JP2007220775A - Grinder for semiconductor substrate, and method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinder for a semiconductor substrate capable of keeping high sizing accuracy of the finished thickness of the semiconductor substrate, even if a thickness of a protective member varies among semiconductor substrates when grinding the rear of the semiconductor substrate with the protective member attached to the surface, and to provide a method of manufacturing a semiconductor device. <P>SOLUTION: Two measurement mechanisms are provided, including a measuring apparatus 10 for continuously measuring a thickness X<SB>2</SB>of the protective member 2 attached to the semiconductor substrate 1 when grinding, and a contact gauge 8 for continuously measuring a total thickness X<SB>3</SB>of the substrate 1 and the member 2 when grinding. The thickness X<SB>1</SB>of the semiconductor substrate 1 is calculated from the difference (X<SB>3</SB>-X<SB>2</SB>) of the respective measurements of each substrate 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor substrate grinding apparatus and a semiconductor device manufacturing method, and more particularly to a mechanism for improving the finished thickness dimensional accuracy when grinding the back surface of a semiconductor substrate having a protective member attached to the surface.

  Conventionally, in a power semiconductor device, a vertical semiconductor device is used in which electrodes are provided on both main surfaces of a semiconductor substrate and current flows in the thickness direction of the substrate. In the vertical semiconductor device, the loss is reduced and the characteristics are improved by forming the substrate with a small thickness. However, if the substrate is too thin, a breakdown voltage is generated, and if it is too thick, the electrical loss is increased. Further, as the substrate becomes thinner, the thickness tolerance for maintaining the characteristics becomes smaller. For example, a device having a thickness of about 130 μm requires a thickness dimensional accuracy of about ± 5 μm.

  In order to make the semiconductor substrate have a desired thickness, a protective film is formed on the gate structure or electrode formed on the surface using a wafer that is thick to some extent, and a protective member for surface protection is attached, A method of grinding the back surface of the wafer with a grindstone is common.

As a method for measuring the thickness dimension of a semiconductor substrate during or after grinding, for example, Patent Document 1 discloses a wafer polishing surface position measuring device that measures the thickness of a workpiece using a laser displacement meter. Yes. Further, in Patent Document 2, a wafer thickness and thickness change amount measuring device for calculating a wafer thickness change amount by detecting a change amount of a wafer back surface position and a change amount of a wafer grinding surface position, respectively. Is disclosed. However, these Patent Documents 1 and 2 introduce a method of grinding a semiconductor substrate before forming a semiconductor element on the surface of the substrate, and no protective member for protecting the surface is used. When these apparatuses of Patent Document 1 and Patent Document 2 are used for grinding a semiconductor substrate having a protective member attached to the surface, the total thickness of the protective member and the semiconductor substrate is measured.
JP-A-10-199951 Japanese Patent Laid-Open No. 10-160420

  In the conventional semiconductor substrate grinding apparatus, when setting the remaining thickness after grinding, the total value of the target substrate thickness and the protective member thickness is set. At this time, as the thickness of the protective member, it is common to refer to the value in lot units indicated at the time of shipment inspection from the manufacturer. However, when the protective member is attached to the semiconductor substrate, the thickness changes due to a tensile force or a pressing force, and the thickness of the protective member increases over time to release the stress introduced by the force even after the protective member is attached. Change again. In addition, the tensile force and pressing force when the protective member is attached to the semiconductor substrate are not always constant, and the time after application is also different, so when grinding, even between the same lots, it protects between the semiconductor substrates. There is variation in the thickness of the members.

  For this reason, when the total value (target value) of the thickness of the semiconductor substrate and the protective member is set to be constant for all the substrates during grinding, the semiconductor substrate after grinding is caused by variations in the thickness of the protective member between the semiconductor substrates. There is a problem that variations in the finished thickness dimension occur. For example, if the actual thickness of the protective member is smaller than the thickness of the protective member set during grinding, the semiconductor substrate after grinding becomes thicker than the target thickness, which affects the electrical characteristics of the device. There is.

  The present invention has been made to remedy the above problems, and when grinding the back surface of a semiconductor substrate having a protective member deposited on the surface, the thickness of the protective member varies between the semiconductor substrates. However, it is an object of the present invention to provide a semiconductor substrate grinding apparatus and a semiconductor device manufacturing method capable of maintaining a high finished thickness dimensional accuracy of a substrate and obtaining a highly reliable device with stable electrical characteristics.

A semiconductor substrate grinding apparatus according to a first aspect of the present invention includes a grinding wheel and a table while holding a protective member side of a semiconductor substrate having a protective member attached to a surface on a table and pressing the grinding wheel against the back surface of the semiconductor substrate. the rotated relative to a grinding apparatus for a semiconductor substrate of grinding the back surface of the semiconductor substrate protection, a first measuring mechanism for measuring the thickness X ₂ of the protective member which is deposited on the semiconductor substrate, a semiconductor substrate a second measurement mechanism for continuously measuring the total thickness X ₃ members during grinding, the difference between each measurement value measured by the first measuring mechanism and second measurement mechanism (X ₃ -X ₂ ) determine the thickness X ₁ of the semiconductor substrate from, in which a control mechanism to terminate the grinding when it becomes equal to the thickness X ₀ of the thickness X ₁ of the semiconductor substrate is a semiconductor substrate target.

The semiconductor substrate polishing apparatus according to the second aspect of the present invention is such that a protective member side of a semiconductor substrate having a protective member attached to the surface is held on a table, and the grinding wheel is pressed against the back surface of the semiconductor substrate. and a table are relatively rotated, a grinding apparatus for a semiconductor substrate of grinding the back surface of the semiconductor substrate, the protective member is a semiconductor substrate coated, the thickness X ₁ of the semiconductor substrate only continuously during grinding a third measuring mechanism for measuring, and a control mechanism to terminate the grinding when the third thickness X ₁ of the semiconductor substrate measured by the measuring mechanism is equal to the thickness X ₀ to the semiconductor substrate target Is.

The method of manufacturing a semiconductor device according to the first aspect of the present invention includes a step of forming an electrode on a surface of a semiconductor substrate, and a semiconductor in a state where a protective member for protecting the electrode is attached to the surface of the semiconductor substrate. a method of manufacturing a semiconductor device comprising the step of grinding the back surface of the substrate, a step of grinding the back surface of the semiconductor substrate, the thickness X ₂ of the protective member which is applied to the semiconductor substrate while grinding the back surface of the semiconductor substrate the total thickness X ₃ of the semiconductor substrate protecting member, respectively a first step of continuously measuring a thickness X ₂ of the measured protective member in the first step, the total of the semiconductor substrate and the protective member in search of thickness X ₁ of the semiconductor substrate from the difference between each measurement value of the thickness _{X 3 (X 3 -X 2)} , the thickness X ₁ of the semiconductor substrate is equal to the thickness X ₀ to the semiconductor substrate target time Research It is intended to include a second step of terminating the.

According to a second aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: forming an electrode on a surface of a semiconductor substrate; and applying a protective member for protecting the electrode to the surface of the semiconductor substrate. a method of manufacturing a semiconductor device comprising the step of grinding the back surface of the substrate, a step of grinding the back surface of the semiconductor substrate, the thickness X ₂ of the protective member which is deposited on the surface of the semiconductor substrate before starting the grinding The first step of measuring at three or more locations in the surface of the semiconductor substrate and _obtaining an average value X _2m of those measured values, and continuously adding the total thickness X ₃ of the semiconductor substrate and the protective member while grinding the back surface of the semiconductor substrate to measure, the thickness X ₃ of the total, the grinding when the sum (X _{2m + X 0)} and is equal to the thickness X ₀ to a mean value X _2m and the semiconductor substrate target of the thickness of the protective member 2nd to finish These steps are included.

Furthermore, the method of manufacturing a semiconductor device according to the third aspect of the present invention includes a step of forming an electrode on the surface of the semiconductor substrate, and a semiconductor in a state where a protective member for protecting the electrode is attached to the surface of the semiconductor substrate. A method of manufacturing a semiconductor device including a step of grinding a back surface of a substrate, wherein the step of grinding the back surface of the semiconductor substrate includes only a semiconductor substrate having a protective member attached while grinding the back surface of the semiconductor substrate. the thickness X ₁ ends a first step of continuously measuring, grinding when the thickness X ₁ of the semiconductor substrate measured by the first step is equal to the thickness X ₀ to the semiconductor substrate target And a second step.

Grinding apparatus of a semiconductor substrate according to the first aspect of the present invention, the thickness X ₂ of the protecting member in a state of being deposited on the semiconductor substrate is measured and the difference between the semiconductor substrate and the total thickness X ₃ of the protective member (X ₃ since the -X ₂₎ to obtain the thickness X ₁ of the semiconductor substrate, even if there are variations in the thickness of the protective member between the semiconductor substrate each other can be determined thickness X ₁ of the semiconductor substrate accurately. As a result, the semiconductor substrate has a higher finished thickness dimensional accuracy, and a highly reliable semiconductor device with stable electrical characteristics can be obtained.

Further, in the polishing apparatus of a semiconductor substrate according to the second aspect of the present invention, the semiconductor substrate a protective member is deposited, since the thickness X ₁ of the semiconductor substrate only as to continuously measure during grinding, protective The influence of the thickness variation of the members can be ignored, the finished substrate thickness accuracy is increased, and a highly reliable semiconductor device with stable electrical characteristics can be obtained.

In the semiconductor device manufacturing method according to the first aspect of the present invention, the thickness X _{2 of the} protective member attached to the semiconductor substrate while grinding the back surface of the semiconductor substrate, and the total thickness X of the semiconductor substrate and the protective member. ₃ is measured continuously, and the thickness X _{1 of the} semiconductor substrate is obtained from the difference (X ₃ −X ₂ ) between the measured values, so even if there is a variation in the thickness of the protective member between the semiconductor substrates , it is possible to obtain the thickness X ₁ of the semiconductor substrate accurately, further, be the thickness X ₂ of the protective member, the load of the grinding wheel is not changed, that determine the thickness X ₂ of the protecting member at the time of change exactly it can. As a result, it is possible to manufacture a highly reliable semiconductor device with high finished thickness dimensional accuracy of the semiconductor substrate and stable electrical characteristics.

In the second aspect a method of manufacturing a semiconductor device according to the present invention, the thickness X ₂ of the protective member which is deposited on the surface of the semiconductor substrate measured in three or more locations in the semiconductor substrate surface, of those measurements Since the average value X _2m is obtained, the thickness variation of the protective member in the semiconductor substrate surface is averaged, and a more accurate protective member thickness is obtained. As a result, it is possible to manufacture a highly reliable semiconductor device with high finished thickness dimensional accuracy of the semiconductor substrate and stable electrical characteristics. Moreover, since so as to measure the thickness X ₂ of the protective member before starting the grinding, there is no need to provide a measuring mechanism for measuring the thickness X ₂ of the protective member to the grinding apparatus, inexpensive grinding apparatus with a simple structure Can be used.

Furthermore, in the third aspect a method of manufacturing a semiconductor device according to the present invention, while grinding the back surface of the semiconductor substrate, the protective member is a semiconductor substrate coated, continuously measuring the thickness X ₁ of the semiconductor substrate only since the way, it is possible to ignore the influence of the variation in thickness of the protective member, it is possible to determine the thickness X ₁ of the semiconductor substrate accurately. As a result, it is possible to manufacture a highly reliable semiconductor device with high finished thickness dimensional accuracy of the semiconductor substrate and stable electrical characteristics.

Embodiment 1 FIG.
Hereinafter, a first embodiment which is the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a main part showing a semiconductor substrate grinding apparatus according to Embodiment 1 of the present invention. A grinding apparatus 100 according to the present embodiment is a table that grinds the back surface 1b of a semiconductor substrate 1 having a protective member 2 attached to the front surface 1a and holds the semiconductor substrate 1 on the protective member 2 side by suction. A chuck table 3 and a cup-type grinding wheel 4 having a width of 2 to 4 mm are provided.

  A spindle 5 and a rotating shaft of a motor (not shown) are connected to the chuck table 3. The grinding wheel 4 is connected to a spindle 6 and a rotating shaft of a motor (not shown), and the chuck table 3 and the grinding wheel 4 are rotated by driving these motors. Further, the grinding wheel 4 is installed so as to be movable in the vertical direction by the drive mechanism 7. At the time of grinding, the grinding wheel 4 and the chuck table 3 are rotated relative to each other while the grinding wheel 4 is pressed against the back surface 1b of the semiconductor substrate 1 by the drive mechanism 7, and the back surface 1b of the semiconductor substrate 1 is ground.

Further, the grinding apparatus 100 of this embodiment, as the first measuring mechanism for measuring the thickness X ₂ of the protective member 2 which is deposited on the surface 1a of the semiconductor substrate 1, provided with a window member 9 and the measuring device 10 Yes. The window member 9 is formed by filling a through-hole formed in the chuck table 3 with a transparent member, and can face the protective member 2. In addition, as for the shape of the through-hole with which the window member 9 is filled, it is desirable to form in the taper shape as shown in FIG. As a result, the chuck table 3 and the window member 9 can be easily fitted, and the window member 9 region exposed to the surface 3a of the chuck table 3 can be reduced, so that the semiconductor substrate 1 and the protection member 2 can be firmly held.

The window member 9 below the substrate holding surface 3a that faces surface 3b of the chuck table 3, the measurement device measures the thickness X ₂ continuously protected member 2 in a non-contact at the time of grinding 10, for example, manufactured by Keyence Corporation LK- 36 is installed. Measuring device 10, the light 11 from the light projecting unit irradiates the protective member 2 through the window member 9, to measure the thickness X ₂ of the protective member 2. As a measuring method, for example, a method of converting the horizontal distance between the optical paths of the reflected light from the front surface 2 a and the reflected light from the back surface 2 b of the protective member 2 into the thickness of the protective member 2 can be used. However, the measuring method of a measuring apparatus 10 for measuring the thickness X ₂ of the protective member 2 is not limited thereto.

Further, the grinding apparatus 100, the total thickness X ₃ of the semiconductor substrate 1 and the protective member 2 as a second measurement mechanism continuously measuring during grinding, and a contact gauge 8. The contact gauge 8 continuously measures the distance from the substrate holding surface 3a of the chuck table 3 to the back surface 1b of the semiconductor substrate 1, that is, the total thickness X3 of the semiconductor substrate 1 and the protection member 2 during grinding.

Furthermore, the grinding apparatus 100 obtains the thickness _{X 1} of the semiconductor substrate 1 from the difference between each measurement value measured by the measuring device 10 and a contact gauge 8 _(X 3 -X _2), the thickness _{X 1} of the semiconductor substrate 1 Is a control mechanism (not shown) that instructs the drive mechanism 7 to stop the lowering of the grinding wheel 4 and terminates the grinding when it becomes equal to the target thickness X ₀ (set value) of the semiconductor substrate 1 set in advance. )).

Thus, the grinding apparatus 100 according to this embodiment includes a measuring device 10 for measuring the thickness X ₂ of the protecting member 2, a contact gauge 8 for measuring the total thickness X ₃ of the semiconductor substrate 1 and the protective member 2 includes two measurement mechanisms, at the time of grinding, these total thickness X ₃ and the protective member 2 of the difference between the thickness X ₂ of the semiconductor substrate 1 and measured by the measuring mechanism protective member 2 (X ₃ -X ₂₎ perform grinding while seeking thickness X ₁ of the semiconductor substrate 1 from the thickness X ₁ of the semiconductor substrate 1 is, when it becomes equal to the thickness X _{0 (set} value) as a target of the semiconductor substrate 1, according to an instruction of the control mechanism The drive mechanism 7 stops the grinding wheel 4 from descending and finishes the grinding.

  Note that a member 12 having substantially the same weight as the measuring device 10 is attached to the chuck table 3 at a point-symmetrical position with respect to the measuring device 10 about the rotation axis. Thereby, the balance of the weight balance at the time of rotation of the spindle 5 is maintained, and vibration generated when the chuck table 3 is rotated is suppressed.

In the present embodiment it has been installed a measuring device 10 for measuring the thickness X ₂ of the protective member 2 in one place, in order to suppress the influence of variation in thickness of the protective member 2 in the semiconductor substrate in-plane, the measuring device 10 may be installed at a plurality of locations. In that case, the plurality of measuring devices 10 may be installed in consideration of the weight balance without using the member 12. For the reason described in the second embodiment described later, it is desirable to measure the thickness X ₂ of the protective member 2 at three or more locations in the surface of the semiconductor substrate 1, and the control mechanism uses an average value X _2m of those measured values. Is preferably used as the thickness of the protective member 2.

  Next, a method for manufacturing a semiconductor device in the present embodiment will be briefly described. The method for manufacturing a semiconductor device in the present embodiment is a method for manufacturing a vertical semiconductor device such as a power semiconductor device, for example, and includes a gate structure and an electrode formed on the surface 1a of the semiconductor substrate 1 by a film forming process, a photoengraving process, and the like. (Both not shown) and the like, and a step of grinding the back surface 1b of the semiconductor substrate 1 in a state where the protective member 2 for protecting these electrodes and the like is attached to the front surface 1a of the semiconductor substrate 1. Is included.

The process of grinding the back surface 1b of the semiconductor substrate 1 is performed using, for example, the grinding apparatus 100 shown in FIG. 1, and includes the following two steps. First, the thickness X ₂ of the protective member 2 attached to the semiconductor substrate 1 while grinding the back surface 1 b of the semiconductor substrate 1 and the total thickness X ₃ of the semiconductor substrate 1 and the protective member 2 are measured with the measuring device 10 and the contact gauge. 8 are measured continuously (first step). Subsequently, the thickness X ₂ of the protective member 2 measured in the first step, the semiconductor substrate from each of the difference between the measured value of the total thickness X ₃ of the semiconductor substrate 1 and the protective member 2 (X 3 _{-X 2)} 1 obtains the thickness X _1, and ends the grinding when it becomes equal to the thickness X _{0 (set} value) of thickness X ₁ of the semiconductor substrate 1 is the target of the semiconductor substrate 1 (second step).

As described above, according to this embodiment, the measuring device 10 for measuring the thickness X ₂ of the protective member 2 which is applied to the semiconductor substrate 1, the total thickness X ₃ of the semiconductor substrate 1 and the protective member 2 By providing two measuring mechanisms of the contact gauge 8 to be measured, the thickness X ₂ of the protective member 2 and the total thickness X _{3 of} the protective member 2 and the semiconductor substrate 1 are measured for each semiconductor substrate 1. the thickness _{X 1} of the semiconductor substrate 1 from the difference between the measured value _(X 3 -X ₂₎ can be obtained accurately. That is, even the thickness X ₂ of the protective member 2 is not varied between the semiconductor substrate 1 cross, it can be kept high finishing thickness dimensional precision of the thickness X ₁ semiconductor substrate 1, is stable and reliable electrical properties You can get a device.

Further, the thickness X ₂ continuously protective member 2 at the time of grinding, in order to measure the total thickness X ₃ of the protection member 2 and the semiconductor substrate 1, protected by the load due to lowering of the grinding wheel 4 during the grinding member 2 even thickness _{X 2} is changed, it is possible to accurately determine the thickness _{X 1} of the difference _(X 3 -X ₂₎ from the semiconductor substrate 1 between the thickness _{X 2} of the protecting member 2 at the time of changing the total thickness _{X 3} Therefore, the influence of the change in the thickness of the protective member 2 during grinding can be suppressed.

  Further, by attaching a member 12 having substantially the same weight as the measuring device 10 at a position symmetrical to the measuring device 10 around the rotation axis of the chuck table 3, the balance of the weight balance when the spindle 5 is rotated is maintained. Since the vibration generated when the chuck table 3 rotates is suppressed, the measurement accuracy can be kept high.

Embodiment 2. FIG.
In the first embodiment, before it has been described grinding apparatus 100 having the first measuring mechanism for measuring the thickness X ₂ continuously protective member 2 at the time of grinding, in the present embodiment, to start the grinding described first grinding device 101 and a grinding method including a measurement mechanism for measuring the thickness X ₂ of the protection member 2. The configuration of the grinding apparatus 101 according to the present embodiment is substantially the same as that of the grinding apparatus 100 according to the first embodiment, and will be described with reference to FIG.

FIG. 2 is a flowchart showing the operation of the apparatus drive system / measurement system and apparatus control system in the semiconductor substrate grinding apparatus 101 according to the present embodiment. An operator of the grinding apparatus 101 inputs a target thickness X ₀ (set value) of the semiconductor substrate 1 to a control mechanism (not shown) that is an apparatus control system, and starts processing (C1). Next, the first measuring mechanism, to three points of the semiconductor substrate in-plane, to measure the thickness X ₂ of the protective member 2 in a state of being deposited on the surface 1a of the semiconductor substrate 1 (C2). The first measurement mechanism for measuring the thickness X ₂ of the protecting member 2, for example, shown in the first embodiment, using the measurement apparatus 10 for measuring the thickness X ₂ of the protective member 2 on the chuck table 3 be able to.

Then, send the data of thickness X ₂ of the protective member 2 in these 3 points to the control mechanism to calculate the average value X _2m protective member 2 of 3 points (C3), further, the average of the three points of the protection member 2 The sum (X _2m + X ₀ ) of the value X _2m and the target thickness X ₀ of the semiconductor substrate 1 is calculated (C4). Thereafter, the apparatus drive system is instructed to start the lowering of the grinding wheel 4 (C5), the lowering of the grinding wheel 4 is started, and the grinding of the back surface 1b of the semiconductor substrate 1 is started (C6). Since the mechanism related to grinding is the same as that of the first embodiment, description thereof is omitted.

After starting grinding, the contact gauge 8 as the second measuring mechanism is used, and the distance from the substrate holding surface 3a of the chuck table 3 to the back surface 1b of the semiconductor substrate 1, that is, the total thickness X of the semiconductor substrate 1 and the protective member 2 ₃ is continuously measured (C7).

The measured total value of the thickness X ₃ of the semiconductor substrate 1 and the protective member 2, during grinding, are always transmitted to the control mechanism. The control mechanism instructs the apparatus drive system to continue the descent of the grinding wheel 4 during X _2m + X ₀ <X ₃ , and when X _2m + X ₀ = X ₃ , the grinding wheel 4 is instructed to stop descending (C8). Upon receiving the grinding stop instruction, the apparatus drive system stops the descent of the grinding wheel 4 and finishes grinding (C9).

Next, the relationship between the measurement points and the measurement error of the thickness X ₂ of the protective member 2 in the semiconductor substrate in-plane, will be described with reference to FIGS. FIG. 3 (b), with respect to 12 pieces of the semiconductor substrate 1, shows a result of measuring the thickness X ₂ of the protective member 2 in the plane 9 points shown in FIG. 3 (a). In FIG. 3B, black points (♦) represent the average value of nine points in the plane, and error bars represent the widths of the minimum value and the maximum value in the surface of the semiconductor substrate 1. In FIG. 4, the horizontal axis represents the number of points (1 to 8 points) arbitrarily extracted from the nine points in the plane shown in FIG. 3A, and the vertical axis represents the thickness average and 9 points. The error from the average during measurement is shown. In addition, when extracting 1-8 points | pieces, it selects so that the error of the thickness average in those points and the average at the time of 9-point measurement may become the largest. As a result, as a matter of course, as the number of points to be extracted increases, the error from the average thickness at the time of measuring nine points becomes smaller.

In general, the in-plane thickness variation of the semiconductor substrate 1 and the thickness variation between the semiconductor substrates 1 due to the grinding apparatus are each about ± 1 μm. Furthermore, the in-plane thickness variation of the semiconductor substrate 1 caused by the protective member 2 is about ± 2 μm. In a thin power device of about 130 μm, the semiconductor substrate 1 necessary for maintaining electrical characteristics such as loss and withstand voltage is provided. since the thickness tolerance is generally ± 5 [mu] m approximately, measured values of thickness X ₂ of the protection member 2 so that the accuracy of within ± 1 [mu] m is required. According to FIG. 4, it can be said that it is necessary to measure any three or more points out of nine points in the plane in response to a request for measuring the thickness of the protective member 2 with an accuracy of 1 μm or less. Therefore, in this embodiment, the measurement is set to be performed at three points in the plane at the positions 1, 3, and 5 shown in FIG.

  Next, a method for manufacturing a semiconductor device in the present embodiment will be briefly described. The method for manufacturing a semiconductor device in the present embodiment is a method for manufacturing a vertical semiconductor device such as a power semiconductor device, for example, and includes a gate structure and an electrode formed on the surface 1a of the semiconductor substrate 1 by a film forming process, a photoengraving process, and the like. (Both not shown) and the like, and a step of grinding the back surface 1b of the semiconductor substrate 1 in a state where the protective member 2 for protecting these electrodes and the like is attached to the front surface 1a of the semiconductor substrate 1. Is included.

The process of grinding the back surface 1b of the semiconductor substrate 1 is performed using, for example, the grinding apparatus 101 shown in FIG. 1, and includes the following two steps. First, the thickness X ₂ of the protective member 2 which is deposited on the surface 1a of the semiconductor substrate 1 measured at three or more locations in the semiconductor substrate surface, the average value X _2m of those measurements (first step) . This first step is performed before starting grinding, and can be performed in the grinding apparatus 101 as in the present embodiment, but the thickness of the protective member 2 as in the third embodiment to be described later. the X ₂ may be carried out in another device capable of measuring.

Then, while grinding the back surface 1b of the semiconductor substrate 1, for example, the total thickness X ₃ of the semiconductor substrate 1 and the protective member 2 continuously measured by a contact gauge 8, the thickness X ₃ of the total, the protection member 2 Grinding is terminated when the average value X _2m of the semiconductor substrate 1 becomes equal to the total value (X _2m + X ₀ ) of the target thickness X ₀ (set value) of the semiconductor substrate 1 (second step).

As described above, according to this embodiment, the first measurement mechanism for measuring the thickness X ₂ of the protective member 2 before starting the grinding, continuously in the semiconductor substrate 1 and the protective member 2 at the time of grinding by providing two measurement mechanism of the second measurement mechanism for measuring the total thickness X _3, and the thickness X ₂ of the protective member 2 for each of the semiconductor substrate 1, the protection member 2 and the total thickness X ₃ of the semiconductor substrate 1 measure the door, from the difference between the respective measurement values (X 3 _{-X 2),} it can be determined thickness X ₁ of the semiconductor substrate 1 exactly. That is, even the thickness X ₂ of the protective member 2 is not varied between the semiconductor substrate 1 cross, it can be kept high finishing thickness dimensional precision of the thickness X ₁ semiconductor substrate 1, is stable and reliable electrical properties You can get a device.

Further, a plurality of points within the thickness X ₂ of the semiconductor substrate 1 side of the protective member 2, preferably measured at three or more positions, by using the average value thereof X _2m, thickness of the protective member 2 of the semiconductor substrate in-plane it is possible to suppress the influence of variation can be more kept high finishing thickness dimensional precision of the thickness X ₁ of the semiconductor substrate 1.

Embodiment 3 FIG.
In the second embodiment, has been described grinding apparatus 101 having the first measuring mechanism for measuring the thickness X ₂ of the protective member 2 before starting the grinding, the first measuring mechanism is necessarily grinding apparatus It does not have to be installed. That is, before the protective member 2 for mounting a semiconductor substrate 1 which is deposited on the chuck table of a grinding device may measure the thickness X ₂ of the protective member 2 in another device. The grinding method in that case will be described below.

As a first step, before starting the grinding, the thickness X ₂ of the protective member 2 which is deposited on the surface 1a of the semiconductor substrate 1, measured at three or more locations of the semiconductor substrate in-plane, thereof The average value X _2m of the measured values is obtained. Not particularly limited method for measuring the thickness X ₂ of the protecting member 2, for example, as in the first embodiment, the horizontal optical path of the reflected light from the reflection light and the back surface 2b of the surface 2a of the protective member 2 A method of converting the distance to the thickness of the protective member 2 can be used. In addition, the average value X _2m of the thickness of the protective member 2 obtained in the first step and the target thickness X ₀ of the semiconductor substrate 1 are input to a control mechanism of a grinding apparatus (not shown).

Next, as a second step, the semiconductor substrate 1 to which the protective member 2 is attached is placed on the chuck table of the grinding apparatus, and the total of the semiconductor substrate 1 and the protective member 2 is ground while grinding the back surface 1b of the semiconductor substrate 1. time of the thickness X ₃ to measure continuously, a thickness X ₃ of the total, becomes equal to the sum of the thickness X ₀ to a mean value X _2m and goals of the semiconductor substrate 1 in the thickness of the protective member 2 ( X _2m + X ₀ = X ₃ ), the control mechanism instructs the descent stop of the grinding wheel, and the apparatus drive system that has received the instruction to stop the grinding stops the descent of the grinding wheel and finishes the grinding. Incidentally, the total thickness X ₃ of the semiconductor substrate 1 and the protective member 2 as a method of continuously measuring during grinding, as in the first embodiment, it is possible to use a contact gauge 8.

As described above, according to this embodiment, even if not provided with a first measuring mechanism for measuring the thickness X ₂ of the protective member 2 to the grinding apparatus, to obtain the same effect as the second embodiment Can do.

Embodiment 4 FIG.
In the second first embodiment and the above embodiment, before grinding or during the grinding of the semiconductor substrate 1, describes a grinding device 100, 101 having a first measuring mechanism for measuring the thickness X ₂ of the protective member 2, Further, in the third embodiment has been described grinding method of measuring the thickness X ₂ of protected before grinding member 2 in the above three semiconductor substrate in-plane. In this embodiment, in a state where the protective member 2 is deposited on the surface 1a, a grinding device, characterized in that the thickness X ₁ of only the semiconductor substrate 1 excluding the protective member 2 is continuously measured during the grinding 102 will be described.

  FIG. 5 is a cross-sectional view of the main part showing the semiconductor substrate grinding apparatus according to the present embodiment. In the drawing, the same and corresponding parts are denoted by the same reference numerals. The grinding apparatus 102 according to the present embodiment is a table that grinds the back surface 1b of the semiconductor substrate 1 with the protective member 2 attached to the front surface 1a and holds the semiconductor member 1 on the protective member 2 side by suction. A chuck table 3 and a cup-type grinding wheel 4 having a width of 2 to 4 mm are provided.

A spindle 5 and a rotating shaft of a motor (not shown) are connected to the chuck table 3. The grinding wheel 4 is connected to a spindle 6 and a rotating shaft of a motor (not shown), and the chuck table 3 and the grinding wheel 4 are rotated by driving these motors. Further, the grinding wheel 4 is installed so as to be movable in the vertical direction by the drive mechanism 7. At the time of grinding, the grinding wheel 4 and the chuck table 3 are rotated relative to each other while the grinding wheel 4 is pressed against the back surface 1b of the semiconductor substrate 1 by the drive mechanism 7, and the back surface 1b of the semiconductor substrate 1 is ground. The target thickness X ₀ (set value) of the semiconductor substrate 1 is input in advance to a control mechanism (not shown).

Furthermore, the grinding apparatus 102 in the present embodiment includes a laser thickness measuring machine 13 as a third measuring mechanism that measures the thickness X1 of only the semiconductor substrate ₁ in a non-contact manner. Laser thickness measuring instrument 13, the laser 16 is irradiated to the semiconductor substrate 1, in which continuously determined during grinding the thickness X ₁ of the semiconductor substrate 1.

For example, when the material of the semiconductor substrate 1 is silicon, an infrared laser having a wavelength of 1.0 to 1.4 μm that is transmissive to silicon is used, and is perpendicular to the back surface (grinding surface) 1b of the semiconductor substrate 1. Irradiate. When the laser 16 reaches the back surface 1b of the semiconductor substrate 1, the intensity component of the laser 16 is divided into a reflection component A1 and a transmission component B1. Next, when the intensity component B1 transmitted through the back surface 1b reaches the front surface 1a, it is again divided into a reflection component A2 and a transmission component B2, and the reflection component A2 passes through the semiconductor substrate 1 and reaches the back surface 1b again. Divided into A3 and transmission component B3. Here, the transmission component B3 and the reflection component A1 first reflected by the back surface 1b interfere with the emitted light of the laser 16 as incident light, respectively. the distance to 1a was measured to determine the thickness X ₁ of the semiconductor substrate 1 and the difference I following.

In the grinding apparatus 102 according to this embodiment performs a grinding while continuously measuring the thickness X ₁ of the semiconductor substrate 1 in the manner described above, the measurements are sent to a control mechanism (not shown). The control mechanism instructs the apparatus drive system to continue the descent of the grinding wheel 4 while X ₁ > X ₀ , and when the X ₁ = X ₀ , the descent stop of the grinding wheel 4 is stopped. Instruct. Upon receiving the grinding stop instruction, the apparatus drive system stops the descent of the grinding wheel 4 and finishes the grinding.

In addition, the grinding apparatus 102 includes an air supply mechanism 14 that feeds air 17 into the laser irradiation region on the back surface 1 b of the semiconductor substrate 1 to clean the laser irradiation region. Air supply mechanism 14, prevents when measuring the thickness X ₁ of the semiconductor substrate 1, chips generated by the grinding, abrasive grain, binding material and grinding water and the like measurement accuracy retained in the laser irradiation region to decrease It is provided to have the air by the supply mechanism 14 by the laser irradiation area is washed clean, enhance the thickness X ₁ measurement accuracy of the semiconductor substrate 1.

  In the present embodiment, the laser thickness measuring device 13 is installed so as to be positioned in the center with respect to the air outlet at the bottom of the cylindrical air supply mechanism 14. A cylindrical tube 15 is joined to the outer peripheral portion of the air supply mechanism 14, and an end 15 a of the cylindrical tube 15 is disposed at a position of several tens to several hundreds μm from the back surface 1 b of the semiconductor substrate 1. By supplying air 17 into the cylindrical tube 15, a high pressure state is created, and the foreign matter existing between the laser thickness measuring machine 13 and the back surface 1 b of the semiconductor substrate 1 is removed.

  Next, a method for manufacturing a semiconductor device in the present embodiment will be briefly described. The method for manufacturing a semiconductor device in the present embodiment is a method for manufacturing a vertical semiconductor device such as a power semiconductor device, for example, and includes a gate structure and an electrode formed on the surface 1a of the semiconductor substrate 1 by a film forming process, a photoengraving process, and the like. (Both not shown) and the like, and a step of grinding the back surface 1b of the semiconductor substrate 1 in a state where the protective member 2 for protecting these electrodes and the like is attached to the front surface 1a of the semiconductor substrate 1. Is included.

The process of grinding the back surface 1b of the semiconductor substrate 1 is performed using, for example, a grinding apparatus 102 shown in FIG. 5, and includes the following two steps. First, the thickness X ₁ of only the semiconductor substrate of the semiconductor substrate 1 to which the protective member 2 is adhered is ground continuously by the laser thickness measuring machine 13 while grinding the back surface 1b of the semiconductor substrate 1 (first Step). Next, the thickness X ₁ of the semiconductor substrate 1 measured in the first step is to end the grinding when it becomes equal to the thickness X _{0 (set} value) as a target of the semiconductor substrate 1 (second step) .

As described above, according to this embodiment, the semiconductor substrate 1 to protect the surface member 2 is deposited, by providing a laser thickness measuring instrument 13 for measuring the thickness X ₁ of only the semiconductor substrate 1, protection without being affected by the variation in thickness of the member 2, it is possible to determine the thickness X ₁ of the semiconductor substrate 1 exactly. As a result, it is possible to maintain a high final thickness dimensional precision of the thickness X ₁ of the semiconductor substrate 1, electric characteristics can be obtained device stable and reliable.

Further, when the thickness X ₁ Measurement of the semiconductor substrate 1, since with an air supply mechanism 14 to the laser irradiation area clean feed air 17 of high pressure in the laser irradiation region of the back surface 1b of the semiconductor substrate 1, caused by grinding It is possible to prevent chips, abrasive grains, a binder, grinding water, and the like from staying in the laser irradiation region and reducing measurement accuracy.

  INDUSTRIAL APPLICABILITY The present invention can be used in the manufacture of a semiconductor device including a step of grinding the back surface of a semiconductor substrate having a protective member attached to the surface, particularly in the manufacture of a vertical semiconductor device such as a power semiconductor device.

It is principal part sectional drawing which shows the grinding device of the semiconductor substrate concerning Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the apparatus drive system, a measurement system, and an apparatus control system in the semiconductor substrate grinding apparatus concerning Embodiment 2 of this invention. It is a figure which shows the dispersion | variation in the thickness between the thickness measurement positions of a protection member, and a semiconductor substrate. It is a figure which shows the error from the number of thickness measurement points of a protection member, and an average. It is principal part sectional drawing which shows the grinding device of the semiconductor substrate concerning Embodiment 3 of this invention.

Explanation of symbols

1 semiconductor substrate, 1a surface, 1b back surface (grinding surface), 2 protective member, 2a surface,
2b Back surface, 3 Chuck table, 3a Substrate holding surface, 4 Grinding wheel,
5, 6 spindle, 7 drive mechanism, 8 contact gauge, 9 window member,
DESCRIPTION OF SYMBOLS 10 Measurement apparatus, 11 Light, 12 member, 13 Laser thickness measuring machine, 14 Air supply mechanism, 15 Cylindrical tube, 15a End part, 16 Laser, 17 Air,
100, 101, 102 Grinding equipment.

Claims (12)

Holding the protective member side of the semiconductor substrate with a protective member attached to the surface on a table, rotating the grinding wheel and the table relatively while pressing the grinding wheel against the back surface of the semiconductor substrate, A semiconductor substrate grinding apparatus for grinding a back surface,
A first measuring mechanism for measuring the thickness X ₂ of the protective member which is deposited on the semiconductor substrate,
A second measurement mechanism for continuously measuring the total thickness X ₃ of the semiconductor substrate and the protective member at the time of grinding,
It obtains the thickness X ₁ of the semiconductor substrate from the difference between each measurement value measured by the first measuring mechanism and the second measurement mechanism (X 3 _{-X 2),} the thickness X ₁ of the semiconductor substrate is the a semiconductor substrate of a grinding device, characterized in that a control mechanism to terminate the grinding when it becomes equal to the thickness X ₀ to the semiconductor substrate target. A semiconductor substrate grinding device according to claim 1, wherein the first measurement mechanism includes a semiconductor substrate grinding device, characterized in that measuring the thickness X ₂ continuously the protective member during grinding. A semiconductor substrate grinding device according to claim 1, wherein the first measurement mechanism includes a semiconductor substrate of a grinding device, characterized in that measuring the thickness X ₂ of the protective member before starting the grinding. 4. The semiconductor substrate grinding apparatus according to claim ₂ , wherein a thickness X _{2 of the} protective member is measured at three or more locations in the surface of the semiconductor substrate by the first measurement mechanism, and the control mechanism is measured. _Uses an average value X _2m of the measured values as the thickness of the protective member.   2. The semiconductor substrate grinding apparatus according to claim 1, wherein the first measurement mechanism includes a transparent window member filled in a through hole formed in the table, and a surface facing the substrate holding surface of the table. A semiconductor substrate grinding apparatus, comprising: a measuring device that is installed in a laser and irradiates the protective member with a laser through the window member to measure the thickness of the protective member.   6. The semiconductor substrate grinding apparatus according to claim 5, wherein a member having substantially the same weight as that of the measuring apparatus is attached to the table at a point-symmetrical position with respect to the measuring apparatus about the rotation axis thereof. A semiconductor substrate grinding apparatus. Holding the protective member side of the semiconductor substrate with a protective member attached to the surface on a table, rotating the grinding wheel and the table relatively while pressing the grinding wheel against the back surface of the semiconductor substrate, A semiconductor substrate grinding apparatus for grinding a back surface,
A third measurement mechanism in which the protective member is continuously measured during the semiconductor substrate coated, the thickness X ₁ of said semiconductor substrate only grinding,
A semiconductor substrate, characterized in that the thickness X ₁ of the third semiconductor substrate measured by the measuring mechanism and a control mechanism to terminate the grinding when it becomes equal to the thickness X ₀ as a target of the semiconductor substrate Grinding equipment. A semiconductor substrate grinding device according to claim 7, wherein the third measurement mechanism from the measuring device for irradiating a laser from the back surface side in the semiconductor substrate of the semiconductor substrate for measuring the thickness X ₁ of said semiconductor substrate A semiconductor substrate grinding apparatus comprising the semiconductor substrate grinding apparatus.   9. The semiconductor substrate grinding apparatus according to claim 8, wherein the third measurement mechanism has an air supply mechanism that feeds high-pressure air into a laser irradiation region on the back surface of the semiconductor substrate to clean the laser irradiation region. A semiconductor substrate grinding apparatus. A method of manufacturing a semiconductor device, comprising: forming an electrode on a surface of a semiconductor substrate; and grinding a back surface of the semiconductor substrate in a state where a protective member for protecting the electrode is attached to the surface of the semiconductor substrate. there are, the step of grinding the back surface of the semiconductor substrate, wherein the thickness X ₂ of the protective member back surface of the semiconductor substrate is deposited on the semiconductor substrate while grinding, the total of the protective member and the semiconductor substrate a first step of measuring the thickness X _3, in each successive,
From the difference (X ₃ −X ₂ ) between the measured values of the thickness X _{2 of the} protective member measured in the first step and the total thickness X ₃ of the semiconductor substrate and the protective member, obtains the thickness X _1, fabrication of a semiconductor device, characterized in that the thickness X ₁ of the semiconductor substrate and a second step of terminating the ground when it becomes equal to the thickness X ₀ as a target of the semiconductor substrate Method. A method of manufacturing a semiconductor device, comprising: forming an electrode on a surface of a semiconductor substrate; and grinding a back surface of the semiconductor substrate in a state where a protective member for protecting the electrode is attached to the surface of the semiconductor substrate. And grinding the back surface of the semiconductor substrate,
The said protective thickness X ₂ of member which is deposited on the semiconductor substrate surface before beginning the grinding was measured in three or more locations in said semiconductor substrate surface, the average value X _2m of those measurements first And the steps
The grinding the back surface of the semiconductor substrate while measuring the total thickness X ₃ of the semiconductor substrate and the protective member continuously, the thickness X ₃ of the total, the average value X _2m and the semiconductor substrate of the thickness of the protective member And a second step of ending the grinding when it becomes equal to the total value (X _2m + X ₀ ) of the target thickness X ₀ of the semiconductor device. A method of manufacturing a semiconductor device, comprising: forming an electrode on a surface of a semiconductor substrate; and grinding a back surface of the semiconductor substrate in a state where a protective member for protecting the electrode is attached to the surface of the semiconductor substrate. And grinding the back surface of the semiconductor substrate,
A first step of measuring said protective member while grinding the back surface of the semiconductor substrate of the semiconductor substrate coated, the thickness X ₁ of said semiconductor substrate only continuously,
Semiconductor, characterized in that it comprises a second step of terminating the ground when the thickness X ₁ of the semiconductor substrate measured by said first step is equal to the thickness X ₀ as a target of the semiconductor substrate Device manufacturing method.

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