CN113948430A

CN113948430A - Wafer conveying mechanical arm

Info

Publication number: CN113948430A
Application number: CN202010697976.4A
Authority: CN
Inventors: 郭挑远; 白国斌; 丁云凌; 王桂磊; 崔恒玮
Original assignee: Institute of Microelectronics of CAS; Zhenxin Beijing Semiconductor Co Ltd
Current assignee: Institute of Microelectronics of CAS; Zhenxin Beijing Semiconductor Co Ltd
Priority date: 2020-07-17
Filing date: 2020-07-17
Publication date: 2022-01-18

Abstract

The invention discloses a wafer conveying mechanical arm, relates to the technical field of semiconductors, and is used for reducing the temperature change rate of a wafer, inhibiting stress generated inside the wafer and improving the quality of the wafer. The wafer transfer robot comprises: a front arm and a thermoelectric assembly. The front arm is provided with a bearing part for bearing the wafer. The thermoelectric assembly is disposed on the carrier portion of the front arm, and the thermoelectric assembly is used for reducing the temperature change rate of the wafer. The wafer transfer robot is applied to the manufacturing of semiconductor devices.

Description

Wafer conveying mechanical arm

Technical Field

The invention relates to the technical field of semiconductors, in particular to a wafer conveying mechanical arm.

Background

Chemical vapor deposition processes are commonly used thin film fabrication processes in the manufacture of semiconductor devices. When the chemical vapor deposition process is adopted to manufacture the film layer, the process temperature in the process chamber is higher (generally more than 100 ℃). After the film layer is formed, the wafer with medium or high temperature needs to be transferred into a vacuum exchange chamber for cooling, so as to facilitate subsequent operation.

However, the wafer transfer robot used to carry and transfer wafers is at a relatively low temperature (typically room temperature). A large temperature difference exists between the wafer and the wafer conveying mechanical arm, so that stress is generated inside the wafer, the wafer is prone to warping, and the quality of the wafer is affected.

Disclosure of Invention

The invention aims to provide a wafer conveying mechanical arm, which is used for reducing the temperature change rate of a wafer, inhibiting the stress generated in the wafer and improving the quality of the wafer.

In order to achieve the above object, the present invention provides a wafer transfer robot, comprising:

the front arm is provided with a bearing part for bearing the wafer;

and the thermoelectric assembly is arranged on the bearing part of the front arm and is used for reducing the temperature change rate of the wafer.

Compared with the prior art, the wafer conveying mechanical arm provided by the invention is provided with the thermoelectric module on the surface of the bearing part for bearing the wafer. Also, the thermoelectric assembly may reduce the rate of temperature change of the wafer. That is to say, the existence of thermoelectric module can make the self temperature of the wafer after the film layer is formed slowly descend to can not appear the phenomenon that the wafer temperature reduces rapidly because of the great difference in temperature of wafer and load-bearing part, can restrain the inside stress that produces of wafer, promote the quality of wafer.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a side view of a forearm and Peltier element configuration provided by an embodiment of the invention;

FIG. 2 is a top view of a front arm and Peltier element structure provided by an embodiment of the present invention;

fig. 3 is a schematic structural view of a peltier element when the carrying part provided by the embodiment of the present invention is in a heating state;

fig. 3a is a schematic structural diagram of a peltier element when the carrying part provided by the embodiment of the present invention is in a cooling state.

Reference numerals:

the front arm 1, the carrier 11, the front stop 12, the rear stop 13, the connection 14, the peltier element 2, the heat generating part 21, the cooling part 22, the N-type material part 23, and the P-type material part 24.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is illustrative only and is not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure.

Various structural schematics according to embodiments of the present disclosure are shown in the figures. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers, and relative sizes and positional relationships therebetween shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, as actually required.

In the context of the present disclosure, when a layer/element is referred to as being "on" another layer/element, it can be directly on the other layer/element or intervening layers/elements may be present. In addition, if a layer/element is "on" another layer/element in one orientation, then that layer/element may be "under" the other layer/element when the orientation is reversed. In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise. The meaning of "a number" is one or more unless specifically limited otherwise.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Chemical vapor deposition processes are commonly used thin film fabrication processes in the manufacture of semiconductor devices. Specifically, the chemical vapor deposition process is to form a solid substance on a wafer through a chemical reaction between gaseous initial compounds under a condition of a medium temperature or a high temperature, so as to realize the manufacture of a film layer. From the above, when the chemical vapor deposition process is used to manufacture the film, the process temperature in the process chamber is relatively high (generally greater than 100 ℃). After the film layer is formed, the wafer with medium or high temperature needs to be transferred into a vacuum exchange chamber for cooling, so as to facilitate subsequent operation.

However, before the wafer is not transferred into the process chamber, the temperature of the wafer is low (typically room temperature), and the temperature in the process chamber is high. After the wafer with lower temperature is sent into the process chamber with higher temperature, the temperature of the wafer is rapidly increased due to the larger temperature difference between the wafer and the process chamber, so that stress is easily generated in the wafer. In addition, after the film layer on the wafer is formed, the wafer transfer robot holds the wafer with higher temperature and transfers the wafer into the vacuum exchange chamber for cooling. Because the temperature of the wafer transfer robot is low (generally, room temperature), a large temperature difference exists between the wafer and the wafer transfer robot, so that the temperature of the wafer is rapidly reduced, and stress is easily generated in the wafer. The wafer with internal stress is easy to warp in the subsequent semiconductor manufacturing process, so that the quality of the wafer is deteriorated and the progress of the semiconductor manufacturing process is influenced.

Furthermore, when the wafer transfer robot enters the chamber to carry the wafer, a film with a certain thickness may be deposited on the carrying portion of the wafer transfer robot. Because the temperature of the wafer transfer robot is much different from the temperature in the chamber, the film formed on the carrier portion may also have stress. On the basis, after the wafer needing cooling is placed on the bearing part, the film layer with stress on the bearing part is easy to attach to the back of the wafer, so that the quality of the wafer is affected.

In order to solve the above technical problem, an embodiment of the present invention provides a wafer transferring robot. In the wafer transfer robot arm provided by the embodiment of the invention, the thermoelectric module is arranged on the bearing part. The thermoelectric component can reduce the temperature change rate of the wafer and inhibit the stress generated inside the wafer, thereby improving the quality of the wafer.

The embodiment of the invention provides a wafer conveying mechanical arm. The wafer transfer robot may carry or transfer wafers during the fabrication of semiconductor devices.

Referring to fig. 1 and 2, the wafer transfer robot includes: the front arm 1 and a thermoelectric module (not shown in the figure).

The forearm 1 has a receiving portion 11. The carrier 11 is used for carrying a wafer. The carrier 11 may be a ceramic carrier or a metal carrier. Of course, the carrying part 11 can also be made of other materials that meet the operational requirements. The specific structure of the front arm 1 may be set according to the actual application scenario as long as it can be used for carrying a wafer.

For example, referring to fig. 1 and 2, the front arm 1 may include at least a bearing portion 11, a front block portion 12, a rear block portion 13, and a connecting portion 14. The bearing part 11 may be a rectangular bearing part. Along the length extension direction of the bearing part 11, the front blocking part 12 is located at one end of the bearing part 11, and the rear blocking part 13 is located at the other end of the bearing part 11. The front stopper portion 12 and the rear stopper portion 13 are disposed opposite to each other. In order to prevent the wafer from sliding on the carrier 11, the front stopper 12 and the rear stopper 13 are each provided with a notch structure matching the shape of the wafer. For example: the front blocking part 12 and the rear blocking part 13 are both provided with arc-shaped notch structures matched with the wafers. The connecting portion 14 is provided on the side of the back barrier portion 13 opposite to the front barrier portion 12. The connection portion 14 is used for connecting a connection structure of the wafer transfer robot. For example: the connecting portion 14 and the connecting structure may be fixedly connected together by welding or the like. Alternatively, the connecting portion 14 and the connecting structure may be detachably connected by a screw connection or the like.

Referring to fig. 1 and 2, the thermoelectric module is disposed on a support portion 11 provided on the front arm 1. The thermoelectric assembly is used to reduce the rate of temperature change of the wafer.

Specifically, the wafer carried by the carrier part 11 may have a preheating state and a cooling state. When the wafer is placed on the carrier 11, the wafer is in a pre-heated state before being transferred into the process chamber. The thermoelectric assembly may be used to reduce the rate of temperature rise of the wafer while the wafer is in the pre-heat state. After the film layer on the wafer is formed and before the subsequent operation is performed on the wafer, the wafer is in a cooling state. The thermoelectric assembly may be used to reduce the cooling rate of the wafer while the wafer is in the cool down state. As can be seen from the above, due to the thermoelectric elements, the lower temperature wafers can be heated slowly before entering the medium or high temperature process chamber. After the film layer on the wafer is formed, the wafer with higher temperature can be slowly cooled on the bearing part 11 with lower temperature, thereby inhibiting the stress generated in the wafer and improving the quality of the wafer. In addition, the film layer formed on the carrier part 11 and having a high temperature does not generate stress due to the low temperature of the carrier part 11, and thus the quality of the wafer is not affected.

The temperature change rate of the wafer, the temperature of the wafer after preheating the wafer, and the temperature of the wafer after cooling the wafer can be set according to practical application scenarios as long as stress generated inside the wafer can be suppressed.

In a possible implementation, referring to fig. 2, 3 and 3a, the thermoelectric module described above can comprise at least one peltier element 2. The peltier element 2 includes a heat generating portion 21 and a cooling portion 22 facing the heat generating portion 21. The carrier part 11 has a heated state and a cooled state. When the wafer is in the cooling state, the carrying part 11 is in the heating state. When the wafer is in the preheating state, or after the cooled wafer is taken down from the carrying part 11, and before the carrying part 11 carries the next wafer to be cooled, the carrying part 11 is in the cooling state.

Referring to fig. 2 and 3, when the carrier part 11 is in a heated state, one end of the peltier element 2 in contact with the carrier part 11 is a heat generating part 21. The other end of the peltier element 2 in contact with the wafer is a cooling section 22.

Referring to fig. 2 and 3a, when the carrier part 11 is in a cooled state, one end of the peltier element 2 in contact with the carrier part 11 is a cooling part 22. The other end of the peltier element 2, which is in contact with the wafer or exposed to the working environment, is a heat generating portion 21.

Specifically, when the wafer is loaded by the front arm 1, first, a part of the wafer contacts the loading portion 11 of the front arm 1. Then, since the surface of the carrier part 11 is smooth, the wafer is stably placed on the carrier part 11 by sliding under the action of gravity. In order to ensure a smooth surface of the carrier part 11 and to smoothly place the wafer on the carrier part 11, the peltier element 2 may be fixedly attached to the carrier part 11 by means of an insert, an adhesive, or a snap fit. The top of the peltier element 2 is flush with the mounting surface of the mounting part 11. The inlaying mode can comprise a clamping mode, an inserting mode and other connecting modes. When the peltier element 2 is fixedly connected to the carrier part 11 by adhesion, a groove with a proper size may be formed on the carrier part 11 according to the specification of the peltier element 2, and the peltier element 2 is adhered in the groove, so that the top of the peltier element 2 is flush with the carrier surface of the carrier part 11. When the peltier element 2 is fixed by a snap-fit method, a groove slightly larger than the peltier element 2 in size needs to be formed in the carrier part 11. The peltier elements 2 are fixed in the recesses on the carrier part 11 by means of snap-in.

The number of the peltier elements 2 disposed on the carrier 11 may be set according to the actual application, and is not limited in particular. For example, the number of peltier elements 2 provided on the carrier 11 may be 1 to 50. When only 1 peltier element 2 is provided on the carrier part 11, the geometric center of this peltier element 2 may coincide with the geometric center of the carrier part 11. When a plurality of peltier elements 2 are provided on the carrier part 11, the plurality of peltier elements 2 may be evenly distributed on the carrier part 11. In this case, when the wafer having a high temperature is placed on the placing section 11, the temperatures of the respective regions of the wafer can be uniformly changed by the plurality of peltier elements 2 which are uniformly distributed. Of course, the distribution position of one or more peltier elements 2 on the carrier part 11 can also be set according to the actual situation.

Referring to fig. 2, 3 and 3a, the peltier element 2 may further comprise an N-type material section 23 and a P-type material section 24. The N-type material portion 23 and the P-type material portion 24 included in the same peltier element 2 are connected to each other through the heat generating portion 21 or the cooling portion 22. Further, when a plurality of peltier elements 2 are provided on the carrier part 11 and the plurality of peltier elements 2 are connected in series, the N-type material part 23 and the P-type material part 24 included in the plurality of peltier elements 2 may be alternately connected in sequence by the heat generating part 21 or the cooling part 22, thereby realizing the series connection of the plurality of peltier elements 2.

The heat generating part 21 and the cooling part 22 of the peltier element 2 may be made of aluminum and/or stainless steel. Of course, the heat generating unit 21 and the cooling unit 22 may be made of other materials having good thermal and electrical conductivity. The materials contained in the N-type material portion 23 and the P-type material portion 24 may be set according to practical applications, and are not particularly limited herein. For example: the N-type material portion 23 may contain materials of: silicon doped with phosphorus. The P-type material portion 24 may comprise: silicon doped with boron.

Specifically, referring to fig. 2 and 3, since the energy level of the P-type material is lower than that of the N-type material, when a forward direct current is applied to the peltier element 2, carriers are conducted from the power source to the N-type material portion 23 through the conductive portion 24 by the conduction portion, and the conductive portion absorbs external heat. That is, in this case, the conduction portion is the cooling portion 22. Then, in the process of the carriers being conducted from the N-type material portion 23 to the P-type material portion 24 through another conducting portion and a power source, the conducting portion will emit heat to the outside. That is, in this case, the conductive portion is the heat generating portion 21.

Referring to fig. 2 and 3a, when reverse direct current is applied to the peltier element 2, carriers are conducted from the power source through the N-type material portion 23 to the P-type material portion 24 through the conducting portion, and the conducting portion emits heat to the outside. That is, in this case, the conductive portion is the heat generating portion 21. Then, in the process of the carriers being conducted from the P-type material portion 24 to the N-type material portion 23 through another conducting portion and the power source, the conducting portion absorbs the external heat. That is, in this case, the conduction portion is the cooling portion 22. As can be seen from the above, the cooling unit 22 and the heat generating unit 21 included in the peltier element 2 are switched depending on the direction in which the direct current is supplied to the peltier element 2.

In practical applications, referring to fig. 2 and 3a, the peltier element 2 may be energized with the reverse direct current before the wafer is introduced into the process chamber. At this time, the carrier part 11 is in a cooling state, and the cooling part 22 of the peltier element 2 absorbs the heat of the carrier part 11, and the heat is radiated from the heating part 21 to the wafer to heat the wafer, thereby realizing the slow transfer of the heat of the carrier part 11 to the wafer and reducing the temperature rise rate of the wafer. And transferring the wafer into the process chamber after the temperature of the wafer meets the requirement, and manufacturing the film layer.

Referring to fig. 2 and 3, after the film layer on the wafer is formed, before the wafer transfer robot enters the process chamber to carry the wafer with a higher temperature, a forward direct current with a proper magnitude is applied to the peltier element 2 on the carrying portion 11, and the peltier element 2 is in a heating state. After the wafer is placed on the placing part 11, the cooling part 22 of the peltier element 2 absorbs the heat of the wafer and the heat is radiated to the placing part 11 from the heat generating part 21, so that the heat of the wafer is slowly transferred to the placing part 11, and the cooling rate of the wafer is reduced. After the temperature of the wafer is lowered to the target range, the wafer is taken down from the carrier part 11, and the next operation is performed. At this time, the susceptor 11 absorbs heat of the wafer, and thus has a high temperature. When the carrier 11 carries the next wafer to be cooled, it also absorbs the heat of the next wafer, so that its temperature continuously rises. In order to avoid damage to the carrier part 11 and the peltier element 2 due to high temperature, the carrier part 11 with higher temperature needs to be cooled down before the carrier part 11 carries the next wafer to be cooled. Specifically, referring to fig. 2 and 3a, reverse direct current may be applied to the peltier element 2. At this time, the carrying part 11 is in a cooling state, and the cooling part 22 of the peltier element 2 absorbs the heat of the carrying part 11 and radiates the heat to the external working environment from the heat generating part 21, thereby cooling the carrying part 11. Specifically, in the above-mentioned process of heating and cooling the carrying part 11, the temperature variation range of the carrying part 11 may be 30 to 200 ℃. In addition, as can be seen from the above, the degree of the peltier element 2 reducing the wafer temperature change rate is influenced by the magnitude of the direct current supplied to the peltier element 2, so that the magnitude of the direct current can be set according to the requirement of the wafer temperature change rate in actual situations.

In another possible implementation, the thermoelectric module may include a heater (not shown), a temperature measuring member (not shown), and a controller (not shown).

The heater is disposed on the carrying part 11, and the heater heats the carrying part 11 under the control of the controller. Illustratively, the heater may be a metal heating wire. To ensure a smooth surface of the carrier part 11, the heater may be embedded in the carrier part 11. And the top of the heater is flush with the bearing surface of the bearing part 11. Alternatively, the heater may be disposed on the other surface of the carrying part 11 opposite to the carrying surface. Of course, the position of the heater on the bearing part 11 may also be set according to the actual situation.

The reference end temperature of the temperature measuring piece is the process temperature. The test end of the temperature measuring member is in contact with the carrier part 11. The temperature measuring member is used for measuring a difference between the temperature of the carrying part 11 and the process temperature and sending the measurement result to the controller. It should be understood that the above process temperature is a temperature of a condition in the process chamber during the film layer manufacturing process.

Illustratively, the temperature measuring member may be a thermocouple. The reference end temperature of the thermocouple is set to the process temperature, i.e., to the conditioned temperature within the process chamber. The test end of the thermocouple is in contact with the carrier part 11, the difference between the carrier part 11 and the process temperature is measured, and the measurement result is output in the form of a potential difference. Specifically, based on the seebeck effect, the larger the difference between the temperature of the bearing part 11 and the process temperature, the larger the potential difference. In contrast, the smaller the difference between the temperature of the carrier part 11 and the process temperature, the smaller the potential difference.

The input end of the controller is connected with the temperature measuring part, the output end of the controller is connected with the heater, and the controller is used for controlling the heater to work according to the measuring result.

Illustratively, the controller may be a solid state relay.

In practical applications, the controller controls the heater to slowly heat the susceptor 11 before the wafer is loaded into the process chamber. Since the wafer is placed on the carrier part 11, the carrier part 11 which is heated slowly can slowly transfer heat to the wafer through heat conduction, so that the wafer and the carrier part 11 are heated slowly together. After the film layer on the wafer is formed, the controller will also control the heater to heat the carrying portion 11 before the wafer transfer robot enters the process chamber to carry the wafer with higher temperature. In the above two heating processes, the temperature measuring member measures the temperature of the carrier part 11 in real time, and outputs the measurement result to the controller. When the temperature of the bearing part 11 is heated to meet the temperature requirement range, the controller controls the heater to stop heating the bearing part 11 according to the measurement result. Therefore, the wafer with a certain temperature enters the process chamber, and the temperature difference between the wafer and the process chamber is small, so that the temperature of the wafer can be slowly increased (or the temperature of the wafer is kept unchanged), and the stress generated in the wafer is inhibited. On the other hand, the carrier 11 with a certain temperature enters the process chamber, and carries and transfers the wafer to the vacuum exchange chamber to cool the wafer. Because the temperature difference between the heated bearing part 11 and the wafer is small, the temperature of the wafer can be slowly reduced, the stress generated in the wafer is inhibited, and the quality of the wafer can be improved.

The embodiments of the present disclosure have been described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The scope of the disclosure is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be devised by those skilled in the art without departing from the scope of the present disclosure, and such alternatives and modifications are intended to be within the scope of the present disclosure.

Claims

1. A wafer transfer robot, comprising:

the front arm is provided with a bearing part, and the bearing part is used for bearing a wafer;

and a thermoelectric assembly disposed on the carrier portion of the front arm, the thermoelectric assembly for reducing a rate of temperature change of the wafer.

2. The wafer transfer robot of claim 1, wherein the wafer has a pre-heat state and a cool-down state;

when the wafer is in a preheating state, the thermoelectric component is used for reducing the temperature rise rate of the wafer;

the thermoelectric assembly is configured to reduce a cooling rate of the wafer while the wafer is in a cooling state.

3. The wafer transfer robot of claim 1 or 2, wherein the thermoelectric assembly comprises at least one peltier element having a heat generating portion and a cooling portion opposite the heat generating portion; the bearing part has a heating state and a cooling state;

when the bearing part is in a heating state, one end of the Peltier element in contact with the bearing part is a heating part, and the other end of the Peltier element in contact with the wafer is a cooling part;

when the bearing part is in a cooling state, one end of the Peltier element in contact with the bearing part is a cooling part, and the other end of the Peltier element in contact with the wafer or exposed to a working environment is a heating part.

4. The wafer transfer robot arm of claim 3, wherein the Peltier element is fixedly connected to the carrier by means of embedding, gluing or snapping, and a top of the Peltier element is flush with a carrying surface of the carrier.

5. The wafer transfer robot of claim 3, wherein the heat generating portion and the cooling portion of the Peltier element are both formed of aluminum and/or stainless steel.

6. The wafer transfer robot arm of claim 3, wherein the number of the Peltier elements provided on the carrier is 1 to 50;

when the number of the Peltier elements is 1, the geometric center of the Peltier elements is overlapped with the geometric center of the bearing part;

when the number of the Peltier elements is multiple, the Peltier elements are uniformly arranged on the bearing part.

7. The wafer transfer robot of claim 1 or 2, wherein the temperature of the susceptor varies in a range of 30 ℃ to 200 ℃.

8. The wafer transfer robot of claim 1 or 2, wherein the thermoelectric assembly comprises a heater, a temperature measurement member, and a controller;

the heater is arranged on the bearing part and heats the bearing part under the control of the controller;

the reference end temperature of the temperature measuring piece is the process temperature, the testing end of the temperature measuring piece is in contact with the bearing part, and the temperature measuring piece is used for measuring the difference value between the temperature of the bearing part and the process temperature and sending the measuring result to the controller;

9. The wafer transfer robot of claim 8, wherein the heater is mounted on the susceptor, and a top of the heater is flush with a susceptor surface of the susceptor; or the like, or, alternatively,

one surface of the bearing part, which is in contact with the wafer, is a bearing surface, and the heater is fixedly connected to the other surface of the bearing part, which is opposite to the bearing surface.

10. The wafer transfer robot of claim 8, wherein the temperature measurement member is a thermocouple.

11. The wafer transfer robot of claim 1 or 2, wherein the carrier is a ceramic carrier or a metal carrier.