounted on the lower surface side of the upper suction block 81 at a position corresponding to the stamper groove 62 of the substrate. The hardness of this elastic body 89 is 3 ° to 8 ° in Shore hardness.
Degree, preferably 5 °. The size of the elastic body 89 is, for example, 8 mm in width and 3 mm in thickness, and protrudes from the lower surface of the upper suction block 81 by about 0.05 to 1 mm.

Similarly to the upper suction block 81, a holding portion 82a of a lower suction block 82 made of high-strength aluminum is provided inside the lower container 68. Holder 82a
Is connected to a shaft 82b extending downward, and the shaft 82b projects outside the lower container 68 through an insertion hole 68a formed in the lower container 68. Insertion hole 68a
Is provided with a seal rubber 83B. One end of a link plate 84B extending in the horizontal direction is connected to an end of the shaft portion 82b protruding from the lower container 68. The other end of the ring plate 84B is connected to a rod 90a of an air cylinder 90 fixed to the lower container 68. The holding portion 82a has a comb-like projection 87 for positioning the substrate.
B is provided.

The upper and lower suction blocks 81, 82
Can move up and down with respect to the upper and lower containers 67 and 68, respectively, and the up and down movement causes the holding portions 81a and 82a of the upper and lower suction blocks 81 and 82 to move toward and away from each other. .

The upper and lower suction blocks 81, 82
The holding portions 81a, 82a have a plurality of suction holes 81c, 82c.
c are provided, and each of the suction holes 81 c and 82 c is
It communicates with one end side of air flow paths 81d and 82d formed in 1b and 82b. The other ends of the air passages 81d and 82d are communicated with either the atmosphere or a vacuum suction pump 94 via three-port two-position solenoid valves 92 and 93. When the solenoid valves 92 and 93 are located at the first positions 92A and 93A, the suction holes 81c and 82c are communicated with the atmosphere via the air flow paths 81d and 82d and the solenoid valves 92 and 93, but are moved to the second positions 92B and 93B. If so, the suction holes 81c and 82c are communicated with the vacuum suction pump 94 via the air flow paths 81d and 82d and the solenoid valves 92 and 93. Therefore, the holding portions 81a,
The substrate on 82a is positioned by positioning projections 87A and 87B, and is suction-held by the suction force of vacuum suction pump 94.

The controller 95 of the joining device 36 includes air cylinders 72, 86, 90, solenoid valves 92, 93, 76.
B and the operation of the vacuum suction pumps 77 and 94 are controlled.

Next, the operation of the joining device 36 (joining step 3)
2) will be described. First, as shown in FIG. 3, in a state where the upper container 67 of the vacuum container 69 is at the upper position and the vacuum container 69 is opened, the first uncured adhesive film 65 is formed by the adhesive film forming device 35. The substrate 2 is carried into the vacuum container 69, and the holding portion 81a of the upper suction block 81 is held.
Hold by suction. Further, the second substrate 3 is carried into the vacuum container 69 and is suction-held by the holding portion 82 a of the lower suction block 82. Specifically, the first and second substrates 2 and 3 are disposed on the holding portions 81a and 81b, the electromagnetic valves 92 and 93 are switched to the second positions 92B and 93B, and the suction is performed by the suction force of the vacuum suction pump 94. .

Next, as shown in FIG. 6, the upper container 67 is moved to the lower position by the cylinder 72, and the vacuum container 69 is closed. Thereafter, the electromagnetic valve 76 is switched from the first position 76A to the second position 76B, and the inside of the sealed space 73 is evacuated by the vacuum suction pump 77. At this time, the holding portions 81a and 82a of the upper and lower suction blocks 81 and 82 are under negative pressure, and the atmospheric pressure acts on the portions of the shaft portions 81b and 82b protruding from the vacuum container 69 and the link plates 84A and 84B. Therefore, due to this pressure difference, the upper and lower suction blocks 81 and 82 have arrows E1 and E1 in FIGS.
As indicated by E2, forces approaching each other act. However, since the air cylinders 86, 90 in the operating state resist this force, the upper and lower suction blocks 8
The first and second substrates 1 and 82 do not move with respect to the upper and lower containers 67 and 68, and the first and second substrates 2 and 3 held by suction by the holding units 81a and 81b maintain a state where they face each other with an interval. I have. In order to resist the forces E1 and E2 due to the pressure difference,
It is necessary to keep the air cylinders 86, 90 at a pressure of at least one atmosphere.

Next, when the degree of vacuum in the closed space 73 measured by the vacuum gauge 78 reaches a predetermined value, the air cylinders 86 and 90 are switched to a non-operating state, and the forces E1,
Release the hold on E2. As a result, as shown in FIG. 7, the upper and lower suction blocks 81, 82 are drawn toward the closed space 73 by the pressure difference, and are held by the holding portions 81a, 81.
b move toward each other, and the second substrate 3 is pressed against the first substrate 2. The air cylinder 8
Only one of 6, 90 is deactivated,
Only the holding of one of the forces E1 and E2 may be released. As described above, in the bonding device 36, since the second substrate 3 is bonded to the first substrate 2 on which the film 65 of the adhesive 8 has been formed in advance in the sealed space 73 in a vacuum atmosphere, air bubbles in the adhesive remain. Can be effectively prevented.

In many cases, burrs generated during the molding of the substrate remain in the vicinity of the stamper groove 62. However, since the elastic body 89 is mounted on the holding portion 81a of the upper suction block 81, when the first and second substrates 2 and 3 are joined, as shown in FIG. 8A and FIG. The stamper groove 62 of the first substrate 2 is pressed against the stamper groove 62 of the second substrate 2. Therefore, the first substrate 2 and the second substrate 3
Even when burrs are present in the stamper groove 62, the burrs are pressed against the other substrate and crushed. Therefore, it is possible to prevent the first and second substrates 2 and 3 from warping due to the presence of burrs.

After the joining of the first and second substrates 2 and 3 is completed, the electromagnetic valve 76 is switched to the first position 76A to open the closed space 73 to the atmosphere. Also, the solenoid valve 92 is moved to the first position 9.
Switching to 2A, the suction holding of the first substrate 2 by the upper suction block 81 is released. In this state, the air cylinder 7
The upper container 67 is moved to the raised position by 2 to open the vacuum container 69. Further, the solenoid valve 76 is moved to the first position 76A.
To release the suction holding of the second substrate 3 by the lower suction block 82, and unload the optical disk 1 including the first and second substrates 2 and 3 and the uncured adhesive layer 4 from the bonding device 36.

The optical disk 1 carried out of the bonding device 36 is irradiated with ultraviolet light 101 by the ultraviolet light generator 100 to cure the adhesive between the first and second substrates 2 and 3.
As a result, the first and second substrates 2 and 3 are fixed, and the optical disc 1 is completed. After the first and second substrates 2 and 3 are bonded in a vacuum atmosphere in the bonding device 36 in this manner, the adhesive is cured without rotating them, so that the load acting on the recording layer 7 is reduced. Pinholes can be prevented.

[0059]

As is apparent from the above description, in the method and apparatus of the present invention, the adhesive is diffused by rotating the substrate to form an adhesive film on one surface of one of the substrates. Therefore, compared to the conventional method in which the two substrates are bonded and then rotated to rotate the adhesive, the thinning of the adhesive near the center of the substrate is suppressed, and the thickness of the adhesive is reduced. The distribution can be made uniform. Further, since the portion corresponding to the stamper groove of one substrate is pressed against the other substrate by the elastic body, the burrs are pressed, so that the occurrence of the warpage of the substrate can be prevented. By making these film thickness distributions uniform and suppressing warpage, the tilt angle of the disk surface of the optical disk can be maintained with high accuracy.

Further, before bonding the two substrates, the adhesive is diffused, and after bonding the two substrates, the adhesive is cured without rotating them, so that it acts on the recording layer. The load can be reduced, and peeling of the pinhole due to peeling of the recording layer can be prevented.

Further, since the two substrates are joined in a state of being evacuated, the bubbles in the adhesive can be effectively prevented from remaining.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a method for bonding an optical disk substrate according to an embodiment of the present invention.

FIG. 2 is a schematic view showing an adhesive film forming apparatus.

FIG. 3 is a schematic view showing a joining device.

FIG. 4 is a plan view of a substrate for explaining supply of an adhesive and film formation.

FIGS. 5A, 5B, and 5C are diagrams illustrating an example of rotation speed control in an adhesive film forming apparatus.

FIG. 6 is a partial cross-sectional view of the joining device showing a state where the upper vacuum container and the lower vacuum container are closed.

FIG. 7 is a partial cross-sectional view of the bonding apparatus showing a state where the first and second substrates are bonded.

FIG. 8A is a partially enlarged cross-sectional view of the joining device showing the first and second substrates before joining, and FIG. 8B is a partially enlarged sectional view of the joining device showing the first and second substrates after joining. is there.

FIG. 9 is a perspective view showing a recording / reproducing optical disk.

FIG. 10 is an enlarged sectional view of a portion X in FIG. 9;

FIGS. 11A, 11B, 11C, and 11D are schematic views showing a conventional method of bonding substrates.

FIG. 12 is a cross-sectional view of the optical disc for explaining non-uniformity of the film thickness distribution of the adhesive layer.

[Explanation of symbols]

 Reference Signs List 1 optical disk 2 first substrate 3 second substrate 4 adhesive layer 5 dye film 6 reflective film 7 recording layer 8 adhesive 25 warp 27 pinhole 28 bubble 35 adhesive film forming device 36 bonding device 41 spin plate 42 positioning protrusion 43 suction Hole 44 Air flow path 50 Adhesive supply mechanism 52 Nozzle 54 Gas supply source 58 Food 62 Stamper groove 65 Membrane 67 Upper container 68 Lower container 69 Vacuum container 73 Sealed space 81 Upper suction block 82 Lower suction block 89 Elastic body L axis

. Front page continued (51) Int.Cl ⁷ identification marks FI Theme coat Bu (Reference) B05D 7/24 301 B05D 7/24 301P B29C 65/54 B29C 65/54 // B29K 101: 10 B29K 101: 10 B29L 11 : 00 B29L 11:00 17:00 17:00 F term (reference) 4D075 AC41 AC64 AC92 AC94 BB05Z BB42Z BB46Z BB56Y BB56Z CA12 CA48 DA08 DB48 DC27 EA21 EA35 4F042 AA02 AA10 AB01 BA05 BA25 BA27 DB41 EB08 A03A03A03A03A03A03A TC04 TC09 TD11 TH24 TJ22 TJ29 TN45 TN63 TQ01 TW34 5D121 AA07 EE22 EE23 EE24 FF03 FF04 FF09 FF11 FF18 JJ03 JJ09

Claims (15)

[Claims] 1. A method of bonding at least one of two substrates for an optical disk having a recording layer with an adhesive, wherein one of the two substrates is rotated at a first rotation speed. An adhesive is applied to one surface thereof, and the one substrate is rotated at a second rotation speed that is higher than the first rotation speed to diffuse the adhesive, and the uncured adhesive is bonded to one surface of the one substrate. A method of bonding a substrate for an optical disk, comprising forming a film of an agent, bonding the other substrate to one surface of the one substrate, and curing the adhesive to fix the two substrates. 2. After the application of the adhesive at the first rotation speed is completed, after maintaining the first rotation speed for a predetermined first time, the rotation speed of the one substrate is changed to the second rotation speed. 2. The method according to claim 1, wherein the rotation speed is increased to the rotation speed. 3. After the lapse of the first time, the rotation speed of the one substrate is increased to a third speed that is higher than the first rotation speed and lower than the second rotation speed. Is accelerated, and the third rotation speed is maintained for a predetermined second predetermined time. After the second predetermined time has elapsed, the rotation speed of the one substrate is accelerated to the second rotation speed. The method of claim 2. 4. The first rotation speed is not less than 30 rpm and not more than 6 rpm.
0 rpm or less, and the second rotation speed is 3000 rpm or more and 4000 rpm or less.
m or less, and the third rotation speed is not less than 1000 rpm and not more than 2000 rpm.
4. The method of claim 3, wherein m is less than or equal to m. 5. A method of bonding at least one of two substrates for an optical disk having a recording layer with an adhesive, comprising: forming an uncured adhesive film on one surface of one of the substrates; And bonding the other substrate to one surface of the one substrate and curing the adhesive to fix the two substrates together. 6. The method according to claim 5, wherein, when the other substrate is joined to one surface of the one substrate, a portion corresponding to a stamper groove of the one substrate is pressed against the other substrate by an elastic body. The described method. 7. The elastic body has a Shore hardness of 3 ° or more.
7. The method of claim 6, wherein the angle is 8 degrees. 8. A method in which at least one of two substrates for an optical disk having a recording layer is bonded with an adhesive, wherein one of the two substrates is rotated at a first rotation speed. Applying an adhesive to one surface thereof, rotating the one substrate at a second rotation speed higher than the first rotation speed to diffuse the adhesive, and curing the uncured one surface of the one substrate. Forming a film of an adhesive, bonding the other substrate to one surface of the one substrate in a vacuum atmosphere, and curing the adhesive to fix the two substrates together; . 9. The adhesive is an ultraviolet-ray-curable adhesive. After bonding the other substrate to one surface of the one substrate, the adhesive is cured by irradiating ultraviolet light to form the two substrates. The method according to claim 8, wherein the substrate is fixed. 10. An adhesive film forming apparatus for forming an adhesive film on a substrate for an optical disk, comprising: a holding mechanism for holding the substrate on an upper surface thereof; A rotation drive mechanism for rotating in a horizontal plane; and an adhesive supply mechanism for supplying an adhesive to the substrate held by the holding mechanism, wherein the rotation drive mechanism rotates the holding mechanism at a first rotation speed to form an adhesive. After applying an adhesive to one surface of the substrate by the agent supply mechanism, the holding mechanism is rotated by the rotation drive mechanism at a second rotation speed higher than the first rotation speed to diffuse the adhesive, An adhesive film forming apparatus for forming an uncured adhesive film on one surface of a substrate. 11. After the application of the adhesive at the first rotation speed is completed, the rotation speed of the substrate is maintained at the second rotation speed after maintaining the first rotation speed for a predetermined first time. The device according to claim 10, wherein the device is accelerated to a speed. 12. After a lapse of the first time, the rotation speed of the substrate is accelerated to a third speed that is higher than the first rotation speed and lower than the second rotation speed. 12. The method according to claim 11, wherein the third rotation speed is maintained for a second predetermined time, and the rotation speed of the substrate is accelerated to the second rotation speed after the second predetermined time has elapsed. An apparatus according to claim 1. 13. A joining apparatus for joining two substrates for an optical disk, comprising: a sealable container; a vacuum suction mechanism for evacuating the container; and a vacuum suction mechanism disposed in the container. A holding unit for holding one of the two substrates on which the uncured adhesive film is formed so as to face each other; and an atmospheric pressure operating unit disposed outside the container, A first and a second holding mechanism, in which the two substrates are movable in directions of approaching and separating from each other, and a first and a second holding mechanism for fixing the first and the second holding mechanism to the container, respectively. A second fixing mechanism, and the first container is evacuated by the evacuation mechanism to the first container.
The fixing by the second fixing mechanism is released, and the holding of the first and second holding mechanisms is brought close to each other by the atmospheric pressure acting on the above-mentioned atmospheric pressure action part, and the holding parts of the first and second holding mechanisms are released. A joining device for joining two substrates held in the apparatus. 14. The first and second holding mechanisms,
14. The apparatus according to claim 13, wherein at least one of the substrates includes an elastic body at a portion corresponding to the stamper groove. 15. A laminating apparatus for laminating two substrates for an optical disk at least one of which has a recording layer with an ultraviolet-curable adhesive, a holding mechanism for holding the substrate on the upper surface thereof, and a holding mechanism for holding the substrate. A mechanism for rotating the mechanism, a rotation drive mechanism for rotating the substrate in a horizontal plane, and an adhesive supply mechanism for supplying an adhesive to one surface of the substrate held by the holding mechanism, wherein the rotation drive mechanism controls the holding mechanism. While rotating at the first rotation speed,
After the adhesive is applied to one surface of the substrate by the adhesive supply mechanism, the holding mechanism is rotated at a second rotation speed, which is higher than the first rotation speed, by the rotation drive mechanism to bond the substrate to the one surface of the substrate. An adhesive film forming device for forming a film of the agent, a sealable container, a vacuum suction mechanism for evacuating the inside of the container, and an uncured adhesive film are formed on one of the containers. A holding portion for holding one of the two substrates facing each other, and an atmospheric pressure acting portion disposed outside the container, wherein the two substrates in the container approach each other and A first and a second holding mechanism, each of which is movable in a separating direction, and a first and a second fixing mechanism for respectively fixing the first and the second holding mechanism to the container; After the chamber is evacuated by the evacuation mechanism, The fixing by the first and second fixing mechanisms is released, and the first pressure is released by the atmospheric pressure acting on the atmospheric pressure action section.
And a substrate bonding apparatus for causing the holding of the second holding mechanism to approach each other and bonding the two substrates held by the holding portions of the first and second holding mechanisms with an adhesive. An apparatus for bonding substrates for optical disks, comprising: an ultraviolet light generator for irradiating the combined two substrates with ultraviolet light to cure the adhesive.