JPS62501978A - Thin film storage disk and method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Thin film storage disk and method 1. Hikari sitting and standing The present invention relates to magnetic recording media, and particularly to thin film magnetic recording media with high performance. This relates to a manufacturing method.

2. Main plate raw rice bowl Magnetic material 8 For example, when the magnetic film of a recording disk is placed in a magnetic field H, the magnetic flux M (In the background explanation, the M-H hysteresis shown in FIG. ).

Each point of the M-H hysteresis loop (as shown in Figure 9) has a magnetic flux Determine the positive and negative magnetic field strengths US at which saturation occurs. Now if the magnetic field changes from Hs to 0 , the material possesses a characteristic magnetic flux density M, or remanence, and this Indicates the ability of the material to retain magnetic flux in its absence. In reality, residual magnetism is signal amplitude that can be read from isolated pulses stored in the media. Decide on the width. Therefore.

The greater the residual magnetism, the greater the signal amplitude that can be detected in the readout. Become.

The second important characteristic of recording media is the magnetic field required to reduce the residual magnetic flux to O, That is, it is defined as the magnetic field required to erase the upper bits stored in the media. This is the unique coercive force Hc. According to FIG. 9, Hc was measured at M=O Defined as a magnetic field. The higher the retention power in the media, the higher.

Adjacent stored bits have closer positions without canceling each other out You can know what you can do. Therefore, the retention force in VA air media is large. This means that the information storage density is high.

Other important magnetic properties are the squareness of the loop and the ratio of coercivity to saturation field, In other words, Hc/Hs. As can be seen from Figure 9, H8 is small. To switch or "write" the media as it approaches the HC In practice, this means that the new signal is written on top of the old signal. The ratio of the old signal remaining to the new signal becomes relatively small when means. This ratio is also called override, and the ratio of override is small. This means that the write performance is good. Overall.

High remanence and coercivity, as well as high squareness of the hysteresis loop, make magnetic recording Significant impact on signal strength, storage density and override characteristics of recording media effect.

Techniques known for the production of magnetic recording media with the desired properties discussed above Great efforts are being made in

One method that is gaining increasing attention is the use of ion-implanted target metals. It uses vapor deposition or sputtering onto a substrate. normal sputtering In the system, a pair of disc-like substrates arranged on a pallet are connected to a series of sputters. One piece is moved from the front to the back through the talling station. or multiple underlayers, an outer magnetic thin film and a protective coating are created. . This comprehensive method creates multilayer thin film media efficiently and with high capacity. be able to.

Despite these advantages, the above types of sputtering systems are complete in that the layer that has been layered exhibits significant crystal anisotropy and/or layer thickness variation It was not entirely satisfactory. Both types of surface non-uniformity mentioned above are particularly important for magnetic This results in angular variations in the magnetic signal characteristics in the outer track area of the disk.

As described later, magnetic recording devices made using the above type of sputtering system In disk.

Approximately 25 when measured on an inner-diameter recording track % and measured in outer-diameter recording tracks. A signal amplitude change of up to about 40% is a normal trend in a given case.

In theory, the substrate can be rotated as it passes through each of the sputtering stations. If so, it should be possible to eliminate crystal anisotropy and film thickness variations.

However, existing sputtering systems can be Is it relatively difficult to modify the base so that motion and rotational motion are simultaneously imparted to the base? It will probably be expensive. For the design of sputtering equipment commonly used today. A suitable alternative is to have multiple locations between the target and the area where the deposit is made. By providing a shield or baffle.

By partitioning each sputtering target into many smaller target areas. Dew. These buff fulls are almost direct high from the target to the top of the substrate. This will help prevent angle deposits. lattice with many webs or a large number of buffed forms containing a large number of relatively closely punctured cylinders. That would be appropriate. This solution has a monoisotropic crystal structure and a relatively uniform thickness. It is possible to create a sputtered layer, but the time required to form two layers and the The amount of get material is relatively large. This is because a large portion of the sputtered material This is because it will be a deposit on the wall of Fuful. Similarly, the deposited The maintenance issue of periodically removing material from the buffful cannot be ignored either. That's probably why.

3. Lord's favor The general object of the invention is to provide a highly efficient sputtering system of the type described above. It has high properties in terms of high coercive force and residual magnetism as well as excellent loop squareness. and the peak-to-peak variation of the recording signal amplitude over the entire circumferential recording path is approximately 15% or more. Provides an alternative method for manufacturing thin-film magnetic recording disks or media. There is a particular thing.

Another object of the invention is the deposition of deposited materials as well as sputtered materials. The objective is to provide an extremely efficient method in terms of rate.

A related object of the present invention is to provide a high performance recording medium in an automated and highly reproducible manner. The object of the present invention is to provide a method for manufacturing deer.

In particular, the method of the invention has a coercive force of about 700, a residual of about 3Xl0-'Enυ/d. magnetic and has a loop squareness ratio of at least about 0.85.

and that the peak-to-peak amplitude of the recording signal does not vary by more than approximately 15% over the entire circumferential path. The purpose of the present invention is to manufacture a thin-film magnetic disk characterized by the following. implement the invention During the process, the disk is sputtered to sputter a lower layer of chrome onto the substrate. first target, and about 70-86% cobalt 10-28 on top of the lower layer. Made to sprocket alloys containing % nickel and 2-12% chromium 9 rotations through the sputtering apparatus with a second or downstream target. It is placed on top of the pallet 7) in order to proceed in a straight line.

The pallet is initially placed in the upstream deposit area below the upstream portion of the first target. during which the substrate is substantially (substrate directly below the al target) area and ('b) sides of the target that are approximately symmetrical about the centerline of the passageway of the substrate; The area is shielded to limit deposition of sputtered material. Upstream deposit The deposit of sputtered material in the cut area should be at least approximately isotropic with crystal orientation. It is also advantageous to create an integral crystalline layer with a thickness of about 200 nm. The target is then , move to the downstream deposit (under the downstream part of the first target) 6i area, In this case, sputtering is performed so that the crystal isotropy of the coalesced crystal layer is almost maintained and Provided that the final chrome underlayer has a thickness between approximately 1000 and 4000 mm. It is done as.

At this time, the substrate is in the SN area (film debossio under the second target) sputtering, which moves through it and there retains approximately the isotropy of the underlying crystal. The alloy is sputtered onto the isotropic underlayer at a tilt angle. The second target and the base Move the shield between the substrates outward from the centerline of the substrate's movement toward the opposite area of the substrate. The substrate is shielded from the second target in a manner that gradually decreases as the number of targets increases. with its final selected film thickness between 300 and 1000 It is possible to create a nearly uniform alloy film.

In a preferred embodiment of the invention, the substrate is configured to target deposits onto the substrate. Buffs with front and back shields that primarily confine the area of the substrate directly beneath the (a) almost symmetrical unhindered side-to-side sputtering on either side of the substrate with those in the front deposit area to allow for rings. and (b) shielded from the first target, usually from the front to the back. covered. Similar types of panfurs and those with front and back shields A pair of front-to-back strips extending between the substrate and the second target Preferably, it is used for shielding. Deposit in membrane deposit area The shield has a uniform thickness.

Its side edges move inward as it moves away from the front or back panful shield. Preferably, the protrusion has a tapered side end.

The above and other objects of the invention will be apparent from the following detailed description of the invention together with the accompanying drawings. By reading it becomes more fully clear.

Brief description of the drawing Figure 1 shows the amount of spatter in a system using two baffles with a structure based on the present invention. FIG. 2 is a front view of the processing station; FIG. 2 is a front view of the FIG. Figure 2 shows a side view of the sputtering station.

FIG. 3 is a plan view of a baffle according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of the panful taken generally along line 4--4 of FIG.

FIG. 5 is a plan view of a buff full according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view taken generally along line 6--6 of FIG.

FIG. 7 is a cross-sectional view of the surface portion of a magnetic recording medium formed according to the present invention. Ru.

Figure 8A shows the inner diameter (solid line) of the magnetic recording media manufactured based on the present invention. and outer diameter (dashed line) as a function of the angular position of the disc in the recording trunk. 3 shows the change in peak-to-peak amplitude of the recorded signal.

FIG. 8B shows recording signals on a disk formed by the conventional sputtering method. Figure 8A is a diagram similar to Figure 8A showing changes in signal amplitude;

FIG. 9 shows the M-H hysteresis of an example of a disk manufactured based on the present invention. It shows the

Figure 10 shows the amplitude as a function of recording density measured for one example of a disk. It is a graph of resolution characteristics.

Kinkai Omega Detailed Report Hoshi Eri Figures 1 and 2 are multi-station sputtering equipment or systems, respectively. Simplified front view of sputtering station 14 in system 16 and A side view is shown. This system has at least two sputtering stations. We are prepared. The station has the lower layer shown in FIGS. 1 and 2 on top of the substrate. a first station 17 where a magnetic thin film is deposited onto the substrate; It has a second station, which is not shown in the figure being printed. basic speed The puttering system (not including the improved pummel described below) Circuits Processing A pparatus) (Fremont, California).

ULVAK' (Japan), Leyba Leyba ldHeraeus) (Germany), VACTEK (Boulder) -.

Colorado), or Materials Research Corporation (Materials Research Corporation) s Re5search Corporation) (Albany, New York Commercially available systems, such as those manufactured by Mark et al., are suitable.

These systems have two inputs for loading and unloading. Double-sided with turlocking chamber.

It is an in-line, highly efficient device.

A typical sputtering station 17 includes an upper tap having a target surface 22. -get 20. and its target surface 26 faces surface 22 as shown. A lower target 24 is provided. Each target is rectangular and its size is A pair of substrates, such as substrates 28 and 30, passing through a puttering station are - It is made to do so. That is, the substrate is sputtered as shown in the figure. When placed in the center of the section, the 2° substrate will be completely above the two targets. or located below.

The sputtering system described here can be applied to one or more 5-z inch diameter substrates. It is designed to be used to build thin layers of. This sputtering system In this system, the target dimensions are approximately 16.5 inches by finches.

The target is created by bonding a film of metal material to the buffing of the target. Sputtering pure metal or metal alloy material, preferably pure ROM It is like that. The rate or percentage of deposits is controlled by traditional methods. , passing through the station at a given speed to change the thickness of the layer formed on the substrate. It can be adjusted to suit your needs.

The substrates such as substrates 28 and 30 are assembled into pallets with their sides together as shown in Figure 1. is supported on the cut 32. It is placed in each base body such as the base body 28 and placed on a pallet. and transported by land. The aperture allows for a slide from the target 24 onto the bottom surfaces of the two substrates. Deposit of puttered material is allowed.

A pallet 32 is provided within the sputtering system and includes one or more pallets in the system. A pair of trunks 36. extend through the stations. '3B top from front to back can pass through the sputtering station in the direction. The two trunks is placed on the substrate via a pallet preferably constructed of conductive material. Even if it is electrically isolated so that the desired voltage potential can be applied. good. The pallet has a top surface and a bottom surface with targets on the top and bottom respectively. Detach the sputtering stay thin film so that it is approximately the same distance from the sputtering surface. The positives can be symmetrical about the two surface planes of each substrate.

Front to back direction through one or more sputtering stations of the system Bare 7) 32 (and a pallet with a series of substrates on it) is shown (from left to right in Figure 2). A conventional chain drive can be used for movement. Here we move The chain drive, also referred to as means, is shown in Figure 2, which shows the direction of movement of the pallet. Indicated by arrow 40. The palette is.

It is typically moved at a speed of about 5 to 100 cm/min.

Also, the same panfur 42° 44 shown in FIGS. Therefore, the target material is configured to be deposited approximately symmetrically on the substrate. It is. The two baffles are connected to a commercially available sputtering system of the type considered. It replaces the usual rectangular metal frame found in systems.

It is bolted onto the target in the same way as a traditional frame.

A typical baffle 42 will be described with particular reference to FIGS. 1 and 4. buff The call has a generally rectangular frame 46, and this is shown in FIG. It has a notched corner such as a corner 47. The frame is The target is approximately the same rectangle as the target indicated by the dashed line 20 in Figure 3. It has the dimensions of a shape. The above plane where the target is approximately 16.5 inches wide In systems with dimensions, bufffuls are identified by a signed arrow. It has the following approximate dimensions: a = 2.1 mini 2.1 inches 12.5 inches .

C=0.9 inch, and d=5.25 inch. Targets with the dimensions listed and buffful sputtering onto 5-z inch or smaller diameter substrates. It is designed so that it can be used to Target and buffful dimensions are: increased in a nearly proportional manner for sputtering onto even larger substrates. It can be tightened.

Buffful frame has front and back shields or frame members 48.50 and each has a flange such as the notch 47 shown in FIG. It has an outer notch or stepped area that forms a hollow notch. front and back The frame members are connected at their side edges to a pair of side frame members 52.5. 4 to be welded to a rigid frame structure. Examples The width of the frame is approximately 2.2 inches. Actually place Panfur on the target The spacing between the substrate and the lower edge of the baffle in this case is approximately 0.5 inch.

The baffle extends between and is welded to the front and back frame members (Figure 3). It has three strips 56, 58, 60 attached to it. center square The trip is placed midway between the sides of the panful so that the buffful is targeted. When placed on the target, it extends along the center line from the front to the back of the associated target. Ru. Each of the other two strips is connected to its associated substrate with respect to the central strip. Located an equal distance from the center line of the path. That is, strip 56 and and 58.

Equal to the center line of the path of the base body 28 indicated by the dashed line 28a in FIG. Keep a safe distance. That is, strips 58, 60 are indicated by dashed lines 30a. maintain an equal distance from the center line of the path of the substrate 30. Next to frame member 48.50 The strips 56, 58 together with the contact portions form a substantially rectangular window 61 in which the base When the body is centered with respect to the buff full as shown, the entire substrate (dashed line 2 8) can be seen. Similarly.

Strips 58, 60, along with adjacent portions of frame members 48 and 50, are generally rectangular. forming a window 63 through which the sides indicated by dashed lines 30 adjoin the entire area of the substrate. can be seen.

The width of the strip is measured in the side to side direction (Figures 1 and 2) as detailed below. The desired amount of sputtered target material can be shielded in the right/left direction in Figure 3). chosen as such. In general, crystalline isotropy is required in sputtered layers. If the degree of The width of the strips is large for symmetry and to increase the shielding of low angle materials. You will be selected carefully. In this case, a particular panful with a frame width of approximately 2.2 inches , the thickness of the strip indicated by arrow f in FIG. 4 is about 0.5 to 1.5 inches. between the two. The strips should be approximately at the top and bottom edges of the frame as shown. Centrally located.

According to Figure 3, Buffful has shield plates 62 and 64 on the front and back. and each fused to the lower edge area of member 48,50. It is attached by connecting.

Each plate has a projection 66 on plate 62 and a plate 64 as shown. Forming a pair of trapezoidal protrusions with their sides lined up, such as the opposing protrusions 68 in ing. On the protrusion of the plate.

The corresponding buff full window tapers radially outward from the central region. the target and base as they move in opposite directions radially outward of the base. The distance from the body and the degree of shielding are gradually reduced. According to arrows f, g and h The dimensions of the protrusions shown are 2.5°, 1.25° and 0. ．． It is 75 inches.

At the end of the explanation of Buffful 42, the left and right terminal parts where the width of Buffful has been narrowed are covered at their lower edges by end plates 72, 74, respectively. That is what we are doing. These plates are attached to the adjacent lower edges of the buffful. Attached by welding. In this embodiment, as shown in the figure.

The plate is preferably notched to a depth of 0.25 inches. Each program The hole in the center of the rate is used to secure the buffful to the target. 4 frames frame member, strip 56, 58.60. 2 shield plates and The buff full 42 including the ground plates 72 and 74 preferably has a thickness of approximately 0.05 to 0.05 mm. Preferably, it is formed from a metal plate such as 0.1 inch stainless steel.

Figures 5 and 6 illustrate other types of brochures useful in carrying out the method of the invention. 1 shows a plan view and a side sectional view of the Frame 82 that Buffful has is Bufffu The frame 46 of the frame 42 is substantially the same as the frame 46 of the frame 42. Frame front and back frame Members 84 and 86 form front and rear shields, respectively, which are connected to the tartar as shown. Limits the deposition of sputtered target material onto the substrate area directly beneath the target. role. At the terminal part where the width of the pamphlet is narrowed, there is a buffful 42. An end play (similar to the plates 72, 74) 85, 87 is provided and associated. It is attached to the lower edge of the frame by welding.

As shown in Figure 5, Buffful consists of four curved parts arranged in a frame. It has members 88,90,92,94.

Each member is attached by welding to the corresponding inner surface of the front or rear frame member. ing. In addition, the opposing curved members are those in the center of the front and back frame members. They are attached to each other by welding at the connection points. In the case of frame 46 mentioned above In a frame having the same dimensions as It has a main diameter of curvature of approximately 2.9 inches. A semicircle formed by each member The center of the shape is indicated by a cross, such as 96 in strip 88. Fifth In the diagram.

A pair of bases 2 whose center is located directly below the target to which the panful is attached. The outline of 8.30 is shown in dashed lines. In addition, sputtering station of two substrates passing through a section.

The center lines of the route are indicated by dashed-dotted lines 28a and 30b, respectively. Each line as shown The paths intersect the centers of opposing curved members in the corresponding panful regions. Shown in Figure 6 The upper end of the loop member is flush with the top edge of the frame, as shown in extending downwardly from the top of the frame the distance indicated by arrow j. Element The width J is approximately 1.5 inches for a panful whose frame width is approximately 2.2 inches. It is Chi.

Each curved member, such as member 88, extends from strips 88a and 8 of strip 88. 8b, it can be thought of as composing a pair of quadrant buff full strips. Wear. As can be seen when referring to FIG. The strips are placed on opposite sides of the substrate with one below the front part of the target. Located symmetrically. The strips are used for depositing layers on each substrate, as described below. Enables nearly symmetrical sputtering from the target side during the initial stage It is like that.

(Margin below) Bufffuls are welded to the lower edges of the front and back members of the frame. It has a pair of shield plates (94.96) attached to it. Each plate is 1 As shown in the figure, the protrusion has approximately the same dimensions as the above-mentioned protrusion on the buff full 42. A trapezoidal protrusion is formed by joining a pair of side edges together. Fifth As shown in the figure, the exposed portion of each curved member, i.e. the associated trapezoidal The portion extending beyond the protrusion forms a roughly semicircular window through which the union Approximately half of the substrate when located in either the front or rear area of the target can be seen. The semicircular window formed by member 88 is designated 9 in FIG. 8. A baffle having the specified dimensions described above is approximately 5.25 inches in diameter. It can be used for sputtering onto a pair of substrates of less than 1.5 inches in size.

For substrates larger than 5.25 inches, target and panful The dimensions of can be scaled almost proportionally as in the case of Buffful 42. Ru.

The method of the present invention for manufacturing high performance magnetic recording media will now be described. It takes A portion of the surface area of media or disk 104 is shown in cross section in FIG.

The disk generally includes a substrate 106. Also, a form in which a thin film layer is continuously formed on the substrate. Chromium lower layer 108. Thin film 110. and a protective coating 112. ing. FIG. 7 shows only one of the two recording surfaces of the disk 104. The magnetic recording surface on the "side" has almost the same structure as the recording surface on the upper side. sputtering The process describes only the phenomena that occur on the upper substrate surface, but It is understood that substantially the same deposits are made at the same time.

In particular, what is said about the substrate located "underneath" the target is This refers to the sputtering performed on the side substrate surface, and the sputtering performed on the bottom substrate surface. is understood to be simultaneously located above its target.

The disk is heated through an initial heating station where the substrate is heated, and an underlayer, magnetic thin film and and an outer coating are successively formed on the substrate. The present invention can be achieved by a sputtering system having four stations. Preferably, it is manufactured according to the following. The substrate that forms the disk is the recording surface. Digital for read/write records by flying hends moving in close proximity to Traditional hard aluminum of the type commonly used in recording discs An alloy substrate is used. Hard aluminum coated with suitable surface alloy Polydisk, Inc. ) (Mouth San Diego, California) and Knudsen Systems Parakeet -poration (Knudsen Systems, Inc.) (Chino, Calif. It can be obtained from (Fornia).

As mentioned above, put it into the system with the sides lined up on the buff full for the two bases. The heated substrate is first sent to a heating station where it is heated to the desired surface temperature. . Typically a 2.5 KW heat source (on each side of the panful) is used.

The heated substrate is then transferred to a first sputtering station where an underlayer of chromium is formed. sent to the The target in the sputtering station is approximately 0. Click with a preferred target power between 8-4KW. It is equipped so that it can be sputtered with ROM. According to Figures 2 and 3. , as the substrate approaches the front of the sputtering station (see Figure 2). (from the right), the front frame member or shield 48 of the buffful 42 is It acts to limit the amount of deposit on the substrate area directly under the deposit. Sunawa Low angle beams from the target to the approaching substrate area outside the target area. Posites are effectively shielded. This allows the substrate to be free of deposits from directly above. Avoid receiving asymmetric low-angle deposits in the back-to-front direction. is guaranteed.

The central strip 58 is also present during the early stages of crystal growth on the substrate.

Each substrate from the material that will be sputtered at a low angle from the opposite side of the target It plays the role of shielding. On each side of the target, such as the 31st left target side. is the central strip across the centerline of the path of the substrate moving under that side of the get. located symmetrically on opposite sides. Each side strip, such as strip 56, , low angle deposits from associated terminal areas with narrowed target width. , so that the sputtering from the side to the substrate becomes almost symmetrical with respect to the path of the substrate. (It works. Also, as you can see from Figure 9 and the explanation, two The lip is virtually unobstructed from the target area directly above the substrate to the substrate. A deposit can be given. That is, the two strips are placed on the substrate. Not limited by deposits directly from the target.

The first layer formation described above is accompanied by the formation of independent crystal nuclei, “island f. growth of independent crystals called J, and formation of continuous crystal layers Contains the final bond of the crystal. The thickness of the bonded bond layer is typically about 200 1 Under normal sputtering conditions, the movement of the substrate through the sputtering station is It is formed in the first 10-25% of the moving distance. The first stage of the crystal layer formation described above This area where the deposit takes place is referred to herein as the front or upstream deposit area. It is located below the upstream part of the target.

Because of the deposit angle, the need to limit symmetry and low angle deposits is largest in the front deposit area, baffle strips and especially in the center Baffle strip removes almost all deposits from the opposite side of the target to the substrate It is desirable to have sufficient width to prevent For baffles with the above dimensions In this case, strips 56, 58 and 60 are preferably approximately 1.5 inches wide. Delicious.

Once a bonded crystalline layer is formed on the substrate, sputtering with poor symmetry will result. Thus, continuous deposits are created in the front deposit area. This can be done without significantly disturbing the orientation of the crystal. The base is that of the deposit that occurs when passing through the panful or downstream deposit area; In the later and final stages, the baffle is placed in the front sputtering area. limit sputtering to an angle that is not substantially smaller than the angle that occurs on the substrate when He works as a master. In Puffful 40, this function is mainly used in the central stream. strip 58, and this strip is Limit low-angle deposits of symmetry. Similarly asymmetrical low angle deposits The target is limited by the backshield 50, which spacing above the target area that is not directly below the target as it exits the target area. It works to prevent stumbling. of the substrate passing through the first sputtering section. The speed and rate of sputtering from the target is such that the final underlayer thickness of chromium is approximately 1 Between ,000 and 4,000 people, preferably between 1,000 and 2,000 people It is controlled so that it is between. Spatter enabled by baffle The angle is the uniformity of the crystals in the bonded crystal layer (formed in the upstream deposit region). It is assumed that the orientation can be almost maintained.

Due to the action of the buffful 80, bufffuls of completely different shapes are produced according to the method of the present invention. shows how this works in creating a nearly iso-directionally sputtered underlayer. First of all The initial stages of bilayer formation (up to the crystal bonding stage) occur within each front curved member. It is recognized that this occurs. As the substrate advances to the sputtering station, the panfur The front shield 84 of It acts to limit.

At the same time, the front/back deposits in each front curved member are determined by the radius of the curved member. is limited to a relatively narrow range of angles allowed. Strip 88 within member 88 The two strips that make up each curved member, such as A and 88B, are Due to the narrow distance between the strips, the lateral direction allowed in the panful 42 is to limit lateral deposits to symmetrical angles that are generally larger than the deposit angle of It acts on

As the substrate moves out of the semicircular area defined by the curved member 88, its second The two inner quadrants are the rearward extensions of the puffful strips 88a, 88b within the member 88. The deposit angle is limited to the side-to-side direction by the curved member 90 forming the Ru゛. In other words, the three members 88 and 90 are the front and back shields in the buff full. forming a pair of strips extending generally from the front to the back therebetween. Also, the base Rear shield 86 limits asymmetric low angle deposits on the body. This is because sputtering onto target areas that are not directly below the backside area of the target Works to prevent rings.

Following the formation of the isotropic crystalline sublayer, the substrate is transferred to a second sputtering station. It moves past where a thin magnetic film is deposited onto the substrate. Book According to certain aspects of the invention, the significant coercivity, remanence and squareness of the loops Contains metal, nickel and chromium, the weight ratio of which is about 70-88% cobalt; 10-28% nickel and about 2-10% chromium, preferably about 2-10% cobalt. 74-78%, 15-25% nickel and 5-10% chromium in the thin film. It can be realized by

During movement of the substrate through the second sputtering station.

The alloy material is sputtered with a deposition angle that approximately maintains the isotropic crystalline properties of the underlying layer. be recorded. This lowers the substrate as in the first sputtering station. Asymmetrical debossiso of the angles [・Performed by shielding from the corners. shielding The function is by a panfle with general characteristics of panfle 42 or 80, i.e. Front and back seals to limit deposits to areas located approximately below the target one side of the target to the substrate area that is under the other side of the target. Extending between the front and back shields to limit small angle asymmetrical deposits This can be accomplished by one or more strips. As mentioned above, the lower layer Once the first bonded part is formed, asymmetric and/or low angle deposits Soto becomes less important in achieving isotropy of the crystal, and the control of the deposit angle The restrictions will be significantly relaxed. Therefore, for example, the center strip in panfuru 42 from the opposite side of the target with the same degree as required during the formation of the first underlayer. sputtering is not required to be shielded.

According to another aspect of the invention, the substrate, as it passes through the SR region (membrane debosis), The target and base move outward from the substrate's path toward opposite areas of the substrate. The substrate is similarly shielded with progressively less shielding from the body. This kind of blockage deposited within the centerline area of the substrate along the path of the substrate. It is intended to prevent the concentration of materials that For example, in Figure 3 In this way, strip 58 and associated side strips 56,60 effectively Divide the target into two rectangular windows, each facing the front by the path of the underlying substrate. It can be seen that it is divided into two parts in the back direction. Without any additional shielding, the device The maximum amount of posits occurs along this path, and as it moves toward the opposite side of the substrate. It is likely that this will gradually decrease. Similarly, from Figure 6 we can see that if there is no compensatory shielding, , it is possible to know how large a portion of the deposit collects along the path of each substrate. can. As expected in these two figures, each panfur 42 or 8 0 shielding projections reduce deposits along the central strip containing the path of the substrate This function allows for progressively increasing occlusion as you move away from the central strip. functions to enable

rate or speed of sputtering at the second target and through the target; The speed at which the substrate is transported is such that the final film thickness is approximately 300 to 1,000, preferably The total number of people is between about 400 and 600.

As a final step in disc manufacturing, the substrate is further processed to form a hard protective coating over the thin film. can form a ring. Coating is done at the third sputtering station easily formed by sputtering a layer of carbon onto a substrate at a .

Let us now consider the operational characteristics of magnetic media manufactured in accordance with the present invention. 9th The figure shows approximately 1,500 chromium oriented layers and 75% cobalt 18 0611-1- with approximately 570 membranes containing % nickel and 7% chromium Figure 2 shows an M-8 curve for an example of a disc named IRFB. magnetic field strength H is indicated in Oersteds. ) lc and l (s directly from the plot of (The markings on each H axis in Figure 4 represent 2 x 102 oersteds. ing). The remanence value is expressed in the form M'・t and can be determined from the M-H plot. Ta. M, (The markings on each M axis in Figure 4 represent 4Xl0-” EMU. ) divided by the test area of the media expressed in crA. Ta.

Similar hysteresis loop measurements were made for two other discs.

Also conducted for 0613-1-IRCIA and 0613-2-1-LCIA. Ta. These disks differ from the above-mentioned LRFB disks in terms of magnetic film thickness 1). As shown in Table 1 below (there are only differences).

The measured values of residual magnetism (t・t), coercive force (Hc), and saturation magnetic field (Hs) are An example of a disc is shown in Table 1. As you can see from the table, there are 6 discs, all of the 3 discs. The residual magnetism value is 3 x 10-'EMU/cfA or more and the 800-hour stainless steel Indicates a coercive force value greater than or equal to . As expected, the thinner the magnetic film is, the larger the coercive force value is. The residual magnetic value becomes smaller.

The Hc/Hs ratio is calculated for each disk from the corresponding llc and Hs values in the table. It was. The ratios shown in Table 1 are approximately 0.9 or greater for each disk. It shows the factor.

The data in the last column of Table 1 is the value of the calculated PI, / l(c).

In other words, it is a demagnetization parameter that indicates a measure of the recording density of the media. The value is Calculated from the corresponding M, t and HcO values shown in Table 1 for the

The small values found for thin magnetic films indicate high information storage density. signal A more direct measure of information bit density based on amplitude and resolution characteristics is given below. will be considered.

IRFB 570 6.2xlQ-38008400,95787IRCIA 480 5.3X10-3946 1050 0.9 559LLCIA 36 03.9xlO-396610700,9406 Figure 10 shows the characteristics shown above. Recording frequency or density for example 0613-1-IRCIA disks Figure 3 shows a plot of signal resolution and signal amplitude as a function of degree. amplitude and resolution Measurements were made by Magnebit Corporation. on) (San Diego, California). through the tank, 35 microinch gap and 0.002 inch track. The experiments were carried out using a 3350 manganese/sub8 thin film flying hesode. Hehe With a write current of 45□A (peak-to-peak), the used at intervals of The disc was rotated at 3.600 rpm and the measurements were taken at 1.3 inches. It was carried out in a radius of 1.5 inches.

The signal amplitude is shown to the left of the graph, as shown by the curve above the graph. It was determined from the peak-to-peak amplitude measured in millivolts. recorded on disc The amplitude of the isolated pulse (1,P,) measured from a single pulse is shown. So, slightly more than 3 millivolts. 10 kmph 7s change/inch ( The signal amplitude at a recording frequency (density) of kfc/in is approximately 2.9 millivolts. As shown, this value decreased with increasing frequency. Amplitude is approximately 1.5mV The recording frequency decreased by 50% from its separated pulse amplitude is indicated by D50 in Figure 1O. It has been done.

Under the above recording conditions, it is approximately 25.5 kfc/in. This value indicates that the disk is Have 25.5 kilobits of information per inch at 50% of the signal level Show that you can.

The lower curve in Figure 10 represents the signal resolution of the disk as a function of recording frequency. Ru. Experimentally, the first signal is written at the recording frequency and the recording signal amplitude is It is determined. The disc is then fed a second signal recorded at twice the frequency of the first signal. is rewritten and the recording amplitude is measured again. the first signal amplitude of the second signal amplitude The ratio to determines the resolution of the disk.

The value is expressed in this case as a percentage. As you can see from the figure, 1 resolution is From about 96% at a recording frequency of 10 kfc/in to about 53 at 25.5 kfc/in %. Recording frequency called DR70.

In this case, approximately 22.2 kfc/in is the recording frequency at which 70% resolution is achieved. Ru. This value, expressed in kilobyfts per inch, is another measure of the disk's information storage density. provides two scales.

To measure the writing ability of the disk, the first signal was selected under the conditions described above. The second signal is written at a frequency 1, for example 1,000 kfc/in, and the second signal Written directly on it with higher frequency without erasing the signal. Remains of the first signal The residual value is then determined. The ratio of this residual value to the original signal amplitude (at the first frequency) is a measure of the residual signal remaining after being overridden to disk. calculated The values are shown in dB in Table 1 below. -36dB override value It shows good writing ability of the disk.

Table 1 below shows the separation pulse amplitude of the IRCIA disk measured above. (l!!(1,P,), Ds. and DR’IO recording frequency, D87° amplitude and and override) (OW) values. with the same head and almost the same recording conditions. Similar measurements for two other examples of discs performed below are shown in Table ■. Ru. By comparing the data in Table ■ with that in Table 1, the one-minute pulse amplitude (residual There is generally an inverse relationship between the coercive force (related to magnetism) and the coercive force in thin films. The higher the holding force is, the lower the separation pulse amplitude value tends to be. all At 50% separation pulse amplitude the disc had approximately Information recording density of over 21,000 bits/inch and resolution of 70% It has an information storage density of approximately 19,000 bits/inch or more. obtained Override value is -36dB or lessTable ■ IRFB 4.25 21.8 19.4 3.02 36IRCIA 3.0 8 25.5 22.2 2.1 38ILCIA 3.42 26.2 22 ．． 9 2.35 36 Similar data using the same three types of discs as an example is 8.7 μH inductance, 35 microinch gap and 0.002 inch Using a 3550 magnesium/zinc thin film flying head with a track width of Created by The head has a peak-to-peak write current of either 60 or 70mA. A spacing from the disk of 15.5 microinches was used. disc times The rotation and radius were the same as in the measurements in Table 2. The data is in the following table. is shown.

Table ■ Disk IP 050 DR70Amp/DR7a OW (mv) (kfc /in) (kfc/in) (mv) (-dB) IRFB 1.94 15 ．． 7 13.3 1.29 32IRCIA 1.42 18.1 15.3 0.94 34LLCIA 1.226 20.5 16.3 0.85 to 3 These data indicate that under the recording conditions used, the example disc has a Indicated to have a recording density of between 20,000 bits/inch (D, in odor). are doing. Similar high performance characteristics.

12μH inductance, 35μinch gap and 0.000F Three cases were tested using a magnesium/zinc mini monohead with a trunk width of 1 inch. Measured on the disc.

In this case, the head has a 40 or 45 mA peak-to-peak current and a 15 micro-inch used at intervals of

As can be seen from the above, the disk of the present invention has both high coercive force and high residual magnetism. , with excellent signal and information recording characteristics. According to one aspect of the invention, the data The coercive force of the disk depends on the selection of the alloy composition used to form the magnetic film, as described below. By doing so, it can be greatly enhanced. Determine the influence of alloy composition on disk coercive force. Cobalt/chromium (88/12% by weight), cobalt/nickel (88/12% by weight) 0/20% by weight) or cobalt/nickel/chromium (75/18/7% by weight) A disk having a magnetic thin film having a composition of is prepared substantially according to the manufacturing method described above. Ta. Briefly, each disc contains approximately 1,500 people with chrome orientation. sputtered layers to a thickness of about 400-500 mm A recording film was formed. t・t and specific holding force values for each disc was determined from the 11-H hysteresis loop curve as detailed above. death ・The value is approximately 4.0 for all three alloys. It was OXIXlo-3E/cnt . The measured coercive force values were: Cobalt/Chromium, 500 Oerste Cobalt/Nickel.

650 oersted; Oyohikobalt/Nickel/Chromium, 950 oersted . As will be seen, one of the alloy compositions used to form the disk of the present invention is Therefore, the coercive force is determined by the binary cobalt/chromium commonly used in known technology. This is almost twice as much as what can be obtained.

in the peak-to-peak recording signal amplitude indicating the uniformity of the thin film and the isotropy of the crystal of the disk. Changes in the angle of rotation were also investigated. Measured by media test specialist Certifa Ia (Media Te5t Specialists Certifier) This was done by using conventional methods. Rotate the disc at 3600 rpm measurements are 1.2 inches inside trunk radius and 2.4 inches outside trunk radius. Performed at rack radius.

The inner trunk peak-to-peak signal amplitude recorded in the form of a trace on an oscilloscope is This is indicated by the inner solid line in FIG. 8A. Measured at the position indicated by M in the diagram. The maximum peak-to-peak signal amplitude determined is the minimum peak-to-peak signal amplitude measured at the location indicated at 9 m. It is about 10% higher than the peak-to-peak amplitude arrow. Outer envelope shown as dashed line in figure indicates the peak-to-peak signal frequency measured on the disk at the outermost trunk. in this case Also the maximum and minimum measured at the angular positions on the disk denoted by M and m There is approximately a 10% difference between the peak-to-peak amplitude measurements of This was done on a disc formed according to a general procedure. In this case, below The layers and magnetic thin films are immediately deposited under conventional sputtering-target baffle conditions. First, the puffful described in this specification can be replaced with a conventional rectangular frame. low-angle asymmetric sputtering and deposited under conditions of variation in film thickness and film thickness. is carried out in the manner described above. The results of the signal amplitude measurements are shown in Figure 8B. As shown in Figure 8A, the solid line and dashed envelopes were measured at inner and outer track positions, respectively. It shows the change in peak-to-peak signal amplitude on the surface of the disk. Seen in Figure 8B The signal trace differs from that of Figure 8A in two important ways. One of them is There are large angular changes in the peak-to-peak signal amplitude, especially on the outer recording tracks. It is to be. The maximum and minimum peak-to-peak signal levels are indicated by arrows M and m. The innermost trunk experienced a change of about 25%, as measured at the location shown, and the outermost trunk The lateral trunk showed a change of approximately 40%. The other one is the second disk (relatively Formed under anisotropic sputtering conditions), the signal changes seen in the outermost This is to show periodic changes in signal amplitude in the side recording track. this cycle The symmetry of side-to-side deposits changes from front-to-back deposit symmetry. For thin film media formed under sputtering conditions vastly different from That's to be expected.

From the above, one can see how the various objects and features of the present invention are achieved. be able to. The method of the invention relates to the underlayer of the disk and the magnetic thin film composition. Manufacture of magnetic recording media with characteristics of high remanence, coercive force and loop squareness ratio It is what makes it possible to create These characteristics are reflected in the recorded signal amplitude between peaks. across the surface of the disc in the inner and outer recording tracks as shown. Almost uniform.

Another advantage of the invention is the ability to control operations with high reproducibility. Discs can be manufactured using a high-power sputtering system, making it the first choice. A deposit layer of uniform thickness and isotropic thickness can be obtained. Specification The quality of a batch of discs manufactured by the method described in The results of the controlled tests are valid for the tested disc unless there is contamination in dust. All qualitatively demonstrate that they meet strict performance specifications.

Magnetic disks manufactured in accordance with the present invention may be used in conjunction with some other commercially available 5-W magnetic disks. It was compared with inch magnetic disks in terms of performance characteristics. Most disk drive According to performance tests conducted by Supplier 6) and discs supplied by other five suppliers (Suppliers 1 to 5). compared. The test was conducted with a trunk width of 0.850 mils and a gear width of 35 microinches. Mini Mono with 13 microinch flying height in cap and inner diameter Tests were carried out using a lithic 3370-type test head. Data speed is 7 ．． 5 Mbit/s, spindle speed was 3600 rpm. The disc is inside Percent resolution at radial and od, id signal-to-noise ratio, signal-to-noise ratio during id pulse Noise ratio and internal pulse width at half amplitude measured in nanoseconds (Piy5.0 ) were compared.

Two discs from each supplier were tested. The test results are shown in Table ■ below. .

Table ■ Italy As can be seen from the table, the three inventive discs (by supplier 6) were compared to other tested discs. Compared to any commercially available disc.

High resolution characteristics, especially in the inner diameter, very good signal-to-noise ratio and sharp pulse width Showing a signal.

FIG. 11 shows a number of commercially available 5-z inch disks including one made in accordance with the present invention. In order to compare the amplitude/resolution characteristics of disc media manufacturers ( The results of tests conducted by persons other than the manufacturer of the invention are shown. Six companies' disk mail Each mosquito is identified by a number. Media numbers 2, 5 and 6 (based on the present invention) (created) is the same as in Table ■. Data as a function of amplitude at outer diameter shows the resolution at the inner diameter at a given frequency. Plot of target value is calculated theoretically It shows the maximum value and shows the inner diameter resolution value of 100 at the outer diameter amplitude value of 100. It has been standardized. Actual test data is plotted against the target value. ing. Everything about media.

It shows the expected inverse relationship between amplitude and resolution.

Six media tested, including three media not shown in Table ■ One of the disks formed according to the present invention (#6) was closest to the theoretical maximum performance value. It showed a high value.

The invention has been described in terms of specific and preferred embodiments.

It is understood that various changes and modifications may be made without departing from the spirit of the invention. Ru.

7L outside City otsu aQ & (kfc/1n) FIG.t.

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Claims (22)

[Claims] 1. Coercive force of at least about 700 Oe, at least about 3 x 10-3 EM with a remanence of U/cm2, a loop squareness ratio of at least about 0.85, and a total circular notation. The recording signal amplitude is characterized by a peak-to-peak variation of approximately 15% or less over the recording path. A method for manufacturing a thin film magnetic disk, comprising: A planar circular substrate is placed in a first tumbler which is adapted to sputter a crystalline underlayer onto the substrate. Approximately 70-88% cobalt, 10-28% nickel or and sputtering magnetic films containing alloys containing 2-12% chromium. A sputtering chamber with a second downstream target is moved along the path. Place it on a bullet to move, in a straight line without rotating the base, the first target in the upstream deposit area below the upstream portion of the first target; The membrane deposit under the second target is passed through the deposit area under the downstream portion of the cut. moving through the positive area; The crystalline material to be sputtered shields the substrate while entering the upstream deposition region. The deposit of quality is substantially divided between (a) the substrate area immediately below the target and (b) the substrate area. lateral regions of the target that are substantially symmetrical with respect to the forming crystals at least about 200 Å thick on the substrate in the cut region; substantially preserves the crystalline isotropy of the bonded crystal layer while passing through the jet region. At the sputtering angle, crystallization to a final underlayer thickness of approximately 1,000 to 4,000 Å sputtering a chemical substance onto a substrate, and The isotropy of the underlying crystal can be substantially preserved during passage through the film deposition region. Sputter the alloy onto the underlying layer at a sputtering angle of Target by shielding the substrate when moving outward from the path in the direction of the opposite area of the substrate and the substrate to a final film thickness of approximately 300 to 1,000 Å. Manufacturing a thin film magnetic disk comprising forming a substantially uniform alloy film having Method. 2. When passing under the first target, place the deposit under the target. A baffle with front and back shields that substantially confines the base area to and (a) an obstructed area substantially symmetrical with that in the front deposit area. on either side of the substrate to provide side-to-side sputtering, (b) a pair of buffs extending between the two shields in a generally front-to-back direction; 2. The method according to claim 1, wherein the substrate is shielded by the strip. 3. As it passes under the second target, deposit the substrate onto the target. Baffles with front and back shields that substantially confine to the underlying substrate area and perform side-to-side deposition from the second target to the substrate. Stretched between two shields generally from front to back so as to be qualitatively symmetrical According to claim 2, the base body is shielded by a pair of baffle strips. How to put it on. 4. A crystalline underlayer is formed using chromium to a final thickness between 1,000 and 2,000 Å. A method as claimed in claim 1 in which the method is formed. 5. The alloy contains about 74-78% cobalt, 15-25% nickel and 5-1 Claim 1 containing 0% chromium and having a thickness of about 400 to 600 Å. The method described in. 6. Coercive force of at least about 700 Oe, at least about 3 x 10-3 EM with a remanence of U/cm2, a loop squareness ratio of at least about 0.85, and a total circular notation. A thin-film magnetic disc with a peak-to-peak recording signal amplitude variation of approximately 15% or less over the recording path. A planar circular substrate is sputtered onto the substrate by sputtering a crystalline lower layer. about 70-88% cobalt, 10-28 Sputtering a magnetic film containing an alloy containing % nickel and 2-12% chromium a sputtering chamber with a second downstream target configured to Place on a bullet to move along a path, rotate the base straight through the upstream deposit area below the upstream portion of the first target. , through the deposit area below the downstream portion of the first target, and into the second target. moving through the membrane deposit area below the target; Shields the substrate and prevents the deposition of sputtered material during entry into the upstream deposition region. The positive is substantially located in (a) the substrate region immediately below the target and (b) in relation to the path of the substrate. lateral regions of the target that are substantially symmetrical with respect to the upstream deposit region. Forming crystals at least about 200 Å thick on the substrate within the downstream deposit A sputter that substantially preserves the crystalline isotropy of the bonded crystal layer while passing through the region. crystalline material to a final underlayer thickness of between approximately 1,000 and 4,000 Å at the taling angle. sputtering onto the substrate, and The isotropy of the underlying crystal can be substantially preserved during passage through the film deposition region. Sputter the alloy onto the underlying layer at a sputtering angle of Target by shielding the substrate when moving outward from the path in the direction of the opposite area of the substrate and the substrate to a final film thickness of approximately 300 to 1,000 Å. A thin film magnetic device formed by forming an alloy film of substantially uniform thickness with disk. 7. The alloy contains about 74-78% cobalt, 15-25% nickel and 5-1 Claim 6 containing 0% chromium and having a thickness of about 400 to 600 Å. Disc described in. 8. An underlayer is formed using chromium to a final thickness of between approximately 1,000 and 2,000 Å. The disc according to claim 6. 9. A thin film was formed by sputtering a crystalline substance onto the surface of the substrate. target, and underneath such target from the front to the back of the target. Front and back along a path offset from the centerline from front to back Movement to move the substrate in a straight line without rotation through one deposit area after another In a sputtering apparatus having a means, in a sputtered crystalline material, A baffle for achieving a substantially isotropic particle structure carried on the moving vehicle. The deposit of material to be sputtered onto the substrate to be sputtered is mainly controlled directly from the target. A frontal or and rear shield, and (a) together with those in the front deposit area, the bases within such front deposit area; Sputtering of material from side to side onto the body is substantially symmetrically inhibited. (b) generally facing the front and back; a pair of baffle strips extending in-plane between the two shields; Baffle with. 10. The baffle strip extends between the shield and the substrate therewith. A virtually square shape that allows the entire substrate to be seen when the target is directly below the target. 10. A baffle as claimed in claim 9 forming a shaped window. 11. The base body is aligned with a second base body and is capable of covering both base bodies during movement. move the deposit area under the rectangular sputtering target with the the pair of baffle strips extending along one side of the target. the first strip extending and the center line from front to back of such target; a second strip extending along the inner surface of the target; a second substance extending along another side of the body and allowing full visibility of the second substrate; a second pair of strips forming a generally rectangular window along the shield; Claim 1 further comprising a third baffle strip forming together with a strip of Baffle according to item 0. 12. The width of the second strip is the center of the target from front to back. The line is sized to prevent virtually all deposits from crossing the line. The baffle according to claim 11. 13. The baffle strip is such that the substrate is approximately halfway into the area below the target. forming a substantially semicircular window through which the front half of the base can be viewed when The baffle according to claim 9. 14. The baffle strip is positioned so that the substrate extends approximately half way out of the area below the target. Claims forming a substantially semi-circular window through which the rear half of the base can be seen when The baffle according to item 13. 15. Extends in the front/back direction and moves radially outward in the direction of the opposite area of the substrate Taper such that the shielding between the target and the substrate is gradually reduced as -Protrusions with a structure and an isotropic particle structure over the entire surface of the circular base. as claimed in claim 9 for use in achieving a structure and substantially uniform layer thickness. baffle. 16. A method in which a thin film layer with a substantially isotropic grain structure is sputtered onto a substrate. There it is, Sputtering a thin layer of material from the target, placing the substrate directly under the target. and moving the back deposit linearly through the area without rotation; A front shield is provided between the target and the substrate to pass through the front deposit area. The deposit of sputtered material onto the substrate is effectively deposited onto the area of the substrate directly below the target. A pair of front baffle plates shall be provided to limit the front deposit area. on the substrate within such area from the direction opposite the target. includes the substantially symmetrical and unhindered sputtering of materials of However, the baffle strip runs between the two shields in a generally front-to-back direction. The baffle strip is extended onto the substrate along with that of the back deposit area. How deposits are limited. 17. Layer sputtered onto the substrate as it passes through the front and back deposit areas For manufacturing magnetic recording media whose thickness is between approximately 1,000 and 4,000 Å. 17. The method according to claim 16 for use in 18. Reduces the thickness of the layer sputtered onto the substrate as it passes through the frontal deposit area. 17. The method of claim 16, wherein the thickness is at least about 200 Å. 19. Claims in which the sputtered layer is comprised of substantially pure chromium The method according to paragraph 18. 20. Approximately 70-88% cobalt, 10-4,000 Å layer on top of 1,000-4,000 Å layer 300-1,000 Å magnetic with 20% nickel and 2-12% chromium 18. The method of claim 17, further comprising forming a membrane. 21. Formation of a layer on which the magnetic film is formed has a thickness of 1,000 to 4,000 Å. during sputtering not substantially less than the sputtering angle to the substrate Spinning of cobalt/nickel/chromium materials under conditions that limit deposits to angles 21. The method of claim 20, comprising puttering. 22. said formation is directed outwardly to an opposite region of the substrate during such sputtering. The shielding between the target and the substrate should gradually decrease as the 21. The method of claim 20, further comprising: