Method of forming manufacturing semiconductor device

Details Method of forming manufacturing semiconductor device Method of forming manufacturing semiconductor device

1998-03-30

2001-10-23

Graybill, David E. (Department: 2814)

Metal working

Barrier layer or semiconductor device making

Reexamination Certificate

active

06306183

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a method of manufacturing a semiconductor device which has a film formation processing step using a single wafer type low pressure CVD (Chemical Vapor Deposition) apparatus capable of preventing foreign substance from being produced on a wafer.
BACKGROUND ART
Conventionally, a low pressure CVD apparatus has been widely utilized, particularly for forming a Si
3
N
4
film, a polysilicon film, and so on, when a semiconductor device is manufactured.
Of the known low pressure CVD devices, a vertical batch type CVD apparatus is currently most popular. However, since wafers are expected to have increasingly larger diameters in future and a short TAT (Turn Around Time) is required for reducing a development term. A single wafer type CVD apparatus (for example, a single-wafer type reduced pressure CVD apparatus) has been developed for replacement of the vertical batch type CVD apparatus and has been gradually introduced into a portion of semiconductor device developing lines.
The single-wafer type reduced pressure CVD apparatus may be generally classified by two types of heating methods: a resistive heating hot wall type and a lamp heating cold wall type.
Within these classes, a single wafer type low pressure CVD apparatus of resistive heating hot wall type is similar to the conventional vertical type low pressure CVD apparatus in process conditions because the vertical low pressure apparatus also belongs to the resistive heating type, so that it can be readily replaced with the conventional apparatus. Moreover, since the resistive heating hot wall type has an additional feature of exhibiting a good temperature controllability, it is regarded as being advantageous over the lamp heating cold wall type.
As such a single wafer type reduced pressure CVD apparatus of resistive heating hot wall type, one capable of simultaneously processing two wafers, for example, silicon wafers for achieving higher through-put is also available partially in the market.
FIGS. 2A and 2B
are a side view and a plan view showing an example of a heat processing chamber for a resistive heating hot wall type single-wafer type reduced pressure CVD apparatus, as mentioned above, which is capable of simultaneously processing two wafers.
This apparatus is provided with a heat processing chamber
1
serving as an reaction chamber for carrying out a film formation processing. A heater (not shown) is arranged outside the heat processing chamber in contact with a upper wall surface and a lower wall surface thereof which allow for adjustment to a desired film formation processing temperature. The heat processing chamber
1
is also provided inside thereof with a wafer carrier
2
. The wafer carrier
2
is composed of an upper stage
2
a
and a lower stage
2
b
, as illustrated in
FIG. 2A
, each of the upper stage
2
a
and the lower stage
2
b
is constructed of legs
3
and a carrier plate
4
. A circular opening
5
, sufficiently larger than a wafer W as illustrated in
FIG. 2B
, is formed through each carrier plate
4
of the respective upper stage
2
a
and lower stage
2
b
, and a pin
6
protruding into the opening
5
is formed on the circumferential edge of the opening
5
at four diametrically opposing positions. These pins
6
, which are made of a quartz boat and arranged below the top surface of the carrier plate
4
, are formed such that the spacing between the opposing pins
6
,
6
is smaller than the diameter of the wafer W to support the wafer W at their tip ends.
In order to subject the wafer W to film formation processing by using a low pressure CVD apparatus having the heat processing chamber
1
constructed as described above, conventionally, the heat processing chamber
1
is heated at first by the heaters to a film formation processing temperature. Then, two wafers W are carried on transporting arms (not shown), respectively which are then inserted into an accommodation port
7
of the heat processing chamber
1
, and the wafers W are immediately mounted on the pins
6
of the upper stage
2
a
and on the pins
6
of the lower stage
2
b
, respectively, in a bridging style for achieving higher through-put.
Subsequently, when the wafer W is heated to the temperature within the heat processing chamber
1
, i.e., the film formation processing temperature, a material gas is introduced into the inside of the heat processing chamber
1
from a material gas introducing tube, not shown, to perform the film formation processing.
In the film forming method as described above, however, when the temperature within the heat processing chamber
1
reaches 700-850° C., many particles of foreign substances are observed on the top surface, i.e., the film forming surface of the wafer W mounted on the lower stage
2
b
. The occurrence of such foreign substances causes a reduced yield.
The present invention has been made in view of the problem mentioned above, and its object is to provide a method of manufacturing a semiconductor device which prevents foreign substances from being produced on a wafer.
DISCLOSURE OF THE INVENTION
As a result of deep investigation into achieving the above-mentioned object, the inventors have reached a belief that the phenomenon of the aforementioned foreign substance is caused by wafers being rubbed with pins of quartz boats for supporting the wafers when the wafers are introduced into the heat processing chamber and mounted on the pins of respective stages of the wafer carrier.
More specifically, when a wafer is introduced into the heat processing chamber and mounted on the wafer carrier, the wafer is exposed to a high temperature within the heat processing chamber abruptly from the room temperature so that peripheral portions thereof, particularly those in contact with the pins, are first heated to exhibit thermal expansion, and subsequently a central portion thereof also gradually expands due to the heat. Thus, the wafer suffers from deformation (warping) due to a temporal deviation of the thermal expansion between the peripheral portion and the central portion thereof. As the deformation is developed, the pins of quartz boat and portions of the wafer in contact therewith are rubbed to cause foreign substances. Particularly, when this phenomenon occurs on the upper stage of the wafer carrier, produced foreign substances P drop onto the film formation surface of the wafer W mounted on the lower stage, as illustrated in
FIG. 3
, to cause the phenomenon that many foreign substances are produced on the film formation surface thereof, as described above.
Thus, to prevent such a phenomenon, in the present invention, when wafers are introduced into a heat processing chamber previously heated to a desired heat processing temperature, those wafers to be mounted on stages except for at least the lowermost stage of the wafer carrier, are left in the heat processing chamber until central portions thereof are heated to the vicinity of the temperature within the heat processing chamber, without immediately mounting them on the stages of the wafer carrier. Thereafter, the wafers are mounted on predetermined stages of the wafer carrier and are subjected to the film formation processing.
According to this manufacturing method, when wafers are introduced into the heat processing chamber with a transporting arm or the like, the wafers are left in the heat processing chamber until central portions of the wafers are heated to the vicinity of the temperature within the heat processing chamber, without immediately mounting the wafers on predetermined stages of the wafer carrier, and the wafers are thereafter mounted on the predetermined stages of the wafer carrier, so that deformation thereof due to thermal expansion occurs when the wafers are left in the heat processing chamber, held by the transporting arm or the like. Since the deformation has substantially disappeared when the wafers are mounted on the wafer carrier, the wafers are prevented from being rubbed with the wafer carrier with the deformation.


REFERENCES:
patent: 5516732 (1996-05-01), Flegal

Affiliated with

Also associated with

Rating

Method of forming manufacturing semiconductor device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of forming manufacturing semiconductor device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of forming manufacturing semiconductor device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2593660