JPS61283049A - Production of optical disk - Google Patents

Abstract

PURPOSE:To obtain the title stabilized optical disk having a low noise level and with less ageing deterioration by forming the film of a recording layer contg. a specified element while intermittently irradiating light. CONSTITUTION:A transparent substrate 1 with a transparent insulating layer formed on the surface is rotated by a motor and intermittently irradiated with a flash lamp 7. A recording layer contg. chalcogen through vaporization sources 8 and 9 and by sequential crystallization at every irradiation. The crystal grains are not coarsened by the sequential crystallization resulting from intermittent irradiation and made uniform. Accordingly, a stabilized optical disk having a low noise level and with less ageing deterioration can be obtained.

Description

【発明の詳細な説明】 〔概要〕 光ディスクは記録層へのレーザ光の照射によって反射率
の異なる状態を作り、これを信号のＯＮ。[Detailed Description of the Invention] [Summary] An optical disc creates states with different reflectances by irradiating the recording layer with laser light, and turns on a signal.

ＯＦＪ／に対応させて読出しを行っているが、この場合
に記録層は微結晶が均等に分布しており、反射率の経時
変化が少ないことが必要である。Reading is performed in accordance with OFJ/, but in this case it is necessary that the recording layer has microcrystals evenly distributed and that the change in reflectance over time is small.

本発明は記録層の形成を光照射しながら行うことにより
、粒径が小さく且つ安定な記録層を備えた光ディスクを
得るものである。The present invention provides an optical disc having a stable recording layer with a small particle size by forming the recording layer while irradiating the recording layer with light.

〔産業上の利用分野〕[Industrial application field]

本発明は粒度分布が均等で反射率の経時変化の少ない光
デイスク記録層の製造方法に関する。The present invention relates to a method for producing an optical disk recording layer having a uniform particle size distribution and little change in reflectance over time.

光ディスクはレーザ光を用いて高密度の情報記録を行う
メモリであり、記録容量が大きく、非接触で記録と再生
を行うことができ、また塵埃の影響を受けないなど優れ
た特徴をもっている。An optical disk is a memory that records high-density information using laser light, and has excellent features such as a large recording capacity, non-contact recording and reproduction, and being unaffected by dust.

すなわちレーザ光はレンズによって直径が約１７１１１
１の小さなスポットに絞り込むことが可能であり、従っ
て１ビツトの情報記録に要する面積が約１μｍ２程度で
足りる。In other words, the diameter of the laser beam is approximately 17111 mm due to the lens.
It is possible to narrow down to one small spot, and therefore the area required to record one bit of information only needs to be about 1 μm2.

そのため磁気ディスク或いは磁気テープが１ビツトの情
報記録に数１０〜数１００μｍ２の面積が必要なのと較
べて這かに少なくて済み、従って大容量記録が可能であ
る。Therefore, compared to the magnetic disk or magnetic tape, which requires an area of several tens to several hundreds of micrometers to record one bit of information, the area is much smaller, and therefore, large-capacity recording is possible.

またレンズで絞り込まれたレーザ光の焦点面までの距離
は１〜２ｍｌとれるため、磁気ディスクで問題となるヘ
ッドクラッシュを避けることができ、また光デイスク基
板の上面で光ビームは約１ｆｌ径となるので基板の上面
に大きさが数１０μｍの塵埃が存在していても記録と再
生に殆ど影響を与えずに済ませることができる。In addition, since the distance to the focal plane of the laser beam narrowed down by the lens can be 1 to 2 ml, it is possible to avoid head crashes that can be a problem with magnetic disks, and the light beam has a diameter of approximately 1 fl on the top surface of the optical disk substrate. Therefore, even if dust with a size of several tens of micrometers exists on the upper surface of the substrate, recording and reproduction can be done with almost no effect.

このように優れた特性を備えた光ディスクは記録媒体と
して低融点金属を用い、情報の記録を穴の有無により行
う読出し専用のメモリ以外に結晶−結晶間あるいは結晶
−非晶質（アモルファス）間の反射率の差を利用した書
替え可能なメモリ（Ｅｒａｓａｂｌｅ　Ｍｅｍｏｒｙ）
が開発されている。Optical disks with such excellent characteristics use low-melting point metals as recording media, and in addition to read-only memories that record information with or without holes, optical discs with such excellent characteristics use crystal-to-crystal or crystal-to-amorphous materials. Erasable memory that uses differences in reflectance
is being developed.

かかるメモリにおいて記録層は微結晶体から構成されて
いるが結晶粒度が均等で経時変化の少ない膜質からなっ
ていることが必要である。In such a memory, the recording layer is composed of microcrystalline material, and it is necessary that the recording layer has a uniform crystal grain size and a film quality that does not change over time.

〔従来の技術〕[Conventional technology]

第１図は光ディスクの断面構造を示すもので、ポリメチ
ル・メタクリエイト（略称ＰＭＭＡ）　、ポリカーボネ
ート（略称ｐｃ）　、あるいは硝子などからなるディス
ク状の透明な基板１の上に二酸化硅素（Ｓｉ０２）など
の透明な絶縁層２を介して記録１１３を層形成し、更に
この上にＳｉ０２などの保護膜４を被覆した構成がとら
れている。Figure 1 shows the cross-sectional structure of an optical disc, in which silicon dioxide (Si02) or the like is deposited on a disc-shaped transparent substrate 1 made of polymethyl methacrylate (abbreviated as PMMA), polycarbonate (abbreviated as PC), or glass. The recording layer 113 is layered with a transparent insulating layer 2 interposed therebetween, and a protective film 4 made of Si02 or the like is further coated thereon.

次ぎにかかる二枚の基板は記録層形成部を内側として内
周部と外周部にプラスチックあるいは金属からなるスペ
ーサリングを置き、上下から接着して封着し、光ディス
クが作られている。Next, the two substrates are sealed with plastic or metal spacer rings placed on the inner and outer peripheries of the two substrates, with the recording layer forming portion inside, and are adhered from above and below to form an optical disk.

そして情報の記録と再生はレーザ光を用い、第１図にお
いて下側から基板１を通して記録層３を照射し、記録情
報の有無によって反射率が異なるのを利用して行われて
いる。Information is recorded and reproduced using a laser beam that irradiates the recording layer 3 from below through the substrate 1 in FIG. 1, taking advantage of the fact that the reflectance varies depending on the presence or absence of recorded information.

ここで記録層を形成する記録媒体の必要条件は■低融点
な材料であること、 ■熱伝導率が低いこと、 ■光吸収率が高いこと、 などを挙げることができ、これに適した材料としてセレ
ン（Ｓｅ）　、テルル（Ｔｅ）のようなカルコゲン元素
またはこれと金属との合金が使われている。Here, the necessary conditions for the recording medium that forms the recording layer are: ■ It must be a material with a low melting point, ■ It must have low thermal conductivity, and ■ It must have high light absorption rate. Materials suitable for this can be listed. As such, chalcogen elements such as selenium (Se) and tellurium (Te) or alloys of these elements and metals are used.

例えばＴｅ　Ｓｅ系、　Ｔｅ錫（Ｓｎ）系、鉛（Ｐｂ）
Ｔｅ　Ｓｅ系。For example, Te Se series, Te tin (Sn) series, lead (Pb)
Te Se type.

砒素（Ａｓ）Ｔｅ　　ゲルマニウム（Ｇｅ）系など各種
のものが知られている。Various types such as arsenic (As) Te and germanium (Ge) are known.

ここで先に記したように記録層は物理的に安定な微結晶
で形成されていることが必要であり、記録層は真空蒸着
法やスパッタ法で作られるのが一般的であるが、作られ
たままの記録層は低密度で結晶配列の乱れた不安定な状
態にあるため、何等かの方法により安定した状態に変え
ることが必要である。As mentioned earlier, the recording layer must be formed of physically stable microcrystals, and the recording layer is generally made by vacuum evaporation or sputtering. Since the recording layer as it is is in an unstable state with low density and disordered crystal alignment, it is necessary to change it to a stable state by some method.

その方法として従来は基板上に記録層を成膜後、加熱す
るか或いは光照射を行って結晶状態に変える方法が採ら
れていた。The conventional method for this has been to form a recording layer on a substrate and then heat it or irradiate it with light to change it into a crystalline state.

然し、ＴｅやＳｅは単体では原子が結合して螺旋形の鎖
状構造をとって高分子性結晶を作る性質があり、またＴ
　ｅ　’ｐ　Ｓ　ｅなどのカルコゲン元素を含む合金に
おいても加熱或いは光照射を加えるとカルコゲン原子同
士が結合して高分子化することにより粒子径が増大し、
このためにノイズレベルが増大すると云う問題があった
。However, when used alone, Te and Se have the property of forming polymeric crystals by combining atoms and forming a helical chain structure.
Even in alloys containing chalcogen elements such as e 'p S e, when heated or exposed to light, the chalcogen atoms combine with each other to form a polymer, resulting in an increase in particle size.
Therefore, there was a problem in that the noise level increased.

また光照射を行う場合に光強度が弱いと結晶化が進まず
、一方高過ぎるとカルコゲン元素の昇華が起こって基板
から剥がれると云う問題があり、照射光の強度調節が難
しく、また基板が、　ＰＭＭＡからなる場合は加熱によ
り変形が起こり易いと云う問題があった。In addition, when performing light irradiation, if the light intensity is too low, crystallization will not proceed, while if it is too high, the chalcogen element will sublimate and peel off from the substrate. This makes it difficult to adjust the intensity of the irradiated light, and the substrate When it is made of PMMA, there is a problem in that it is easily deformed by heating.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

以上記したように基板上に形成した記録層は成膜後に結
晶化処理して安定化することが必要であるがノイズレベ
ルの増加を抑え、また収率よく微結晶化させる方法を見
いだすことが問題である。As described above, the recording layer formed on the substrate needs to be stabilized by crystallization treatment after film formation, but it is necessary to find a method to suppress the increase in noise level and to microcrystallize with high yield. That's a problem.

ｃ問題点を解決するための手段〕 上記の問題は透明基板上にカルコゲン元素を含む光ディ
スクの記録層を成膜する際、間欠的に光照射を行いなが
ら膜成長を行うことにより逐次結晶化した記録層を形成
する光ディスクの製造方法により解決することができる
。c) Means for solving the problem] The above problem occurs when the recording layer of an optical disk containing a chalcogen element is formed on a transparent substrate, and the film is grown while being intermittently irradiated with light, resulting in successive crystallization. This problem can be solved by a method of manufacturing an optical disc in which a recording layer is formed.

〔作用〕[Effect]

本発明は記録層の形成時に間欠的に光照射を行い、成膜
されるアモルファス記録媒体を逐次結晶化させることに
よって粒子径の増大を防ぎ、ノイズレベルの増大を抑制
するものである。The present invention prevents an increase in particle size and suppresses an increase in noise level by intermittently irradiating light during the formation of a recording layer and successively crystallizing the amorphous recording medium being formed.

すなわち成膜中に連続的に光照射を行って熱エネルギを
与える場合は結晶成長が起こって粗大化するが、光照射
を間欠的に行うことにより膜形成したアモルファス膜が
微細な結晶となって層形成し、また光照射が間欠的に行
われるために基板および記録層への過度の加熱を防ぐこ
とができる。In other words, if thermal energy is applied by continuous light irradiation during film formation, crystal growth will occur and the film will become coarse, but if light irradiation is performed intermittently, the formed amorphous film will become fine crystals. Since layers are formed and light irradiation is performed intermittently, excessive heating of the substrate and recording layer can be prevented.

〔実施例〕〔Example〕

直径が２０ｃｍのＰＭＭＡ基板１の上に真空蒸着法で約
２００ｎｍの厚さにＳｉ０２の絶縁Ｎ２を形成した後、
かかる試料５を第２図に示す真空蒸着装置に装着し、こ
の絶縁層２の上にＴｅ　Ｓｎよりなる記録層を二元蒸着
法で形成した。After forming an insulating N2 layer of Si02 to a thickness of about 200 nm by vacuum evaporation on a PMMA substrate 1 with a diameter of 20 cm,
The sample 5 was mounted on a vacuum evaporation apparatus shown in FIG. 2, and a recording layer made of TeSn was formed on the insulating layer 2 by a binary evaporation method.

すなわち試料５はモータ６により低速回転でき、また装
置内の側面には４本のキセノン（Ｘｅ）フラッシュラン
プ７が試料５より２０ｃｍ離れて対向して設けられてお
り、また装置基板の上にはステムに保持されて２個の独
立した蒸発源８，９が゛あり、それぞれＴｅとＳｎの粉
末が充填されている。That is, the sample 5 can be rotated at a low speed by a motor 6, and four xenon (Xe) flash lamps 7 are installed on the side of the device facing each other at a distance of 20 cm from the sample 5. There are two independent evaporation sources 8 and 9 held by the stem, each filled with Te and Sn powders.

かかる蒸着装置を用い、ＴｅとＳｎを同時に蒸着してＴ
ｅとＳｎとの組成比が８５　：　１５となるように蒸発
速度を調整し、５００秒かけて厚さが２００ｎｍの記録
層３を形成したが、その間５０秒おきに１１１秒のパル
ス幅でＸｅフラッシュランプを２０回に互って照射した
。Using such a vapor deposition apparatus, Te and Sn are simultaneously vapor deposited to form T.
The evaporation rate was adjusted so that the composition ratio of e and Sn was 85:15, and a recording layer 3 with a thickness of 200 nm was formed over 500 seconds. The flash lamp was irradiated 20 times alternately.

なお光源出力は８５０Ｊである。Note that the light source output is 850J.

このようにして記録層３を形成した後、Ｓｉ０２よりな
る保護膜４を１００　ｎｍの厚さに形成することより光
デイスク用基板を作った。After forming the recording layer 3 in this manner, a protective film 4 made of SiO2 was formed to a thickness of 100 nm, thereby producing an optical disk substrate.

次にかかる基板について本発明の効果を比較するために
先と同様にＳｉＯ２の絶縁層２を設けたＰＭｉ＾よりな
る基板１に先と同じ条件でＴｅ　Ｓｎ層を蒸着し、その
後にＸｅランプを１ｆ１秒のパルス幅で２０回繰り返し
照射して結晶化させた後保護膜４をつけたものと、Ｘｅ
ランプの照射を行わないで保護膜４をつけた光デイスク
用基板を作った。Next, in order to compare the effects of the present invention on such a substrate, a TeSn layer was evaporated under the same conditions as before on a substrate 1 made of PMi^ on which an insulating layer 2 of SiO2 was provided, and then a Xe lamp was applied. The one with the protective film 4 attached after crystallization by repeated irradiation 20 times with a pulse width of 1f1 second, and the one with Xe
An optical disk substrate with a protective film 4 attached was made without lamp irradiation.

後者の記録層はアモルファス状態である。The latter recording layer is in an amorphous state.

さて、蒸着中に間欠的に光照射した記録層３の表面と蒸
着後に光照射した記録層３の表面を保護膜４の側から顕
微鏡で観察したところ前者の表面は滑らかで均一な微粒
子が配列しているのに対し、後者の表面には０．５〜３
μｍの粒子が不均一に存在していた。Now, when the surface of the recording layer 3 that was intermittently irradiated with light during vapor deposition and the surface of the recording layer 3 that was irradiated with light after vapor deposition were observed using a microscope from the protective film 4 side, the surface of the former was smooth and had uniform fine particles arranged in it. 0.5 to 3 on the surface of the latter.
Particles of μm were present non-uniformly.

また両者のノイズレベルをディスク基板の回転数１２０
０ｒｐｍ、読出しパワー１ｍｗ、測定バンド幅３０Ｋ　
Ｈｚの条件で測定したところＩ　ＭＨｚ以下の低周波で
のノイズレベルは前者は後者よりも約６ｄｂ少なかった
。In addition, the noise level of both was determined at the rotation speed of the disk substrate 120.
0rpm, read power 1mw, measurement bandwidth 30K
When measured under Hz conditions, the noise level at low frequencies below I MHz was approximately 6 db lower in the former than in the latter.

次に結晶化による安定化の効果をみるために上記３種類
の光デイスク基板を温度７０℃、湿度８５％の恒温槽に
入れ、反射率の経時変化を波長８３０ｎｍで測定した。Next, in order to examine the stabilizing effect of crystallization, the three types of optical disk substrates mentioned above were placed in a constant temperature bath at a temperature of 70° C. and a humidity of 85%, and the change in reflectance over time was measured at a wavelength of 830 nm.

第３図はこの結果であって本発明に係る蒸着中光照射し
た記録層１０は当初より安定で経時変化は無く、また蒸
着後に照射した記録層１１も暫時経過後に安定化するが
、光照射を行わない記録層１２は長時間に互って不安定
であり、結晶化処理を行わなわなげれば光ディスクとし
て使用できないことを示している。FIG. 3 shows the results, and the recording layer 10 that was irradiated with light during vapor deposition according to the present invention was stable from the beginning and did not change over time, and the recording layer 11 that was irradiated after vapor deposition also stabilized after a while, but when irradiated with light, The recording layer 12 which is not subjected to the crystallization treatment is unstable for a long time, indicating that it cannot be used as an optical disc unless the crystallization treatment is performed.

〔発明の効果〕〔Effect of the invention〕

以上記したように本発明に係る製造方法の実施により、
従来と比べてノイズレベルが低く、また経時変化が少な
く安定し・た光ディスクを製造することができる。As described above, by implementing the manufacturing method according to the present invention,
It is possible to manufacture optical discs that have a lower noise level and less change over time than conventional ones and are stable.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は光ディスクの断面構造図、 第２図は本発明に使用する真空蒸着装置の構成図、 第３図は光デイスク記録層の経時変化の説明図である。 図において、 Figure 1 is a cross-sectional structural diagram of an optical disc. FIG. 2 is a configuration diagram of a vacuum evaporation apparatus used in the present invention, FIG. 3 is an explanatory diagram of changes over time in the optical disc recording layer. In the figure,

Claims (1)

【特許請求の範囲】[Claims] 透明な基板（１）の上にカルコゲン元素を含む光ディス
クの記録層（３）を成膜する際、間欠的に光照射を行い
ながら膜成長を行うことにより、逐次結晶化した記録層
（３）を形成することを特徴とする光ディスクの製造方
法。When forming the recording layer (3) of an optical disk containing a chalcogen element on a transparent substrate (1), the recording layer (3) is successively crystallized by growing the film while intermittently irradiating light. A method of manufacturing an optical disc, the method comprising: forming an optical disc.