Multilayer Load Beam Flexure for Magnetic Memory Devices

Abstract

To provide a multi-layer load beam flexure for a magnetic storage device to reduce variation in a separation distance between a read / write head of a suspension assembly of the magnetic storage device and a disk that reads and writes data.SOLUTION: A suspension assembly 135 for a magnetic storage device includes a base plate 192, a load beam 196, and a flexure 140. A hinge 141 of the load beam is configured to flex to move a tip portion of the load beam relative to the base plate. The flexure includes a hinge portion 140B and fixation portions adjacent to the hinge portion. Each of the fixation portions of the flexure includes a first layer 119 and a second layer 110 and the first layer is sandwiched between the second layer and the load beam. The hinge portion of the flexure includes the second layer but does not include the first layer. A thickness of the second layer of the hinge portion of the flexure is thinner than a thickness of the second layer of the fixation portion of the flexure.SELECTED DRAWING: Figure 4O

Description

Technical Field

[0001] The present disclosure generally relates to magnetic storage devices, and more specifically to multi-layer load beams flexures for magnetic storage devices.

Background Art

[0002] Magnetic storage devices, such as hard disk drives ("HDDs"), are widely used for storing digital data or electronic information in corporate data processing systems, computer workstations, portable computing devices, digital audio players, digital video players, and the like. Generally, an HDD includes a read / write head that facilitates data storage on a magnetic disk. Each read / write head is supported on a suspension assembly. Some HDDs include a suspension assembly having a flexure.

Summary of the Invention

[0003] There is a need for a manufacturing method that reduces variations in the separation distance between a magnetic storage device, a read / write head of the suspension assembly of the magnetic storage device, and a disk for reading and writing data. The subject matter of the present application has been developed in response to the current state of magnetic storage devices, and more specifically, in response to problems and needs in the art that are not fully solved by currently available magnetic storage devices as described above. Accordingly, embodiments of the present disclosure address at least some of the disadvantages of the prior art.

[0004] The following is a non-exhaustive list of examples of the subject matter disclosed herein, which may or may not be claimed.

[0005] This specification discloses a suspension assembly for a magnetic storage device. The suspension assembly includes a base plate and a load beam attached to the base plate. The load beam includes a tip and a hinge. The hinge is sandwiched between the tip and the base plate and is configured to flex to move the tip relative to the base plate. The suspension assembly includes a flexure attached to and movable with the base plate and the load beam. The flexure has a hinge portion spanning the hinge of the load beam and a fixed portion adjacent to the hinge portion. Each of the fixed portions of the flexure has a first layer and a second layer. The first layer is sandwiched between the second layer and the load beam. The hinge portion of the flexure includes the second layer but not the first layer to define a gap spanning the hinge between the first layers of the fixed portions of the flexure. The thickness of the second layer of the hinge portion of the flexure is thinner than the thickness of the second layer of the fixed portion of the flexure. The foregoing subject matter of this paragraph characterizes Example 1 of the present disclosure.

[0006] The ratio of the thickness of the first portion of the second layer to the thickness of the second portion of the second layer is greater than 1 and less than or equal to 2.4. The foregoing subject matter of this paragraph characterizes Example 2 of the present disclosure, where Example 2 also includes the subject matter described in Example 1 above.

[0007] The load beam is made of a metallic material. The foregoing subject matter of this paragraph characterizes Example 3 of the present disclosure, where Example 3 also includes the subject matter described in any of Examples 1-2 above.

[0008] The first layer is made of a metallic material. The foregoing subject matter of this paragraph characterizes Example 4 of the present disclosure, where Example 4 also includes the subject matter described in any of Examples 1-3 above.

[0009] The first layer is located directly on the load beam. The foregoing subject matter of this paragraph characterizes Example 4 of the present disclosure, where Example 5 also includes the subject matter described in any of Examples 1 to 4 above.

[0010] Each of the fixing portions of the flexure has a third layer. The foregoing subject matter of this paragraph characterizes Example 4 of the present disclosure, where Example 6 also includes the subject matter described in any of Examples 1 to 5 above.

[0011] The second layer is sandwiched between the first layer and the third layer. The foregoing subject matter of this paragraph characterizes Example 7 of the present disclosure, where Example 7 also includes the subject matter described in Example 6 above.

[0012] The third layer has a substantially uniform thickness. The foregoing subject matter of this paragraph characterizes Example 8 of the present disclosure, where Example 8 also includes the subject matter described in any of Examples 6 to 7 above.

[0013] The third layer is made of copper. The foregoing subject matter of this paragraph characterizes Example 9 of the present disclosure, where Example 9 also includes the subject matter described in any of Examples 6 to 8 above.

[0014] The first layer, the second layer, and the third layer are arranged in a stacked form. The foregoing subject matter of this paragraph characterizes Example 10 of the present disclosure, where Example 10 also includes the subject matter described in any of Examples 6 to 9 above.

[0015] The second layer is made of a photosensitive polyimide material. The foregoing subject matter of this paragraph characterizes Example 11 of the present disclosure, where Example 11 also includes the subject matter described in any of Examples 1 to 10 above.

[0016] The second layer is made of a dielectric material. The foregoing subject matter of this paragraph characterizes Example 12 of the present disclosure, where Example 12 also includes the subject matter described in any of Examples 1 to 11 above.

[0017] This specification discloses a magnetic storage system. The magnetic storage system includes a base plate, a large number of disks, and a carriage arm. The carriage arm includes a load beam attached to the base plate. The load beam includes a tip, a hinge, and a flexure. The hinge is sandwiched between the tip and the base plate and is configured to bend to move the tip relative to the base plate. The flexure is attached to the base plate and the load beam and is movable therewith. The flexure includes a hinge portion spanning the hinge of the load beam and a fixed portion adjacent to the hinge portion. Each of the fixed portions of the flexure includes a first layer and a second layer. The first layer is sandwiched between the second layer and the load beam. The hinge portion of the flexure includes the second layer but does not include the first layer to define a gap spanning the hinge between the first layers of the fixed portions of the flexure. The thickness of the second layer of the hinge portion of the flexure is thinner than the thickness of the second layer of the fixed portion of the flexure. The foregoing subject matter of this paragraph characterizes Example 13 of the present disclosure.

[0018] The ratio of the thickness of the first portion of the second layer to the thickness of the second portion of the second layer is greater than 1 and less than or equal to 2.4. The foregoing subject matter of this paragraph characterizes Example 14 of the present disclosure, where Example 14 also includes the subject matter described in Example 13 above.

[0019] The hinge biases against the surface of at least one of the large number of disks so that the head at the tip can read and write data to the at least one disk. The foregoing subject matter of this paragraph characterizes Example 15 of the present disclosure, where Example 15 also includes the subject matter described in any of Examples 13-14 above.

[0020] This specification also discloses a method for manufacturing a suspension assembly of a magnetic storage device. The method includes the step of forming a second layer on a first layer. The method also includes the step of applying a mask on the second layer. The light transmittance of a first portion of the mask is different from that of a second portion of the mask. The method also includes the step of irradiating light through the first portion and the second portion of the mask. The method includes the step of removing the mask from the second layer, and etching the second layer such that a first portion of the second layer coated with the first portion of the mask has a first thickness, and a second portion of the second layer coated with the second portion of the mask has a second thickness, where the second thickness is thinner than the first thickness. The foregoing subject matter of this paragraph characterizes Example 16 of the present disclosure.

[0021] This specification discloses a method for manufacturing a suspension assembly of a magnetic storage device. The method includes the step of forming a fourth layer on the second layer and a fifth layer under the first layer, and then forming a third layer on the second layer by etching at least a part of the fourth layer. The method also includes the steps of removing the fourth layer and the fifth layer by chemical cleaning, forming a sixth layer on the third layer, forming a seventh layer under the first layer, and removing a part of the first layer and a part of the seventh layer. Each removed part is aligned with the second portion of the mask. The method also includes the step of removing the sixth layer and the seventh layer. The foregoing subject matter of this paragraph characterizes Example 17 of the present disclosure, where Example 17 also includes the subject matter described in the above Example 16.

[0022] A part of the mask includes a halftone glass mask. The foregoing subject matter of this paragraph characterizes Example 18 of the present disclosure, where Example 18 also includes the subject matter described in any of the above Examples 16 - 17.

[0023] The first layer is made of stainless steel. The second layer is made of a polyimide material. The third layer is made of copper. The fourth, fifth, sixth, and seventh layers are each made of a dry film photoresist. The foregoing subject matter of this paragraph characterizes Example 19 of the present disclosure, where Example 19 also includes the subject matter described in the foregoing Examples 16 - 18.

[0024] A method of manufacturing a suspension assembly of a magnetic storage device includes attaching the flexure to a base plate and a load beam such that the second portion of the second layer spans the hinge portion of the load beam. The foregoing subject matter of this paragraph characterizes Example 20 of the present disclosure, where Example 20 also includes the subject matter described in any of the foregoing Examples 16 - 19.

[0025] The described features, structures, advantages, and / or characteristics of the subject matter of the present disclosure can be combined in any suitable form in one or more embodiments and / or implementations. In the following description, numerous specific details are provided to comprehensively understand embodiments of the subject matter of the present disclosure. A person skilled in the art will recognize that the subject matter of the present disclosure can be implemented without one or more of the detailed features, details, components, materials, and / or methods of a specific embodiment or implementation. In other instances, additional features and advantages may be recognized in a specific embodiment and / or implementation, but may not be present in all embodiments or implementations. Further, in some instances, well - known structures, materials, or operations are not illustrated or described in detail so as not to obscure aspects of the subject matter of the present disclosure. The features and advantages of the subject matter of the present disclosure will become more fully apparent from the following description and the appended claims, or may be understood by practice of the subject matter described below.

Brief Description of the Drawings

[0026] To facilitate an understanding of the advantages of the present disclosure, a more specific description of the present disclosure outlined above is provided with reference to specific embodiments shown in the accompanying drawings. It should be understood that these drawings merely illustrate typical embodiments of the present disclosure and should not be regarded as limiting the scope of the present disclosure. By using the accompanying drawings, the subject matter of the present application is further described and interpreted more specifically and in detail. A description of the drawings is set forth below.

[0027]

Figure 1

[0028]

Figure 2

[0029]

Figure 3

[0030]

Figures 4A - O

[0031]

Figure 5A

[0032]

Figure 5B

DETAILED DESCRIPTION OF THE INVENTION

[0033] Throughout this specification, references to "one embodiment", "an embodiment", or similar expressions mean that the particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the present disclosure. References to "in one embodiment", "in an embodiment", and the like throughout this specification do not necessarily refer to the same embodiment. Similarly, the term "implementation example" as used means an implementation example having the particular features, structures, or characteristics described in connection with one or more embodiments of the present disclosure, but an implementation example may be associated with one or more embodiments unless there is an obvious correlation indicating otherwise.

[0034] Referring to FIG. 1, a magnetic storage device 100 according to one embodiment is described as a hard disk drive (HDD). However, in another embodiment, the magnetic storage device 100 may be any of various magnetic storage devices without departing from the essence of the subject matter of the present disclosure. The magnetic storage device 100 includes a housing 102 that seals or encloses an internal cavity 114 defined therein. The housing 102 includes a base 130 and a cover 132 (shown in dashed lines so as not to obscure the internal mechanisms in the internal cavity 114 of the housing 102 of the magnetic storage device 100). The cover 132 is coupled to the base 130 to surround the internal cavity 114 from the external environment of the housing 102. In some implementation examples, a seal or gasket is disposed between the base 130 and the cover 132 to facilitate sealing therebetween. In some embodiments, the base 130 is made of a metallic material, such as stainless steel.

[0035] The magnetic storage device 100 includes various mechanisms located within the internal cavity 114 of the housing 102. In some embodiments, the magnetic storage device 100 includes a carriage 103, a disk 115, a spindle motor 121, and a voice coil motor (VCM) 125 within the internal cavity 114. The carriage 103 includes a head stack assembly 107 that includes a plurality of carriage arms 105 and at least one head gimbal assembly 109 (e.g., a suspension) coupled to the tip of each of the plurality of carriage arms 105. Each head gimbal assembly 109 includes a suspension assembly 135 and a slider 142. The slider 142 includes at least one read / write head coupled to (e.g., embedded in) the slider 142. The magnetic storage device 100 of FIG. 1 is shown as having five carriage arms 105 and four disks 115, but in other embodiments, the magnetic storage device 100 may have more than five or less than five carriage arms 105, or more than four or less than four disks 115. In one embodiment, each side of the carriage arm 105 facing the disk 115 has a head gimbal assembly 109 (e.g., each of the upper and lower carriage arms 105 may have one head gimbal assembly 109, and the middle carriage arm 105 between the upper and lower carriage arms 105 may have two head gimbal assemblies 109). Similarly, the magnetic storage device 100 is shown as having one spindle motor 121 and one VCM 125, but in other embodiments, the magnetic storage device 100 may have any number of spindle motors 121 and VCMs 125.

[0036] The spindle motor 121 is coupled to the base 130. Generally, the spindle motor 121 includes a stationary portion fixed immovably relative to the base 130, and a spindle rotatable relative to the stationary portion and the base 130. Accordingly, the spindle of the spindle motor 121 can be considered to be part of or integral with the spindle motor. Generally, the spindle motor 121 is operable to rotate the spindle relative to the base 130. The disk 115 or platter is rotatably fixed to the spindle of the spindle motor 121 via each hub 122, and these hubs 122 are fixedly attached to each disk 115 and the spindle for co-rotation. When the spindle of the spindle motor 121 rotates, the disk 115 rotates correspondingly. Thus, the spindle of the spindle motor 121 defines the axis of rotation of each disk 115. The spindle motor 121 can be controlled to operate so as to rotate the disk 115 in the rotational direction 190 at a controlled amount and a controlled speed.

[0037] Each of the disks 115 may be any of various types of magnetic recording media. Generally, in one embodiment, each disk 115 includes a substrate and a magnetic material applied directly or indirectly on the substrate. For example, the magnetic material of the disk 115 may be a conventional granular magnetic recording disk or wafer having magnetic layer bits with a plurality of magnetic particles on each bit. In a granular magnetic medium, the bits are all in the same plane, and the surface 116 of the disk is substantially smooth and continuous. In one embodiment, each bit has a magnetic dipole moment that can have either an in-plane (longitudinal) orientation or an out-of-plane (perpendicular) orientation.

[0038] When the disk 115 rotates in the read / write mode, the VCM 125 electromagnetically engages with the voice coil of the carriage arm 105 and rotates the carriage arm 105 and the head gimbal assembly 109 coupled to the carriage arm 105 with respect to the disk 115 in a rotational direction along a plane parallel to the read / write surface 155 of the disk 115. The carriage arm 105 can be rotated to position the read / write head of the head gimbal assembly 109 on a designated radial region of the corresponding read / write surface 155 of the disk 115 for performing read and / or write operations. The VCM 125 engages with the voice coil of the carriage arm 105 and is fixed to the base 130, and the carriage arm 105 is rotatably coupled to the base 130 via a spindle 127 passing through the carriage 103. Generally, the spindle 127 defines a rotation axis about which the carriage arm 105 rotates when actuated by the VCM 125.

[0039] The carriage arms 105 are immovably fixed to the base of the carriage 103 (e.g., integrated as a single-piece monolithic body) and extend away from the base of the carriage 103 at intervals from each other. In some implementations, the carriage arms 105 are equidistantly spaced from each other and extend parallel to each other. Each of the disks 115 is positioned between adjacent carriage arms 105. In the idle mode (e.g., when no read / write operation is being performed), the VCM 125 is actuated to rotate the carriage arm 105 in a radially outward direction with respect to the disk 15, whereby the head gimbal assembly 109 is stopped or lowered onto the lamp support 117 fixed to the base 130.

[0040] Each read / write head of slider 142 includes at least one read transducer and at least one write transducer. The read transducer is configured to detect the magnetic characteristics (e.g., magnetic bit pattern) of disk 115 and convert the magnetic characteristics into an electrical signal. In contrast, the write transducer changes the magnetic characteristics of disk 115 in response to an electrical signal. For each head gimbal assembly 109, the electrical signal is transmitted between the read / write head via electrical traces or electrical wires 198 formed in or coupled to slider 142 and flexure 140 (e.g., see FIGS. 5-7). The electrical traces of slider 142 and flexure 140 are electrically interconnected to facilitate the transmission of electrical signals between the read / write head and flex connector 104 of magnetic storage device 100 that communicates with the control module of magnetic storage device 100 (e.g., see FIG. 1). The control module is configured to process the electrical signal and facilitate the communication of electrical signals between magnetic storage device 100 and one or more external computing devices. Generally, the control module includes software, firmware, and / or hardware for controlling the operation of various components of magnetic storage device 100. The control module may include a printed circuit board on or in which the hardware is mounted. Solder joints are utilized to electrically connect the corresponding electrical contact pads (and corresponding electrical traces) of slider 142 and flexure 140.

[0041] Although not shown, in some implementations, head gimbal assembly 109 also includes a head actuator selectively operable to move the read / write head relative to hinge portion 140B of flexure 140.

[0042] FIG. 2 is a bottom view of a suspension assembly 135 of a magnetic storage device 100 according to one or more embodiments of the present disclosure. In some embodiments of the present disclosure, the suspension assembly 135 includes a base plate 192 and a load beam 196 having a tip 133, as shown as the bottom surface in FIG. 2. The base plate 192 spans between the tip 133 of the carriage arm 105 and the load beam 196 and couples them. The load beam 196 is coupled to the base plate 192 of the suspension assembly 135 via a hinge 141 of the load beam 196 and bends with respect to it. In some embodiments, the hinge 141 includes two hinges on both sides of a gap 199 within the load beam 196. The hinge 141 biases the load beam 196 onto the surface 116 of at least one of a large number of disks 115 so that data can be read from and / or written to at least one of the large number of disks 115. In some embodiments, the read / write head 134 floats above the surface 116.

[0043] In some embodiments, the load beam 196 is made of a metallic material. When bent, the hinge 141 functions as a spring to generate a force (referred to herein as "gram load") to move the head 134 of the load beam 196 into a position where the flying height between the surface 116 and the read / write head 134 is minimized toward the surface 116. This is achieved, for example, by forced air. The gap between the read / write head 134 and the disk 115 may be referred to herein as "flying height" or "floating height". In many cases, it is preferable to minimize and / or stabilize this gap in order to maximize the signal quality of the data transmitted between the disk 115 and the read / write head 134. In some embodiments, the flying height is about 5 nanometers ("nm") or less. However, embodiments of the present disclosure are not limited thereto.

[0044] The suspension assembly 135 also includes a flexure 140 that extends along the lower surfaces of the base plate 192 and the load beam 196. The flexure 140 includes a portion 140B that extends over (e.g., crosses) the hinge 141. In an embodiment of the present disclosure, the thickness of the flexure 140 is reduced at the hinge portion 140B of the flexure 140. As used herein, the "hinge portion" of a mechanism refers to any portion that intersects and / or overlaps the hinge 140. Thus, the hinge portion 140B of the flexure 140 is the portion of the flexure 140 within the region substantially shown by the dashed line in FIG. 2. Correspondingly, the hinge portion 110B of the second layer 110 of the flexure 140 is the portion of the second layer 110 within the hinge portion 140B, as shown in FIGS. 5A and 5B.

[0045] The stiffness of the hinge 141 (i.e., the stiffness of the hinge portion 140B of the flexure 140) affects the flying height. If the stiffness of the hinge portion 140B is relatively high, the load beam 196 cannot position itself to minimize the flying height because rotation around the hinge 141 is restricted. Therefore, a system and method for minimizing the stiffness around the hinge 141 are advantageous. Additionally, the stress applied to the hinge portion 140B results in variations in the flying height. The gram load or reaction force for loading the head 134 onto the surface 116 at the required flying height varies due to the stress (e.g., rearward bending stress or thermal stress) in the hinge region 140B. This causes unwanted variations in the flying height and ultimately affects the signal quality. In some examples, these variations can be compensated for by thermal flying height control ("TFC"). For example, a TFC slider such as the slider 142 can control the flying height. However, if the variations become too large, compensation by TFC becomes impossible. Therefore, in some embodiments, it is preferable to improve the flying height control by reducing the stress in the hinge portion 140B.

[0046] FIG. 3 is a flowchart of a method 300 for manufacturing a suspension assembly 135 of a magnetic storage device 100 according to one or more embodiments of the present disclosure. Specifically, the method 300 includes steps of manufacturing a flexure 140 of the suspension assembly 135 of the magnetic storage device 100. Some steps of the method 300 and additional steps of a method for forming a multilayer flexure 140 according to one or more embodiments of the present disclosure are shown in FIGS. 4A - O which are cross - sections of the suspension assembly 135 of the magnetic storage device 100. Thus, some of the steps illustrated in FIGS. 4A - O include the steps of the method 300 shown in FIG. 3. However, in addition to the steps listed in FIG. 3, additional steps are illustrated in FIGS. 4A - O. Those skilled in the art will understand that any combination of the steps shown in FIGS. 3 and 4A - O and / or described herein may be employed.

[0047] As shown in FIGS. 4A and 4O, the suspension assembly 135 includes a flexure 140 designed to reduce stress in portions overlapping the hinge portion 140B or the hinge 141. The flexure 140 is a multilayer flexure including, for example, a first layer 119, a second layer 110, and a third layer 124. As described herein, portions of the different layers 119, 110, and / or 124 have different thicknesses to reduce stress in the hinge portion 140B.

[0048] The method 300 includes a first step 340 of forming a first layer of the flexure 140 (i.e., layer 119 in FIGS. 4A - M). In some embodiments, the first layer 119 is formed directly on the load beam 196. Similar to the load beam 196, the first layer 119 is often made of stainless steel or other similar materials and has a greater thickness than other layers of the multi - layer flexure 140. In some embodiments, the first layer 119 is made of a metallic material. In some embodiments, for example, the first layer 119 is a stainless - steel sheet. According to some embodiments, the first layer 119 has a thickness (denoted as t2 in FIG. 5A) of about 20 micrometers (「μm」). In some embodiments, after the multi - layer flexure 140 is formed, the first layer 119 is attached to the load beam 196 to attach the entire flexure 140 to the load beam. In other words, the first layer 119 is directly adjacent to the load beam 196.

[0049] Since the first layer 119 is often made of stainless steel or other metallic materials with a relatively great thickness, preferably, in some embodiments, when the carriage arm 105 (and thus the load beam 196) is in the floating position above the disk 115, the first layer 119 does not extend over the hinge 141 to avoid applying an increasing downward pressure on the carriage arm 105 (e.g., above the head 134). Avoiding the application of the increasing pressure helps prevent fluctuations in the flying height. For this reason, as shown in FIG. 5A, there is a gap 144 in the first layer 119. Since the gap 144 is substantially aligned with the hinge region 140B, it is substantially aligned with the hinge 141. Additionally, as shown in FIG. 5B, the gap is substantially aligned with the hinge portion 110B of the second layer 110, which has a reduced thickness t4 compared to the thickness t3 of the non - hinge portion 110A of the second layer 110 to accommodate the bend around the hinge 141.

[0050] The second layer 110 of the flexure 140 is formed (e.g., coated) on the first layer 119 (i.e., step 342 in FIG. 3). In some embodiments, the second layer 110 is made of a dielectric material and / or a photosensitive material such as a liquid polyimide. As shown in FIG. 5A, the second flexure layer 110 forms a barrier between the first layer 119 and the third layer 124. This is important for maintaining signal quality. The thickness of the second layer 110 has a positive correlation with signal quality. However, if the second layer 110 in the hinge region 140B becomes too thick, tension may occur in the hinge region 140B. This tension promotes the spring force of the hinge 141 against the carriage arm 105, resulting in fluctuations in the flying height between the read / write head 134 and the upper surface 116 of the disk 115. Therefore, removing the first layer 119 from the hinge portion 140B can reduce the stress in the hinge portion 140B, but reducing the thickness t4 of the hinge portion 110B of the second layer 110 can further reduce this stress. Thus, embodiments of the present disclosure reduce fluctuations in the flying height by reducing the tension in the hinge region 140B.

[0051] After the second layer 110 is formed on the first layer 119, a mask (e.g., mask 120 in FIG. 4A) is disposed on the second layer 110 (step 344 in FIG. 3). Although the expression "disposed on" is used herein, embodiments of the present disclosure are not limited thereto. For example, the mask 120 may be formed on the second layer 110. This mask 120 includes a portion 120B that is located over the hinge portion 140B of the flexure 140. This portion 120B has a different light transmittance from the remaining portion 120A of the mask 120. The portion 120B is substantially aligned with the hinge portion 140B. In some embodiments, the portion 120B has a higher light transmittance than the portion 120A. In some embodiments, the mask 120 is a glass photomask and / or a halftone mask. For example, the hinge portion 120B of the mask 120 is a halftone glass mask, and the remaining portion 120A of the mask 120 is a full-surface glass mask.

[0052] In some embodiments, mask 120 is an opaque plate having one or more openings or transparent or translucent portions. Thus, light can pass through mask 120. In some embodiments, portion 120B aligned with hinge portion 140B is more translucent than remaining portion 120A. In other words, portion 120B is aligned with portion 110B of second layer 110 where a thinner thickness (e.g., t4 in FIG. 5A) is desired. In some embodiments, the higher translucency of mask 120 in portion 120B is due to the material used to form portion 120B having a higher translucency than the material used to form remaining portion 120A. In some embodiments, the higher translucency is at least partially due to a greater number and / or density of openings and / or transparent portions in portion 120B.

[0053] As shown in step 346 of FIG. 3, light is irradiated through mask 120. Light is irradiated through both hinge portion 120B and fixed portion 120A of mask 120. In some embodiments, this is accomplished by a lens. Although portion 120B has a higher translucency than remaining portion 120A, light is still irradiated through the entire mask 120.

[0054] The mask 120 is then removed from the second layer 110. The next step 348 includes etching away or removing residues from the second layer 110 such that the hinge portion 110B of the second layer has a thickness t4 that is thinner than the thickness t3 of the remaining non-hinge portion 110A of the second layer 110. The non-hinge portion 110A may be referred to herein as the "fixed portion".

[0055] FIG. 4B shows such an embodiment. By irradiating light through mask 120, it becomes easier to later remove a portion of hinge portion 110B. Thus, the use of mask 120 makes it possible to reduce the thickness of hinge portion 110B in a less burdensome process.

[0056] In some embodiments, thickness t3 is approximately twice thickness t4. For example, non-hinge portion 110A has a thickness t3 of 10 micrometers (「μm」), and etched hinge portion 110B has a thickness t4 of 5μm. However, embodiments of the present disclosure are not limited thereto. In some embodiments, the thickness t3 of the etched portion 110B is between 30% and 70% of the thickness t4 of the remaining non-hinge portion 110A. Due to the difference between thicknesses t3 and t4, a recess 197 in the second layer 110 is formed.

[0057] In some embodiments, due to different light transmittances, hinge portion 110B becomes aligned with portion 120B of mask 120 having a higher light transmittance, and non-hinge portion 110A becomes aligned with remaining portion 120A of mask 120 having a lower light transmittance.

[0058] As shown in FIG. 4C, in some embodiments, a photoresist material 113 is formed on the second layer 110. For example, photoresist material 113 is a dry film photoresist. In some embodiments, photoresist material 113 is formed on the second layer 110 by first attaching a layer of photoresist material 113 to the second layer 110 and then forming the layer of photoresist material 113 through a mask. In some embodiments, the mask is similar to mask 120 used to form different thicknesses t3 and t4 of the second layer 110 as shown in FIG. 4A.

[0059] The photoresist material 113 is also formed on the first layer 119 on the side that does not contact the second layer 110. The photoresist material 113 is formed on the flexible layers 110 and 119 by first attaching the photoresist material 113. Although not shown in FIG. 4C, in some embodiments, the photoresist material 113 is then formed on the layers 119 and 110 by irradiating ultraviolet (「UV」) light through a patterned glass mask. The layer of the photoresist material 113 may be referred to herein as the 「fourth layer」, 「fifth layer」, 「sixth layer」, and / or 「seventh layer」 of the flexure 140. However, as described herein, in some embodiments, the process of forming the multi-layer flexure 140 includes removing one or more layers of the photoresist material 113 after they have served their purpose (i.e., after the corresponding layers 110, 119 of the flexure have been removed).

[0060] As shown in FIG. 4D, one or more openings 111 are etched into the photoresist material 113. FIG. 4D shows a cross-section of the suspension assembly 135 in a plane perpendicular to the plane of the cross-section shown in FIG. 4C. As shown in FIG. 4D, one or more openings 111 can expose the first second layer 110, which is the layer on which the etched photoresist material 113 is formed.

[0061] As shown in FIG. 4E, in some embodiments, an additional third layer is added to the flexure 140. As shown in FIG. 4J, each of the fixing portions 140A of the flexure 140 includes a third layer 124. In some embodiments, only the fixing portion 140A includes the third layer 124. In another embodiment, both the fixing portion 140A and the hinge portion 140B include the third layer. In these embodiments, the third layer 124 is made of a material that is relatively flexible and does not generate excessive tension in the hinge 141 like the material of the first layer 119 (e.g., stainless steel). For this reason, the third layer 124 can be included in the hinge portion 140B without causing fluctuations in the flying height of the read / write head 134.

[0062] In some embodiments, the third layer (e.g., the layer shown in FIGS. 4E - 4M and 5A - B) is made of copper. In some embodiments, since the copper of the third layer 124 is of high purity, it has low rigidity and high flexibility. For example, the third layer 124 includes copper having a purity of more than 99% or a purity similar to that of an electronic - grade copper foil.

[0063] As shown in FIG. 4E, in some embodiments, the third layer 124 is formed on the second layer 110 by depositing the material intended to form the third layer 124 into the opening 111 of the photoresist 113. For example, the material is deposited into the opening 111 until enough material is deposited to form a third layer 124 having a thickness t5 (FIG. 4E) of about 6 micrometers (「μm」). As shown in FIGS. 4A - 5B, the second layer 110 is sandwiched between the first layer 119 and the third layer 124. In some embodiments, the thickness t5 of the third layer 124 is thicker than the thickness t4 of the hinge portion 110B of the second layer 110, but thinner than the thickness t2 of the first layer 119. In another embodiment, the thickness t5 of the third layer 124 is substantially equal to the thickness t3 of the non - hinge portion 110A of the second layer 110, but still thinner than the thickness t2 of the first layer 119. In another embodiment, the thicknesses t2, t3, and t5 are each approximately equal, and the thickness t4 is thinner than any of the thicknesses t2, t3, and t5.

[0064] In some embodiments, the third layer 124 is part of one or more signal traces for the flexure 140. In some embodiments, the flexure 140 includes signal traces (sometimes referred to as 「circuit traces」) for communicating signals from the read / write head 134 to other components of the device 100. This trace is often made of copper and / or copper foil, but the embodiments of the present disclosure are not limited thereto. For example, in some embodiments, the trace is made of aluminum, gold, or any combination thereof. The width w of the opening 111 is equal to the required width w of the trace of the flexure 140. The number of the openings 111 is the required number of copper traces for the flexure 140. For example, two openings 111 are for forming two traces on the flexure 140, as shown in FIGS. 4D and 4E.

[0065] Although not shown in this specification, in some embodiments, the cross-section of the suspension assembly 135 perpendicular to the cross-section shown in FIG. 4E may appear similar to the cross-section shown in FIG. 4C, which includes the bottom layer of the photoresist material 113, the first layer 119 of the flexure, the second layer 110 of the flexure having different thicknesses, and the top layer of the photoresist material 113. In some embodiments, the top layer of the photoresist material 113 has a substantially uniform thickness, but includes a recess 136 that fills the difference in thickness between the hinge portion 110B of the second layer 110 having a thinner thickness t4 and the portion 110A having a thicker thickness t3.

[0066] The photoresist material 113 is removed from the flexure 140. In some embodiments, this is accomplished by chemical cleaning. As shown in FIG. 4F, after the photoresist material 113 is removed, the flexure includes the first layer 119, the second layer 110, and the third layer 124. The second layer 110 includes a hinge portion 110B having a thickness thinner than that of the non-hinge portion 110A and thinner than that of the first layer 119. The third layer 124 has a substantially uniform thickness and includes a recess 138 because it is adjacent to the second layer 110.

[0067] FIG. 4G is a cross-sectional view of the suspension assembly 135 at the stage shown in FIG. 4F, where the plane of FIG. 4G is perpendicular to the plane of FIG. 4F. As shown in FIG. 4F, in some embodiments, the suspension assembly 135 includes two copper traces 124.

[0068] At this stage, the portion of the first layer 119 still needs to be removed to ensure that the hinge portion 140B of the flexure 140 does not include any of the rigid material of the first layer 119. Therefore, as shown in FIG. 4H, more photoresist material 113 is attached to the flexure 140 to enable the removal of the portion of the first layer 119. In some embodiments, the photoresist material 113 is deposited on the third layer 124. However, the embodiments of the present disclosure are not limited thereto. For example, the photoresist material 113 is formed only on a specific portion of the first layer 119.

[0069] As shown in FIG. 4H, the photoresist material 113 is formed on a portion of the first layer 119 that is not the portion to be removed to accommodate the hinge region 140B. In other words, the photoresist material 113 is attached to a portion of the first layer 119 that does not intersect or overlap the hinge portion 140B when the flexure 140 is placed on the load beam 196.

[0070] FIG. 4I is a cross-section of the suspension assembly 135 at the stage shown in FIG. 4H. However, the cross-section of FIG. 4I is perpendicular to the cross-section shown in FIG. 4H. The cross-section of FIG. 4I is within a portion 110B of the second layer 110 that is substantially aligned with the hinge portion 140B of the flexure 140. Thus, only the photoresist 113 covering the layer 124 (which is a trace in some embodiments) is shown in FIG. 4I.

[0071] As shown in FIG. 4J, the portion of the first layer 119 is removed such that the hinge portion 140B does not include any of the first layer 119. In other words, all of the first layer 119 of the hinge portion 140B is removed. The photoresist 113 functions to hold some portions of the second layer 110 in place while other portions are removed. In some embodiments, the removal is achieved by etching.

[0072] FIG. 4K shows a cross-sectional view of the suspension assembly 135 within the hinge region 140B of the flexure 140. The cross-section shown in FIG. 4K is perpendicular to the cross-section shown in FIG. 4J. As shown in FIG. 4K, the portion of the flexure 140 included in the hinge portion 140B is only the portion 110B of the second layer 110 and the third layer 124 (or trace). The photoresist material 113 is also shown in FIG. 4K to illustrate an embodiment where the portion of the first layer 119 is removed while the photoresist material 113 is also applied on top of the second layer 110.

[0073] As shown in FIG. 4L, the photoresist material 113 is then removed. In some embodiments, this is accomplished by chemical cleaning as described in connection with FIG. 4F.

[0074] Figure 4M shows a cross-section of the suspension assembly 135 within the hinge region 140B of the flexure 140. The cross-section shown in Figure 4M is perpendicular to the cross-section in the gap 144 of the first layer 119 shown in Figure 4L.

[0075] Figure 4N shows the assembly 135 intersecting the hinge portion 140B in the gap 199 of the load beam 196 shown in Figure 2. As shown in Figure 4N, the final step of the method includes attaching the flexure 140 to the base plate 192 and the load beam 196 such that the second layer portion 110B spans the hinge portion 141 of the load beam 196. For example, the load beam 196 is attached on the side opposite the second layer 110 of the first layer 119.

[0076] In the embodiment shown in Figure 4N, the assembly 135 is in a non-bent, straight position. The hinge 141 is shown in Figure 4N. In some embodiments, the hinge 141 is located on one or more sides of the gap 199 in the load beam 196 shown in Figure 2.

[0077] The flexure 140 is attached to the base plate 192 and the load beam 196 and is movable therewith. The first layer 119, the second layer 110, and the third layer 124 of the flexure 140 are arranged in a stacked configuration. The second layer 110 is sandwiched between the first layer 119 and the third layer 124. The flexure 140 includes a hinge portion 140B that overlaps the hinge 141 of the load beam. The flexure 140 also includes a fixed portion 140A adjacent to the hinge portion 140B. Each of the fixed portions 140A of the flexure 140 includes the first layer 119 and the second layer 110. The first layer 119 is sandwiched between the second layer 110 and the load beam 196.

[0078] Since the second layer 110 is formed of a material that allows bending around the hinge 141, such as a liquid polyimide, the flexible hinge portion 140B includes the hinge portion 110B of the second layer 110. However, since the hinge portion 140B does not include the first layer 119, the first layer 119 can be formed of a material having higher rigidity. In addition to the lower rigidity of the material of the second layer 110 compared to the material of the first layer 119, the reduced thickness t4 of the hinge portion 110B compared to the thickness t3 of the non-hinge portion 110A of the second layer 110 also reduces the tension in the hinge region 140B and minimizes the variation in the floating amount. In some embodiments, the ratio of t3 to t4 is greater than 1 and less than or equal to 2.4. For example, if t4 is 5 μm and t3 is about 10 μm, the ratio of t4 to t3 is 2.

[0079] The first layer 119 has a uniform thickness t2 and a gap 144 across the entire hinge portion 140B. Thus, the hinge portion 140B includes the second layer 110 (e.g., a portion 110B of the second layer) but does not include the first layer 119. In some embodiments, the hinge portion 140B also includes at least a portion of the third layer 124. The load beam 196 also has a substantially uniform thickness t1, at least along the hinge 141. The second layer 110 of the flexure 140 has two portions 110A and 110B having different thicknesses. The portion 110B (which is part of the hinge portion 140B of the flexure 140) overlapping the gap 144 and the hinge 141 has a thickness t4 that is thinner than the thickness t3 of the portion 110A that does not overlap it. The third layer 124 has a uniform thickness t5.

[0080] In FIG. 4O, the flexure 140 and the load beam 196 of FIG. 4N are bent about the hinge 141 for movement relative to the base plate 192. Thus, the tip of the load beam 196 (e.g., portion 133 shown in FIG. 2) moves relative to the base plate 192. When the load beam 196 is bent as shown in FIG. 4O, it is bent toward the surface 116 of at least one disk (e.g., disk 115 shown in FIG. 1), thereby minimizing the flying height between the read / write head 134 at the tip 133 and the surface 116. For example, when the disk 115 is located under the load beam 196, by bending the load beam 196 and the flexure 140 about the hinge 141, the tip 133 comes closer to the surface 116 of the disk 115.

[0081] FIGS. 4N and 4O show a third layer 124 that is part of both the fixed portion 140A and the hinge portion 140B (i.e., extending along the entire second layer 110), but embodiments of the present disclosure are not limited thereto. Some embodiments include gaps in the third layer 124, similar to the gap 144 in the first layer 119. In such embodiments, only the fixed portion 140A includes the third layer 124, and the hinge portion 140B does not.

[0082] FIGS. 4N and 4O show the gap 144 in the first layer 119 and the recesses 197 in the second layer 110 and the third layer 124. The recess 197 is due to (1) the difference in the respective thicknesses t3 and t4 between the non-hinge portion 110A and the hinge portion 110B of the second layer, (2) the hinge portion 110B (as shown in FIG. 4B) formed by removing the material of the second layer 110 on the side opposite to the side contacting the first layer 119 of the second layer 110, and (3) the third layer 124 formed directly on the recess 197 (e.g., recess 197 shown in FIG. 4B) of the second layer 110. In other words, the second portion 110B is open toward the third layer 124.

[0083] However, the embodiments of the present disclosure are not limited thereto. FIGS. 5A and 5B are cross-sectional views of the suspension assembly 135 of the magnetic storage device 100 perpendicular to the hinge 141 at the gap of the load beam 196 (e.g., gap 199 in FIG. 2) according to one or more embodiments of the present disclosure. As shown in FIGS. 5A - B, the material of the second layer 110 may be removed from the side facing the first layer 119 of the second layer. In this way, since the side where the third layer 124 of the second layer 110 is formed becomes relatively flat, there is no recess 197 on that side of the second layer 100 or in the third layer 124. The second portion 110B defines a recess that opens towards the gap 144 instead of the third layer 124.

[0084] FIG. 5A shows the suspension assembly 135 in a non - bent, straight - line position. FIG. 5B is a cross - sectional view of the suspension assembly 135 of FIG. 5A where the flexure 140 and the load beam 196 are slightly bent around the hinge 141, where the hinge 141 is sandwiched between the tip portion (e.g., tip portion 133 shown in FIG. 2) and the base plate 192.

[0085] Portion 110B may be referred to herein as the "second layer of the hinge portion 140B". Portion 110A having thickness t3 in FIG. 5B may be referred to as the "second layer of the fixed portion 140A".

[0086] As used herein, the term "layer" can be used to describe a plurality of continuous or discontinuous layers. However, it can also be used to describe a plurality of portions of a material layer. For example, as shown in FIG. 5A, the second layer 110 includes a plurality of portions having various thicknesses including portions 110A and 110B. Portions 110A and 110B may be collectively referred to as the "second layer 110" and / or "the second layer 110". In addition, portion 110A may be referred to as the "second layer of the fixed portion 140A of the flexure".

[0087] In the above description, specific terms such as "upper", "lower", "upper part of", "lower part of", "horizontal", "vertical", "left", "right", "above", "below", etc. may be used. These terms are used when applicable to clarify the description when dealing with relative relationships. However, these terms are not intended to imply absolute relationships, positions, and / or directions. For example, for a certain object, just by turning the object over, the "upper" surface can become the "lower" surface. Nevertheless, the object remains the same. Further, the terms "include", "comprise", "have" and their variants mean "including... but not limited to..." unless otherwise specified. An enumerated list of items does not imply that any or all of the items are mutually exclusive and / or mutually inclusive unless otherwise specified. The terms "a", "one" and "the" also refer to "one or more" unless otherwise specified. Further, the term "plurality" may be defined as "at least two".

[0088] As used herein, a system, apparatus, structure, article, element, component, or hardware "configured to" perform a specified function is not merely one that has the potential to perform the specified function after further modification, but can actually perform the specified function without any change. In other words, a system, apparatus, structure, article, element, component, or hardware "configured to" perform a specified function is one that has been specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing the specified function. As used herein, "configured to" indicates the existing characteristics of the system, apparatus, structure, article, element, component, or hardware that enable it to perform the specified function without further modification. For the purposes of the present disclosure, a system, apparatus, structure, article, element, component, or hardware described as "configured to" perform a particular function may additionally or alternatively be described as "adapted to" and / or "operates to" perform that function.

[0089] In addition, examples in this specification where one element is "coupled" to another element may include direct or indirect coupling. Direct coupling may be defined as one element being coupled to another element and having some contact. Indirect coupling may be defined as a coupling between two elements that are not in direct contact with each other but have one or more additional elements between the coupled elements. Further, as used in this specification, attaching one element to another element may include direct attachment and indirect attachment. Also, as used in this specification, "adjacent" does not necessarily indicate contact. For example, one element may be adjacent to another element without contacting it.

[0090] As used in this specification, the phrase "at least one of" when used in a list of items means that different combinations of one or more of the listed items may be used and that only one of the items in the list may be required. The items may be specific objects, things, or categories. In other words, "at least one of" means that any combination or number of items may be used from the list, but not all of the items in the list may be required. For example, "at least one of item A, item B, and item C" may mean item A, a combination of item A and item B, item B, a combination of item A, item B, and item C, or a combination of item B and item C. In some cases, "at least one of item A, item B, item C" may mean, for example, a combination of two of item A, one of item B, and ten of item C, a combination of four of item B and seven of item C, or other suitable combinations, but is not limited thereto.

[0091] Unless otherwise specified, terms such as "first", "second", etc. are used in this specification merely as labels and are not intended to impose sequential, positional, or hierarchical requirements on the items referred to by these terms. Also, for example, a reference to the "second" item does not require or exclude the existence of, for example, an item numbered "first" or lower, and / or, for example, an item numbered "third" or higher.

[0092] The schematic flowcharts included in this specification are generally described as logical flowcharts. Thus, the described order and labeled steps represent an example of the presented method. Other steps and methods that are equivalent in function, logic, or effect to one or more steps or portions thereof of the illustrated method may be considered. Additionally, the format and symbols employed are provided to interpret the logical steps of the method and are not understood to limit the scope of the method. Although various arrow types and line segment types may be used in the flowchart, they are not understood to limit the scope of the corresponding method. In fact, some arrows or other connectors may be used merely to indicate the logical flow of the method. For example, an arrow may indicate a waiting period or a monitoring period during an unspecified period between the enumerated steps of the described method. Additionally, the order in which a specific method is executed need not strictly conform to the order of the corresponding steps shown.

[0093] The subject matter of the present invention can be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments should be considered in all respects to be illustrative rather than restrictive. All changes that come within the meaning and range of equivalents of the claims are to be embraced within their scope.

Claims

1. A base plate, A load beam attached to the base plate and including a tip portion and a hinge, wherein the hinge is sandwiched between the tip portion and the base plate and is configured to bend to move the tip portion relative to the base plate; A flexure attached to the base plate and the load beam, The flexure includes a hinge portion overlapping at least a part of the hinge of the load beam and a fixed portion adjacent to the hinge portion, Each of the fixed portions of the flexure includes a first layer and a second layer, The first layer is sandwiched between the second layer and the load beam, The hinge portion of the flexure includes the second layer but does not include the first layer so as to define a gap between the first layers of the fixed portions of the flexure, A suspension assembly for a magnetic storage device, wherein a thickness of the second layer of the hinge portion of the flexure is thinner than a thickness of the second layer of the fixed portion of the flexure.

2. The suspension assembly according to claim 1, wherein a ratio of the thickness of the second layer of the fixed portion to the thickness of the second layer of the hinge portion is greater than 1 and less than or equal to 2.

4.

3. The suspension assembly according to claim 1, wherein the load beam is made of a metallic material.

4. The suspension assembly according to claim 1, wherein the first layer is made of a metallic material.

5. The suspension assembly according to claim 1, wherein the first layer is directly adjacent to the load beam.

6. The suspension assembly according to claim 1, wherein each of the fixed portions of the flexure further includes a third layer.

7. The suspension assembly according to claim 6, wherein the second layer is sandwiched between the first layer and the third layer.

8. The suspension assembly according to claim 6, wherein the third layer has a uniform thickness.

9. The suspension assembly according to claim 6, wherein the third layer is made of copper.

10. The suspension assembly according to claim 6, wherein the first layer, the second layer, and the third layer are arranged in a stacked form.

11. The suspension assembly according to claim 1, wherein the second layer is made of a photosensitive polyimide material.

12. The suspension assembly according to claim 1, wherein the second layer is made of a dielectric material.

13. The load beam is made of a metallic material, The first layer is made of a metallic material, The suspension assembly according to claim 1, wherein the first layer is directly adjacent to the load beam.

14. Each of the fixing portions of the flexure further includes a third layer, The second layer is sandwiched between the first layer and the third layer, The third layer has a uniform thickness, The third layer is made of copper, The suspension assembly according to claim 1, wherein the first layer, the second layer, and the third layer are arranged in a stacked form.

15. The suspension assembly according to claim 14, wherein the second layer is made of a photosensitive polyimide material or a dielectric material.

16. A base plate, At least one disk, A carriage arm, and the carriage arm includes A load beam attached to the base plate, and the load beam includes A tip portion, A hinge sandwiched between the tip portion and the base plate and configured to flex to move the tip portion relative to the base plate, A flexure attached to the base plate and the load beam, The flexure includes a hinge portion spanning the hinge of the load beam and a fixing portion adjacent to the hinge portion, Each of the fixing portions of the flexure includes a first layer and a second layer, The first layer is sandwiched between the second layer and the load beam, The hinge portion of the flexure includes the second layer but does not include the first layer so as to define a gap spanning the hinge between the first layers of the fixing portions of the flexure, A magnetic storage system, wherein a thickness of the second layer of the hinge portion of the flexure is thinner than a thickness of the second layer of the fixing portion of the flexure.

17. The magnetic storage system according to claim 16, wherein a ratio of a thickness of the fixing portion to a thickness of the second layer of the hinge portion is greater than 1 and less than or equal to 2.

4.

18. The magnetic storage system according to claim 16, wherein the hinge is configured to bias onto a surface of the at least one disk so that a head at the tip portion can read and write data to the at least one disk.

19. The load beam is made of a metallic material, The first layer is made of a metallic material, The magnetic storage system according to claim 16, wherein the first layer is directly adjacent to the load beam.

20. each of the fixing portions of the flexure further includes a third layer, the second layer is sandwiched between the first layer and the third layer, the third layer has a uniform thickness, the third layer is made of copper, The magnetic storage system according to claim 16, wherein the first layer, the second layer, and the third layer are arranged in a stacked form.

Images