JP2023002198A - Inspection wafer and inspection wafer manufacturing method - Google Patents

Abstract

To provide an inspection wafer and an inspection wafer manufacturing method that make it possible to quantitatively verify the performance evaluation of a cleaning function.SOLUTION: An inspection wafer manufacturing method includes: a heating plate placing step of providing an inspection wafer W having a first surface Wa and a second surface Wb and having dust particles S adhering to at least the first surface Wa, and placing the second surface Wb on a heating plate 40 with the first surface Wa of a wafer W exposed; and a dust adhesion step of spraying liquids L1 and L2 mixed with the dust particles S onto the first surface Wa to make the dust particles S adhere thereto, heating the wafer W with the heating plate 40, and forming a dust particle layer.SELECTED DRAWING: Figure 3

Description

The present invention relates to an inspection wafer and an inspection wafer manufacturing method.

A wafer having a plurality of devices such as ICs, LSIs, etc. partitioned by dividing lines and formed on the front surface thereof is ground by a grinding device on the back surface thereof to have a desired thickness, and then is divided into individual device chips by a cutting device. , cell phones, and personal computers.

Further, the grinding device and the cutting device are equipped with a cleaning function, and the ground wafer or the cut wafer is cleaned as appropriate (see Patent Documents 1 and 2, for example).

Japanese Unexamined Patent Application Publication No. 2011-003611 JP 2010-036275 A

By the way, with regard to the cleaning function installed in grinding and cutting equipment, until now there has been no method for properly evaluating the cleaning ability. Evaluate how much the rotation speed, the shape of the cleaning nozzle, the swing speed of the cleaning nozzle, etc. affect the cleaning power, find the conditions with the highest cleaning effect, and compare the cleaning effect with the cleaning function of other companies' products. There was a problem that objective judgment such as implementation of

The present invention has been made in view of the above facts, and its main technical problem is to provide an inspection wafer and a method for manufacturing the inspection wafer that enable quantitative verification of the performance evaluation of the cleaning function. That's what it is.

In order to solve the above main technical problems, according to the present invention, there is provided an inspection wafer comprising:
An inspection wafer is provided having a first side and a second side, with dust adhering to at least the first side.

The dust is preferably grinding dust discharged by a grinding device for grinding a wafer. Also, the dust is preferably shavings discharged by a cutting device that cuts a wafer. The dust is preferably of the same quality as the inspection wafer.

It is preferable that the first surface is formed with a plurality of areas having different amounts of accumulated dust. Moreover, it is preferable that a groove is formed in the first surface.

In order to solve the main technical problems described above, according to the present invention, there is provided a method for manufacturing a wafer for inspection, which comprises a heating plate mounting method in which a first surface of a wafer is exposed and a second surface of the wafer is mounted on a heating plate. and a dust adhering step of spraying a liquid containing dust onto the first surface to adhere the dust and heating the wafer with the heating plate to form a dust layer. is provided.

In the dust adhesion step, it is preferable to form the dust layer multiple times. Also, the dust is preferably of the same quality as the wafer.

The inspection wafer of the present invention has a first surface and a second surface, and dust is attached to at least the first surface. It becomes possible to easily verify the cleaning effect of That is, by changing the flow rate and pressure of the washing water, the mixing form of the washing water and the gas, the rotation speed of the spinner table, the shape of the washing nozzle, the rocking speed of the washing nozzle, etc., we can find conditions with high washing effect. It is possible to make an objective judgment by comparing the cleaning effect with the cleaning function of the product.

Further, the method for manufacturing a wafer for inspection according to the present invention includes a heating plate placing step of exposing the first surface of the wafer and placing the second surface on the heating plate, and placing a liquid containing dust on the first surface. and a dust adhesion step of forming a dust layer by heating the wafer with the heating plate to adhere dust to the surface of the wafer. be possible.

(a) Overall perspective view of a grinding device, (b) Overall perspective view of a cutting device. 1 is a perspective view of an inspection wafer and a heating plate; FIG. It is a perspective view which shows the embodiment of a dust adhesion process. 1 is a perspective view of an inspection wafer having a first surface formed with a plurality of regions having different dust accumulation amounts; FIG. FIG. 4 is a perspective view of three inspection wafers with different amounts of dust accumulation;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an inspection wafer and an inspection wafer manufacturing method according to the present invention will be described in detail below with reference to the accompanying drawings.

The wafer for inspection realized by the present embodiment is, for example, a wafer that reproduces a wafer requiring cleaning due to adherence of grinding debris or cutting debris to the surface thereof. Therefore, in order to attach the dust necessary for the reproduction to the inspection wafer, waste water L1 after grinding obtained from the grinding apparatus 1 shown in FIG. The wastewater L2 after cutting is used. The wafer 20 processed by the grinding apparatus 1 and the cutting apparatus 3 is a silicon (Si) wafer having a front surface 20a on which devices and the like are formed and a back surface 20b on which no devices and the like are formed. , the base wafer forming the inspection wafer also uses a wafer formed of the same material silicon (Si).

A grinding apparatus 1 is shown in FIG. The grinding apparatus 1 includes a substantially rectangular parallelepiped apparatus housing 10, and on the apparatus housing 10, there are a grinding means 16 for grinding a workpiece (wafer 20), a chuck table 15 for holding the wafer 20, and a wafer before grinding. A first cassette 12a arranged on the front side in the figure for accommodating wafers 20, and a first cassette 12a arranged on the other side of the first cassette 12a in the Y-axis direction in the figure for accommodating the wafers 20 after grinding. A second cassette 12b, temporary placement means 13 for centering wafers 20 arranged adjacent to the first cassette 12a in the X-axis direction in the figure, and adjacent to the second cassette 12b in the X-axis direction. and the wafers 20 stored in the first cassette 12a are transported to the temporary placement means 13, and the wafers 20 cleaned by the cleaning means 19 are transported to the second cassette 12b. and a second transport means for transporting the wafer 20 placed and centered on the temporary placement means 13 onto the chuck table 15 positioned at the loading/unloading position (front side in the figure). 14 and third transfer means 18 for transferring the ground wafer 20 from the chuck table 15 positioned at the loading/unloading position to the cleaning means 19 .

The grinding means 16 is attached to the inner surface of a support wall 10a erected on the rear end side of the apparatus housing 10 so as to be vertically movable. The grinding means 16 comprises a grinding wheel on which grinding wheels 162 are arranged in an annular shape, and the grinding wheel is rotated by an electric motor or the like. The grinding means 16 is advanced and retracted in the Z-axis direction (vertical direction) indicated by the arrow Z in the figure by the grinding feed mechanism 17 . A grinding water supply means (not shown) is connected to the grinding means 16 . After being used for the grinding process, the pure grinding water supplied from the grinding water supply means is guided to the drain port 10b formed on the upper surface of the device housing 10 together with the grinding dust D1 generated by the grinding process. The waste water is discharged from a waste water drain 10c formed on the side surface of the apparatus housing 10 and stored in the waste water tank 100 as the waste water L1 mixed with the grinding dust D1.

In contrast to FIG. 1(a) described above, FIG. 1(b) shows a cutting device 3 that is used to obtain chips D2 generated by cutting.

As shown in FIG. 1(b), the cutting device 3 includes a substantially rectangular parallelepiped device housing 30, a chuck table 35 for holding a wafer 20 as a workpiece, and a wafer 20 held by the chuck table 35. and a cutting means 37 having a cutting blade for cutting. The cutting device 3 includes a cassette 31 (indicated by a chain double-dashed line) accommodating a plurality of wafers 20, a temporary placement table 32 for unloading and temporarily placing the wafers 20 accommodated in the cassette 31, and a temporary placement table 32 for holding the wafers. 20, a conveying means 34 for rotating and conveying the wafer 20 carried out to the temporary placement table 32 onto the chuck table 35, and a cleaning means 37 for cleaning the cut wafer 20. means 39, cleaning and conveying means 38 for conveying the cut wafer 20 from the chuck table 35 to the washing means 39, imaging means 36 for imaging the wafer 20 on the chuck table 35, control means (not shown), It has When the wafers 20 are unloaded from the cassette 31 by the loading/unloading means 33, the height of the cassette 31 is appropriately adjusted by a lifting means (not shown).

In the apparatus housing 30, X-axis feed means for relatively feeding the chuck table 35 and the cutting means 37, and for moving the chuck table 35 in the X-axis direction indicated by the arrow X, which is the feeding direction for cutting. (illustration is omitted), Y-axis feeding means (not illustrated) for moving the cutting means 37 in the Y-axis direction indicated by the arrow Y orthogonal to the X-axis direction, and cutting means 37 in the X-axis direction and the Y-axis direction. A Z-axis feeding means (not shown) is provided for moving in the Z-axis direction indicated by an arrow Z orthogonal to the axial direction. The cutting means 37 is also provided with a cutting water supply nozzle 372 for supplying cutting water, which is pure water, to the cutting portion when the wafer 20 sucked and held on the chuck table 35 is cut.

The cutting water supplied from the cutting supply nozzle 372 is provided in the cutting device 3 together with the cutting waste D2 generated by the cutting after being supplied to the cutting position when the cutting is performed. Waste water L2 is collected by the recovery path, discharged from the waste water drain 30a to the waste water tank 110, and mixed with the cutting waste D2.

In this embodiment, using the waste water L1 obtained by the grinding device 1 or the waste water L2 obtained by the cutting device 3, a wafer for inspection is manufactured as described below.

Before carrying out the manufacturing method of the wafer for inspection according to the present embodiment, the wafer W serving as the base of the wafer for inspection shown in FIG. 2 and the heating plate 40 are prepared. The wafer W is a circular plate-like object made of silicon (Si), which is the same material as the wafer 20 processed by the grinding device 1 or the cutting device 3 described above. A device is not formed on the wafer W, and the front surface and the back surface forming flat surfaces are referred to as a first surface Wa and a second surface Wb. The heating plate 40 has a flat surface 42, is configured to be rotatable by a rotation drive means (not shown), and has a heating means such as an electric heater (not shown) inside to heat the surface 42 at a constant temperature. It can be maintained in a range (eg, 80° C.-100° C.).

In the inspection wafer manufacturing method of the present embodiment, first, the wafer W is placed on the heating plate 40 with the first surface Wa exposed and the second surface Wb facing downward (heating plate mounting process). At this time, the second surface Wb of the wafer W and the surface 42 of the heating plate 40 are brought into close contact with each other by interposing an appropriate bonding means. After the wafer W is placed on the heating plate 40, the heating means of the heating plate 40 is operated to heat the surface 42 to the above temperature range, and the liquid supply shown in FIG. A means 44 (only partially shown) is positioned.

The liquid supply means 44 includes a swing arm 45 configured to be swingable in the direction indicated by the arrow R1, and an injection nozzle 46 formed at the tip of the swing arm 45. As shown in FIG. The swing arm 45 or the injection nozzle 46 is provided with an ultrasonic applying device (not shown) capable of applying a predetermined ultrasonic vibration V. As shown in FIG. The liquid supply means 44 stores the waste water L1 containing the grinding waste D1 discharged from the grinding device 1 or the waste water L2 containing the cutting waste D2 discharged from the cutting device 3. Illustration is omitted. A storage tank is connected, and the waste water L1 or the waste water L2 is pressurized and supplied by a pumping pump (not shown). The inside of the storage tank is agitated so that the grinding waste D1 and cutting waste D2 contained in the waste water L1 or the waste water L2 supplied to the liquid supply means 44 are not uniform in the waste water L1 and the waste water L2. Means are preferably provided.

Once the liquid supply means 44 is positioned on the heating plate 40 as described above, the compressing pump is operated to swing the swinging arm 45 in the direction indicated by R1 as shown in FIG. While the plate 40 is rotated in the direction indicated by the arrow R2, the waste water L1 or the waste water L2 is jetted from the jet port 47 of the jet nozzle 46 of the liquid supply means 44 onto the first surface Wa of the wafer W. At this time, the ultrasonic vibration V is applied to the waste water L1 or the waste water L2 and jetted onto the first surface Wa of the wafer W due to the operation of the ultrasonic applying device. Since the wafer W is heated to 80° C. to 100° C. by the heating plate 40, the water contained in the waste water L1 or the waste water L2 supplied to the first surface Wa quickly evaporates. As shown in the lower left of , the grinding dust D1 or cutting dust D2 contained in the waste water L1 and the waste water L2 adhere as dust, forming a dust layer S on the first surface Wa of the wafer W (dust adhesion process). In the above-described embodiment, the liquid containing the grinding waste D1 and the cutting waste D2 supplied to the liquid supply means 44 was exemplified by the wastewater L1 and the wastewater L2, but the present invention is not limited to this. For example, the grinding dust D1 and cutting dust D2 remaining as dust after removing water from the waste water L1 and the waste water L2 are mixed with a liquid such as alcohol, stored in a storage tank, and supplied to the liquid supply means 44. You may do so.

The wafer W manufactured by carrying out the heating plate mounting process and the dust adhesion process described above and being sprayed with the waste water L1 is a wafer for inspection that reproduces a wafer requiring cleaning due to adhesion of the grinding dust D1 to the surface. The wafer W to which the waste water L2 has been sprayed becomes a wafer for inspection W which reproduces a wafer requiring cleaning due to adhesion of cutting waste D2 on the surface thereof. Further, the dust constituting the dust layer S adhered to the first surface Wa of the inspection wafer W is ground dust D1 obtained by grinding or cutting the silicon (Si) wafer 20, Or, since it is the cutting waste D2, it is of the same quality as the wafer W for inspection of silicon. Therefore, it becomes closer to the actual wafer 20 subjected to grinding or cutting, and by using such an inspection wafer W, it becomes possible to properly verify the cleaning effect of the cleaning function. In other words, by changing the flow rate and pressure of the cleaning water, the form of mixing with the gas, the rotation speed of the spinner table, the shape of the cleaning nozzle, the oscillation speed of the cleaning nozzle, etc., we can find out the conditions with the highest cleaning effect. It is possible to make an objective judgment by comparing the cleaning effect with the function.

Further, grooves may be formed on the first surface Wa of the wafer W on which the dust adhesion step is performed. This groove is provided, for example, on an inspection wafer W used when verifying the cleaning effect of the cleaning means 19 of the cutting device 3 . When manufacturing an inspection wafer W for verifying the cleaning effect of the cleaning means 19 of the cutting device 3, the actual wafer 20 is formed with cutting grooves, and the cleaning means 19 removes chips entering the cutting grooves. It is important to. In the case of verifying whether or not the shavings entering such cutting grooves are removed by the cleaning means 19, it is necessary to form grooves having a form conforming to the cutting grooves formed on the wafer 20. is preferred.

By the way, as described above, in order to find out the conditions under which the cleaning function has a high cleaning effect, or to compare the cleaning effect with the cleaning function of another company's product, inspection wafers W with different amounts of accumulated dust are prepared. preferably. An inspection wafer that satisfies such requirements will be described below.

FIG. 4 shows an inspection wafer W0, which is another embodiment of the present invention different from the above embodiment. The inspection wafer W0 shown in FIG. 4 is based on a wafer formed of silicon (Si) as in the above-described embodiment, and has a surface (first surface) having a plurality of regions, For example, it has a first area Wa1, a second area Wa2, and a third area Wa3 that are divided into three equal parts with a central angle of 120 degrees. When obtaining the inspection wafer W0 shown in FIG. 4, the first area Wa1 and the second area Wa2 are masked, and the above-described dust adhesion step is performed only on the third area Wa3. Next, only the first region Wa1 is masked, and the dust adhesion step is performed on the second region Wa2 and the third region Wa3. Finally, the mask is completely removed, and the above-described dust adhesion step is performed on the entire surface of the wafer W0. As a result, a single dust layer S1 formed by one dust adhesion step is formed in the first region Wa1, and a two-layer dust layer S1 formed by two dust adhesion steps is formed in the second region Wa2. A dust layer S2 is formed, and a three-layer dust layer S3 is formed in the third area Wa3 by three dust adhesion steps. That is, the inspection wafer W0 shown in FIG. 4 is formed with three areas having different amounts of accumulated dust. Functionality can be evaluated in more detail.

Further, referring to FIG. 5, the case of preparing two or more inspection wafers having different amounts of accumulated dust according to the present invention will be described.

FIG. 5 shows an inspection wafer set WS comprising a first inspection wafer W1, a second inspection wafer W2, and a third inspection wafer W3. Base wafers forming the first inspection wafer W1, the second inspection wafer W2, and the third inspection wafer W3 are the same wafers as the silicon wafer W described with reference to FIG. The first inspection wafer W1 is obtained by subjecting the first surface Wa of the wafer W to the heating plate mounting process and the dust adhesion process once to form a single dust layer S1. be. The second inspection wafer W2 is subjected to the heating plate placing step and the dust adhesion step twice on the first surface Wa, thereby forming two dust layers S2. . Further, the third inspection wafer W3 was subjected to the heating plate mounting step and the dust adhesion step described above three times on the first surface Wa to form a three-layered dust layer S3. be. These wafers are prepared as a set of wafers for inspection, and are washed by a predetermined washing means to determine the flow rate and pressure of the washing water, the mixing form with the gas, the rotational speed of the spinner table, the shape of the washing nozzle, the washing It is possible to make objective judgments by changing the swing speed of the nozzle to find out the conditions with high cleaning effect, and by comparing the cleaning effect with the cleaning function of other companies' products. The cleaning function can be evaluated in more detail by using three inspection wafers with different deposit amounts and sequentially applying the cleaning function to actually clean them and observing how the dust layer falls.

Although the set WS of inspection wafers described above includes three inspection wafers having different amounts of accumulated dust, the set WS is not necessarily limited to three inspection wafers. A set including two inspection wafers with different accumulation amounts, or a set including four or more inspection wafers with different accumulation amounts of dust may be used. In addition, a plurality of inspection wafers having different accumulated amounts of dust are prepared, and a necessary inspection wafer is selected and used from the inspection wafer set according to the cleaning performance of the cleaning function to be evaluated. may

In the above-described embodiments, the inspection wafer is formed of a silicon wafer, but the present invention is not limited to forming the inspection wafer of silicon. The inspection wafer of the present invention is preferably formed of a wafer of the same quality as the wafer processed by the grinding device 1 or the cutting device 3. For example, the wafer processed by the grinding device 1 or the cutting device 3 is made of silicon. In the case of a carbide (SiC) wafer or a sapphire wafer, the inspection wafer may also be manufactured from a silicon carbide (SiC) wafer or a sapphire wafer depending on the material of the workpiece.

1: Grinding device 10: Device housing 10a: Support wall 10b: Drain port 10c: Drainage drain 11: First conveying means 12a: First cassette 12b: Second cassette 13: Temporary placing means 14: Second conveying Means 15: Chuck table 16: Grinding means 162: Grinding wheel 17: Grinding feed mechanism 18: Third conveying means 19: Cleaning means 3: Cutting device 30: Device housing 31: Cassette 32: Temporary placement table 33: Loading/unloading means 34: Conveying Means 35: Chuck Table 36: Imaging Means 37: Cutting Means 38: Washing Conveying Means 39: Washing Means 20: Wafer 40: Heating Plate 42: Surface 44: Liquid Supplying Means 45: Swing Arm 46: Injection Nozzle 47 : Ejection ports 100, 110: Drainage tank D1: Grinding waste D2: Cutting waste L1, L2: Drainage W, W0: Inspection wafer W1: First inspection wafer W2: Second inspection wafer W3: Third Wafer for inspection Wa: first surface Wb: second surface Wa1: first area Wa2: second area Wa3: third area WS: set of wafers for inspection S: dust layer S1: one dust layer S2: 2-layer dust layer S3: 3-layer dust layer

Claims (9)

An inspection wafer,
An inspection wafer comprising a first surface and a second surface, and having dust adhered to at least the first surface. 2. The wafer for inspection according to claim 1, wherein said dust is grinding dust discharged by a grinding device for grinding the wafer. 2. The wafer for inspection according to claim 1, wherein the dust is shavings discharged by a cutting device for cutting the wafer. 4. The wafer for inspection according to claim 1, wherein the dust is of the same quality as the wafer for inspection. 5. The inspection wafer according to any one of claims 1 to 4, wherein the first surface is formed with a plurality of regions having different amounts of accumulated dust. 2. The inspection wafer according to claim 1, wherein grooves are formed on said first surface. A method for manufacturing an inspection wafer, comprising:
a heating plate mounting step of exposing the first surface of the wafer and mounting the second surface on the heating plate;
a dust adhering step of spraying a liquid containing dust onto the first surface to adhere the dust and heating the wafer with the heating plate to form a dust layer;
A method for manufacturing an inspection wafer comprising: 8. The method for manufacturing a wafer for inspection according to claim 7, wherein the formation of the dust layer is carried out a plurality of times in the dust adhesion step. 9. The method for manufacturing an inspection wafer according to claim 7, wherein said dust is of the same quality as said wafer.

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