Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making – Radiation mask
Reexamination Certificate
2001-10-30
2004-08-03
Young, Christopher G. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Radiation modifying product or process of making
Radiation mask
Reexamination Certificate
active
06770402
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2000-333914, filed Oct. 31, 2000; and No. 2001-290118, filed Sep. 21, 2001, the entire contents of both of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to method for manufacturing a semiconductor device using a stencil mask, a stencil mask used the method for manufacturing a semiconductor device, and method for manufacturing the stencil mask.
2. Description of the Related Art
There is a method in which a stencil mask (or an aperture) having an opening is set at a certain distance on a substrate and an ion implantation is carried out, in a manufacturing process of a semiconductor device, in a process where a MOSFET in which its electrically conductive types of a channel within the same substrate are different or a MOSFET in which its threshold voltages are different is manufactured, when an ion implantation of an impurity is carried out into a well, a channel or Poly-Si.
In the case where a stencil mask is used in the ion implantation process in the manufacturing for a semiconductor device, it is carried out by employing a stencil mask having an opening limited to a region for ion implantation of the object of a substrate to be processed. Specifically, in the desired ion implantation region, ions are implanted through the opening of a stencil mask, and in a region for non-ion implantation, ions are shielded by a stencil mask shielding portion. However, on the stencil mask for shielding an ion, shielded ions are accumulated by repetitive ion implantations. Damages are also accumulated by shielded ions repeatedly crushing. As a result, after a plurality of ion implantation processes, the stencil mask is deformed and the ion implantation cannot be carried out with a high precision for positions.
For example, as shown in
FIG. 39
, when an impurity ion
4204
is implanted into a Si substrate
4201
on which an isolation region
4202
is formed through the opening of a stencil mask
4203
interspatially installed, if a distortion is generated on the stencil mask
4203
, since the position of the opening is displaced, an ion implantation region
4205
is not formed over the whole desired region, and a non-ion implantation region
4206
is formed. Moreover, depending on the shape of rough coating pattern, a problem is occurred that an n-type impurity is implanted over to a region in which a p-type region is to be formed.
As a result, the electric characteristics of a manufactured semiconductor product are varied, or the product poorly operates. Therefore, a stencil mask becomes unusable after it is used in the process of a plurality of ion implantations. The cost of manufacturing a stencil mask is converted to the cost of a manufacturing a semiconductor device, it leads to the rise of the manufacturing cost of the semiconductor device.
Moreover, in the case of a stencil mask employing a SOI substrate, since it is shielded by a thin film portion region having an opening and a supporting portion for supporting the thin film portion region in which the oxide film is an insulating film, its electrical conductivity and thermal conductivity are poor, and when it is used in the manufacturing process of a semiconductor, there has been a problem that the deformation due to the heat occurs or the ability of pattern formation is lowered due to the accumulation of charges.
By the way, in the manufacturing for a semiconductor device employing charged particles represented by ion implantation process, it is required that the desired particles uniformly reach to the region of the object. Therefore, it is needed that the uniformity is confirmed, that is, the amount of particles is measured by spatial separation, and when it does not have the desired uniformity, the uniformity should be maintained by performing the adjustment of the particle generation source within the apparatus for manufacturing a semiconductor device and the transport system of the particles on the basis of the measured signal. Moreover, in order to maintain the uniformity of the processing state among a plurality of processing substrates, it is required that the amount of particles reaching to the processing substrate is finely and precisely measured.
For the confirmation of this uniformity and the definition of the number of the particles reached to the substrate, there is a method of confirming the state of the substrate to be processed using another measurement device by actually performing the processing to the substrate to be processed. However, in this case, since the time is taken from the processing to the measurement, it is difficult to readjust the device on the basis of the result.
Therefore, it is desirable that the measurement for the uniformity is performed within the device, the re-adjustment of the device is performed on the basis of the measurement of the results and the uniformity is measured again. For the measurement of the uniformity within the device, there is a method of evaluating the uniformity by measuring the output from the probes, for example, such as Faraday gauges or the like arranged in lines for measuring the electric charge amount of the particles passing through the specific region.
However, since these probes measure the valence electrons, any information concerning with the neutralized particles cannot be obtained. On the other hand, for example, in the ion implantation process, an ion may be neutralized due to the influence of the residual gas in the device, and the neutralized particles also act similarly as the ion does to the substrate to be processed. Therefore, a probe capable of measuring particles including the neutral particles has been required. Moreover, it has been desired that the spatial resolution is enhanced upon the measurement along with the miniaturization and refinement of a semiconductor element, however, it has been difficult to miniaturize a probe for it.
As described above, it has been desired that in-plane distribution of the number of the neutral particles and the charged particles reached to the semiconductor substrate is measured and the number of particles reached to the semiconductor substrate is precisely controlled.
As described above, in the case where a stencil mask is used in the ion implantation process a plurality of times, the distortion of the mask is generated, and the ion implantation position with respect to the semiconductor substrate is deviated, thereby making the electric characteristics of the semiconductor products to be varied or making the product poorly operate. Therefore, in order to lower the manufacturing cost of the semiconductor device, a stencil mask capable of being made in a cheap cost or a stencil mask having a long life has been desired.
Moreover, there has been a problem that an ability of pattern formation is lowered due to the deformation with heat and the accumulation of electric charges caused by electrification.
A device for measurement capable of measuring an in-plane distribution of the number of the neutral particles and the charged particles reached to the substrate has been required.
BRIEF SUMMARY OF THE INVENTION
The present invention is configured so as to achieve the above-described objects as the followings.
(1) According to one aspect of the present invention, there is provided a method for manufacturing a semiconductor device comprising: a method for manufacturing a semiconductor device comprising: preparing a stencil mask comprising a silicon thin film in which an opening for selectively irradiating charged particles to a semiconductor substrate is provided and whose irradiation surface on which the charged particles are irradiated is implanted with an impurity; and selectively irradiating charged particles to the semiconductor substrate using the stencil mask which is opposingly arranged on the semiconductor substrate.
(2) According to one aspect of the present invention, there is p
Matsuo Kouji
Shibata Takeshi
Sugihara Kazuyoshi
Suguro Kyoichi
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Young Christopher G.
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