JP2015023113A - Flattening and grinding method of semiconductor substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a 3D through-electrode semiconductor substrate having a TTV (Total Thickness Variation) value of 0.1 μm or less and an in-plane uniformity of 3.0% or less.SOLUTION: In the middle of a conventional substrate flattening and grinding process using a numerical control grinding device 1 with a mechanism for tilting an axis angle of a cup wheel type grinding stone, a plurality of thicknesses (t) of the substrate measured in the flattening process are transmitted to a memory (ROM) of the numerical control device, and a correction flattening and grinding process of changing a grindstone axis moving amount and a grindstone axis tilting angle in consideration of a TTV value and an in-plane uniformity value calculated by an operation part, that are fed back to the numerical control grinding device 1, is added.

Description

  In the present invention, a flat semiconductor (TTV) value, which is a thickness variation distribution in the width direction of the substrate diameter after grinding a disk-shaped semiconductor substrate, is 0.1 μm or less, and the in-plane uniformity indicating the thickness variation is 3. The present invention relates to a method of manufacturing a planarized semiconductor substrate of 0% or less. The flattened semiconductor substrate obtained by the implementation of the present invention is a transistor, a capacitor, a memory card, a displacement sensor measuring element, an imaging element, etc., as a mobile phone, a digital camera, a video camera, a car navigation system, a personal computer, a game machine, a liquid crystal television. Used for John, printer, etc.

  It is known to manufacture a flattened semiconductor substrate excellent in TTV by using a grinding apparatus capable of tilting a grindstone axis with respect to a substrate on a work table. For example, in Japanese Patent Publication No. 1-52148 (Patent Document 1), a spherical recess is formed at the center of a spindle head that rotatably supports a spindle with a grinding tool attached to the tip, and the spindle head further slides. A spherical spindle tilting joint is fixed to the sliding member, and is coupled to the concave portion of the spindle head by a spherical surface. Disclosed is a spindle tilt adjusting mechanism of a grinding apparatus in which the sliding member and the spindle head are bolted to each other after being adjusted at right angles to the plane of the worktable.

  Japanese Patent Laid-Open No. 4-2011178 (Patent Document 2) discloses that the spindle is tilted by a holding mechanism so that the upper surface plate (tool) is not parallel to the lower surface plate (work table), and the outer peripheral side of the workpiece is After polishing the workpiece into a convex surface with the center angle of the workpiece as the elevation angle, and then polishing the concave surface with the center side of the workpiece as the depression angle and the outer periphery side of the workpiece as the elevation angle, the spindle is vertically aligned with the holding mechanism. A method is disclosed in which the workpiece surface is polished to a flat surface with a tool while holding the upper surface plate and the lower surface plate in parallel.

  Japanese Patent Application Laid-Open No. 8-170912 (Patent Document 3) discloses that a chuck mechanism is disposed on a rotary table below a spindle shaft having a grinding wheel at the lower end and is not affected by thermal expansion of the rotary table. A measuring method and a grinding method of a final finish grinding step of a semiconductor wafer vacuum-adsorbed on the upper surface of the chuck mechanism, wherein a two-point in-process gauge is provided independently on a peripheral portion of the chuck mechanism, the upper surface of the chuck mechanism In the state in which the semiconductor wafer is vacuum-adsorbed with the above-mentioned two-point in-process gauge, the measurement value of the most recessed portion between the most recessed portion of the processing surface of the semiconductor wafer and the upper surface of the chuck mechanism is measured. The most convex measurement value of the most convex part of the surface and the upper surface of the chuck mechanism is measured using the two-point in-process gauge, and the most convex measurement value A semiconductor, characterized in that a measurement value difference from the measurement value of the recess is obtained, and a final finish grinding process is performed in which the measurement value difference is ground by bringing the upper surface of the chuck mechanism and the lower surface of the grinding wheel as close as possible to a parallel state. A wafer measurement method and a grinding method are proposed.

Patent No. 3472784 patent specification (Patent Document 4) is a numerically controlled grinding apparatus for grinding a work material that is rotationally driven in a horizontal plane with a grindstone attached to a lower portion of a spindle head arranged in a vertical direction. Drive means for relatively moving the spindle head and the work material in the vertical z-axis direction, tilting means for rotating the spindle head or the work material around the x axis and the y axis in a horizontal plane, the drive means and the tilt Control means for controlling the means to change the feed amount of the spindle head and the relative inclination between the spindle head and the work material stepwise or continuously according to the stage of grinding, and from the processing start point of the grindstone for the work material The direction of the deepest incision point located between the machining end points from the center of the grindstone, and the machining material at the machining start point and the machining end point. Numerical control with a wheel axis angle adjustable, comprising means for calculating a feed amount in the z-axis direction and a rotation amount about the x-axis and about the y-axis, and an angle measurement means, using the difference in height of the wheel as an input parameter A grinding device is proposed. Also proposed is a semiconductor substrate grinding method in which the control means controls the feed amount of the spindle head and the relative inclination between the spindle head and the work material to be initially large and gradually small.

  Japanese Patent Laying-Open No. 2005-22059 (Patent Document 5) includes a turntable that holds and rotates a workpiece (workpiece) and a grinding tool (grinding wheel shaft) that is rotationally driven by attaching a cup wheel grinding wheel. A grinding machine for grinding a surface to be ground in a planar shape by relatively moving the object to be ground and the grinding tool in a state where the grindstone of the grinding tool is pressed against the object to be ground held on the turntable. In the grinding tool, a magnetic bearing for controlling the posture of the grinding tool is installed in the grinding tool, and a sensor for detecting a relative posture of the grinding tool with respect to an object to be ground and detection data detected by the sensor are used. And a posture control means for controlling the magnetic bearing so that the grinding tool assumes a preset posture, and the sensor is a relative position between the stationary member of the magnetic bearing and the grinding tool. Suggest grinding apparatus for a semiconductor substrate which is a displacement sensor for detecting a displacement in a plurality of locations.

Patent No. 5184910 (Patent Document 6) discloses a grinding head in which a cup wheel type grindstone supported by a grindstone shaft capable of rotation / linear movement is supported by a hydrostatic bearing and a magnetic bearing so as to be rotatable and linearly movable. Rotating / linearly acting combined actuator for rotating / linearly moving the grindstone shaft, a fixed plate having a grinding head fixed at the center of the lower surface so that the grindstone shaft is in the vertical direction, and a porous ceramic rotary provided below the grinding head A work wheel rotary table mechanism in which a chuck table is supported by a hollow spindle, and the hollow spindle is supported by a hydrostatic bearing, wherein a horizontal surface of the porous ceramic rotary chuck table is supported by the grindstone shaft. Work chuck rotary tape provided so as to be parallel to the bottom of the grinding wheel And a kinema coupling and a cylinder rod that move the fixing plate up and down at three positions of the apex of an equilateral triangle or an isosceles triangle with respect to the center point of the lower surface of the fixing plate provided with the grinding wheel shaft in the vertical direction. a surface grinding device for the substrate provided with a fixing plate lift mechanism 3 group comprising the fixed plate lifting mechanism, cross-section having a bore ball screw centrally fixed to the machine frame base surface of the workpiece chuck rotary table mechanism penetrates V Coupling female member having a hole through which a ball screw penetrates in the center and fitting to the inner wall of the V recess of the coupling female member. A ball screw installed through the hole and the through hole of the coupling female member on the vertical line, with the lower end at the work chuck rotary table Fixed at the bottom of the machine base of the machine mechanism by a fixing tool, and fixed at the upper end by a fixed fitting plate at the lower surface of the grinding head fixing plate. A ball screw to which an encoder and a ball screw threaded body are attached, and a tip of a ball screw capable of moving forward and backward by driving a micro servo motor in a space formed by a V recess of the coupling female member and a bottom surface of the coupling male member A fixed plate height position adjusting mechanism, wherein the fixed plate height position can be determined by contact between the wedge and the bottom surface of the coupling male member. A substrate surface grinding machine is proposed.

On the other hand, Japanese Patent No. 5219569 (Patent Document 7) is a wafer grinding apparatus comprising a grinding means for holding a wafer and grinding the wafer, and a feeding means for grinding and feeding the grinding means.
Detecting means for measuring the actual thickness of the wafer during the grinding process;
A calculation unit for calculating the feed amount of the grinding means during the grinding step;
A derivation unit that extracts the thickness of the wafer corresponding to the feed amount of the grinding means from pre-stored data during the grinding step;
During the grinding process, the wafer thickness extracted by the derivation unit is compared with the actual wafer thickness measured by the detection means, and the wafer thickness extracted by the derivation unit and the actual thickness are compared. Monitoring whether or not the difference between the wafer thickness is within a predetermined range and determining whether or not the back surface of the wafer is processed;
Using a wafer grinding apparatus comprising:
During the grinding process, calculate the feed amount of the grinding means,
During the grinding process, the wafer thickness corresponding to the feed amount of the grinding means is extracted from pre-stored data;
During the grinding process, the actual wafer thickness is measured,
During the grinding step, the wafer thickness corresponding to the feed amount of the grinding means is compared with the actual wafer thickness, and the wafer thickness corresponding to the feed amount of the grinding means and the actual thickness are compared. Monitoring whether the difference between the thickness of the wafer is within a predetermined range and determining whether the processing of the back surface of the wafer is good,
We propose a method for determining machining quality.

Patent No. 4875409 patent specification (Patent Document 8) was calibrated by a lever-type autonomous calibration method with respect to a standard straight ruler using two displacement meters A and B having the same measurement range, sensitivity, and resolution. Workpieces in which the rows of displacement gauges A and B can be moved in the left-right direction on a grinding wheel head mounted on a tool table that can be moved in the front-rear direction of a numerically controlled surface grinding machine by separating both displacement gauges A and B by a pitch distance p supported apart a distance p to face in the longitudinal direction of the table, through the following steps to measure the straightness S _a of the surface grinding work piece on the work table,
1) _A distance S _A (X _i ) between the standard straight ruler surface fixed on the work table by the relative movement of the work table and the displacement gauges A and B and the displacement gauges A and B probes, S _B (X <sub>i
+ P</sub> ) is detected and recorded in memory.
2) The difference {S _B (X _{i + p} ) −S _A (X _i )} between the two is calculated by the calculation unit, and between the reference surface of the surface ground workpiece and the probe electrode of the non-contact capacitive displacement meter A distance Z _0A of the difference between the distance Z _0B and the distance Z _0A, assuming that the distance Z _0B between the probe electrodes and the reference plane of the surface grinding was the non-contact type electrostatic capacity type displacement gauge B (Z _0B -Z _0A ) is stored in the memory.
3) Using the displacement meters A and B, the distances m ₁ (X _i ) and m ₂ (X _{i + p} ) between the surface of the workpiece to be ground on the work table and the probes of the displacement meters A and B are detected. , Memory.
4) The difference between the detected values m _2d (X _i ) = [m ₂ (X _{i + p} ) −m ₁ (X _i )] is calculated and stored.
5) the equation for m _{2d (X i)} / p is performed an operation of substituting _{{S B (X i + p} ) -S A (X i)}, the surface grinding of the m _{2d (X i)} / p Approximate it as a differential value df (X) / dX of the height displacement function f (X) of the object surface, and integrate this derivative from each value that was detected with the differential value represented by the following equation: Record in memory.
df (X) / dX≈ [f (X _{i + p} ) −f (X _i )] / p + {S _B (X _{i + p} ) −S _A (X _i )} / p
6) Output the displacement function f (X) obtained by integrating the derivative of the previous equation as a straightness displacement graph of the surface of the surface-ground workpiece measured by the displacement meter A, or the maximum value of the f (X) value. - to output a click value as straightness S _a of the surface grinding work piece.
Next,
The value of f (X _i ) output in the above step 6), S _A (X _i ) of the displacement meter A detected in step 1) and the value of m ₁ (X _i ) detected in step 3) The scanning motion error Ez (X _i ) is calculated by the following equation:
Ez (X _i ) = m ₁ (X _i ) −f (X _i ) + S _A (X _i )
This scanning motion error Ez (X _i ) is stored in the numerical controller,
The grinding wheel shaft of the grinding wheel head is rotatably provided by the relative movement of the surface grinding workpiece placed on the work table movable in the left-right direction of the numerically controlled surface grinding machine and the grinding wheel head. When the surface of the workpiece to be ground is ground at the work table coordinate position X _i by the grinding wheel, the vertical movement distance of the grinding wheel during the surface grinding of the workpiece is expressed as Ez (X _i We propose a surface grinding method for surface-ground workpieces, characterized in that surface grinding is performed while correcting the up and down movement.

Japanese Patent Publication No. 1-52148 JP-A-4-2011178 JP-A-8-170912 Patent No. 3472784 Patent Specification JP 2005-22059 A Japanese Patent No. 5184910 Patent No. 5219569 Patent Specification Patent No. 4875409 Patent Specification

  The tool (cup wheel type grinding wheel or polishing pad) described in Patent Document 1 to Patent Document 6 described above is capable of tilting a semiconductor substrate machine tool, a capacitance thickness meter or non-contact near-infrared light after flattening the substrate. The flatness (TTV value) of the flattened semiconductor silicon substrate using the sensor was improved to a value of 0.2 μm. However, in the grinding apparatus for semiconductor substrate capable of tilting the grinding wheel axis described in Patent Document 1 to Patent Document 6, the measurement of the thickness of the semiconductor substrate during planarization is on the circumference around the rotation center point of the semiconductor substrate, Since the angle of depression of the tool axis with respect to the semiconductor substrate surface is changed from 88.0 degrees to 90 degrees, flattening is performed, and therefore a ridge phenomenon is observed near the inner periphery of the flattened semiconductor substrate. Existence is the best value of TTV 0.2 μm. Therefore, in order to obtain a flattened semiconductor substrate having a TTV of 0.1 μm, a subsequent CMP flattening step has been required. Also, in-plane showing the thickness variation degree of the processed substrate flattened using a numerically controlled grinding machine that can tilt the through electrode substrate in which a large number of copper electrode columns with different diameters are provided on the silicon substrate with different dispersion density. The uniformity value is 10 to 15%, and the protruding height of the cued copper electrode from the silicon substrate surface is different from 50 nm to 18 μm. Manufacturers of through-electrode semiconductor devices are requesting that the TTV value of the planarized through-electrode substrate be 0.1 μm or less and the in-plane uniformity be 3% or less.

  The inventors of the present application feed back the physical property value (thickness or straightness) of the workpiece (workpiece) subjected to the above-described flattening grinding process described in Patent Document 7 or Patent Document 8 to a numerically controlled machine tool to provide a new workpiece. In view of applying the method of flattening the grinding object to the above-mentioned machine tool for semiconductor substrate capable of tilting the tool axis, the non-contact sensor of the linear movement type is used to determine the thickness of the substrate in the radial direction during the flattening processing. Measured by, and recorded in the memory unit (ROM) of the numerical control device (CPU), calculated the TTV curve by the arithmetic unit of the numerical control device, recorded the TTV curve in the memory unit, and fed back to the numerical control machine tool Then, the inventors studied to planarize a new semiconductor substrate and came up with the present invention.

  An object of the present invention is to provide a method for planarizing a semiconductor substrate, from which a planarized semiconductor substrate having a TTV value of 0.1 μm or less and an in-plane uniformity of 3% or less can be obtained.

The invention of claim 1 uses a numerically controlled grinding apparatus capable of tilting a cup wheel grinding wheel axis, and a plurality of displacements in which a non-contact sensor of a linear motion type or a plurality of non-contact sensors are arranged in parallel in the radial direction of the substrate. The thickness (t _i ) of the semiconductor device that is being ground is measured using a sensor, the value (t _i ) is transmitted to the memory unit of the numerical controller, and a TTV curve is created by the calculation unit. A semiconductor substrate by a cup wheel type grinding wheel that calculates an in-plane uniformity value and feeds back the TTV value and the in-plane uniformity value from the numerical control device to the numerical control grinding device while storing them in the memory unit ( Work) In a semiconductor substrate flattening grinding method for surface flattening,
The thickness of the semiconductor substrate corresponding to the feed amount of the cup wheel grinding wheel shaft is calculated during the grinding process, while calculating the feed amount of the cup wheel grinding wheel shaft during the grinding process. (T ₀ ) is extracted from data stored in the memory unit in advance,
Measuring the thickness (t _i ) of the actual semiconductor substrate during the planarization process;
During the flattening step, the thickness (t ₀ ) of the semiconductor substrate corresponding to the feed amount of the cup wheel grinding wheel shaft is compared with the actually measured thickness (t _i ) of the semiconductor substrate. The difference between the thickness (t ₀ ) of the semiconductor substrate corresponding to the feed amount of the cup wheel grinding wheel shaft and the actually measured thickness (t _i ) of the semiconductor substrate is within a desired TTV value range (
The determination unit of the numerical controller determines whether or not it is 0.1 μm or less) and the in-plane uniformity value transmitted from the calculation unit to the memory unit is a desired in-plane uniformity value (3 % Or less) is monitored by the determination unit of the numerical controller.
When the determined TTV value, in-plane uniformity value, and processed semiconductor substrate thickness (t _e ) are within the desired thickness (T _e ) range, the semiconductor substrate is planarized by a cup wheel grinding wheel Finish processing
If any one of the determined TTV value and in-plane uniformity value and the thickness (t _e ) of the ground semiconductor substrate is outside the desired range, the feed amount of the cup wheel grinding wheel shaft and the planarization grinding by cup wheel grinding wheel of the semiconductor substrate by changing the cup wheel grinding wheel axis inclination angle, TTV value to be determined, in-plane uniformity value, and processed semiconductor substrate having a thickness (t _e ) Continue until everything is within the desired range,
The present invention provides a method for flattening and grinding a semiconductor substrate.

  The invention according to claim 2 is that the distance between the grinding wheel edge that is not used for surface grinding of the semiconductor substrate of the cup wheel grinding wheel during the planarization processing for the semiconductor substrate by the cup wheel grinding wheel is 5 to 5 Grinding stone blade cleaning (pressure water dressing) to wash away foreign matter such as electrode grinding waste, insulating layer grinding waste, resin grinding waste, etc. adhering to the grinding wheel blade by spraying cleaning water with a pressure of 3-20 MPa from the nozzle outlet located at 20 mm position. The present invention provides a method for planarizing and grinding a semiconductor substrate according to claim 1.

  By adopting a feedback grinding process with thickness measurement in the radial direction of the semiconductor substrate in the middle of the conventional grinding process, a flat surface with a TTV value of 0.1 μm or less and an in-plane uniformity value of 3.0% or less A ground semiconductor substrate can be obtained. Further, by adding the pressurized water dressing process of the cup wheel type grinding wheel, the wiring metal (Cu, AG, Al) grinding dust contamination (Smearing) problem on the surface of the 3D through electrode semiconductor substrate is solved.

FIG. 1 is a front view of a numerically controlled grinding apparatus showing a state in which a semiconductor substrate is flattened. FIG. 2 is a block diagram showing a procedure for planarizing the semiconductor substrate. FIG. 3 is a diagram illustrating a change in the TTV curve of a planarized semiconductor substrate created during the planarized semiconductor substrate planarization process.

  Hereinafter, the planarization method of the semiconductor substrate (work) w using a cup wheel grinding wheel will be described in detail with reference to FIGS. 1 and 2.

Example 1
(1). The semiconductor substrate w is placed on the porous ceramic chuck table 2a of the grinding apparatus 1 capable of adjusting the cup wheel grinding wheel axis angle.

(2). The thickness (T ₀ ) of the workpiece before grinding, the thickness of the desired flat processed workpiece (T _e ), and the thickness of the semiconductor substrate corresponding to the feed amount of the cup wheel grinding wheel axis are stored in the memory section (ROM) of the numerical controller. (T ₀ ), a desired upper limit TTV value (0.1 μm), a desired upper limit in-plane uniform value (3.0%), a measurement position (i) of the displacement sensor, and the number of measurement points.

The thickness (t _i ) of a semiconductor device using a non-contact displacement sensor (near-infrared light displacement sensor) of a linear motion type using a numerically controlled semiconductor substrate flattening apparatus 1 capable of tilting a cup wheel grinding wheel axis. Cup wheel type, while transmitting the value (t _i ) to the memory unit (ROM) of the numerical control device, calculating the TTV value in the arithmetic unit, and creating the TTV curve and storing it in the memory unit Flattening grinding of the surface of the semiconductor substrate w by the grinding wheel 3 is started.

  Specifically, a cup wheel type grinding wheel shaft is used in accordance with a command from a grinding program stored in a storage unit (RAM) of the numerical control device using the numerical control semiconductor substrate flattening processing device 1 shown in FIG. The surface of the semiconductor substrate is flattened while changing the feed amount of the wheel (inclination angle of the grinding wheel axis, infeed cutting amount of the cup wheel grinding wheel 3, position coordinates where the grinding wheel 3 g of the cup wheel grinding wheel 3 contacts the semiconductor substrate surface). Processing. The change in the inclination angle of the grindstone axis may be as usual, starting at 88 degrees and ending at 90 degrees (the upper surface of the semiconductor substrate and the lower surface of the grindstone blade are parallel). Further, a plurality (three in FIG. 1) of non-contact displacement sensors may be arranged side by side in the radial direction of the semiconductor substrate, or one non-contact displacement sensor of linear motion type is linearly arranged in the radial direction of the semiconductor substrate. It may be moved and monitored.

The numerically controlled grinding apparatus 1 includes a substrate suction chuck mechanism 2 in which a substrate chuck 2a is supported on a rotating shaft 2b, a grinding wheel head 3 including a cup wheel type grinding wheel 3a having a high grinding number supported on a grinding wheel shaft 3b, and the grinding. the grinding wheel cutting edge 3a _g of the grinding wheel comprises a grinding liquid supply nozzle 5 for supplying a grinding fluid to a surface cleaning liquid injection device 4 and the through electrode with the ceramic substrate through electrode is formed with a nozzle 4a of the high-pressure jet cleaning.

  The cup wheel type grinding wheel 3 can use a vitriaide bond wheel, a metal bond wheel, a resin bond wheel, etc. using diamonds of diamond numbers # 300 to # 1,200, cBN, and SiC as abrasive materials. . Among them, the diamond vitrified bond cup wheel type grinding wheel is excellent in terms of surface flatness finish (in-plane uniformity) and grinding speed.

  As the grinding fluid supplied from the grinding fluid supply nozzle 5, pure water is generally used, but depending on the type of the semiconductor substrate material (silicon, glass, ceramic) and the metal of the electrode material (copper, aluminum, silver), pure water may be used. An ethanolamine aqueous solution other than water, a tetramethylammonium hydroxide aqueous solution, a caustic potash aqueous solution, a conductive aqueous solution such as acetic acid or hydrochloric acid, a silica water dispersion, a ceria aqueous dispersion, an alumina aqueous dispersion, or the like may also be used.

As the cleaning liquid supplied from the nozzle 4a of the cleaning liquid injection device 4, the above-described grinding liquid may be used, but pure water is generally used from the viewpoint of wastewater treatment. Injection angle to the grindstone blade 3a _g of washing water, 3 to 20 degrees, preferably, 5 to 18 degrees of fan shape.

  As the cleaning liquid injection device 4, a precision high-pressure jet water cleaning machine “HPMJ AFS5400S” (trade name) manufactured by Asahi Sunac Corporation can be used.

Cue grinding work of the copper through electrode that performs surface flattening of the silicon substrate (workpiece) w on which the copper through electrode is formed by using the cup wheel type grinding wheel grinding wheel 3g of the numerical control grinding apparatus 1 is a rotation. by the shaft 2b 100~150min ^-1 rotated to rotate the workpiece while the grinding wheel shaft 3b of Kotsubudo cup wheel grinding wheel 3a 1,200~2,000min ^-1 rotated downward by 30 [mu] m / min lowering speed by, with the finish grinding of the workpiece to the desired amount of thickness is rubbed grinding wheel cutting edge 3a _g on the workpiece w surface of the cup wheel grinding wheel (2 to 50 [mu] m) is reduced, during the grinding The grindstone cutting edge 3a of the outer region of the porous ceramic table 2a not subjected to the surface grinding of the semiconductor substrate of the cup wheel grinding wheel Copper electrode grinding debris adhered to the grinding wheel by injecting cleaning water with a pressure of 3 to 20 MPa, preferably 10 to 12 MPa from the nozzle outlet 4a located at a distance of 5 to 20 mm from the grinding wheel to _g. A grinding wheel cleaning process (pressurized water dressing) for washing away scraps, resin grinding scraps and the like is performed. During the grinding process, the grinding liquid is supplied from the grinding liquid supply nozzle 5 to the surface of the workpiece at a rate of 10 to 20 liters / minute.

(3). During the flattening grinding process of the semiconductor substrate surface, the feed amount of the cup wheel type grinding wheel shaft 3a is calculated by a calculation unit of a numerical controller (CPU), and the cup wheel during the flattening process. The thickness (t ₀ ) of the semiconductor substrate corresponding to the feed amount of the die grinding wheel shaft is extracted from the data stored in the memory unit in advance.

(4). During the flattening grinding process, the actual thickness (t _i ) of the semiconductor substrate is simultaneously measured by three near infrared light displacement sensors.

(5). Further, during the flattening process, the thickness (t ₀ ) of the semiconductor substrate corresponding to the feed amount of the cup wheel type grinding wheel shaft is compared with the actually measured thickness (t _i ) of the semiconductor substrate. In addition, the absolute value of the difference between the thickness (t ₀ ) of the semiconductor substrate corresponding to the feed amount of the cup wheel grinding wheel shaft and the thickness (t _i ) of the actually measured semiconductor substrate | t _i −t ₀ | is monitored by the determination unit of the numerical control device to determine whether it is within a desired TTV value range (0.1 μm or less), and the measured semiconductor substrate stored in the memory unit is monitored. The thickness variation from the thickness (t _i ) is calculated by the calculation unit, and monitoring is performed to determine whether the in-plane uniformity value is within a desired value (3% or less) by the determination unit of the numerical controller.

(6). When the determined TTV value and in-plane uniformity value and the thickness (t _e ) of the processed semiconductor substrate are within a desired range (T _e ), the semiconductor substrate is planarized by a cup wheel grinding wheel. Exit.

(7). If any one of the TTV value and the in-plane uniformity value determined in the step (5) and the thickness (t _e ) of the processed semiconductor substrate is outside the desired range, the cup wheel grinding wheel shaft Returning to the step (5) in which the feed amount and the grindstone axis angle are changed, the flattening grinding process of the semiconductor substrate by the cup wheel type grinding grindstone is performed, the TTV value to be determined, the in-plane uniformity value, and the thickness of the processed semiconductor substrate all (t _e) is continued until the desired range, then reaches the above step (6) ends.

  As can be seen from the multiple TTV curves shown in FIG. 3, as the feedback flattening grinding process progresses, the resulting TTV curve changes from the top TTV curve to the bottom TTV curve. The lowest TTV curve shows the physical properties of the planarized and ground copper through-electrode semiconductor substrate with a TTV of 0.094 μm and an in-plane uniformity of 2.8%. It is understood that Accordingly, a planarized copper through electrode semiconductor substrate that satisfies the demands of the semiconductor device manufacturer can be provided.

1 Grinding device w Silicon substrate on which copper through electrode is formed (to-be-ground object)
DESCRIPTION OF SYMBOLS 2 Substrate chuck mechanism 2a Vacuum chuck table 2b Rotary shaft of vacuum chuck table 3 Cup wheel type grinding wheel 3ag Cup wheel type grinding wheel edge 3b Cup wheel type grinding wheel shaft 4 Cleaning fluid injection device 4a High pressure jet cleaning nozzle 5 Grinding fluid Supply nozzle

Claims (2)

It is ground using a numerically controlled grinding machine capable of tilting the cup wheel type grinding wheel axis, using a non-contact sensor of linear motion type or a plurality of non-contact sensors arranged in parallel in the radial direction of the substrate. The thickness (t _i ) of the semiconductor device being measured is measured, the value (t _i ) is transmitted to the memory unit of the numerical controller, a TTV curve is created by the calculation unit, the TTV value is calculated, and in-plane uniformity The surface of the semiconductor substrate (work) is planarized by a cup wheel grinding wheel that calculates a value and feeds back the TTV value and the in-plane uniformity value to the numerical control grinding device from the numerical control device while storing them in the memory unit. In the semiconductor substrate flattening grinding method,
The thickness of the semiconductor substrate corresponding to the feed amount of the cup wheel grinding wheel shaft is calculated during the grinding process, while calculating the feed amount of the cup wheel grinding wheel shaft during the grinding process. (T ₀ ) is extracted from data stored in the memory unit in advance,
Measuring the thickness (t _i ) of the actual semiconductor substrate during the planarization process;
During the flattening step, the thickness (t ₀ ) of the semiconductor substrate corresponding to the feed amount of the cup wheel grinding wheel shaft is compared with the actually measured thickness (t _i ) of the semiconductor substrate. The difference between the semiconductor substrate thickness (t ₀ ) corresponding to the feed amount of the cup wheel grinding wheel axis and the actually measured semiconductor substrate thickness (t _i ) is within a desired TTV value range. Whether or not the in-plane uniformity value transmitted from the calculation unit to the memory unit is at a desired in-plane uniformity value. Performs monitoring to be determined by the determination unit,
When the determined TTV value, in-plane uniformity value, and processed semiconductor substrate thickness (t _e ) are within the desired value range, the semiconductor substrate is planarized by a cup wheel grinding wheel. Exit
If any one of the determined TTV value and in-plane uniformity value and the thickness (t _e ) of the ground semiconductor substrate is outside the desired range, the feed amount of the cup wheel grinding wheel shaft and the planarization grinding by cup wheel grinding wheel of the semiconductor substrate by changing the cup wheel grinding wheel axis inclination angle, TTV value to be determined, in-plane uniformity value, and processed semiconductor substrate having a thickness (t _e ) Continue until everything is within the desired range,
A method for planarizing and grinding a semiconductor substrate.   Nozzle outlet located at a distance of 5 to 20 mm from the grinding wheel edge that is not used for surface grinding of the semiconductor substrate of the cup wheel grinding wheel during the planarization of the semiconductor substrate by the cup wheel grinding wheel The grinding wheel cleaning is performed to wash away foreign matters such as electrode grinding waste, insulating layer grinding waste, and resin grinding waste adhering to the grinding wheel blade by spraying cleaning water at a pressure of 3 to 20 MPa. A method for flattening and grinding a semiconductor substrate.

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