JP2002287371A - Optical disk recording apparatus and method - Google Patents

Abstract

(57) [Problem] To provide a pit width correction for each pit length by a beam intensity in a master disk exposure apparatus for an optical disk using an electron beam while keeping a beam current taken out from a source stable. It is an object of the present invention to provide an optical disc master recording apparatus and a method thereof that enable the above. SOLUTION: A source 1 for irradiating the optical disk with an electron beam, deflection electrodes 4a and 4b for deflecting the electron beam irradiated by the source 1 under the control of a voltage controller 12, and deflection by the deflection electrodes 4a and 4b. A shielding plate 8 for partially shielding the electron beam, and adjusting a spot size of the electron beam by changing a shielding amount of the shielding plate 8 by the voltage controller 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk recording apparatus and method for recording information on an optical disk by irradiating the optical disk with an electron beam through an objective lens.
In particular, the present invention relates to an optical disc recording apparatus and a method for adjusting the beam diameter of an electron beam when exposing the optical disc with the electron beam, whereby the spot size of a beam spot irradiated on the optical disc can be adjusted.

[0002]

2. Description of the Related Art A substrate for an optical disk is usually manufactured by injection molding using a stamper having pits which are pre-pits for pre-format signals and pits for transferring guide grooves. As an initial process for forming the pits of the stamper, a master disc exposing operation is performed in which a master disc is exposed with a desired pattern of pits and guide grooves by irradiating a laser beam onto a glass master disc coated with a photoresist. In this master exposure operation, the spot size of the light spot formed on the master should be recorded with a weaker recording light intensity than in the case of short pits when recording long pits, assuming that the pits are largely expanded in advance. The pit width is corrected for each pit length in accordance with the signal to be recorded, and good reproduction characteristics are obtained.

[0003] With the recent increase in the density of optical disks, recording on the master optical disk has been changed from using a conventional laser beam to using an electron beam capable of reducing the beam spot diameter. When recording pits on an optical disk master using this electron beam, the irradiation time is lengthened for long pits and the irradiation time is shortened for short pits, with the beam current of the electron beam being stabilized. The electron beam is irradiated on the master optical disc according to the length of each pit.

However, in this optical disk master recording apparatus using an electron beam, it is essential that the beam current is stable. Therefore, the pit width for each pit length is adjusted by adjusting the light intensity like laser light. Correction could not be performed, and pits corresponding to each pit length were simply recorded on the master optical disc by changing the irradiation time of the electron beam.

[0005]

As described in the prior art, when recording a master using a laser beam, the pit width is corrected for each pit length by adjusting the optical recording intensity to obtain good reproduction characteristics. However, in an optical disk master recording device using an electron beam, it is essential for accurate master recording that the beam current of the electron beam is stable, so optimizing the pit width for each pit length by adjusting the beam intensity is required. It was very difficult.

In particular, in the exposure of a DVD-RAM master, concentric or spiral grooves (recesses) are formed.
A pre-format data (pre-pit) in which header data is recorded, and a data recording surface composed of lands (convex portions) are formed. Since the spot size is different between the groove and the pre-pit, the pre-pit is formed from the groove. Changes the pit size (the spot size for pre-pit formation is smaller than that for grooves)
Must be exposed. Furthermore, DVD-RAM
In the master exposure, grooves and prepits are mainly formed by a constant angular velocity (CAV) method, so that the beam intensity must be changed according to the difference in linear velocity between the inner and outer circumferences.
In other words, in the CAV method, the linear velocity is higher at the outer circumference than at the inner circumference, and the irradiation time of the electron beam within a certain time is shorter at the outer circumference than at the inner circumference. Therefore, it is necessary to increase the beam intensity and widen the spot size. There is.

Therefore, the present invention has been made in view of the above circumstances, and even in an optical disk master recording apparatus using an electron beam, the pit length is adjusted for each pit length by adjusting the beam intensity while keeping the beam current extracted from the source stable. It is an object of the present invention to provide an extremely good optical disk recording apparatus and a method thereof capable of performing pit width correction.

[0008]

An optical disk recording apparatus according to the present invention comprises: an irradiating means for irradiating an optical disk with an electron beam; an electron beam deflecting means for deflecting the electron beam irradiated by the irradiating means; First shielding means for partially shielding the electron beam deflected by the deflecting means, and changing the shielding amount of the first shielding means by the electron beam deflecting means so as to change the spot size of the electron beam. Is adjusted.

According to the above configuration, by changing the voltage applied to the deflecting electrode for each pit length of the signal to be recorded, the amount of shielding of the electron beam by the shielding plate can be changed and the beam spot size can be changed. It is possible to perform pit width correction for each pit length in an extremely stable state without changing the electron beam current from the pit.

An optical disk recording apparatus according to the present invention comprises: an irradiating means for irradiating the optical disk with an electron beam; an electron beam deflecting means for deflecting the electron beam before irradiating the optical disk with the electron beam; A first shielding unit provided between the electron beam deflecting unit and the electron beam deflecting unit, and partially shielding the electron beam deflected by the beam deflecting unit.

According to the above configuration, if the shielding plate for shielding the electron beam is provided between the optical disk and the electron beam deflecting means, even the slightly deflected electron beam can be shielded. The spot size can be finely adjusted for any pit length.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an overall configuration diagram of an optical disc recording / reproducing apparatus showing an embodiment of the present invention. Note that widths A and B in the figure indicate widths orthogonal to the electron beam converging direction, and it is assumed that A <B.

This apparatus comprises a fixed source 1 (electron source) and an extraction electrode 2 for extracting an electron beam from the source 1.
A first lens 3 for condensing the electron beam extracted by the extraction electrode 2; deflection electrodes 4 a and 4 b for deflecting the electron beam condensed by the first lens 3; A second lens 6 for condensing the beam, a blanking plate 5 provided between the deflection electrodes 4a and 4b and the second lens 6, and a blanking plate 5 provided between the blanking plate 5 and the second lens 6 A shielding plate 8, a spindle motor 9 for rotatingly driving the optical disk master 7, a feed control unit 10 for moving the optical disk master 7 from the inner circumferential direction to the outer circumferential direction, and a control table for storing a voltage value corresponding to a signal to be recorded. 14, a voltage controller 12 for applying a voltage to the deflection electrodes 4a and 4b based on the control table 14 to deflect the trajectory of the electron beam, and a control unit 1 for controlling the operation of the entire apparatus. When, and a storage unit 13 for temporarily storing data signals to be recorded.

In such a configuration, the blanking plate 8 is provided close to a position having a width A where the diameter of the electron beam passing through the deflection electrodes 4a and 4b is small to some extent. In the opposite direction,
The width of the diameter of the electron beam passing through the deflection electrodes 4a and 4b is provided near a position having a width B larger than the position where the blanking plate 5 is provided. The shielding plate 8 provided in this manner can reliably block a part of the electron beam even if the deflection amount of the electron beam deflected by the deflection electrodes 4a and 4b is small, and adjusts all spot sizes. can do.

Although the optical disk master recording apparatus of the present invention is configured so that the source 1 is fixed and the optical disk master 7 moves, the present invention can be implemented even when the source 1 moves and the optical disk master 7 is fixed. it can.

The data signal to be recorded is modulated data obtained by modulating actual data. For example, when the data bit synchronization clock is T and the space is S, "1T, 2T, 3T"
.. ”, Pit length (polarity inversion interval),“ 1S, 2S,
3S ... ”means a data signal in which spaces are alternately arranged (hereinafter, referred to as a data recording signal).

FIG. 2 shows the relationship among recording pulses, data recording signals, and recording marks. For example, if the data recording signal is "3
T, 3S, 4T, 3S, 5T, 3S... ”, A recording pulse corresponding to the pit length and space of the data recording signal is generated. Record the recording mark. That is, a recording mark corresponding to the width from the fall to the rise of the recording pulse is recorded.

FIG. 3 shows voltage values corresponding to the pit lengths stored in the control table 14. For example, if the pit length of the data recording signal is "1T", a positive voltage (+ X1 voltage) is applied to the deflection electrode 4a, a negative voltage (-X1 voltage) is applied to the deflection electrode 4b, and the pit length is increased. Is "14T", a positive voltage (+ X14 voltage) is applied to the deflection electrode 4a, and a negative voltage (-X1 voltage) is applied to the deflection electrode 4b.
4 voltage). Therefore, it is set so that a larger voltage is gradually applied to the deflection electrodes 4a and 4b as the pit length of the data recording signal becomes longer.

The space of the data recording signal is "mS
(M ≧ 1) ”, the negative electrode (−Y voltage) is applied to the deflection electrode 4a, and the positive voltage (+ Y voltage) is applied to the deflection electrode 4b. Here, the relationship between the voltage values applied to the deflection electrodes 4a and 4b at the time of each pit length and space is as follows: 0 <X1 ≦ X2 ≦ X3 ≦... X14, 0 <Y (constant).

FIG. 4 shows a state diagram of the electron beam when it is applied to the deflection electrodes 4a and 4b based on the control table 14. FIG. 4 (a) shows an electron beam when the data recording signal has a pit length. It is a state diagram of a beam, and (b) is a state diagram of an electron beam when a data recording signal is a space.

As shown in FIG. 4A, when the data recording signal has a pit length, when a positive or negative X voltage is applied to the deflection electrodes 4a and 4b based on the control table 14, the deflection electrode 4a , 4b are deflected in the direction of the shielding plate 8 and partially shielded by the shielding plate 8, and are irradiated on the optical disk master 7. For example, when the pit length is “3T”, the irradiated electron beam is shielded by the shielding plate 8, so that the electron beam width becomes narrower than usual and the electron beam is irradiated onto the master optical disk 7. FIG. 4
As shown in (b), when the data recording signal is a space, the deflection electrodes 4a, 4a
When a positive and negative Y voltage is applied to b, the deflection electrodes 4a,
The electron beam passing through 4b is deflected in the direction of the blanking plate 5, and is entirely shielded by the blanking plate 5. That is, when the data recording signal is a space, the electron beam is not irradiated on the optical disk master 7.

FIG. 5 is a flowchart for explaining the operation for adjusting the beam spot size of the electron beam applied to the optical disk master 7.

First, when the optical disk master 7 is instructed to start master exposure (step 1), the control unit 11 notifies the application of a voltage to the extraction electrode 2 (step 2). 2 applies a voltage to extract an electron beam from a source 1 which is an electron source (step 3). The extracted electron beam is focused by the first lens 3 so as to be orthogonal at a position connecting the deflection electrodes 4a and 4b.

Further, the control section 11 transmits the data recording signal stored in the storage section 13 to the voltage controller 12 (Step 4). When receiving the transmitted data recording signal (step 5), the voltage controller 12 compares the data recording signal with the control table 14 (step 6), and determines that the data recording signal is “nT (n ≧ 1)”. Alternatively, it is determined whether “mS (m ≧ 1)” (step 7). "N
If "T", n is determined (step 8), and a voltage based on n is applied to the deflection electrodes 4a, 4b (step 9). If it is "mS", m is determined (step 10), and a preset positive / negative Y voltage is applied to the deflection electrodes 4a, 4b (step 11).

When a voltage is applied in step 9, the electron beam is drawn toward the deflection electrode 4a (step 1).
2) Part of the electron beam is shielded by the shield plate 8 (step 13). Due to this shielding, the width B of the electron beam
Becomes narrower, and the optical disk master 7 passes through the second lens 6.
(Step 14). That is, the electron beam is deflected by changing the voltage value to the deflecting electrodes 4a and 4b based on n, and the beam width is changed using the shielding amount by the shielding plate 8 to form the disk master 7.

When a voltage is applied in step 11, the electron beam is sufficiently attracted to the deflecting electrode 4b (step 16) and deflected toward the blanking plate 5 provided behind the deflecting electrodes 4a and 4b. All the electron beams are shielded by the blanking plate 5 (step 1).
7) No pits are formed on the optical disk master 7 without irradiation (step 18). That is, in the case of a space, a preset Y voltage is applied to the deflection electrodes 4a and 4b so that the electron beam is not irradiated on the optical disk master 7.

For example, “3T, 3S, 4T, 3S, 14
When the data recording signal “T, 3S...” Is sent, the voltage controller 12 refers to the control table 14 and determines that the first pit length is “3T”. Then, based on the control table 14, a + X3 voltage is applied to the deflection electrode 4a and a -X3 voltage is applied to the deflection electrode 4b. Thereby, the electron beam is drawn to the deflection electrode 4a side. As shown in FIG. 4A, a part of the attracted electron beam is shielded by a shield plate 8 provided behind the deflection electrodes 4a and 4b, and the width (width B) of the electron beam is reduced. In this state, the optical disk master 7 is irradiated via the second lens 6. Therefore, pits are formed on the optical disk master 7 with a beam spot size corresponding to “3T”.

Next, the voltage controller 12 determines that the space is "3S" and refers to the control table 14. Then, based on the control table 14, the deflection electrode 4a
And a + Y voltage (constant) is applied to the deflection electrode 4b. Thereby, the electron beam is sufficiently attracted to the + Y voltage of the deflection electrode 4b. As shown in FIG. 4B, the attracted electron beam is applied to a blanking plate 5 provided behind deflection electrodes 4a and 4b.
The electron beam is entirely shielded by the blanking plate 5 so that the optical disk master 7 is not irradiated. Therefore, no pits are formed on the optical disk master 7.

Further, the voltage controller 12 determines that the next pit length is "4T", and refers to the control table 14. Then, based on the control table 14, + X4 voltage is applied to the deflection electrode 4a and -X4 voltage is applied to the deflection electrode 4b.
Voltage is applied respectively. Thereby, the electron beam is drawn to the deflection electrode 4a side. According to the relationship of the voltage values in the control table 14, since the X4 voltage value is set higher than the X3 voltage value, the electron beam is drawn to the deflection electrode 4a side more than when the X3 voltage is applied, that is, The deflection amount increases, and a part of the electron beam is shielded by the shield plate 8. Needless to say, the amount of shielding by the shielding plate 8 at this time is greater than that when the X3 voltage is applied because the amount of deflection is larger. Accordingly, the electron beam is irradiated onto the optical disk master 7 via the second lens 6 in a state where the width B of the electron beam is narrower than that at the time of “3T”.

Then, the data recording signal "3"
S, "14T" and "3S" are also processed with reference to the control table 14 in the same manner as described above. In the master recording using an electron beam, long pits need to be irradiated with a narrower electron beam width than shorter pits. This is because if irradiation is always performed with the same electron beam width regardless of the length of each pit, the irradiation time is longer for a longer pit and the entire pit is formed larger. Therefore,
Here, the longer the pit length is, the smaller the electron beam width is adjusted so as to irradiate.

As described above, the voltage controller 12 changes the amount of electron beam deflection by applying a voltage value corresponding to each pit length to the deflecting electrodes 4a and 4b based on the control table 14, and the shield plate is affected by the effect. The shielding amount at 8 is also changed to adjust the beam spot size. Therefore, for example, in the exposure of a DVD-RAM master, even when grooves and pre-pits having different pit sizes are formed, recording can be performed by changing the beam spot size.
Further, even when grooves or prepits are formed by the constant angular velocity (CAV) method, the inner circumference can be irradiated with a smaller beam spot by increasing the amount of beam deflection than the outer circumference.

Next, a series of operations up to the creation of the DVD optical disk substrate will be described. Here, since it is different from the gist of the present invention, it will be briefly described.

A photoresist sensitive to an electron beam is applied to the surface of the optical disk master 7 formed of a glass substrate or the like, and each pit length is recorded on the surface of the disk master 7 according to the method described above. After that, when a developing process (a process of immersing the optical disc master 7 in a developing solution) is performed, the recorded pit portions are melted to form an uneven shape.

Then, a conductive film is coated on the optical disk master 7 on which the irregularities are formed by an electroless plating method. The electroless plating method is, for example, a method in which a Ni (nickel) plate is hit with high-speed particles, and the ejected Ni atoms are stacked on the optical disk master 7 to form a Ni film (Ni plating) on the surface of the master. It is a method of generating.

Then, a stamper is formed by electroforming using the conductive film as an electrode. In the electroforming method, for example, a master having a Ni film is placed in a solution containing Ni ions to apply a voltage to the Ni film. According to this method, Ni ions in the solution are attracted to the Ni film by this voltage, adsorbed and laminated, and a Ni plate is completed on the Ni film, and this plate is used as a stamper.

Using this stamper, a resin molded substrate is formed by an injection molding method. Usually, Ni or the like is used for the material of the stamper, and polycarbonate resin or the like is used for the material of the resin molded substrate. The injection molding method is, for example, a method in which the stamper is mounted in a mold having a space of an optical disk type, and a polycarbonate resin melted by heating is injected (injected). The injected polycarbonate resin is cooled in a state in which the irregular shape is transferred by the stamper, and is taken out after hardening, and this is used as a master disk.

Thereafter, the ROM is formed by a stamper method or the like.
In the case of (Read Only Memory), a reflection film is formed on the unevenness transferred to the master disk, and in the case of RAM (Random Access Memory), a reflection film and a recording film are formed. What is the stamper method?
For example, a material such as Al or SiO ₂ used for a reflective film or a recording film is hit with high-speed particles, and the ejected atoms and molecules are laminated on the disk master to form a reflective film or a recording film layer on the disk master surface. How to Actually, a recording surface protection layer having a thickness of, for example, about 0.1 mm is formed on a sheet such as a transparent resin on the reflective film or the recording film, and is formed on a DVD optical disk substrate. As described above, the shield plate is provided between the blanking plate and the second lens, and a small voltage is applied to the deflection electrode to slightly deflect the electron beam in the shield plate direction. The beam spot width is changed by reflecting only a part of the beam spot, and the spot size can be changed at a high speed for each pit length without changing the beam current drawn from the source.

The shielding plate for adjusting the spot size is installed between the blanking plate and the objective lens to improve the adjustment accuracy, and is installed at a position where the width of the electron beam passing through the deflection electrode is large. Thus, the spot size can be changed with a slight deflection of the electron beam.

It should be noted that the present invention is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the scope of the invention.

[0040]

As described in detail above, according to the present invention,
In an optical disk master exposure system using an electron beam,
It is possible to perform pit width correction according to each polarity inversion interval while keeping the beam current extracted from the source stable, thereby enabling accurate recording on the optical disc master.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an optical disk master recording apparatus showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship among a recording pulse, a data recording signal, and a recording mark.

FIG. 3 is a diagram showing voltage values corresponding to pit lengths stored in a control table 14;

FIG. 4 shows deflection electrodes 4a and 4a based on a control table 14.
It is a figure which shows the state of an electron beam when applying to b.

FIG. 5 is a flowchart shown to explain a series of operations in the embodiment collectively.

[Explanation of symbols]

 Reference Signs List 1 source (electron source) 2 extraction electrode 3 first lens 4a, b deflection electrode 5 blanking plate 6 second lens 7 optical disk master 8 shielding plate 9 spindle motor 10 feed control unit 11 control unit 12 voltage controller 13 storage unit 14 Control table

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/027 H01L 21/30 541E

Claims (7)

[Claims] 1. An irradiating means for irradiating an optical disk with an electron beam, an electron beam deflecting means for deflecting the electron beam irradiated by the irradiating means, and a part of the electron beam deflected by the beam deflecting means. An optical disk recording apparatus, comprising: a first shielding unit for shielding, wherein a spot size of the electron beam is adjusted by changing a shielding amount of the first shielding unit by the electron beam deflecting unit. An irradiating means for irradiating the optical disk with an electron beam; an electron beam deflecting means for deflecting the electron beam before irradiating the optical disk with the electron beam; An optical disk recording apparatus, comprising: a first shielding unit provided between the first and second electron beams and partially shielding the electron beam deflected by the beam deflection unit. 3. The electron beam deflecting means has a control table for storing a voltage value corresponding to a signal for recording a pit pattern of the optical disk, and the electron beam deflecting means is provided based on the voltage value of the control table. 3. The optical disc recording apparatus according to claim 1, wherein the amount of deflection is adjusted. 4. The control table is set with the voltage value for increasing the amount of polarization of the electron beam when a pit pattern recorded on the optical disk is long,
4. The optical disk recording device according to claim 3, wherein the voltage value for reducing the amount of polarization of the electron beam is set when the pit pattern is short. 5. A second shielding means provided between the beam deflecting means and the optical disk, for shielding all the electron beams deflected by the beam deflecting means, wherein the first shielding means 2. The apparatus according to claim 1, wherein said optical disk is provided between said second shielding means and said optical disk.
An optical disk recording device according to claim 2. 6. A step of irradiating an optical disk with an electron beam, a step of deflecting the irradiated electron beam, and a step of adjusting a spot size of the electron beam by partially shielding the deflected electron beam. And an optical disk recording method. 7. A step of irradiating an optical disk with an electron beam, wherein a voltage value corresponding to a signal for recording a pit pattern of the optical disk is stored, and the electron beam is deflected based on the stored voltage value. An optical disc recording method, comprising: adjusting the spot size of the electron beam by partially blocking the deflected electron beam.