Press for pre-sintering or sintering silicon wafers

Abstract

A press for pre-sintering or sintering silicon wafers includes a lower block and an upper block, wherein the lower block includes a lower base and a lower plate. The lower plate rests only on the top surface of the bodies of at least three compression load cells, the load cell bodies being supported by the lower base, such that the top surfaces are substantially coplanar with each other.

Description

[Technical Field]

[0001] This invention relates to the field of silicon wafer manufacturing processes, and more particularly to a press suitable for pre-sintering or sintering silicon wafers. [Previous Technology]

[0002] Pre-sintering (also known as “wafer lamination”) and sintering (“wafer sintering”) are two stages in the silicon wafer manufacturing process. They can be achieved using the same dedicated press, but there are significant differences between them in the operating parameters (especially temperature) of the pressing operation. [Summary of the Invention]

[0003] According to the foregoing of claim 1, a press for pre-sintering or sintering silicon wafers includes a lower block and an upper block, wherein the lower block includes a lower base and a lower plate supported by the lower base and forming a lower surface for supporting the silicon wafer to be sintered. The upper block includes an upper plate forming an upper surface facing the lower surface.

[0004] The press is provided with an actuator device adapted to translate the lower plate and / or the upper plate between mutually separated inactive and active positions, wherein the upper surface applies a predetermined pressure to the silicon wafer present on the lower surface.

[0005] The pre-sintering and sintering of silicon wafers should meet the following assumptions to be considered reliable:

[0006] - A freely programmable process temperature from about 100°C to about 350°C;

[0007] - The processing temperature is uniformly distributed on the processed wafer, with an allowable deviation of approximately + / -3℃;

[0008] - A freely programmable process pressure of approximately 1 MPa to approximately 40 MPa;

[0009] - Process pressure uniformly distributed on the processed wafer, with an allowable deviation of approximately + / - 0.5 MPa.

[0010] To meet these requirements, the press should ensure that:

[0011] - Strength and absolute stiffness of the lower and upper surfaces;

[0012] - Absolute parallelism between the lower and upper surfaces.

[0013] The purpose of this invention is to provide a press of the type described above that can meet the above requirements.

[0014] This objective is achieved using a pre-sintering or sintering machine as described in claim 1.

Implementation Method

[0019] In the following description, elements common to the various embodiments will be indicated by the same reference numerals.

[0020] Referring to the attached drawing, 1 and 100 together represent presses used for pre-sintering or sintering silicon wafers.

[0021] According to a general embodiment, the presses 1 and 100 include lower blocks 10 and 110 and upper blocks 12 and 112.

[0022] The lower blocks 10 and 110 include lower bases 14 and 114 and lower plates 16 and 116 supported by the lower bases and forming lower surfaces 16' and 116' for supporting silicon wafers to be pre-sintered or sintered.

[0023] In some embodiments, as illustrated in the accompanying drawings, the lower plates 16, 116 may comprise two overlapping, rigidly connected plate portions (e.g., 116a and 116b, as shown in Figures 2 and 3), on which the upper portion 116a, on which the silicon wafer is placed, serves as a heating plate, while the upper portion 116b, in contact with the load cell, is maintained at a lower temperature.

[0024] Upper blocks 12 and 112 include upper plates 18 and 118 that form upper surfaces 18' and 118' facing the lower surfaces 16' and 116'.

[0025] The press is equipped with an actuator device, such as hydraulic or electric, adapted to translate the lower plate 16, 116 and / or the upper plate 18, 118 between mutually separated inactive and active positions, wherein the upper surface applies a predetermined pressure to the silicon wafer on the lower surface.

[0026] According to the present invention, the lower plates 16, 116 rest only on the top surfaces of the main body 20 of at least three compression load elements supported by the lower bases 14, 114, such that these top surfaces are substantially coplanar with each other.

[0027] In the embodiment of Figure 1, the lower plate 16 rests on the body 20 of the three load elements, for example, arranged at the vertices of an equilateral triangle.

[0028] In the embodiments of Figures 2 and 3, the lower plate 116 rests on the body 20 of the four load elements, for example, arranged at the vertices of a square.

[0029] The number of load cells can depend on the surface to be sintered and / or the pressure applied to the silicon wafer.

[0030] The body 20 of the load cell is adapted to deflect in a manner that allows the lower plate to pivot in order to compensate for any non-parallelism between the lower and upper surfaces and / or between the upper and lower surfaces and / or between the upper and lower surfaces of the silicon wafer.

[0031] Therefore, using the main body 20 or the outer shell of the load cell as the sole supporting element of the lower plate allows for complete adhesion between the lower surfaces 16', 116' and the upper surfaces 18', 118'.

[0032] In one embodiment, the load cell body 20 does not have a pressure sensor. Therefore, in this case, the load cell is specifically used as a pivot support device.

[0033] In other embodiments, the load cell body 20 is equipped with a pressure sensor, such as a strain gauge, adapted to detect the pressure applied to the silicon wafer by the upper surface.

[0034] Therefore, in this case, the load cell can function as both a pivot support for the lower plate and a pressure sensor.

[0035] In one embodiment, the load cell bodies 20 have substantially the same height. For example, the top surfaces of the load cell bodies are simultaneously subjected to a grinding process, resulting in the bodies having the same height.

[0036] In one embodiment, the load elements are identical to each other.

[0037] In some embodiments, the lower plates 16, 116 are held in place by connecting rods 22, 122 (e.g., adjustable deflection rods). In other words, the connecting rods 22, 122 prevent the lower plates 16, 116 from translating undesirably relative to the load cell body 20, which rests on the load cell body 20 without any other constraints.

[0038] For example, in the case of rectangular lower blocks 10 and 110, at least two opposite sides of the lower plates 16 and 116 are connected to opposite sides of the lower bases 14 and 114 by corresponding connecting rods 22 and 122. Specifically, each connecting rod 22 and 122 connects the vertex of the lower plates 16 and 116 to the opposite vertex of the corresponding side of the lower bases 14 and 114. Furthermore, preferably, the rods 22 and 122 on opposite sides of the lower blocks are connected to their respective vertices in opposite ways. In other words, the two opposite rods connect the opposite vertices of the lower plates (i.e., the ends of the diagonals of the rectangle defining the perimeter of the lower plates in the plan view) to the opposite vertices of the lower bases.

[0039] In one embodiment, connecting rods 22, 122 are connected to lower plates 16, 116 and lower bases 14, 114 via ball joints 24 to allow any tilting of the lower plate relative to the lower base without affecting the interaction between the lower plate and the load cell body.

[0040] In one embodiment, the load element body has a maximum deflection of about 0.5 mm under nominal load.

[0041] For example, the press can compensate for edge-to-edge non-parallelism of up to about 0.3 mm on the surface defined by the centerline of the load cell.

[0042] For embodiments of the press according to the present invention, to meet possible needs, those skilled in the art can make various changes, adjustments and substitutions to the components with other functional equivalents without departing from the scope of the invention claims. Each feature described as belonging to a possible embodiment may be obtained independently of the other described embodiments. [Simplified Explanation of the Diagram]

[0015] However, the features and advantages of the press according to the invention will become apparent from the following description of preferred exemplary embodiments given by way of non-limiting example with reference to the accompanying drawings, wherein:

[0016] - Figure 1 is a perspective view of a press according to an embodiment of the present invention.

[0017] - Figure 2 is a perspective view of a press according to another embodiment of the present invention.

[0018] - Figure 3 is a schematic front view of the press in Figure 2. [Biomaterial Storage]

[0044] Domestic storage information (please note in order of storage institution, date, and number): None. International storage information (please note in order of storage country, institution, date, and number): None.

Claims

1. A press for pre-sintering or sintering multiple silicon wafers, comprising a lower block and an upper block, wherein the lower block includes a lower base and a lower plate supported by the lower base and forming a lower surface for supporting the silicon wafers to be sintered, and wherein the upper block includes an upper plate forming an upper surface facing the lower surface, the press including an actuator device adapted to translate the lower plate and / or the upper plate between a mutually separated inactive position and an active position, wherein the upper surface applies a predetermined pressure to the silicon wafers present on the lower surface. The lower plate rests solely on the top surface of at least three compression load cells supported by the lower base, such that the top surfaces are substantially coplanar with each other. The load cells are adapted to deflect in a manner that allows the lower plate to pivot in order to compensate for any non-parallelism between the lower and upper surfaces and / or between the upper and lower surfaces and / or between the upper and lower surfaces of the silicon wafers. The number of the load cells is based on the lower surface and / or a pressure applied to the silicon wafers.

2. The press as described in claim 1, wherein the load cell body does not have a pressure sensor.

3. The press as claimed in claim 1, wherein the load cell body is provided with a pressure sensor adapted to detect the pressure applied from the upper surface to the silicon wafers.

4. The press as described in claim 1, wherein the load cells have substantially the same height.

5. The press as claimed in claim 1, wherein the lower plate is held in place by a plurality of connecting rods connecting the lower plate to the lower base.

6. The press as claimed in claim 5, wherein at least two opposite sides of the lower plate are connected to the corresponding opposite sides of the lower base by means of corresponding connecting rods of the connecting rods.

7. The press as described in claim 6, wherein each deflection rod connects a vertex of the lower plate to an opposite vertex on a corresponding side of the lower base.

8. The press as described in any one of claims 5 to 7, wherein the connecting rods are connected to the lower plate and the lower base by means of a plurality of ball joints.

9. The press as claimed in claim 1, wherein the load cells have a maximum deflection of 0.5 mm under nominal load.

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