CN107808675B - Machining test method, machining test monitoring device and machining equipment for magnetic head slider - Google Patents
Machining test method, machining test monitoring device and machining equipment for magnetic head slider Download PDFInfo
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- CN107808675B CN107808675B CN201610814757.3A CN201610814757A CN107808675B CN 107808675 B CN107808675 B CN 107808675B CN 201610814757 A CN201610814757 A CN 201610814757A CN 107808675 B CN107808675 B CN 107808675B
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B15/00—Systems controlled by a computer
- G05B15/02—Systems controlled by a computer electric
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Abstract
The application discloses a processing test method, a processing test monitoring device and processing equipment of a magnetic head slider, wherein the processing test method of the magnetic head slider comprises the following steps: providing at least one stress sensor in the wafer, and providing a control device connected with the stress sensor; and processing the wafer into a magnetic head slider by using a processing device, monitoring the performance parameters of the stress sensor by the control device in the processing process of the magnetic head slider to determine whether the current processing parameters are proper, sending an adjusting signal to the processing device when the current processing parameters are out of specification, and adjusting the processing parameters by the processing device according to the adjusting signal. The application of the method can monitor the processing test of the magnetic head slider in real time, thereby more effectively and conveniently carrying out the processing test on the magnetic head slider.
Description
Technical Field
The present application relates to a hard disk drive, and more particularly, to a method, a monitoring device and a processing apparatus for processing a magnetic head slider of a hard disk drive.
Background
A hard disk drive including a plurality of rotating magnetic disks is commonly used to store data on magnetic media on a magnetic disk surface thereof, and typically, a magnetic head embedded in a head slider of the hard disk drive includes a reproducing element (read head) having a magnetoresistive element (hereinafter, MR element) for reading data, and a recording element (write head) having an inductive electromagnetic transducer for writing data. FIG. 1a illustrates a typical configuration of a hard disk drive. The hard disk drive 100 includes a spindle motor 30, a series of rotatable magnetic disks 80 mounted on the spindle motor 30, a Head Gimbal Assembly (HGA) 40, a driving arm 50 connected to the HGA 40, a head slider 60 disposed at a distal end of the driving arm 50 and including a read head, and a case 70 for assembling the above components. As is well known to those skilled in the art, when the hard disk drive 100 operates, the magnetic disk 80 is rotated by the spindle motor 30, and the generated air pressure makes the magnetic head slider 60 fly above the magnetic disk 80 (the height from the magnetic disk when the magnetic head slider flies is called flying height, referred to as flying height), so that the read head on the magnetic head slider 60 reads data on a magnetic disk track. Fig. 1b and 1c show the detailed structure of the read head, the read head 10 includes a first shield layer 111 formed on a substrate 110, a second shield layer 114, an MR element 112 laminated between the first and second shield layers 111, 114, and a pair of hard magnets 113 located at both sides of the MR element 112.
For the read head, a Giant Magnetoresistive (GMR) element using a giant magnetic effect has been used as an MR element. One conventional GMR element has a Current-In-Plane (CIP) type structure In which a direction of a Current (hereinafter referred to as an induced Current) used to detect a magnetic field signal is parallel to a Plane In which layers of the GMR element are located; another conventional GMR element has a "Current-Perpendicular-to-Plane" (CPP) structure, i.e. the direction of the induced Current intersects the Plane of the layers of the GMR element, e.g. Perpendicular to the Plane of the layers of the GMR element. Another MR element is a Tunnel Magnetoresistive (TMR) element, which also has a CPP structure.
Conventionally, the magnetic head slider is manufactured through a plurality of processes such as wafer formation and rowbar grinding. In the whole manufacturing process, the magnetic head slider undergoes a plurality of force application processes such as cutting, grinding and the like, and the force application processes inevitably affect the magnetic head slider material, such as stress bending, processing thermal deformation and the like, and further affect the performance of the finally generated magnetic head. At present, the magnetic head slider can only be analyzed before and after being stressed, so that the stress response of the magnetic head slider can be obtained, and a method for monitoring the whole force application process in real time is not available.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, according to one aspect of the present application, a method for testing the machining of a magnetic head slider is provided, which can monitor the machining stress of the magnetic head slider in real time.
The processing test method of the magnetic head slider comprises the following steps: providing at least one stress sensor in the wafer, and providing a control device connected with the stress sensor; and processing the wafer into a magnetic head slider by using a processing device, monitoring the performance parameters of the stress sensor by the control device in the processing process of the magnetic head slider to determine whether the current processing parameters are proper, sending an adjusting signal to the processing device when the current processing parameters are out of specification, and adjusting the processing parameters by the processing device according to the adjusting signal.
In one embodiment, the stress sensor further comprises a thermal sensor for monitoring the fly height of the magnetic head.
In one embodiment, the stress sensor is made of a material selected from one or more of nickel, copper, chromium, molybdenum, iron, manganese, platinum, iridium, and aluminum.
In one embodiment, the performance parameter of the stress sensor comprises a resistance value of the stress sensor.
In one embodiment, the stress sensor includes a first stress sensor disposed near an air bearing surface of a read head in the magnetic head slider or the magnetic head slider, and a second stress sensor disposed at a predetermined reference point of the magnetic head slider, and the control device determines whether the processing parameter meets the specification according to a difference between performance parameters of the first stress sensor and the second stress sensor.
In one embodiment, the stress sensor takes at least two measurements during the testing of the sample, and the control device determines whether the sample meets the specification based on the difference between the two measurements.
In one embodiment, a control group is provided for at least two measurements of the stress sensor on the sample and the control group, respectively, during testing of the sample, and the control device determines whether the sample meets the specification based on a difference between the two measurements of the sample based on compensation of the control group.
According to another aspect of the present application, a magnetic head slider processing test monitoring apparatus of the present application includes a monitoring unit and a control unit connected to the monitoring unit; the monitoring unit is connected with a stress sensor in a wafer for processing the magnetic head slider and is used for monitoring the performance parameters of the stress sensor in the processing process of the magnetic head slider; and the control unit is used for determining whether the current processing parameters of a processing device for processing the magnetic head slider are suitable or not according to the performance parameters of the stress sensor, and sending an adjusting signal to the processing device to instruct the processing device to adjust the processing parameters when the current processing parameters are out of specification.
According to still another aspect of the present application, a magnetic head slider processing apparatus of the present application includes: the processing device is used for processing a wafer into a magnetic head slider, and the wafer contains at least one stress sensor; the control device is connected with the stress sensor in the wafer and used for monitoring the performance parameters of the stress sensor in the machining process of the magnetic head slider so as to determine whether the current machining parameters of the machining device are proper or not and sending an adjusting signal to the machining device when the current machining parameters are out of specification; and the processing device adjusts the processing parameters according to the adjusting signal.
The magnetic head slider processing and testing method can monitor the processing and testing of the magnetic head slider in real time, so that the processing and testing of the magnetic head slider can be effectively and conveniently adjusted, the processing yield of the magnetic head slider is improved, and the testing process of the magnetic head slider can be simplified.
Drawings
The present application will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1a is a block diagram of a typical hard disk drive;
FIG. 1b is a perspective view of a typical read head configuration of a magnetic head slider;
FIG. 1c is a cross-sectional view of the readhead mechanism shown in FIG. 1 b;
FIG. 2a is a flow chart of a magnetic head slider fabrication according to one embodiment of the present patent application;
FIG. 2b is a diagram of a wafer structure according to one embodiment of the present patent application;
FIG. 2c is a view of a rowbar structure according to one embodiment of the present patent application;
FIG. 2d is a head slider structure diagram according to one embodiment of the present patent application;
FIG. 2e is a diagram of a sensor arrangement according to an embodiment of the present patent application;
FIG. 3 is a flow chart of a monitoring method according to a first embodiment of the present patent application;
FIG. 4 is a flow chart of a monitoring method according to a second embodiment of the present patent application;
FIG. 5 is a flow chart of a monitoring method according to a third embodiment of the present patent application;
FIG. 6 is a flow chart of a monitoring method according to a fourth embodiment of the present patent application;
FIG. 7 is a flow chart of a monitoring method according to a fifth embodiment of the present patent application;
FIG. 8 is a block diagram of a monitoring device according to an embodiment of the present patent application;
FIG. 9 is a block diagram of an abrasive machining portion of a machining apparatus according to one embodiment of the present patent application;
FIG. 10 is a graph of stress-stress sensor performance variation according to an embodiment of the present patent application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present patent application and are not limiting of the present patent application.
Typically, the magnetic head slider is manufactured by first dicing a wafer having a plurality of magnetic head elements into a plurality of rowbars (Row Bar) on which a plurality of magnetic head slider elements are arranged; each row bar is then ground to adjust the height of the element to a predetermined size. One of the lapping surfaces is the media-facing surface of each head slider, referred to as the "air bearing surface" (ABS, see 117 in FIG. 1 b). Specifically, the rowbar is pressed against a rotating grinding disk with a predetermined pressure to grind the ABS of the rowbar to a predetermined gauge. Finally, the row bar is cut into a plurality of individual magnetic head sliders.
FIG. 2a is a schematic diagram showing a process of manufacturing a magnetic head slider according to an embodiment of the present patent application; fig. 2b, 2c and 2d show the wafer, the row bar and the head slider, respectively, during the manufacturing process shown in fig. 2 a. With reference to these drawings, a method of manufacturing a magnetic head slider according to an embodiment of the present patent application will be described below.
As shown in fig. 2a, a wafer is first formed (step S21). In the wafer forming process, a plurality of magnetic head slider elements having magnetic heads (typically, a plurality of thin film layers are laminated) are formed on a wafer 20 made of a ceramic material by a thin film technique (for example, a photolithography method). Each head has a read head and a write head thereon.
Next, a machining process is performed (step S22). In this process, the wafer 20 is first cut into a plurality of blocks, and each block is then cut into a plurality of elongated strips 210 (fig. 2 b). On each row bar 210, a plurality of magnetic head slider elements 220 are arranged (see fig. 2 d). As shown in fig. 2c and 2d, the row bar 210 has an ABS 211, a back surface 213 opposite to the ABS 211, an adhesive surface 212, a bottom surface 214 opposite to the adhesive surface 212, and two side surfaces 215. Each head slider element 220 is embedded with a magnetic head 230.
With continued reference to fig. 2a, after the machining process, a grinding process (including at least steps S23 and S24) is performed. To enhance the grinding effect, grinding can be divided into coarse grinding and fine grinding. Rough grinding is first performed before finish grinding, specifically, the bottom surface 214 of the rowbar 210 is rough ground to a predetermined size (step S23). Next, the ABS 211 of the row bar 210 is finely lapped (step S24), thereby controlling the characteristics of the magnetic head 230. In addition, the backside 213 of the row bar 210 may also be ground to a predetermined size before or after the ABS 211 is ground. After the lapping process is performed on the lapping surface, the row bar 210 is cut into a plurality of individual magnetic head sliders 220 (step S25). After the magnetic head slider 220 is processed, the magnetic head slider 220 can be assembled into the hga 40 through an assembling process until the hard disk drive 100 is formed. During the HGA assembly process, the head slider 220 is generally connected to the HGA 40 by a GBB (gold ball bond) or an SBB (ball bond).
As shown in fig. 2e, in the elongated strip 210, one or more stress sensors 240 may be arranged, which are spaced apart from the read head (not shown). The stress sensor 240 may function to monitor stress during processing. It should be noted that the illustration only shows the row bar 210, and does not mean that the stress sensor 240 is formed in the row bar 210 after obtaining the row bar 210, and the stress sensor 240 may be formed in the wafer together with the magnetic head element in the wafer forming process by the same or similar thin film forming technique as the magnetic head element. The stress sensor 240 may be made of a material selected from nickel (Ni), copper (Cu), chromium (Cr), molybdenum (Mo), iron (Fe), manganese (Mn), platinum (Pt), iridium (Ir), aluminum (Al), and the like.
Because the change of mechanical stress applied to the wafer, the long strip and the like in the magnetic head slider processing process can cause the change of performance parameters, such as resistance values, of the stress sensor in the magnetic head slider, the stress sensor can be used for monitoring the force application change in the magnetic head slider processing process in real time, so that the force application in the processing process is correspondingly adjusted, and the self-protection effect is achieved on the whole processing. Furthermore, when the performance test is carried out on the magnetic head slider, the performance test can also be monitored by using the stress sensor. The following describes a process for monitoring the process of manufacturing and testing a magnetic head slider using a stress sensor.
Referring to fig. 3, the monitoring method according to the first embodiment of the present invention has the following process:
s301: starting the process;
s302: starting processing, for example, a processing device cuts the wafer; during the treatment process, the stress sensor always monitors the force application change, the monitoring is expressed by the performance parameter of the stress sensor, such as the resistance value change of the stress sensor, and the stress sensor feeds back the performance parameter to the monitoring device;
s303: the monitoring device determines whether the stress is within the specification, if so, the current processing parameters can be maintained and the processing can be continued; otherwise, the flow advances to step S305;
s304: determining whether the whole processing process is finished, if so, ending the process in step S306, otherwise, returning to step S302;
s305: when the stress is out of specification, the machining parameters are adjusted, and then, the process returns to step S303 to determine whether the stress is in specification.
Referring to fig. 4, the monitoring method according to the second embodiment of the present invention has the following process:
s401: starting the process;
s402: starting processing, for example, dicing the wafer; during the process, the stress sensor is constantly monitoring the force variation, in this case, two stress sensors are used for monitoring, wherein sensor 1 is arranged near the read head/ABS for real-time measurement (step S403), and sensor 2 is arranged at a preset reference point for real-time measurement (step S404);
s406: in this example, whether the force application is proper or not is determined by judging whether the performance parameters of the two sensors, such as the difference of the resistance values, are within the specification, if not, the process goes to step S405 to adjust the processing parameters, and then the process returns to step S402; if appropriate, the process ends in step S407.
Referring to fig. 5, the monitoring method according to the third embodiment of the present invention has the following process:
s501: processing the input;
s502: starting processing, and carrying out first measurement by the stress sensor;
s503: the process continues, whereupon, at step S504, the stress sensor takes a second measurement;
s505: determining whether the difference of the two measurement results is within the specification, if so, entering step S506, and processing output; otherwise, step S507 is performed to reject the sample, and to perform inspection and fine adjustment.
Referring to fig. 6, the monitoring method according to the fourth embodiment of the present invention has the following process:
s601: processing the input; subsequently, based on the test sample and the control population, the flow is divided into two branches; to process the test sample and control population separately;
for the test sample branch, it first takes a first measurement of the stress sensor (S602), followed by processing (S604), and then a second measurement of the stress sensor (S605);
for the control group branch, first, the first measurement of the stress sensor is performed (S603), and then the second measurement of the stress sensor is performed (S606);
in step S607, it is determined whether the difference between the two measurement results of the test sample is within the specification based on the compensation of the control group, if so, the output is processed (S608), otherwise, the sample is rejected, checked and fine-tuned (S609).
Since the stress sensor may be affected by the external factors, in the above embodiment, a control group is established for removing the difference of the external factors, i.e., the control group may be used for monitoring the influence of the external factors. The control group is used as a reference, the influence condition of the test sample by the external factors can be judged, the compensation based on the control group can be used, when the difference of the two measurement results of the test sample is judged, the difference of the external factors is firstly removed based on the control group, and then the comparison is carried out.
Referring to fig. 7, the monitoring method according to the fifth embodiment of the present invention has the following process:
s701: the process starts;
s702: carrying out a no external stress test;
s703: carrying out an external stress test;
s704: if the test parameters are in the specification, the step S705 is carried out, whether all stress conditions are finished is determined, if yes, the step S706 is carried out, and if not, the step S703 is carried out; if the test parameters are not within the specification, go to step S706;
s706: processing the test parameters; subsequently, the flow ends the processing in step S707.
It can be seen from the above that, based on the stress sensor, the monitoring method of the present application can analyze and monitor the force application in real time in the whole process of the processing, thereby adjusting the processing parameters in real time, and thus, the processing of the magnetic head slider can be effectively performed, and the processing yield of the magnetic head slider is provided.
On the other hand, it can be seen that the monitoring method of the present application can also be used in performance testing of a magnetic head slider, for example, the current performance parameter of the stress sensor is determined at the present time of a test item, after the test item is completed, the new performance parameter of the stress sensor is determined again, and based on the change of the performance parameter of the stress sensor, whether the difference between the two measurement results is within the specification is determined, so that a sample can be screened.
Currently, before the magnetic head is used, a series of performance tests, such as high temperature resistance, Dynamic Flying Height (DFH) performance, Signal-to-Noise Ratio (SNR) performance, reliability, stability, etc., must be performed. For example, a magnetic head having poor high temperature resistance generates a large amount of noise in a high temperature environment. The performance test of the magnetic head is important and necessary because the poor SNR performance of the magnetic head deteriorates the read stability of the magnetic head and eventually affects the read performance of the magnetic head.
The monitoring method of the present patent application can be applied to these performance tests of the magnetic head. For example, in testing the high temperature resistance of a magnetic head, heat and stress may be applied to an MR element in the head using a heating element. Specifically, when electricity is applied, the heating element generates heat, and in this case, the MR element and its surrounding material thermally expand, thereby causing a large amount of internal stress to be generated in the MR element, and further, the MR element is internally deformed. Similarly, the foregoing stress sensor disposed in the magnetic head is affected by internal stress, and its performance parameter, for example, its resistance value, changes, and by monitoring the performance parameter of the stress sensor, it can be determined whether the thermal deformation of the MR element meets the specification, and if not, it can be determined that the magnetic head fails the performance test, and belongs to an unconventional sample. That is, a performance test of the magnetic head may be performed based on the stress sensor. In addition, when the MR element is deformed, for example, by heat, the flying height from the head to the disk is also changed, and a thermal sensor is generally used to monitor the change in flying height. In the present application, the thermal sensor can also be used as the aforementioned stress sensor to monitor the machining process of the magnetic head slider in real time, so as to conveniently perform the performance test of the magnetic head.
Referring to fig. 8, an elongated bar 801, for example, may be placed on a bar bending tool 802, and the bar bending tool 802 may apply a force to the elongated bar 801 to bend the elongated bar, thereby applying an external stress to a stress sensor inside the elongated bar 801, the stress corresponding to a processing test for processing or testing the elongated bar. If necessary, the stress sensor and the reading head can be monitored in real time by the analyzer 803. While monitoring the applied external stress using the stress sensor, a magnetic field B is then applied to the readhead to monitor the change in performance of the readhead. The analyzer 803 may then receive the signal, analyze the force applied to the rowbar to determine if the process test parameters are within specification, and if so, may continue to apply additional force, and the analyzer 803 may then receive a new signal to analyze the new process test parameters, which continues until the test parameters exceed specification. In this way, a corresponding relation table of the stress sensor performance parameters and the processing parameters of the wafer processed to the magnetic head and/or the testing parameters of the magnetic head can be established in advance, or only the specification range of the stress sensor performance parameters can be determined. Referring back to fig. 3, with the steps shown in fig. 3, the stress can be monitored in real time and the machining parameters can be adjusted in real time.
In this patent application, can set up a magnetic head slider processing test monitoring device independently, the magnetic head slider processing test monitoring device who independently sets up like this can include: the monitoring unit and the control unit are connected with the monitoring unit; the monitoring unit is connected with a stress sensor in a wafer for processing the magnetic head slider and is used for monitoring the performance parameters of the stress sensor in the processing process of the magnetic head slider. The control unit is used for determining whether the current processing parameters of the processing device for processing the magnetic head slider are suitable or not according to the performance parameters of the stress sensor, and sending an adjusting signal to the processing device to instruct the processing device to adjust the processing parameters when the current processing parameters are out of specification. The monitoring unit may include, for example, a signal collector, a signal converter, and the like, and is connected to the stress sensor through, for example, a metal wire, the signal collector may collect a performance parameter of the stress sensor, such as a resistance value, and the signal converter may convert the collected signal, such as converting the resistance value into a current value, or even performing analog-to-digital conversion, and the like. The control unit may be, for example, an MCU (micro control unit), a DSP (digital signal processor), an FPGA (field programmable logic array), an ARM (advanced reduced instruction set machine), or the like machine having a computation processing capability. As described above, the specification range of the performance parameter of the stress sensor corresponding to the machining test specification of the magnetic head slider can be determined by, for example, the method shown in fig. 8, and the specification range can be stored in a database, and after the control unit obtains the performance parameter of the stress sensor from the monitoring unit, the control unit determines whether the performance parameter of the stress sensor is in compliance according to the specification range of the performance parameter of the stress sensor through database query, and further determines whether the current machining parameter is in compliance, and generates an adjustment signal when the machining parameter is not in compliance, so as to instruct the machining device of the magnetic head slider to adjust the machining parameter. With this arrangement, the magnetic head slider processing apparatus, such as a cutter, a rough grinder, a refiner, etc., is physically independent of the magnetic head slider processing test monitoring apparatus.
In another embodiment, the magnetic head slider processing test monitoring function of the present application may be integrated into a processing device, and such an integrated processing device is formed as a magnetic head slider processing apparatus of an embodiment of the present application. The processing equipment can comprise a processing device, a processing device and a processing device, wherein the processing device is used for processing a wafer containing at least one stress sensor into a magnetic head slider; the control device is connected with the stress sensor in the wafer and used for monitoring the performance parameters of the stress sensor in the machining process of the magnetic head slider so as to determine whether the current machining parameters of the machining device are proper or not and sending an adjusting signal to the machining device when the current machining parameters are out of specification; subsequently, the processing device adjusts the processing parameter according to the adjusting signal.
Fig. 9 is a block diagram of a row bar grinding process portion of the processing apparatus of an embodiment of the present patent application. In the grinding section 91 of the processing apparatus, there are a rotating grinding plate 92 for grinding the bar 210, a load generating device 94 for providing a force for pressing the bar 210 against the grinding plate 92, and a plurality of load transmitting jigs 95. The load generator 94 uses, for example, an electromagnetic or hydraulic (hydraulic) micro actuator (activator). The load generating device 94 is connected to the control device 98 and performs feedback control based on the resistance value of the stress sensor 240 to process the MR height (height measured perpendicularly from the ABS of the MR element) to a predetermined value. The load transmission jig 95 is positioned between the load generator 94 and the support 96 supporting the rowbar 210, and transmits the pressure generated in the load generator 94 to the rowbar 210 via the support 96, thereby pressing the ABS formation surface G of the rowbar 210 against the polishing plate 92. The load transmission jig 95 is provided in plural in the longitudinal direction of the support 96. The elongated bar 210 mounting surface of the support body 96 may be separated by the groove 97 at the contact point of the load transmission jig 95, and the pressure transmitted from each load transmission jig 95 can be transmitted only to the periphery thereof. The surface of the polishing plate 92 can be formed by embedding diamond abrasive grains in a disc surface made of Sn (tin), for example. The polishing plate 92 is connected to a rotating shaft 93 and rotated by a power mechanism (not shown). When polishing is performed, first, the rowbars 210 are fixed to the support 96, and the longitudinal direction of the rowbars 210 is aligned with the radial direction of the polishing plate 92. The ABS formation surface G is pressed against the rotating lapping plate 92 so that the ABS formation surface G is lapped, and the stress sensor 240 senses the stress during lapping so that a performance parameter, such as a resistance value, is changed. The control device 98 determines whether the process parameters are appropriate based on the resistance of each stress sensor 240 and adjusts the process parameters when not appropriate and instructs the load generating device 94 to change the process parameters, which real-time monitoring and adjustment can be performed throughout the grinding process. It will be appreciated that other parts of the processing tool may be configured in a similar manner, for example, the wafer dicing portion of the processing tool, the force of which dicing is also monitored by the stress sensor 240 and fed back to the control device 98 so that the processing parameters of the wafer dicing portion are adjusted accordingly.
Fig. 10 is a graph of the performance variation of a stress-stress sensor (made of nickel) according to an embodiment of the present application, in which the horizontal axis represents externally applied pressure (Gpa in units), negative values represent external stress as tensile force, and positive values represent external stress as compressive force. The vertical axis dR/R represents the ratio (% in unit) of the resistance value change to the initial resistance value, i.e., the relative change amount of the resistance value, a negative value represents that the resistance value is decreased relative to the original resistance value, and a positive value represents that the resistance value is increased relative to the original resistance value. It can be seen that the resistance value increases continuously with increasing tensile force. On the other hand, as the compressive force increases, the resistance value decreases. And the relationship between stress-resistance versus change is approximately linear. Based on such a relational map, the applied stress can be obtained from the resistance value of the stress sensor, thereby judging whether the application of force during machining is appropriate.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (10)
1. A method for testing the machining of a magnetic head slider, comprising:
providing at least one stress sensor in the wafer, and providing a control device connected with the stress sensor;
processing the wafer into a magnetic head slider by using a processing device, monitoring the performance parameters of the stress sensor by the control device in the processing process of the magnetic head slider to determine whether the current processing parameters are suitable or not, sending an adjusting signal to the processing device when the current processing parameters are out of specification, and adjusting the processing parameters by the processing device according to the adjusting signal, wherein the processing process of the magnetic head slider comprises the following steps:
forming a wafer, and forming a magnetic head slider element and a stress sensor on the wafer in a wafer forming process;
cutting the wafer into a plurality of blocks, and then cutting each block into a plurality of rectangular strips;
the row bar is ground to cut the row bar into a plurality of individual magnetic head sliders.
2. The process test method of claim 1 wherein said stress sensor further comprises a thermal sensor for monitoring the fly height of said magnetic head.
3. The process test method of claim 1, wherein the stress sensor is made of a material selected from one or more of nickel, copper, chromium, molybdenum, iron, manganese, platinum, iridium, and aluminum.
4. The process test method of claim 1, wherein the performance parameter of the stress sensor comprises a resistance value of the stress sensor.
5. The process test method as claimed in claim 1, wherein the stress sensor includes a first stress sensor disposed adjacent to a read head in the magnetic head slider and a second stress sensor disposed at a predetermined reference point of the magnetic head slider, and the control unit determines whether the process parameter meets the specification based on a difference in performance parameters of the first stress sensor and the second stress sensor.
6. The process test method according to claim 1, wherein the stress sensor performs at least two measurements during the test of the sample, and the control means determines whether the sample meets the specification based on a difference between the two measurements.
7. The process test method according to claim 1, wherein in the sample test, a control group is provided, at least two measurements of the stress sensor are performed for the sample and the control group, respectively, and the control device determines whether the sample meets the specification based on a difference between the two measurements of the sample based on the compensation of the control group.
8. A magnetic head slider process test monitoring apparatus for use in the process test method of any one of claims 1 to 7, comprising: the monitoring unit and the control unit are connected with the monitoring unit; wherein,
the monitoring unit is connected with a stress sensor in a wafer for processing the magnetic head slider and is used for monitoring the performance parameters of the stress sensor in the processing process of the magnetic head slider;
and the control unit is used for determining whether the current processing parameters of a processing device for processing the magnetic head slider are suitable or not according to the performance parameters of the stress sensor, and sending an adjusting signal to the processing device to instruct the processing device to adjust the processing parameters when the current processing parameters are out of specification.
9. The process test monitoring device of claim 8, wherein the performance parameter of the stress sensor comprises a resistance value of the stress sensor.
10. A magnetic head slider processing apparatus for use in the processing test method according to any one of claims 1 to 7, comprising:
the processing device is used for processing a wafer into a magnetic head slider, and the wafer contains at least one stress sensor;
the control device is connected with the stress sensor in the wafer and used for monitoring the performance parameters of the stress sensor in the machining process of the magnetic head slider so as to determine whether the current machining parameters of the machining device are proper or not and sending an adjusting signal to the machining device when the current machining parameters are out of specification;
and the processing device adjusts the processing parameters according to the adjusting signal.
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| CN201610814757.3A CN107808675B (en) | 2016-09-09 | 2016-09-09 | Machining test method, machining test monitoring device and machining equipment for magnetic head slider |
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| CN201610814757.3A CN107808675B (en) | 2016-09-09 | 2016-09-09 | Machining test method, machining test monitoring device and machining equipment for magnetic head slider |
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| JP4145162B2 (en) * | 2003-02-18 | 2008-09-03 | 富士通株式会社 | Magnetic head slider lapping method and lapping apparatus |
| CN100495541C (en) * | 2005-01-26 | 2009-06-03 | 新科实业有限公司 | Thin-film magnetic head crystal wafer |
| CN102376310A (en) * | 2010-08-13 | 2012-03-14 | 新科实业有限公司 | Magnetic stripe for forming magnetic heads and method for manufacturing magnetic heads |
| US20130219699A1 (en) * | 2012-02-29 | 2013-08-29 | Sae Magnetics (H.K.) Ltd. | Manufacturing method of a slider and manufacturing apparatus thereof |
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