JP5767461B2 - Manufacturing method of semiconductor wafer - Google Patents

Description

  The present invention relates to a technique for manufacturing a semiconductor wafer by cutting a semiconductor ingot, and more particularly, to a semiconductor wafer manufacturing method and a semiconductor ingot cutting position determination method for reliably obtaining a semiconductor wafer having a predetermined resistivity.

  When manufacturing a semiconductor wafer (for example, silicon wafer; hereinafter referred to as “wafer”) from a silicon single crystal ingot, for example, a single crystal ingot grown by the Czochralski (CZ) method (including the MCZ method) is ground into a cylindrical shape. Then, the top and tail parts that can not be used as products are cut off, the ingot is cut at a predetermined position, and the block has a length that can be put into a slicing device such as an inner peripheral blade or a wire saw. To. At this time, a sample for inspection such as electrical resistance can be cut out at the same time. Further, each block is sliced to a predetermined thickness to obtain a wafer.

  In addition to the CZ method described above, the floating zone melting method (FZ method) is also known as a method for producing silicon single crystal ingots. It can be said that all single crystal ingots for large-diameter wafers used in semiconductors are made by this method. However, the production of ingots by the CZ method has a problem that the resistivity changes greatly along the crystal growth direction.

  This is because in the CZ method, the dopant concentration and the oxygen concentration that greatly affect the resistivity of the wafer tend to change along the crystal growth direction. For example, the change in the concentration of the dopant in the silicon melt due to the segregation of the dopant and the change in the contact state between the silicon oxide crucible and the silicon melt inevitably occur during crystal growth. In particular, when the dopant is volatile, such as arsenic, antimony, and phosphorus, and the resistivity is large with a large amount of doping, various factors are involved and the resistivity is likely to change. In recent years, there has been a growing need for a silicon single crystal whose resistivity has been shifted to a lower resistance. However, in such a single crystal ingot, variation in the length direction has become larger than before.

  In addition, demands on wafer quality are severe, and it is important to keep the resistivity within a predetermined range. For this reason, if the resistivity is measured for each block, and the optimum block is selected and a desired wafer is cut out from the block, the resistivity of the block can be determined only after cutting into blocks. The product yield you get is not always good.

  For this reason, it is preferable that the resistivity is known in the state of a silicon single crystal ingot. For example, when the resistivity is high, the resistivity in the ingot length direction can be calculated from the segregation coefficient, and it is possible to predict the resistivity at a predetermined distance in the length direction before dividing into blocks. is there. However, a low resistivity material contains a large amount of volatile arsenic, antimony, and phosphorus dopants, and various factors are involved, making it difficult to predict. For example, an oxygen concentration distribution has been proposed as a method of measuring the change in characteristics in the length direction of an ingot as it is. According to this method, the oxygen concentration distribution is measured by an infrared absorption spectrum device or the like along the growth axis direction of the ingot (for example, Patent Documents 1 and 2). And the method of cut | disconnecting only the part suitable for a predetermined oxygen concentration as a block for slicing is proposed. Specifically, after cylindrical grinding of a single crystal ingot, infrared rays are incident from the radial direction, and the oxygen concentration is measured from the absorption, and this is performed at a predetermined interval along the length direction of the ingot. Thus, the oxygen concentration distribution in the length direction is measured.

JP 2002-174593 A Japanese Patent No. 4396640

  However, what is obtained by such a method is a distribution in the length direction (growth direction) of the oxygen concentration, not a resistivity distribution. The oxygen concentration is also related to the resistivity, but since the correlation can be obtained only under very limited conditions, the change in resistivity cannot be known before cutting into blocks. In addition, if the resistivity is low, the change in resistivity cannot be predicted from the segregation coefficient as described above. Therefore, if the actual distribution is not cut into multiple blocks, the distribution of resistivity will not be known and the variation within the block will be large, so it will not only take time to obtain a product with the desired resistivity range, but also the sample In addition, there is a problem that the product loss is large and the productivity and yield are lowered.

  In view of the problems as described above, in the present invention, in a method of manufacturing a wafer from a single crystal ingot, a resistivity distribution in a growth axis direction on a side surface of the single crystal ingot is measured, and a desired resistance exhibiting a desired resistivity is obtained. Provided is a wafer manufacturing method in which a rate position is specified, a block having a predetermined length is cut out, and a wafer is sliced therefrom. The resistivity in the growth axis direction can be measured by applying a resistivity measuring method by a so-called four-probe method.

More specifically, the following can be provided.
(1) In a method of manufacturing a semiconductor wafer from a single crystal ingot, a resistivity distribution in a growth axis direction on a side surface of the single crystal ingot is measured, a desired resistivity position indicating a desired resistivity is specified, and the growth axis A method for producing a semiconductor wafer, comprising: cutting a block having a predetermined length including the desired resistivity position by cutting the ingot in a direction perpendicular to the direction; and manufacturing the semiconductor wafer by slicing the block Can be provided.

(2) The resistivity of the sliced semiconductor wafer is 1 Ωcm or less, and the method for producing a semiconductor wafer according to (1) can be provided.

  Here, the resistivity (hereinafter referred to as “desired resistivity”) of the wafer (semiconductor wafer) to be obtained is preferably 1 Ωcm or less. A single crystal ingot pulled by the CZ method has an oxygen concentration of a certain level or more, but a resistivity range that has little influence even when this oxygen is converted into a donor can be set to 1 Ωcm or less, for example. The resistivity measured here can be considered as the resistivity of the wafer as a product. Furthermore, the desired resistivity is preferably 0.03 Ωcm or less. In this range, naturally, oxygen hardly contributes to the resistivity as a donor. Furthermore, in order to obtain a wafer in this range, a large amount of dopant is required. In the case of a volatile dopant, evaporation of the dopant during pulling up by the CZ method can affect this resistivity. Here, the wafer is N-type.

(3) The method for producing a semiconductor wafer according to (1) or (2) above, wherein the semiconductor wafer contains phosphorus, antimony, or arsenic as a dopant.

  As described above, in order to obtain a low-resistivity wafer (semiconductor wafer), many dopants are required. However, depending on the type of the dopant, a preferable resistivity range may exist. For example, when antimony is used, a range of 0.03 Ωcm or less is preferable. When arsenic is used, a range of 0.01 Ωcm or less is preferable. And when phosphorus is used, the range of 0.007 Ωcm or less is preferable. The preferred range varies depending on the type of these elements, such as the difference in the degree of release of elements out of the system due to evaporation or decomposition (including sublimation) and the ease of incorporation into single crystals called segregation coefficient. This is because they are different, and the ease of adjusting the lifting conditions and the like is also different. Therefore, even when a wafer having the same desired resistivity is manufactured, a dopant that is easier to make may exist. For example, it is preferable to use phosphorus if the desired resistivity is in the range of 0.007 Ωcm or less. If the desired resistivity is in the range of 0.01 Ωcm or less, it is preferable to use phosphorus or arsenic. If the desired resistivity is in the range of 0.03 Ωcm or less, it is preferable to use phosphorus, arsenic, or antimony.

(4) the single crystal ingot can provide a method for producing a semiconductor wafer according to any one of (1), wherein the performing cylindrical grinding before the resistance measurements up (3) . Here, the single crystal ingot can be stably measured on its side surface by cylindrical grinding. The resistivity measurement performed in the length (axis) direction may be performed while the ingot is stationary and may be performed while rotating the ingot. In the latter case, the measurement path has a spiral shape (spiral shape or string-wound shape). If the measurement path is formed in a spiral shape, it is expected that the variation in resistivity in the circumferential direction can be taken into consideration. Accordingly, the resistivity distribution in the length direction can be measured before cutting into blocks, and blocks having a desired resistivity can be cut out based on this distribution.

(5) The method for manufacturing a semiconductor wafer according to any one of (1) to (4) above, wherein the resistivity measurement uses a four-probe method. Regarding the four-probe method, for example, JP-A-2003-232822 can be referred to.

(6) The degree of change in the resistivity distribution in the growth axis direction of the single crystal ingot is obtained, and the block is set so that the degree of change in the growth axis direction of the desired resistivity position is longer on the lower side. The method for producing a semiconductor wafer according to any one of (1) to (5) above, wherein the semiconductor wafer is cut out can be provided.

For example, assuming that the resistivity distribution in the axial direction can be expressed by a function y = f (x) (x is a distance from the top of the ingot), dy / dx = f ′ (x) and the position x0 When the desired resistivity is obtained by comparing the absolute value (f ′ (x0 + Δx)) and the absolute value (f ′ (x0−Δx)) on the x0 + side and the x0− side, the smaller one is obtained. Since the change on the side is small, there is little possibility of obtaining a product with stable resistivity quality with little change in resistivity. Therefore, it is possible to cut out a block having more parts on that side. For example, when an upper limit and a lower limit are provided for a desired resistivity value, the ingot positions corresponding to the upper limit and the lower limit may be used as the upper and lower limits (or the lower limit and the upper limit) of the ingot position. Further, if the inclinations on the + side and − side of the ingot position x0 are absolute values (f ′ (x0 + Δx)) and absolute values (f ′ (x0 − Δx)), they are inversely proportional to these absolute values. The upper limit (ΔxU by the bottom side) and the lower limit (ΔxUL by the top side) of the ingot position may be determined. Specifically, the upper and lower limits of the ingot position may be determined so that ΔxU · absolute value (f ′ (x0 + Δx)) = ΔxUL · absolute value (f ′ (x0 − Δx)).

(7) The resistivity distribution in the growth axis direction measured in the method for manufacturing a semiconductor wafer according to (1) and the condition for pulling up the single crystal ingot are associated with each other and stored in a storage means by a computer. Among the factors that increase the resistivity and the factor that decreases the resistivity, the computer stores them in the storage means, and according to the input of a new desired resistivity (referred to as “next resistivity”), The computer causes the output means to output predetermined information from the storage means, but the predetermined information to be output when the next resistivity is higher than the desired resistivity is the increase factor, and the next resistivity The predetermined information that is output when the resistivity is lower than the desired resistivity is the descending factor, and by applying the condition based on each output predetermined information, the next single crystal The next single crystal ingot is prepared by adjusting the single crystal pulling conditions so that the degree of change in the resistivity distribution is reduced in the growth axis direction, and the side surface of the next single crystal ingot is formed. Measuring a resistivity distribution in a growth axis direction at a position, specifying a desired resistivity position indicating a desired resistivity, and cutting the ingot in a direction perpendicular to the growth axis to include a predetermined resistivity position including the desired resistivity position It is possible to provide a method for manufacturing a semiconductor wafer, in which a semiconductor wafer is manufactured by cutting out a block having a length and slicing the block.

  There is a single crystal pulling condition in which the amount of dopant is increased or decreased so as to increase or decrease the resistivity. If these are adjusted well, many wafers can be taken out from the top to the bottom of the ingot without waste. For example, if the input amount of dopant is originally large, the resistivity of the ingot as a whole is considered to be low. On the other hand, when the pulling is performed under conditions where the dopant is easy to evaporate or decompose (including sublimation), the amount of the dopant may decrease particularly in the bottom portion, and the resistivity may increase as a whole and particularly in the bottom portion. There is. Since the resistivity can be measured in the ingot state, it is possible to tune up the next ingot pulling condition based on this information. Thus, the feedback reading time is shortened, and the quality of the product can be improved.

  As described above, according to the invention of the present application, when manufacturing a low-resistivity wafer, the block can be cut out so as to include more portions having a desired resistivity. The manufacturing method of can be provided. More specifically, a cylindrically ground ingot is fixed to an insulator, and four probes are brought into pressure contact with a predetermined position in the length direction from the radial direction. The current flowing through the object to be measured and the object to be measured The voltage drop of the resistance of the object is measured, and the resistivity is calculated based on these measured values. If such a resistivity measurement is performed at a predetermined interval (for example, 100 mm interval) in the length direction, a resistivity distribution in the length direction can be obtained, and based on the distribution, a region having an optimum resistivity can be obtained. The ingot can be cut to identify and cut out the block containing the site. Further, if an ingot having a resistivity exceeding 1 Ωcm is used, the resistivity cannot be measured as easily as this. However, in the invention of the present application, when applied particularly to an N-type ingot having a low resistivity, a great effect can be obtained. Play.

In the Example of this invention, it is a schematic schematic diagram of the resistivity measuring system of the single crystal ingot which can be used. It is a graph which shows the resistivity measurement result using the sample sampled from the block actually cut out from the single crystal ingot. It is a graph which compares the result of the resistivity measurement in the ingot side surface of the Example of this invention with the result of the resistivity measurement which cut | disconnected the some block and sampled from each block. In the Example of this invention, it is a graph illustrating the method of specifying the position which should be cut out as a block from a single crystal ingot based on the distribution result of the resistivity measured along the growth axis.

  Next, embodiments of the present invention will be described with reference to the drawings. In the drawings, components having the same configuration or function and corresponding parts are denoted by the same reference numerals, and description thereof is omitted. Moreover, in the following description, the example of the embodiment which concerns on this invention is shown, and it can change suitably based on the technical common sense of those skilled in the art, without exceeding the range of this invention. Therefore, the scope of the present invention is not limited to these specific examples. Also, these drawings are emphasized for the purpose of explanation, and may differ from actual dimensions.

  In order to produce a wafer having a resistivity of 1 Ωcm or less, a silicon single crystal ingot added with phosphorus as a dopant was grown by the CZ method. A desired amount of polycrystalline silicon was put into a crucible made of silicon oxide, and further a desired amount of red phosphorus was added. After heating and melting, a silicon single crystal ingot was pulled from the seed crystal. Predetermined atmospheric conditions, temperature conditions, pulling conditions such as pulling speed, crucible rotation speed, and the like were used. Of these, an increase in the amount of red phosphorus input increases the amount of dopant and acts to reduce the resistivity, and the temperature rise of the crucible promotes the evaporation or decomposition (including sublimation) of red phosphorus as a dopant. It acts to reduce the concentration of phosphorus and increase the resistivity.

  Thus, after cutting the top and bottom with respect to the grown single crystal ingot, cylindrical grinding (it is also called outer periphery grinding) was implemented, and the cylindrical (or column) -shaped ingot was obtained. The resistivity at the outer periphery was measured at a pitch of 100 mm in the crystal growth axis direction (or growth direction, axial direction) with a simple resistivity measuring machine described below. A measurement method using a resistivity measuring machine will be described below with reference to FIG.

  FIG. 1 schematically shows an outline of a measurement system 10 using an ingot resistivity measuring machine. The ingot 12 to be measured is fixed on the insulating base 14 with the top position 12a on the left and the bottom position 12b on the right, and the resistivity at a predetermined position (x) is determined from the top 12a of the ingot. measure. For the measurement, four probes 16a, 16b, 16c, 16d arranged at equal intervals T on a straight line, a constant current power source 20 for supplying a constant current to the ingot 12, and a current for measuring the current flowing through the ingot A resistivity measuring machine comprising a total 22 and a potentiometer 24 for measuring a voltage drop due to the resistance of the ingot is used. In FIG. 1, four probes are drawn large, but in actuality, these are small enough to fit within the point x. As an example of such a resistivity measuring machine, RT70 / TS7D manufactured by Napson Co., Ltd. can be used, but other devices may be used.

In order to measure the resistivity of the ingot using such a measurement circuit, four probes 16a arranged vertically at equal intervals T on the surface of the outer periphery of the ingot 12 fixed to the insulating base. , 16b, 16c, 16d (hereinafter referred to as “four probes”) are brought into pressure contact. Here, among the four probes, the constant current power source 20 is connected to the probe 16 a vertically disposed on the leftmost side via an ammeter 22. A constant current I supplied to the ingot 12 by the constant current power source 20 is measured by an ammeter 22. On the other hand, a potentiometer 24 is connected between the two probes 16b and 16c arranged vertically on the inside of the four probes, and the potential difference V is measured by the potentiometer 24. Further, the probe 16 d vertically arranged on the rightmost side is connected to the constant current source 20.

Thus, the current I [A] flowing through the ingot 12 measured by the ammeter 22, the potential difference V [V] between the probes measured by the potentiometer 24, and the distance T [cm] between each probe, The resistivity ρ [Ωcm] is obtained by the following equation.
ρ = 2πTV / I [Ωcm]

  Such measurements were measured at 100 mm intervals at each position x and plotted as a function of distance x and resistivity ρ. Since the measurement by the measurement system 10 shown in FIG. 1 is simple resistivity measurement, the measured value of the simple resistivity measuring machine and the resistivity measurement at each cut end face after actually cutting into a plurality of blocks are performed. It is preferable to perform calibration. This is because a relative resistance value can be obtained, but if the absolute resistance value is different, the block cutting position may be mistaken. It goes without saying that the difference between the two measured values can be calibrated by deriving an approximate expression from the correlation between the two in advance.

  FIG. 2 shows the results of measuring the resistivity of a silicon single crystal ingot having a low resistivity by cutting into a plurality of blocks and using samples sampled from the respective blocks, and the distance (position) from the top of the original ingot. Is plotted against. As can be seen from this figure, although the resistivity varies considerably, the resistivity is high on the top side and low on the bottom side. That is, in order to manufacture a wafer having a resistivity range P of 0.0018 Ωcm to 0.0019 Ωcm from this ingot, it is necessary to cut out a block as a material from a position within the range A from the top. I understand that there is. In addition, in order to manufacture a wafer having a resistivity range Q of 0.0015 Ωcm to 0.0016 Ωcm, it is necessary to cut out a block as a material from a position B within the range from the top. I understand. In other words, when this ingot is divided into 10 equal parts, the first to third blocks from the top are used to obtain a wafer having a resistivity range P, but the third block is within the resistivity range P. There seems to be few things to enter, and there is a high possibility that it became a block containing many unnecessary parts. In addition, since the boundary between the first block and the second block is considered to be the most preferable range, if such a place is lost as a cutting margin for cutting, the yield is lowered. On the other hand, the 4th to 10th blocks are used to obtain a wafer having a resistivity range Q. If the resistivity is measured from the top, in order to select an appropriate block that occupies more than half of the ingot. It is difficult to find a suitable block without measuring the resistivity of at least four blocks. Therefore, time loss is large and productivity is low. Moreover, the variation in resistivity is particularly large in the second block, and when the resistivity is measured with a sample sampled from the block, it is difficult to grasp the range of the resistivity of the block. However, if the resistivity of another block is known in advance, the upper and lower limits of the resistivity of the second block can be easily grasped.

  FIG. 3 is a graph showing a result of resistivity measurement performed on another silicon single crystal ingot grown by the CZ method with respect to an example of the present invention. The ingot was produced by the CZ method described above, and after cutting the top and bottom, cylindrical grinding was performed to form a cylindrical shape. The resistivity at the outer periphery, which is the side surface of the ingot, is measured at a pitch of 100 mm in the crystal growth axis direction by the resistivity measuring machine in FIG. 1 and is shown in a graph with respect to the length in the growth direction. On the other hand, after cutting into a plurality of blocks, the resistivity is measured at the end face of each block, and the result is plotted according to the length of the original ingot in the growth direction. As can be seen from this figure, the results of the resistivity measured by the simple type resistivity measuring machine on the side of the ingot are in good agreement with the results of the resistivity measured by the end faces of each block. It can be seen that resistivity measurements can replace measurements by sampling from multiple blocks.

  Furthermore, the resistivity is large at the top, but the resistivity decreases rapidly toward the bottom, and the resistivity becomes almost constant as it approaches the bottom. Such a tendency is common to the results of FIG. 2, but a method of cutting a silicon single crystal ingot into blocks using such a profile will be described with reference to FIG.

FIG. 4 explains a block cutting method and a cutting position determination method for obtaining a wafer having a resistivity range R, S, T using the result of FIG. Arranged below the graph corresponding to the graph of FIG. 3 is a simulation of a silicon single crystal ingot. The left end is the top and the right end is the bottom. If you want to obtain a wafer in the resistivity range R, draw a horizontal line at the median value of the resistivity range R, and hit the resistivity curve obtained from the measurement. It can be seen that a block centered on the position of the distance C may be cut out. Also, if a wafer is to be obtained in the resistivity range S, a horizontal line is drawn at the median value of the resistivity range S, and when it hits a resistivity curve obtained by measurement, it is obtained by dropping the line vertically. It can be seen that a block centered on the position of the relative distance D can be cut out. At this time, the length of the block having the resistivity in the resistivity range R is short at the relative distance C that is encountered at a steep slope. On the other hand, the length of the block having the resistivity in the resistivity range S where the steep slope is gentle is short on the left side of the center position D and long on the right side. Therefore, a preferable cutout portion exhibits a long asymmetry on the bottom side with respect to the relative distance D. In this figure, the ingot positions corresponding to the upper limit and lower limit of the desired resistivity range are set as the lower limit and upper limit of the ingot position. In addition, the inclination of the + side and the − side of the ingot position corresponding to the desired resistivity value is (0.001759−0.001738) / (0.400−0.344) = 0.000021 / Since 0.056 = 3.75 × 10 ⁻⁴ and (0.001794−0.001759) / (0.344−0.300) = 0.000035 / 0.044 = 7.95 × 10 ⁻⁴ The range can be determined so that the negative side of the ingot position has a ratio of 0.47 to the positive side. That is, when the lower limit of the ingot position is 0.300, (0.344−0.300) /0.47+0.300=0.394 is the upper limit of the ingot position.

  Further, in the block having the resistivity in the resistivity range T, the resistivity graph is almost flat, so that it is not particularly necessary to find the center position, and the resistivity range T is entered (the portion between the upper and lower limits). Can be extracted at the relative distance from top to bottom. The range of the ingot corresponding to the resistivity range T substantially corresponds to the bottom half of the ingot including the relative distance E. Here, since the resistivity does not change so much and is constant, it is expected that the degree of quality assurance of the resistivity is high. In addition, the length of the block to be cut (also referred to as thickness) is a length suitable for processing in the next process, and is a length that can supply the required wafer. It may be determined on the basis of high productivity considering the above.

  Here, the low resistivity is considered. As described above, it was found that a silicon single crystal ingot having a resistivity of 1 Ωcm or less has characteristics different from those having a resistivity higher than that. In particular, when the dopant and the target resistivity are (A) antimony: 0.03 Ωcm or less, (B) arsenic: 0.01 Ωcm or less, and (C) phosphorus: 0.007 Ωcm or less, the resistivity varies in the growth direction. Becomes larger and difficult to predict. In the method of cutting a wafer-shaped sample after measuring the ingot into a plurality of blocks and measuring the resistivity, a time loss sample and a product loss are large in order to obtain a product in a desired resistivity range, and the productivity and yield. Decreases. However, according to the present invention, by measuring the resistivity in the length direction of the ingot that can be measured because of its low resistance and taking a profile, (1) the cutting position without measuring the resistivity after making the block (2) Monitor resistivity changes by measuring the resistivity profile for each crystal (such as changes over time between batches and between batches) and immediately compensate for any changes. (3) A pulling condition that affects the resistivity can be determined, and the condition can be appropriately controlled. As a result, it is possible to provide a method for manufacturing a low-resistance silicon single crystal that stabilizes the resistivity and efficiently yields a high yield.

  Here, the reason why the measurement is possible due to the low resistance is as follows. The oxygen concentration affects the amount of evaporation in the case of antimony, but electrons are given as thermal donors in the case of high resistance, so if measured as it is, the resistance is higher in the case of the P type and lower than in the case of the N type. The For this reason, heat treatment is required before the resistivity measurement. For example, it is possible to measure the resistivity in the length direction on the side surface by performing heat treatment with the ingot, but if the diameter is 100 mm or more, heat treatment with the ingot is substantially impossible. This is because it is difficult to rapidly cool the center of the ingot, and the donor does not disappear in the center. For this reason, it has been necessary to cut out a wafer sample and measure the resistivity after heat treatment at a large diameter. However, if the resistance is 1 Ωcm or less, the dopant concentration is sufficiently high compared to the amount of donor, and the influence of the donor is small even without heat treatment, so that the ingot remains as it is (ie, without heat treatment). Resistivity can be measured.

  The concentration of the dopant in the silicon single crystal ingot that directly affects the resistivity is adjusted based on the dopant concentration in the silicon melt, segregation coefficient, and easiness of evaporation or decomposition (including sublimation) of the dopant. be able to. For example, the segregation coefficient is 0.35 for phosphorus, 0.3 for arsenic, and 0.02 for antimony. Incidentally, the segregation coefficient of boron is 0.8. This indicates that the segregation coefficient is smaller than that of boron, and the dopant concentration in the silicon melt may increase with the pulling time. In addition, antimony, arsenic, and phosphorus also have a high segregation coefficient in ascending order of antimony. Therefore, it can be seen that it is preferable to carefully adjust the dopant concentration during the pulling in order in this order.

  As described above, for ingots with low resistivity, the inventors have found that the resistivity measurement results can be used for wafers as products, and have made an epoch-making invention as in the present application. It can be understood that the resistivity measurement before block cutting is very effective in various points such as improvement in yield and quality in wafer manufacturing.

DESCRIPTION OF SYMBOLS 10 Resistivity measurement system of single crystal ingot 12 Single crystal ingot 14 Insulation base 16a, 16b, 16c, 16d Probe 20 Constant current power supply 22 Ammeter 24 Potentiometer

Claims (4)

In a method of manufacturing a semiconductor wafer from a single crystal ingot,
The resistivity distribution in the growth axis direction on the side surface of the single crystal ingot is measured by a four-probe method,
Identify the desired resistivity position that shows the desired resistivity,
Cutting a block of a predetermined length including the desired resistivity position by cutting the ingot in a direction perpendicular to the growth axis,
By slicing the block, a semiconductor wafer of 0.007 Ωcm or less containing phosphorus as a dopant, a semiconductor wafer of 0.03 Ωcm or less containing antimony as a dopant, or a semiconductor wafer of 0.01 Ωcm or less containing arsenic as a dopant is manufactured. A method for manufacturing a semiconductor wafer. The method for manufacturing a semiconductor wafer according to claim 1, wherein the single crystal ingot is subjected to cylindrical grinding before resistivity measurement. The degree of change in the resistivity distribution in the growth axis direction of the single crystal ingot is obtained, and the block is cut out so that the degree of change in the growth axis direction of the desired resistivity position is longer on the lower side. A method for producing a semiconductor wafer according to claim 1 or 2 . The resistivity distribution in the growth axis direction measured in the semiconductor wafer manufacturing method according to claim 1 and the condition for pulling up the single crystal ingot are associated with each other and stored in a storage unit by a computer,
Among the above conditions, an increase factor for increasing the resistivity and a decrease factor for decreasing the resistivity are distinguished and stored in the storage means by the computer,
In response to an input of a new next desired resistivity (referred to as “next resistivity”), the computer causes the output means to output predetermined information from the storage means,
The predetermined information output when the next resistivity is higher than the desired resistivity is the increase factor, and the predetermined information output when the next resistivity is lower than the desired resistivity is the decrease. Factor,
Applying the above-mentioned conditions based on each output predetermined information, the next single crystal ingot is pulled up, and at that time, the single crystal pulling condition is set so that the degree of change in resistivity distribution is reduced in the growth axis direction. To make the next single crystal ingot,
Measure the resistivity distribution in the growth axis direction on the side surface of the next single crystal ingot,
Identify the desired resistivity position that shows the desired resistivity,
Cutting a block of a predetermined length including the desired resistivity position by cutting the ingot in a direction perpendicular to the growth axis,
A method of manufacturing a semiconductor wafer, comprising manufacturing a semiconductor wafer by slicing the block.

Images