JPS58213440A - Surface profile adapted for transferring heat from thin and soft product - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heat transfer apparatus including an object, a hot needle 1N, and a device, particularly for cooling KIA of semiconductor wafers processed by ion implantation, subtooling, etc. be.

BACKGROUND OF THE INVENTION A processing technology in which the processed product is subjected to a high radiant flux! In this case, the heat released into the processed product may be a limiting factor for the processing. In particular, ion implantation of semiconductor materials has been shown to have limited workpiece match for several reasons. If the wafer is coated with a resist layer as part of a lithographic tin salt, then the DM will degrade or deteriorate in warm temperatures raised well above 100°C. One area in a semiconductor wafer that has distinctly changed characteristics is that the wafer is long and exposed to radiation and is not well-diffused, or has been previously implanted, etc.; It will probably happen.

Therefore, it is critical to remove the heat generated in semiconductor wafers as a result of ion implantation processes and the like.

During ion implantation, the semiconductor wafer is bent into a convex shape and
It is known in the prior art to actively cool semiconductor wafers by tightening them.

The platen has a coating of flexible thermally conductive material on its surface. The clamping ring cooperates with the grating to ensure that the convexly curved platen is compliant (c, om).
The semiconductor wafer is positioned to press firmly against a surface (plimnt), and its clamping further enhances the transfer of thermal energy from the wafer to the active cold MJ+ stage provided within the platen. Such a device is disclosed in US Pat. No. 2,212.
No. 9211.

The aforementioned technology is based on a conduction mechanism for heat transfer. Thermal energy is generated near the outer surface of the wafer by the kinetic energy of the incident beam absorbed by the wafer. Therefore, since heat transfer needs to take place through the wafer material, a thermally conductive /Al component is present throughout in the heat transfer S properties of the wafer material. (It is assumed for simplicity that the heat passes through the walls of the pipe.) Similarly, between the way/1 and way/1 contacting platen surfaces, there are cooling channels for circulating cooling fluid. The platen is made of a material having thermal conductive properties characterized by roundings which are distributed to allow heat transfer to occur through the S area of the platen. In the realm of darkness between Waeno 1 and Grab/, heat transfer G! Is there a clear contribution to the struggle? 4)
Leave it to me. Thermal conduction in region c is approximately proportional to the area of contact between the wafer and platen and inversely proportional to the average thermal conductivity of the two materials.

On a microscopic scale, their markings are completely flat and uneven, pointing in irregular directions. Due to the assumptions made in the hardness of the material and the surface roughness distribution of each contact surface, the contact IMi can be estimated by optical measurements, but in reality only a fraction of the macroscopic area This is only a part of the theory of conductive heat transfer between solids in the air.
s Transfer, 12%.

219-500 members (196 u)). It has been shown that the contact heat transfer depends on the conductivity and the actual contact area. The actual contact area depends on the surface density of the uneven portions of the mating surfaces and the elastic or plastic compatibility (K1) of the materials. Due to the pressing force acting on the top, the irregularities first deform into contact with each other, or into conformity, and more contact Pj! 1-I (Jil will be generated. 15r due to more contact surface area)
The effect of M is driven by the large stress that can be supported by the wafer. In US Pat. Heat conduction fit in contact with wafer.

An outer layer of (compatible) material is bonded. Therefore, it is provided with a surface layer that deforms to accommodate small irregularities in the wafer. In this example, its adaptation (
compl Iant) in the length of the thermal path through the material j! There is a geometric layering in. Its length is
It becomes shorter in proportion to the increase in contact pressure.

This effect is initially visible, but the small deformations that usually occur are quite small in %O.

The various effects that affect the thermal impedance of the interface include the ability to provide selectively controllable thermal impedance where it is desirable to maintain a predetermined wafer temperature t with respect to thermal radiation. 9.

An example of this attribute is provided in copending U.S. Application No. 28,915, hereinafter assigned.

Therefore, the purpose of this invention is to effectively cool the conductive wafer during ion implantation.
The objective is to provide a device that can uniformly provide such cooling.

SUMMARY OF THE INVENTION An improved heat transfer device for a medium conductor tube 1 subjected to a radiant flux includes a platen surface having nine wafers preferably clamped about its circumference. The platen has a profile that maximizes the transfer of heat through the wafer to the tip, independent of the field on the surface of the wafer.

The contact pressure distribution between the wafer and the platen is such that the clamping of the wafer to the platen is uniform over the entire nD surface of the wafer, with respect to the boundary conditions added by means. A contour matching the wafer is calculated to correspond to the surface. The amount of contact pressure is scaled up to an amount that can be tolerated without the wafer subsequently cracking.

In one embodiment, the tensile structure consists of a rigid metal member and a compliant layer bonded thereon. The properties of the bonded layer and the internal profile of the member at the bonding surface meet the above requirements. Outside that satisfies the conditions @ - Guo 1
well controlled.

In either approach, the platen preferably includes cooling means for removing p6 from 70 to effect 11'J.

Preferred Embodiment A summary of the present invention describes a typical ion implantation 1+! ! This is clearly shown in Figure 1, which shows the 7th prisoner. The high voltage voltage terminal 2 is typically +10 to +2 with a threshold of 1- to ground.
00 k@ma? The voltage is maintained at a selectable voltage. In the terminal 2, an ion source 8 and its combination 9i! The source IO is located and the extraction, group and focus area pressures are overlooked for purposes of the present invention.

In general, the ion source operates on a gas-handling device that requires a gaseous gas, and its A- is used to select between several gas cylinders and to control the selected gas. It may also be used to feed the ion source by leakage. The high flux ion beam lFi diverging from the ion source 8 is J! The volume is analyzed and flows out of the seven magnets, shaped by holes 22 and further defined by a variable slit system 24. The beam is then accelerated to ground potential in pre-acceleration 26. An optical element 28, such as a four-pronged pole/shaft, acts on the beam to produce a nine-opening beam at the target surface 56 or 8. Typical of 141 figures: 4! ! The koshiki uses an electrostatic deflection device. That stillness! The deflection device includes a Y deflection plate 40 and a wing deflection plate vine 2 for directing the beam 111 over a selected target field. The waveforms applied to plates 40 and -2 to form the desired scan pattern are created by the scanning device. A dual channel target chamber 6 is provided for rounding the product to be processed. Beamforming slits approximately 8 and 49 for each processing channel, and a radial cage 50 and another for the power collection and assembly are included in the target chamber. When the moving wafer handling equipment containing supply channels 2 and 54t is activated, the two processing channels are filled, one at a time, through each of two vacuum locks for staggered introduction into the target chamber. Semiconductor wafers are introduced.

The wafer handling equipment properly positions, aligns, and cools the wafer between the tin salts and processes the wafer t-Mi1. Excluding b. The wafer handling equipment is described in a series of accompanying publications.

It will be appreciated that the entire area traversed by the ion beam is kept at high pressure, eg, typically on the order of tow, ht.

As shown in FIG. 2A, it will be seen that the clamping force applied around the wafer 62 results in a contact force that is unevenly distributed across the wafer surface. This creates uneven loading on the wafer. The small uniform load therein is created by the platen 611, which has a convex profile 65t*. Local stresses are symbolized by vector components 66. wafer 6
The thermal conductivity of the 2 and platen 6N and 0 interfaces is a function of the thermal and mechanical properties of the material as well as the contact collar applied on the wafer towards the graten. As mentioned above,
This means that - cotton has 1 wafer and platen (i
This is because of the visual surface roughness and compressibility, which is a factor in the visual field, and the contact area in each material, which can vary in proportion to the applied force. In a convex spherical platen that typically cools a peripherally clamped wafer, as shown in Fig. Therefore, during processing
・It is known that it progresses widely in the central area of ・.

The optimal platen profile can be described by a differential equation that describes a uniformly loaded thin disk supported along its periphery. This problem,! By Margu@rre and Woernle') CW
It has been argued that (0 elasticity*” No. 11).

Price Dell Publishing, Waltham, Masachi Hyoro-Setsutsu I
l'11.1969). With reference to this, the deviation for a thin flexible disk uniformly loaded and supported by 9 MI#BA (de (lee t 5 on) 7 (
r) is. Here, r radial position 1) m 2 y, (wafer diameter) t - wafer thickness pm force applied to the wafer B - elastic modulus Poynnon's ratio Described by the above equation (1) K , satisfying criteria for optimal contact cooling as perceived during processing, such as a uniform contact pressure distribution applied to the wafer.

It is desirable to maximize the contact force between the wafer and the wafer during rounding to maximize the heat transfer from the wafer to the surface. The maximum contact force is 1[11jPft due to its Quafer material O customization. Since the wafer is deformed into a convex shape, the retrace direction component of the L force (
The 41# direction component with respect to the normal stirrup contact force forces bending, thereby compressing the vicinity of the inner surface of the workpiece and tightening the vicinity of its outer (convex) surface. The retrace direction component of the stress on each surface is expressed above as a magnitude that gives a range of design parameters (in particular, the %1i force stress at the outer 9Ailu).

For a uniformly loaded, round and thin disk, the maximum surface pressure resulting from the difference formed in this way is g=p (-!!ri) ['-(3+ν)]
(2) is given by s, the maximum pressure of which is limited by the maximum tension pressure at which 9A is safe, as in the following equation:

In ζζ, the maximum tension pressure that can be withstood when the tension force 'd For a disk, the maximum deviation is given as:

'maxkl history, becomes.

Type 9 eliminates the Damenge cylinder, and H against the platen is F.
It is given by dividing Equation (1) by Equation (5) described in the outer shape of -.

Therefore, equation (4) shows that there is no single heat transfer over the entire surface of the wafer and that the maximum heat transfer r from the wafer is
It should be noted that Equation (II) expressing the joint condition ζ depends on Young's modulus and that Poisson's ratio hardly changes for various materials. The formula (ri) expresses a scheme that can be applied to the proposed purpose.
There is. In actual use, the value of 'nIRK is constrained to the thickness of the curved edge 4 (mmpHtude) or the scale r
However, it should also be noted that a variety of different 9Ah shrines can be accommodated without making any real sacrifices to heat transfer characteristics.

Therefore, in the J2B diagram, the platen 70 of the present invention is
The wafer 12 is pressed against the platen 70 with a circumferential clamping by a ring 7 and with a force Lt. A stress distribution symbolically represented by the vector component 7g is imposed by the boundary conditions of the surrounding clamping and by matching the wafer 72 and the contour 71. It can be seen that the force of a cart with a uniform constant force is uniform across the entire wafer.The entire wafer surface #
For a constant amount of force for touching the body, the contact pressure is assumed to be a value that does not change with respect to further increases in LO. Further increase in I contact force71.
is applied to the wafer t- without affecting the load distribution 41t-
It is simply passed through and transferred to the substrate.

As another example (FIG. 20), the platen assembly may be formed from a rigid member platen IO and a suitable thermally conductive coating 82.

The intermediate profile 90 of the platen 60 is determined to take into account the timing of the cargo oil and compounded material 82 that the wafer 86 receives. The load force, the boundary ring νμ8 bar between the wafer 86 and the platen 80 under the design load conditions, for the boundary condition determined by clamping the wafer to the platen, the entire surface of the grating-wafer boundary. It is imposed to match the desired contour to create a uniform contact pressure distribution over . The simplest ab 4-chi is a scrap of conforming material of uniform thickness, with a boundary contour 84 and an intermediate contour 9G S! 4 qualitatively] to the intermediate contour 90 so as to form one li.

In the general case, a compressed conformal material would exhibit a radial thickness distribution due to increasing circumferential loads and a complex design procedure would be required. . Such a ksrl! + can be easily accomplished by practicing the =7 Vinita model. The a noviator model IC2 is, @1') f7 (D intermediate Wa section 90 tHtWAayt (r, ') is the compatible material layer 8
2 deviation 1-**, f is varied to form the desired outer surface contour, the pulling field defined by successive rounds of tightening (whereas there is no θ dependence, These functions are radially symmetric.

It has a large t1 thickness of the J6 product. For a typical silicone wafer (direct yklooa, Jl 525 electric 4), 562. ζ6s7m (gooopst) O tension menu
ding stress is acceptable. The maximum deviation α1511cm (QO5
291nch) is taken. α*? l K#/Cm
A constant pressure of (0,6 T psl ) is maintained onto a thermal tank made of aluminum (6061-T6) so contoured. The contact resistance is about 6 in vacuum.
5 C/ watt /aI. 1
In one embodiment, the Aluminum platen, the compatible substrate, and the typical Waeno 1 each have a 0.0. )1.2
．． 11, αU5-071°C/W Otori 11/d. The main contribution to the total thermal impedance is predicted to be the contact impedance, but the practical value of the thermal contact resistance depends entirely on the surface properties of both the heat sink and the waveform46.
Soft aluminum or indium λ is known to have excellent properties for this purpose. A related aspect of the invention is that a gas is introduced within the wafer mass boundary region to enhance the heat transfer. The pressure should be approximately equal to the contact pressure of The material line in question is described in this and a series of applications.

Other fastenings, such as locking, are also conceivable. Another such tightening is at symmetrically discrete points, i.e., as shown in the example of FIG.
Equal tightening is performed by applying a swivel to the wafer at equally spaced points along the circumference of the wafer. In such cases, a complex saddle-shaped profile results. That is, the way/S will be transformed into the table IiI'1y(rel') of Niro, where 0 is the azimuthal angle around its surroundings. If you refer to wallunle, you can do business. The platen 108 is given such a saddle-shape which is further enforced by the staining of the largest side l. Necessary and multiple 1-
Forming the shell can be obtained by using multi-axis mechanical techniques. As another example, the platen 1081feJ may be formed with a layer of compatible material as in the embodiment described above, or the desired contour may be determined by more complex calculations than required. The advantage obtained in this set of embodiments is that the additional wafer Sg area is accessible to the fabrication of the device on the bottle, and the 6°I
! If we take the fraction of the continuous 9th circumference of ω and the total surface, we get 2Kr@III m 2πre re p, which is the typical number of values of (2ms) and r. It is on the order of a percentage. This embodiment is a complete example of the object of the application filed herewith.

Although the explanation is directed to the uniform contact pressure between the wafer and the heat sink member, other cocoon distributions can be obtained in a similar manner.
QIIR will explain this in 4 ways. For example, if the temperature gradient is iJi
Other processing steps than those in the example discussed may be required, and a corresponding contact force distribution may be obtained by designing the contact profile in a gradual manner.

The explanation has focused on the secret of ion implantation and the removal of heat from semiconductor wafers.

It will be readily appreciated that ion implantation is just one example of a radiation process for which the present invention is suitable. To the father-in-law, the heat conduction transfer from the thin flexible disk is to this more I-family heat conduction IfIp movement! The contact KpA is slow.

Thus, processes such as heating thin flexible workpieces would also benefit from similar benefits of the present invention.Although the examples described use thin flexible disks, the present invention It can also be applied to workpieces that are not symmetrical or have surface contours that are not uniformly thick or flat. If it is a question of what is necessary to obtain a contour for a thin flexible workpiece of a particular shape and material and the desired load conditions of the workpiece whose particular boundary conditions are consistent with the present invention, You will find that everything is. It will be appreciated that various modifications and changes may be made within the scope of the claims.

[Explanation of main side code]

62--Wafer 611--Platen 65-One wheel lls 66--Vector component 70--
Pututen 71-1 72-1 wafer
7 * --M type is ring 76-1 cooling channel
80--Platen 82--Compatible material 1@H*-
One word 6-1 wafer 88-1 tightening is ring 9
0-One contour 108--Putuchi/same Patent attorney Tomi 1) Shu self, σ:l抛1/2

Claims (1)

Claims: 1. An apparatus for removing heat from a flat article under a radiant flux, comprising: -) a radiation source that directs the radiant flux across the article; and b) an apparatus for removing incoming heat from a flat article. C) tightening a peripheral portion of the flat article to a non-flat, convex contoured surface of the heat sink, thereby deforming the flat article to conform to the contoured surface; The apparatus comprises means for clamping, and wherein the contour imposes a uniform contact pressure over the entire surface of the wafer in contact with the contoured surface. and the apparatus of claim 1, wherein the peripheral portion is a narrow continuous area around the contoured surface of the workpiece. '5. % The apparatus according to claim 2, wherein the workpiece has a radius r. , is a thin flat disk of thickness t, and the general formula for the contour is y(r)-pe(r'-βr), where α, β are constants, and y is the radial coordinate r The device where is the vertical component from the base plane. FOX Apparatus according to claim 2, characterized in that the tightening means are adapted to produce a tension stress component near the elastic limit on the outer convex surface of the disc. When working with the surface, the device of zeta-filament. - The device according to claim 4, in which 1+ν α is given by (■〒7), β is given by 2(3+sz), and 1++ν is for a front-handled workpiece. A device that is Poisson's ratio. & A method for optimizing conductive heat transfer between a thin deformable workpiece and a heat sink surface, comprising: a) clamping a peripheral portion of the workpiece to a portion of the heat sink surface; b) ) deforming the workpiece toward the heat sink surface; and C) maintaining a uniform contact pressure between the workpiece and the heat sink surface. 7. The method according to claim 6, wherein the step of deforming is a step of applying a stress to the workpiece in order to approach the critical elastic stress thereon. (Margin below)