DD285663A5 - METHOD FOR ASSURING THE DEFORMATION FREEDOM OF SILICONE WELDING MATERIAL IN THE HOT WALL PIPE REACTOR - Google Patents

Abstract

The invention relates to a method for ensuring the freedom from deformation of silicon wafer material in the Heiszwand-Rohrreaktorprozesz that a non-critical for the plastic deformation heat transfer between the Substratscheibenbereichen each of the closely associated substrate discs, regardless of the geometric shape of the silicon material discs and without adversely affecting the on the substrate wafer already fabricated component structures, by setting a, the Ausgangsgetses of the heat transfer of the silicon material and the geometric proportions of the silicon slices taking into account charging temperature TP and Rampingrate VR, allows. {silicon wafer material; Heiszwand-Rohrreaktorprozesz; heating; Cooling down; plastic deformation; Freedom of deformation; Prozesztemperatur; charging temperature; Rampingrate; Temperaturaenderungsregime}

Description

and that a temperature rise or fall in temperature between the process temperature T ₀ and the charging temperature Tp is performed with a ramping rate VR satisfying the condition Vr = (AT _m O ¹ ) Mi _n ,

where T _{m + 1} = T _m -AT _m

with AT _m = C (m + 1) - ¹ e - ¹ exp (U ₀ / kTJ

and Q = cpd (8f _z e6) - ¹ T _p -. ³

It is

C = 1.8E-6Ks " ¹

U ₀ = 2.2 OeV

k = 0.862E-4eVK- ¹

ε = 0.6

5 = 1,36E- 12cal ^Cm-1 V K ^"4

ρ = 2.32 like " ³

c = 0.2calg - ¹ K " ¹

T _F = 823K

f _R = f _B (R / H)

fz = fz (R / H)

R = disc radius, H = disc distance.

2. The method according to claim 1, characterized in that the Rarnpingrate V _{R of} the temperature increase is set to be greater than the rate of decrease Vr of the temperature drop.

3. The method according to claim 1, characterized in that to increase the ramping rate V _H any temperature Τχ in the temperature range T ₀ > T _x > T _{P is selected} as the temperature-holding point T _x .

Field of application of the invention

The invention relates to a method for securing the freedom from distortion of silicon wafer material in the hot wall tubular reactor process and is thus particularly applicable in the processing of large diameter silicon wafer material in the context of diffusion, oxidation, CVD and annealing processes in the manufacture of electronic components.

Characteristic of the known state of the art

In the processing of silicon wafer material for the purpose of the production of integrated circuits is increasingly silicon wafer material of larger diameter application. This is done for reasons of higher efficiency of machining processes and increasing degree of integration of the circuits. The processing of larger diameter silicon wafers in high temperature processes of microelectronics technology is usually associated with the formation of temperature inhomogeneities over the silicon wafer body. Such temperature inhomogeneities

condition the formation of thermal stresses in the disk body, which can lead to the plastic deformation of the disk body. Temperature inhomogeneities in the disk body occur u. a. also in the processing of silicon wafer material in the hot wall tubular reactor, in particular both during charging and heating up to the process temperature, for reasons of economic process management in the tight disc group, the batch, standing silicon material discs, as well as during cooling and subsequent decharging of the disc assembly, up to room temperature.

In particular, when heating the silicon wafer charge up to the process temperature and cooling of the silicon wafer charge to room temperature occur between dom edge and the center of each silicon material slices of the batch temperature differences, due to an uneven heat transfer to or from silicon wafer areas and by mutual radiation shielding of the Silicon wafers of a batch are due. To minimize these temperature differences that occur in the disk body primarily during charging and heating and during cooling and decharging, to a size that minimizes the plastic deformation of the discs as far as possible, a number of technical equipment and process engineering solutions are known. Thereafter, silicon wafers with diameters starting at 76 mm, standing in a narrow disc dressing, no longer arbitrarily subjected to rapid temperature changes in the range of high temperatures, but from one or to one depending on the disc diameter and disc spacing of the discs empirically determined, the plastic deformation excluding temperature to process temperature heated in the hot wall tubular reactor or cooled to this temperature in the hot wall tubular reactor. Previously known Temperaturänc'erungsregimo in the heating and cooling phase of the slices in the hot wall tube reactor were based on the technical parameters of the system, they are realized by switching or interrupting the power supply. Such, the thermal-mechanical strength of the silicon substrate discs little considered method, ensures with disc diameters> 100 mm, standing in tight disc association, no freedom of deformation in the processing of silicon wafer material in the hot wall tubular reactor. For deformation-free machining of silicon material discs with diameters> 100 mm, standing in close-meshed association, the temperature difference between disk edge and disk center, which excludes the deformation, can be achieved by a low rate of temperature change over the silicon wafer bodies. However, an increasing reduction in the rate of temperature change that must be associated with a time increase in heat exposure for the closely spaced substrate disks also increasingly results in negatively affecting the device structures already fabricated on the substrate disks. By Dotandumverteilungsvorgänge and Yerclusterung any reduction in the rate of temperature change and thus an increase in time on heating or cooling phase of the substrate wafer in the hot wall tubular reactor limits. The extension of the thermomechanical Belas (limits) serve to change the geometric shape and the material-technical nature of the substrate wafers, inter alia by changing the thickness or the introduction of implants, in order to achieve a higher dimensional stability of the disc.

Object of the invention

The aim of the invention is to provide a method for ensuring the freedom from deformation of silicon wafer material in the hot wall tubular reactor, which both a plastic deformation of the substrate wafers as well as a negative effect on this substrate wafer already manufactured component structures, regardless of their geometric shape, in particular the size of their diameter , largely excludes.

Explanation of the essence of the invention

The invention is based on the object to provide a method for securing the deformation freedom of silicon wafer material in the hot wall tubular reactor, which is a non-critical for the plastic deformation heat transfer between the substrate wafer areas of each dsr in close association substrate discs, regardless of their geometric shape and without negative Influencing the already on the substrate wafer manufactured component structures allows.

This object is achieved by the method of ensuring the freedom of deformation of silicon wafer material in the hot wall tubular reactor, wherein the silicon wafer material is placed and removed in close-meshed relation to the hot wall tubular reactor and in particular for the processing of large diameter silicon wafer material in diffusion, oxidation, CVD and annealing processes, according to the invention solved in that the stationary wafer discs are entered and removed at a charging temperature Tp the hot wall tubular reactor and the height of the charging temperature dor condition

ever =txgenügend, is set, where

t _B = Cr ² exp (U ₀ / kTp) Ta ¹⁴

mitt

and that a temperature rise or drop in temperature between the process temperature T ₀ and the charging temperature T _{P is carried out} with a ramping rate V _n satisfying the condition V _B = (AT _m o "') min,

where T _n , ₊ , = T _n , - AT _n ,

with AT _n , = C {m + 1) - 'e-'exp (U ₀ / kTJ

m = 0,1,2, ...;

and θ = cpd (8f _z e6) - 'Tp- ³ .

It is

C = 1.8E-6Ks "'

U ₀ = 2.2 OeV

k = 0,862E - 4eVK- '

ε = 0.6

6 = 1.36E- ^ CaICnTV ¹ K- ⁴

ρ = 2.32 according to " ³

c = 0.2calg-'K- '

TF - 823K

f _R = f _R (R / H)

fz = fz (R / H)

R = disc radius, H = disc distance

The invention is advantageously designed in that the ramp rate V _{R of} the temperature rise between the charging temperature Tp and the process temperature T _{0 is} slightly greater than the rate of decrease V _{R of} the temperature drop between the process temperature T ₀ and the charging temperature Tp. Furthermore, any temperature T _x in the temperature range T ₀ > T _x > Tp can be selected as a temperature stop point T _x to increase the ramp rate Vr.

embodiment The invention will be explained in more detail with reference to an exemplary embodiment.

Silicon substrate discs with a diameter of 150mm and a thickness of 675μηι, which are in a long row at a distance of 4-5mm on a quartz boat, ie standing in close association, are in the oven, after Hochtamperaturbearbeitung in hot wall tubular reactor of 115O ⁰ C. cooled to room temperature. According to the oven technical nature of the cooling process can be controlled by implementing a defined temperature change regime in the oven room. If a defined setting of the temperature change regime in the oven space is not feasible due to lack of control options, the cooling rate required for deformation-free cooling of the slices in the slab package can be configured by changing the wafer spacing on the quartz boat in such a way that it corresponds to the natural cooling rate of the tubular reactor. In the realization of the heating and cooling process by means of setting a defined temperature change regime such a temperature profile in the furnace chamber is set, that based on the wheel diameter of 150 mm, the thickness of 675pm, a disc spacing in the quartz boat of about 5 mm, a ramping rate V _n = 10 K / min. This ramp rate Vr is determined from the quotient of a variable temperature difference, which has the edge of the silicon material disc relative to its center during the cooling process and the time over which this temperature difference, without causing plastic deformation phenomena on the disc material act. The determination of the ramping rate Vr takes place taking into account the process temperature T ₀ , the charging temperature T _P and the geometric conditions of the silicon material disks, such as disk thickness, disk diameter and distance of the disks on the quartz boat. Taking into account the already valid for silicon material constants and the fulfillment of the condition t _B - Ta, ie the allowable heating and cooling rate of the silicon wafers is equal to their heating and cooling, also results taking into account the process temperature T ₀ and the geometric conditions of the These necessary output variables, which according to the exemplary embodiment assume the above values, result in a charging temperature Tp = 875 ^° C. while maintaining the condition t _B = t _A. The deformation-free cooling process of the silicon material disks and geometric parameters is based on the to cause process temperature T ₀ = 115o ⁰ C with a Rampingrate Vr = 10 K / min up to the charging temperature Tp = 875 "C in the hot-wall tubular reactor. After reaching Cha / yaw temperature Tp = 875 ⁰ C the disk package is the hot-wall tubular reactor taken and the room temperature for further cooling. The cooling process is thus carried out in two stages, a controlled cooling in the hot wall tubular reactor, starting from the process temperature T ₀ to the charging temperature Tp while maintaining the ramp rate V _R , and a free cooling outside the reactor space from the charging temperature Tp to room temperature. The deformation-free cooling process of silicon material wafers takes place, taking into account the dimension of the silicon wafer material, its arrangement geometry and the process temperature, specifically for the parameters to be considered. In a necessary increase in the process temperature T _0, the permissible Rampingrate V _R becomes extremely small and reaches, for example, at 1200 ⁰ C in fact, the zero-border, so that a technically technological use due to possible clustering and Dotandenumverteilung becomes impossible. This is to be countered by pushing apart the substrate disks, ie by increasing the parameter H. The thus changed radiation behavior of the substrate disks in the tubular reactor leads to technically feasible cooling rates even for very high process temperatures. For example, at the same geometric disk ratios and a distance of the discs on the quartz boat of 25 mm, and a process temperature of 118O ⁰ C for the cooling process, a charging temperature Tp = 875 ⁰ C and a ramping rate V _R = 3K / min required.

Claims (1)

A method of ensuring the freedom from distortion of silicon wafer material in the hot wall tubular reactor, wherein the silicon wafer material is placed and withdrawn in close contact with the hot wall tubular reactor, in particular for the processing of large diameter silicon wafer material in diffusion, oxidation, CVD and annealing pessures; characterized in that the substrate discs standing in a close-meshed arrangement are introduced and removed at a charging temperature T _{P from} the hot-wall tubular reactor and the height of the charging temperature of the condition Tb = Ta is set sufficiently, where T ₈ = - Cr ² exp (IVkTp) T _A = 2f _R e6 (cpd) - ¹ tp ⁴ mitt = cpd (θίηεδΓ ¹ (V ³ -T p " ³ )