JP2006302528A - Ion implantation device and ion implantation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion implantation device improved in positional accuracy of ion implantation by making an error of positional accuracy of ion implantation caused by thermal expansion of a mask and a wafer fit into a prescribed range. <P>SOLUTION: The ion implantation device is provided with a temperature administration control system composed of a mask thermometer 11 measuring temperature of the mask 20; a mask heating/cooling system 13 controlling the temperature of the mask 20; a wafer thermometer 12 measuring temperature of the wafer 30; a wafer heating/cooling system 14 controlling the temperature of the wafer 30; and a heating/cooling controller 15 in which characteristic relation between temperature difference of the mask 20 and the wafer 30 is stored, controlling the mask heating/cooling system 13 and the wafer heating/cooling system 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ion implantation apparatus and an ion implantation method, and in particular, improves ion implantation position accuracy by making an ion implantation position accuracy error due to thermal expansion of the mask and the substrate within a predetermined range. The present invention relates to an improved ion implantation apparatus and ion implantation method.

As an example of a conventional ion implantation apparatus, an ion implantation apparatus described in Patent Document 1 will be described with reference to FIG.
FIG. 4 is a perspective view showing the overall configuration of a conventional ion implantation apparatus, and corresponds to FIG. 1 disclosed in Patent Document 1. In FIG.

As shown in FIG. 4, the main configuration of the conventional ion implantation apparatus 100 includes an ion source 110 that generates ions, an ion irradiation optical system 120, a stencil mask 130, an ion projection optical system 140, a sample stage 150, a control apparatus 142, It is a display device 144.
In addition, the ion source stage driving device 112 and the mask stage driving device 132 are controlled by the control device 142 to perform control such as operating a desired ion source for a predetermined pattern.

  The ion implantation apparatus 100 of Patent Document 1 has a plurality of stencil masks 130, a specific stencil mask 130 is selected from the plurality of stencil masks 130, and a plurality of dopant ions corresponding to the stencil mask 130. The process of selecting a specific dopant ion species from the seed and injecting it into the sample can be performed a plurality of times.

JP-A-8-213339

Hereinafter, problems of the conventional ion implantation apparatus will be described with reference to FIGS.
FIG. 5 is a perspective view showing an ion beam implantation state in the vicinity of a mask and a substrate in order to explain a problem of a conventional ion implantation apparatus.
6 to 8 are plan views of a substrate including an ion implantation position error in order to explain problems of the conventional ion implantation apparatus.

For example, as shown in FIG. 5, when an ion beam transmitted through a mask 130 having an opening pattern such as a stencil mask is implanted into a substrate 152 such as a semiconductor wafer, the mask pattern is implanted into the substrate 152 as it is, and an implantation position accuracy error occurs. It is desirable that there is no.
However, an injection position accuracy error occurs due to various factors as described below.

First, there is a case where a mask pattern called shift as shown in FIG. 6 shifts in a predetermined direction, resulting in an ion implantation position accuracy error.
Secondly, a mask pattern called a “rotation” as shown in FIG. 7 is rotated by a predetermined rotation angle to cause an ion implantation position accuracy error.

Third, there is a case where an ion implantation position accuracy error occurs due to a difference in thermal expansion between the mask 130 and the substrate 152 called a mag (Magnification) as shown in FIG.
This is because high energy ions are implanted into the mask 130 and the substrate 152, so that ions are irradiated to the ion shielding portion of the mask 130 or ions that are transmitted through the opening pattern of the mask 130 and irradiated to the substrate 152. This is a positional accuracy error caused by a difference in thermal expansion between the mask 130 and the substrate 152 when the mask 130 and the substrate 152 are heated.

By the way, the shift and rote described above are installation errors between the mask 130 and the substrate 152, and can be solved by improving the alignment accuracy between the mask 130 and the substrate 152.
Also, with regard to the mag, the positional accuracy error can be reduced to some extent by controlling the temperature of the mask 130 and the substrate 152. However, in order to implant ions with a more precise positional accuracy, it is extremely difficult for the following reasons. It is difficult to.

First, when the mask 130 and the substrate 152 are made of different materials, the linear expansion coefficients are different, and the difference in the linear expansion coefficients must be taken into consideration.
Even if the temperature control is performed in consideration of the difference in linear expansion coefficient between the mask 130 and the substrate 152, or the mask 130 and the substrate 152 are made of the same material and have the same linear expansion coefficient, the mask 130 is It has a predetermined opening pattern and the shape change due to thermal expansion is not isotropic.

  Further, in the process of manufacturing the mask, distortion and residual stress are applied to the mask 130, and due to this distortion and residual stress, the shape change due to thermal expansion is not isotropic, and it is not necessarily the same shape as the substrate 152. No thermal expansion.

  Therefore, the conventional ion implantation apparatus has the problem that the position accuracy of the ion implantation by the mag is inevitably limited, which has been an obstacle to the achievement of the next generation high precision ion implantation apparatus.

  The present invention solves the above-described conventional problems, and makes the ion implantation position accuracy error greatly improved within a predetermined range by causing the ion implantation position accuracy error due to the thermal expansion of the mask and the substrate to be within a predetermined range. And an ion implantation method.

The ion implantation apparatus according to the present invention has a mechanism for holding a mask having an opening pattern, and ions accelerated to a desired energy through the opening of the mask are applied to a substrate such as a semiconductor wafer. In an ion implantation apparatus for implantation,
A mask temperature measuring unit that measures the mask temperature of the mask and a substrate temperature measuring unit that measures the substrate temperature of the substrate are provided.

  The ion implantation apparatus according to claim 2 includes a mask temperature adjusting unit that adjusts a mask temperature of the mask and a substrate temperature adjusting unit that adjusts the substrate temperature of the substrate.

  The ion implantation apparatus according to claim 3 includes a temperature management control mechanism that controls the mask temperature adjustment unit and the substrate temperature adjustment unit so that the mask temperature and the substrate temperature become desired temperatures. .

  The ion implantation apparatus according to claim 4, wherein the temperature management control mechanism stores in advance a characteristic relationship between the mask temperature and a positional accuracy error that occurs in the mask and the processing substrate with respect to the substrate temperature, The mask temperature measured by the mask temperature measurement unit, the substrate temperature measured by the substrate temperature measurement unit, and the control command to the mask temperature control unit according to the characteristic relationship stored by the storage unit and the substrate temperature And a calculation unit that calculates a control command to the control unit.

  The ion implantation method according to claim 5 is configured to measure a mask temperature of the mask and a substrate temperature of the processing substrate in an ion implantation method in which desired ions are implanted into the processing substrate through a mask having an opening pattern.

  The ion implantation method according to claim 6 includes a step of adjusting the mask temperature and the substrate temperature.

  8. The ion implantation method according to claim 7, wherein in the step of adjusting the mask temperature and the substrate temperature, when the mask temperature is higher than a preset temperature range, the mask is cooled and the mask temperature is preset. Heating the mask when the temperature is higher than the set temperature region; cooling the substrate when the substrate temperature is higher than the preset temperature range; and cooling the substrate from the preset temperature range. If it is lower, either one or both of heating the substrate is employed.

  9. The ion implantation method according to claim 8, wherein the step of adjusting the mask temperature and the substrate temperature cools the mask when a difference between the mask temperature and the substrate temperature is higher than a preset temperature range. And / or heating the substrate, and if the difference between the mask temperature and the substrate temperature is lower than a preset temperature range, heating the mask and the substrate It was set as the structure which implements any one or both of cooling.

Since the ion implantation apparatus of the present invention is configured as described above, it has the following excellent effects.
(1) If it comprises as described in Claim 1, the temperature measurement of a mask and a board | substrate will be attained, and it can be set as the ion implantation apparatus which improved the position accuracy of ion implantation.

(2) With the configuration as described in claim 2, it becomes possible to measure and adjust the temperature of the mask and the substrate, suppress an error in ion implantation position accuracy due to thermal expansion of the mask and the substrate, and improve the position accuracy of the ion implantation. The ion implantation apparatus can be obtained.

(3) With the configuration described in claim 3, the temperature management and temperature control of the mask and the substrate are possible, the ion implantation positional accuracy error due to the thermal expansion of the mask and the substrate is suppressed, and the positional accuracy of the ion implantation is improved. The ion implantation apparatus can be obtained.

(4) When configured as described in claim 4, the ion implantation position accuracy error due to the thermal expansion of the mask and the substrate is always within a predetermined range, thereby dramatically improving the ion implantation position accuracy. An improved ion implantation apparatus can be obtained.

Since the ion implantation method of the present invention is configured as described above, it has the following excellent effects.
(1) If it comprises as described in Claim 5, the temperature measurement of a mask and a board | substrate will be attained, and it can be set as the ion implantation apparatus which improved the positional accuracy of ion implantation.

(2) With the configuration described in claim 6, the temperature of the mask and the substrate can be adjusted, an ion implantation position accuracy error due to the thermal expansion of the mask and the substrate is suppressed, and the ion implantation has improved the position accuracy of the ion implantation. It can be a device.

(3) Since the temperature of the mask and the substrate can be brought close to a desired set value when configured as described in the seventh aspect, an ion implantation position accuracy error due to thermal expansion of the mask and the substrate is suppressed, and the position of the ion implantation is reduced. An ion implanter with greatly improved accuracy can be obtained.

(4) With the configuration described in claim 8, since the temperature difference between the mask and the substrate can be brought close to a desired setting range, an error in ion implantation position accuracy due to thermal expansion of the mask and the substrate is suppressed, and the ion implantation is performed. It is possible to provide an ion implantation apparatus with greatly improved positional accuracy.

An embodiment of the ion implantation apparatus of the present invention will be described below with reference to FIGS.
FIG. 1 is a block diagram showing the main configuration of the ion implantation apparatus of the present invention.
FIG. 2 is a flowchart for explaining the basic operation of the ion implantation apparatus of the present invention.
FIG. 3 is an actually measured characteristic diagram showing a relationship between a temperature difference between a mask and a substrate used in the ion implantation apparatus of the present invention and a mag which is a positional accuracy error due to thermal expansion.

First, the ion implantation apparatus of the present invention is characterized in that a mask and substrate temperature management control mechanism is added to the conventional ion implantation apparatus, and therefore, this temperature management control mechanism will be mainly described below.
In the following embodiments, a stencil mask having an opening pattern (sometimes simply referred to as “mask”) is used as the mask, and a semiconductor wafer (simply simply referred to as “wafer”) is used as the substrate. Explain with things.

  The temperature management control mechanism 10 includes a mask thermometer 11 that measures the temperature of the stencil mask 20, a mask heating / cooling system 13 that controls the temperature of the mask 20, a substrate thermometer 12 that measures the temperature of the wafer 30, and a substrate. And a substrate heating / cooling system 14 for controlling the temperature of 30.

As described above, the stencil mask 20 has an opening pattern and does not always thermally expand isotropically in proportion to the coefficient of linear expansion due to the material of the mask 20 due to distortion or residual stress in the manufacturing stage. Absent.
Therefore, as shown in FIG. 3, the temperature management control mechanism 10 of the present embodiment measures in advance the characteristic relationship between the temperature difference between the mask 20 and the wafer 30 and the mag component, which is a positional accuracy error due to thermal expansion. The measured data is stored, and a stencil mask heating / cooling system (CS1 in FIGS. 1 and 2) 13 and a wafer heating / cooling system (CS2 in FIGS. 1 and 2) 14 for controlling the temperature of the wafer 30 are provided. A heating / cooling controller 15 to be controlled (hereinafter sometimes simply referred to as “controller”) is provided.
In FIGS. 1 and 3, the horizontal direction of the paper is set as the X axis, and the vertical direction of the paper is set as the Y axis. In FIG. 3, the variables are x and y, respectively.

Next, the basic operation of the ion implantation apparatus of the present invention having the above configuration will be described with reference to FIGS.
In the ion implantation apparatus of the present invention, after the ion implantation into the wafer 30 is started, the temperature management and control mechanism 10 described above also starts the temperature management and control of the mask 20 and the wafer 30.

That is, first, as shown in FIG. 2, the temperature Tc1 of the mask 20 and the temperature Tc2 of the wafer 30 are measured by the mask thermometer 11 and the wafer thermometer 12 (ST1).
Next, the temperature difference Tr is calculated by subtracting the temperature Tc2 of the wafer 30 from the temperature Tc1 of the mask 20 (ST2).

  At this time, when the relationship between the temperature Tc1 of the mask 20, the temperature Tc2 of the wafer 30, and the temperature difference Tr is Tc1 ≦ Tr ≦ Tc2, that is, the temperature difference Tr is within the range of the temperature Tc1 of the mask 20 and the temperature Tc2 of the wafer 30. In some cases, the heating / cooling state of the stencil mask heating / cooling system 13 that controls the temperature of the mask 20 and the wafer heating / cooling system 14 that controls the temperature of the wafer 30 is maintained (ST5).

On the other hand, if the relationship between the temperature Tc1 of the mask 20 and the temperature difference Tr is Tr <Tc1, that is, if the temperature difference Tr is smaller than the temperature Tc1 of the mask 20, the mask 20 is heated by the mask heating / cooling system 13 to 30 is cooled by the wafer heating / cooling system 14 (ST3).
After this temperature control, the temperature Tc1 of the mask 20 and the temperature Tc2 of the wafer 30 are measured again (ST1), and this temperature control is performed until the temperature difference Tr falls within the range of the temperature Tc1 of the mask 20 and the temperature Tc2 of the wafer 30. repeat.

Similarly, when the relationship between the temperature Tc2 of the wafer 30 and the temperature difference Tr is Tc2 <Tr, that is, when the temperature difference Tr is larger than the temperature Tc2 of the wafer 30, the mask 20 is cooled by the mask heating and cooling system 13, The wafer 30 is heated by the wafer heating / cooling system 14 (ST4).
After this temperature control, the temperature Tc1 of the mask 20 and the temperature Tc2 of the wafer 30 are measured again (ST1), and this temperature control is performed until the temperature difference Tr falls within the range of the temperature Tc1 of the mask 20 and the temperature Tc2 of the wafer 30. repeat.

  That is, if the temperature management control mechanism in the ion implantation apparatus of the present embodiment is used, the temperature difference Tr between the temperature Tc1 of the mask 20 and the temperature Tc2 of the wafer 30 is repeated by appropriately repeating the temperature control of the mask 20 and the wafer 30. It is possible to always keep the relationship within a desired range.

  As the temperature difference Tr at this time, a numerical value that minimizes the mag is selected from the pre-measured characteristic curve shown in FIG. 3 stored in the controller 15, and the temperature control of the mask 20 and the wafer 30 is also performed by the controller. 15 is performed.

  That is, according to the ion implantation apparatus of the present embodiment, since the mag, which is an ion implantation accuracy error due to thermal expansion, can be controlled based on the actually measured data, it can be controlled within the desired range. It becomes possible to improve dramatically compared with the thing.

The ion implantation apparatus of the present invention can be variously modified without being limited to the above embodiment.
For example, in the above-described embodiment, the stencil mask is used as the mask and the wafer is used as the substrate. However, the present invention is not limited to these, and various masks and substrates can be used.

It is a block diagram which shows the main structures of the ion implantation apparatus of this invention. It is a flowchart explaining the basic operation | movement of the ion implantation apparatus of this invention. It is the measured characteristic figure which shows the relationship between the temperature difference of the mask and wafer used for the ion implantation apparatus of this invention, and the mug which is a position accuracy error by thermal expansion. It is a perspective view which shows the whole structure of the conventional ion implantation apparatus. It is a perspective view which shows the state of the ion beam implantation in the mask and board | substrate vicinity, in order to demonstrate the problem of the conventional ion implantation apparatus. It is a top view of the board | substrate containing an ion implantation position error in order to demonstrate the problem of the conventional ion implantation apparatus. It is a top view of the board | substrate containing an ion implantation position error in order to demonstrate the problem of the conventional ion implantation apparatus. It is a top view of the board | substrate containing an ion implantation position error in order to demonstrate the problem of the conventional ion implantation apparatus.

Explanation of symbols

10: Temperature management control mechanism 11: Mask thermometer 12: Wafer thermometer (substrate thermometer)
13: Stencil mask heating / cooling system (mask heating / cooling device)
14: Wafer heating / cooling system (substrate heating / cooling device)
15: Heating / cooling controller 20: Stencil mask (mask)
30: Wafer (substrate)

Claims (8)

In an ion implantation apparatus having a mechanism for holding a mask having an opening pattern, and implanting ions accelerated to a desired energy through the opening of the mask into a substrate such as a semiconductor wafer,
A mask temperature measuring unit for measuring a mask temperature of the mask;
An ion implantation apparatus comprising: a substrate temperature measurement unit that measures a substrate temperature of the substrate. A mask temperature adjusting unit for adjusting the mask temperature of the mask;
The ion implantation apparatus according to claim 1, further comprising a substrate temperature adjusting unit configured to adjust a substrate temperature of the substrate. The ion implantation apparatus according to claim 2, further comprising a temperature management control mechanism that controls the mask temperature adjustment unit and the substrate temperature adjustment unit so that the mask temperature and the substrate temperature become desired temperatures. . In the temperature management control mechanism,
A storage unit for storing in advance a characteristic relationship between the mask temperature and a positional accuracy error generated in the processing substrate and the mask with respect to the substrate temperature;
The mask temperature measured by the mask temperature measurement unit, the substrate temperature measured by the substrate temperature measurement unit, and the control command to the mask temperature control unit according to the characteristic relationship stored by the storage unit and the substrate temperature The ion implantation apparatus according to claim 3, further comprising a calculation unit that calculates a control command to the control unit. In an ion implantation method for implanting desired ions into a processing substrate through a mask having an opening pattern,
An ion implantation method comprising measuring a mask temperature of the mask and a substrate temperature of the processing substrate. 6. The ion implantation method according to claim 5, further comprising a step of adjusting the mask temperature and the substrate temperature. Adjusting the mask temperature and the substrate temperature;
When the mask temperature is higher than a preset temperature range, the mask is cooled, and when the mask temperature is higher than a preset temperature range, the mask is heated, and the substrate temperature is preset. When the temperature is higher than the set temperature range, the substrate is cooled, and when the substrate temperature is lower than the preset temperature range, one or both of the heating is performed. The ion implantation method according to claim 6. The step of adjusting the mask temperature and the substrate temperature includes:
If the difference between the mask temperature and the substrate temperature is higher than a preset temperature range, perform one or both of cooling the mask and heating the substrate,
7. The method according to claim 6, wherein if the difference between the mask temperature and the substrate temperature is lower than a preset temperature range, one or both of heating the mask and cooling the substrate is performed. The ion implantation method described in 1.

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