Wafer heating equipment and wafer heating method

Abstract

The invention relates to wafer heating equipment and a wafer heating method. The wafer heating equipment comprises a hot plate and wafer thimbles, the hot plate is used for heating a target wafer, and a through hole is formed in the hot plate; the wafer ejector pin is arranged below the hot plate, ascends and descends in the direction perpendicular to the hot plate and is used for connecting a target wafer and the hot plate; the wafer thimble comprises a main body and a top cap arranged at the top of the main body, the top cap is at least partially located in the through hole, and the upper end surface of the top cap is in contact with the bottom surface of the target wafer; wherein the length of the top cap is greater than a preset length. In the wafer heating equipment, a hot plate is used for heating a target wafer, a top cap of a wafer ejector pin is at least partially located in a through hole of the hot plate, the upper end face of the top cap makes contact with the bottom face of the target wafer, and the length of the top cap is larger than the preset length. Therefore, the length of the top cap is increased, so that the overheating of the contact part of the top cap and the target wafer can be effectively improved, and the problem of non-uniform heating of the wafer is improved. The problem of non-uniform wafer heating can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer manufacturing, and in particular to a wafer heating device and a wafer heating method. Background Art

[0002] In the bumping process of packaged products, the bump size must be uniform. With the development of wafer manufacturing technology, the height requirements of bumps manufactured using the high-density fan-out (HDFO) process are getting higher and higher, and the corresponding requirements for the thickness of the photoresist coating are also getting thicker.

[0003] However, since the thicker the photoresist is, the higher the viscosity of the photoresist is required, and the higher the viscosity of the photoresist is, the worse the fluidity of the photoresist on the wafer is, the thickness uniformity of the photoresist on the wafer coated with thicker photoresist will also deteriorate. Therefore, when the photoresist pre-bake process (softbake) is performed on the wafer after the photoresist is coated using traditional wafer heating equipment, uneven heating is likely to occur. Summary of the invention

[0004] Based on this, the embodiments of the present application provide a wafer heating device and a wafer heating method, which can effectively improve the problem of uneven wafer heating.

[0005] According to some embodiments, the present application provides a wafer heating device, which includes a hot plate and a wafer ejector pin; the hot plate is used to heat the target wafer, and a through hole is provided in the hot plate; the wafer ejector pin is provided under the hot plate, and is raised and lowered in a direction perpendicular to the hot plate, and is used to connect the target wafer and the hot plate; the wafer ejector pin includes a main body and a top cap provided on the top of the main body, the top cap is at least partially located in the through hole, and the upper end surface of the top cap is in contact with the bottom surface of the target wafer; wherein the length of the top cap is greater than a preset length.

[0006] In the wafer heating device of the above embodiment, the hot plate is used to heat the target wafer, the top cap of the wafer ejector pin is at least partially located in the through hole of the hot plate, the upper end surface of the top cap contacts the bottom surface of the target wafer, and the length of the top cap is greater than the preset length. In this way, by lengthening the length of the top cap, the overheating of the contact portion between the top cap and the target wafer can be effectively improved, thereby improving the problem of uneven heating of the wafer.

[0007] In some embodiments, the top cap includes a first heat-resistant part and a second heat-resistant part that are vertically connected, and the upper end surface of the second heat-resistant part is in contact with the bottom surface of the target wafer; the length of the first heat-resistant part is equal to a preset length.

[0008] In some embodiments, the length of the second heat-resistant member is not less than a preset length.

[0009] In some embodiments, the first heat-resistant component and the second heat-resistant component are integrally formed.

[0010] In some embodiments, the top cap is made of polyetheretherketone.

[0011] In some embodiments, there are multiple through holes and wafer ejector pins, and the number of through holes is the same as the number of wafer ejector pins; the upper end surfaces of the multiple wafer ejector pins are flush; the top caps are correspondingly located in the multiple through holes and are synchronously raised and lowered in a direction perpendicular to the hot plate.

[0012] According to some embodiments, the present application further provides a wafer heating method, which uses the wafer heating device in any of the above embodiments to heat the target wafer; the method further includes the following steps:

[0013] Controlling the upper end surface of the wafer ejector pin to rise and fall to a first preset height, and controlling the hot plate to heat the target wafer for a first preset time;

[0014] Controlling the upper end surface of the wafer ejector pin to rise and fall to a second preset height, and controlling the hot plate to heat the target wafer for a second preset time;

[0015] Among them, the first preset height is greater than the second height; the first preset time is less than the second preset time.

[0016] In the wafer heating method of the above embodiment, by lengthening the length of the top cap, the overheating of the contact part between the top cap and the target wafer can be effectively improved, thereby improving the problem of uneven wafer heating. In addition, by controlling the upper end surface of the wafer ejector pin to rise and fall to a first preset height, and controlling the hot plate to heat the target wafer for a first preset time, the contact time between the wafer and the wafer ejector pin can be reduced, thereby further improving the uneven wafer heating, and then by controlling the upper end surface of the wafer ejector pin to rise and fall to a second preset height, and controlling the hot plate to heat the target wafer for a second preset time, the heating temperature of the target wafer can be made more uniform. In addition, the heating process of the target wafer can be completed in two steps, thereby simplifying the process flow, shortening the process time, and improving processing efficiency.

[0017] In some embodiments, the first preset time is less than 10 seconds; and / or the second preset time is not greater than 360 seconds.

[0018] In some embodiments, the second preset height is equal to 0 mm;

[0019] Controlling the upper end surface of the wafer ejector pin to rise and fall to a second preset height, and controlling the hot plate to heat for a second preset time, includes: controlling the upper end surface of the wafer ejector pin to descend to be flush with the top surface of the hot plate, so that the upper surface of the hot plate contacts the bottom surface of the wafer.

[0020] In some embodiments, the first preset time is equal to 5s. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A top view of a wafer obtained by heating a wafer using a wafer heating device;

[0022] Figure 2 This is a schematic diagram of a wafer heating device in one embodiment of the present application;

[0023] Figure 3 This is a schematic diagram of a wafer ejector pin in a wafer heating device according to an embodiment of the present application;

[0024] Figure 4 This is a schematic flow chart of a wafer heating method in one embodiment of the present application;

[0025] Figure 5 A schematic diagram of a wafer obtained by a wafer heating method in an embodiment of the present application.

[0026] Explanation of the reference numerals: 10, wafer heating equipment; 20, hot plate; 21, through hole; 30, wafer ejector pin; 31, main body; 32, top cap; 321, first heat-resistant part; 322, second heat-resistant part; 40, target wafer; 41, abnormal defect. DETAILED DESCRIPTION

[0027] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present invention are provided in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0029] In the case of using “including”, “having”, and “comprising” described herein, another component may be added unless a clear limiting term such as “only”, “consisting of”, etc. is used. Unless mentioned otherwise, a term in the singular form may include a plural form and should not be understood as being one in number.

[0030] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0031] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0032] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0033] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0034] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0035] Embodiments of the invention are described herein with reference to schematic diagrams of idealized embodiments (and intermediate structures) of the invention, and variations from the illustrated shapes as a result, for example, of manufacturing techniques and / or tolerances are to be expected. Thus, embodiments of the invention should not be limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing techniques.

[0036] In the bumping process of packaged products, the bump size is required to maintain uniformity. With the development of wafer manufacturing technology, the height requirements of bumps manufactured by high-density fan-out process (HDFO) are getting higher and higher, and the corresponding requirements for the thickness of photoresist coating are also getting thicker and thicker. For example, in the copper bumps of products made by flip chip packaging process (Ball Attach Flip Chip Organic, BAFO) and the controlled collapse chip interconnection (Controlled Collapse Chip Connection, C4) process of products made by fan-out packaging process (FOP), thick glue process is required. When the height of the bump is above 100um, the corresponding photoresist coating thickness also needs to reach more than 100um. At this time, the coating process needs to use a secondary coating process to meet the glue thickness requirements, and the secondary coating process puts forward higher requirements on the process flow.

[0037] As one of the basic steps of the photolithography process, the softbake process can allow the solvent in the photoresist film to escape slowly and fully at a certain temperature, thereby drying the photoresist film. After the photoresist is applied to the surface of the silicon wafer, it must undergo a softbake process to remove the solvent in the photoresist. The softbake process can improve adhesion, thereby improving the uniformity of the photoresist on the silicon wafer, and achieving better line width control during etching. It can be understood that the thicker the coating thickness, the higher the viscosity of the photoresist required, and the higher the viscosity of the photoresist, the worse the fluidity on the wafer, and the thickness uniformity of the wafer coated with thicker photoresist also deteriorates accordingly.

[0038] Therefore, when using traditional wafer heating equipment to perform a photoresist pre-bake process on the target wafer 40 after being coated with glue, the target wafer 40 enters the hot plate for baking after being coated with glue, and the target wafer 40 is placed on three ejector pins by an arm and then the height of the ejector pins is gradually lowered for heating. Since the hot plate 20 is already in a set high temperature state before the target wafer 40 enters the hot plate 20, the corresponding ejector pins are also in a high temperature state. When the target wafer 40 is placed on the ejector pins for baking, the entire target wafer 40 is slowly and evenly heated by the heat radiation of the heating plate, while the position of the target wafer 40 in contact with the three ejector pins is heated by heat conduction through the ejector pins. This position is rapidly heated and over-baked, resulting in a baking difference between the photoresist on the entire surface of the target wafer 40 and the photoresist at the position in contact with the three ejector pins. Figure 1 As shown in the figure, the CD of the three top contact positions and the surrounding areas after photolithography development is too small, resulting in abnormal defects 41. The corresponding electroplating result is that the bump size is too small and exceeds the specification requirements, resulting in abnormal bump process. In the use of thick glue process, the unevenness of the superposition of the secondary glue coating process will be further amplified.

[0039] Based on this, an embodiment of the present application provides a wafer heating device and a wafer heating method.

[0040] See also Figure 2 According to some embodiments, the present application provides a wafer heating device 10. The wafer heating device 10 includes a hot plate 20 and a wafer ejector pin 30.

[0041] like Figure 2 As shown, the hot plate 20 is used to heat the target wafer 40, and a through hole 21 is provided in the hot plate 20. It can be understood that the hot plate 20 is used to provide uniform heating for the target wafer 40 during the production process to ensure that the chemical reaction or physical process can be carried out at the required temperature. For example, the hot plate 20 can be applied to a variety of different semiconductor processes, including thin film deposition, chemical vapor deposition (CVD), physical vapor deposition (PVD), and annealing. For example, in the photolithography process, heating can help maintain the fluidity of the photoresist material, thereby improving the clarity of the pattern.

[0042] For example, the hot plate 20 can be directly heated by an electric heating element (e.g., a resistance wire or a thermocouple), and the heat is transferred to the target wafer 40 by thermal radiation. For example, the hot plate 20 can also be heated by infrared heating or microwave heating. Infrared heating can be used for rapid heating and is suitable for applications that require rapid temperature rise. Microwave heating can improve reaction rate and material uniformity in some special applications.

[0043] In some embodiments, the hot plate 20 may include a single-sided symmetrical hot plate 20 and a double-sided heated hot plate 20. The single-sided symmetrical hot plate 20 can be understood as heating only on one side, and is mostly used for smaller wafers or specific process requirements. The double-sided heated hot plate 20 can heat both sides of the wafer at the same time, and is usually used for processes that require rapid temperature rise or larger wafers. Those skilled in the art can select a suitable type of hot plate 20 according to specific application scenarios, and this application does not limit this.

[0044] In some embodiments, the wafer heating device 10 also includes a temperature control system. For example, the temperature control system can be arranged below the hot plate 20, and the temperature control system can adjust the heating temperature of the hot plate 20 to maintain the temperature required for the target wafer 40, which is conducive to improving product consistency and yield. Providing uniform heating for the target wafer 40 through the hot plate 20 can avoid hot spots and temperature differences. For example, the temperature control system may include a temperature sensor (such as a thermocouple) and a temperature feedback controller to ensure that the temperature required by the hot plate 20 is reached and maintained. For example, the temperature sensor and the temperature feedback controller can both be arranged below the hot plate 20, and the temperature feedback controller can be directly connected to the temperature sensor; or, the temperature feedback controller can be arranged at a remote end and remotely connected to the temperature sensor through a wireless network. The temperature feedback controller can achieve precise temperature control through a feedback mechanism. For example, the temperature feedback controller includes a PID controller, which can adjust the heating power according to the real-time temperature to keep the temperature stable.

[0045] In some embodiments, the hot plate 20 also has a cooling function to reduce the temperature of the target wafer 40 when necessary, thereby protecting the semiconductor material and structure of the target wafer 40. By way of example, the hot plate 20 can be a circulating water cooling hot plate 20 to quickly reduce the temperature, and the circulating water cooling hot plate 20 is suitable for rapid annealing or other specific processes.

[0046] In some embodiments, the heat plate 20 is made of a high temperature resistant material (such as aluminum, silicon, ceramic, etc.) to ensure that it will not deform or release harmful substances during high temperature processes. At the same time, the surface of the heat plate 20 is smooth to ensure good contact between the wafer and the heat plate 20 to improve heat conduction efficiency.

[0047] like Figure 2 As shown, the wafer ejector pin 30 is disposed below the hot plate 20 and is lifted and lowered in a direction perpendicular to the hot plate 20. It can be understood that the lifting and lowering of the wafer ejector pin 30 can drive the target wafer 40 to move in the vertical direction. The wafer ejector pin 30 is used to connect the target wafer 40 with the hot plate 20. The wafer ejector pin 30 disposed below the hot plate 20 can achieve a precise connection between the target wafer 40 and the hot plate 20. The wafer ejector pin 30 can also provide mechanical support during the lifting process to ensure that the wafer remains stable during heating or processing, and reduce the possibility of vibration and displacement.

[0048] like Figure 2 As shown, the wafer ejector pin 30 includes a main body 31 and a top cap 32 disposed on the top of the main body 31. The main body 31, as the main structure of the wafer ejector pin 30, carries the overall functionality and stability of the wafer ejector pin 30, and can ensure that the wafer ejector pin 30 can obtain sufficient support and stability during the lifting process. The top cap 32 is at least partially located in the through hole 21, and the upper end surface of the top cap 32 is in contact with the bottom surface of the target wafer 40; wherein, the length of the top cap 32 is greater than the preset length. Since the wafer ejector pin 30 is configured to be liftable, the operator can adjust the ejector pin height as needed, thereby adjusting the heating condition of the target wafer 40.

[0049] In the wafer heating device of the above embodiment, the hot plate 20 is used to heat the target wafer 40, the top cap 32 of the wafer ejector pin 30 is at least partially located in the through hole 21 of the hot plate 20, the upper end surface of the top cap 32 is in contact with the bottom surface of the target wafer 40, and the length of the top cap 32 is greater than the preset length. In this way, by lengthening the length of the top cap 32, the overheating of the contact portion between the top cap 32 and the target wafer 40 can be effectively improved, thereby improving the problem of uneven wafer heating.

[0050] Please combine Figure 2 and Figure 3 It is understood that in some embodiments, the top cap 32 includes a first heat-resistant member 321 and a second heat-resistant member 322 that are vertically connected, and the upper end surface of the second heat-resistant member 322 is in contact with the bottom surface of the target wafer 40; the length of the first heat-resistant member 321 is equal to the preset length. Since the length of the first heat-resistant member 321 is equal to the preset length, the overall length of the top cap 32 is greater than the preset length, and the first heat-resistant member 321 and the second heat-resistant member 322 can effectively prevent heat from being directly conducted to the target wafer 40 through the wafer ejector pin 30. By lengthening the total length of the top cap 32, the heat-resistant effect of the top cap 32 can be enhanced, thereby improving the uneven heating of the target wafer 40.

[0051] In some embodiments, the length of the second heat-resistant member 322 is not less than a preset length. It is understood that conventional wafer heating devices usually only include a top cap that is less than a preset length. When the length of the second heat-resistant member 322 is not less than a preset length, the length of the top cap 32 in the embodiment of the present application can be doubled at least, thereby better improving the problem of uneven heating of the target wafer 40.

[0052] In some embodiments, the first heat-resistant member 321 and the second heat-resistant member 322 are integrally formed. The integrally formed first heat-resistant member 321 and the second heat-resistant member 322 can reduce movable parts in the wafer heating device 10 and reduce the device processing cost.

[0053] In some embodiments, the material of the top cap 32 is polyetheretherketone (PEEK). PEEK has good heat resistance, and its continuous use temperature can reach 260°C (about 500°F). It can withstand higher temperatures (over 300°C) in a short time, making it very suitable for applications in high temperature environments. At the same time, PEEK has excellent thermal stability. Since the thermal degradation threshold of PEEK is relatively high, it has good thermal stability at high temperatures and is not easy to degrade. This means that in a long-term high temperature environment, PEEK will not easily lose its physical and chemical properties. In addition, PEEK has a low coefficient of thermal expansion, which gives it a certain dimensional stability, meaning that its size changes less when the temperature changes, which is particularly important for the application of precision parts, and can maintain good dimensional stability and durability. At high temperatures, the tensile strength, compressive strength and bending strength of PEEK can be maintained at a relatively high level, so that it has good performance when bearing loads. PEEK also has excellent electrical insulation properties, which can achieve electrical insulation under high temperature resistance, and its dielectric strength can be maintained at a high level even in a high temperature environment. The polyetheretherketone material has good resistance to thermal aging, and it can maintain good mechanical properties and chemical stability even under high temperature conditions. The resistance of polyetheretherketone to many chemicals and solvents enables it to maintain its performance in a combination of chemical corrosion and high temperature, thereby extending its service life. For example, the first heat-resistant member 321 and the second heat-resistant member 322 are integrally formed polyetheretherketone.

[0054] In some embodiments, there are multiple through holes 21 and wafer ejector pins 30, and the number of through holes 21 is the same as the number of wafer ejector pins 30; the upper end surfaces of the multiple wafer ejector pins 30 are flush; the top caps 32 are correspondingly located in the multiple through holes 21, and are synchronously raised and lowered in a direction perpendicular to the hot plate 20.

[0055] For example, there are three through holes 21 and three wafer ejector pins 30, and the through holes 21 are evenly distributed around the center of the hot plate 20, and the distances from the three through holes 21 to the center of the hot plate 20 are the same. That is, the through holes 21 form an equilateral triangle layout around the center of the hot plate 20. This layout makes the distance between each through hole 21 and the center of the hot plate 20 exactly the same, ensuring the symmetry and uniformity of the system. The equidistantly arranged through holes 21 enhance the mechanical stability of the equipment and reduce the risk of uneven deformation caused by thermal expansion or mechanical stress, thereby better preventing the displacement or distortion of the target wafer 40 during the heating process and ensuring the processing accuracy. At the same time, the structure of the through holes 21 allows the wafer ejector pins 30 to be evenly and closely contacted with the target wafer 40, which helps to improve the stability and uniformity of the process, ensure the temperature of each area of ​​the target wafer 40 is consistent, and thus improve product quality.

[0056] See also Figure 4 According to some embodiments, a wafer heating method is also provided, which uses the wafer heating device in any of the above embodiments to heat the target wafer; the method also includes the following steps.

[0057] Step S10, controlling the upper end surface of the wafer ejector pin to rise and fall to a first preset height, and controlling the hot plate to heat the target wafer for a first preset time;

[0058] Step S30, controlling the upper end surface of the wafer ejector pin to rise and fall to a second preset height, and controlling the hot plate to heat the target wafer for a second preset time; wherein the first preset height is greater than the second height; and the first preset time is less than the second preset time.

[0059] In the wafer heating method of the above embodiment, by lengthening the length of the top cap, the overheating of the contact portion between the top cap and the target wafer can be effectively improved, thereby improving the problem of uneven wafer heating. In addition, by controlling the upper end surface of the wafer ejector pin to rise and fall to a first preset height, and controlling the hot plate to heat the target wafer for a first preset time, the contact time between the wafer and the wafer ejector pin can be reduced, thereby further improving the uneven wafer heating. Then, by controlling the upper end surface of the wafer ejector pin to rise and fall to a second preset height, and controlling the hot plate to heat the target wafer for a second preset time, the heating temperature of the target wafer can be made more uniform.

[0060] See also Figures 2 to 4 In step S10, the upper end surface of the wafer ejector pin 30 is controlled to rise and fall to a first preset height, and the hot plate 20 is controlled to heat the target wafer 40 for a first preset time.

[0061] Please continue reading Figures 2 to 4 In step S30, the upper end surface of the wafer ejector pin 30 is controlled to rise and fall to a second preset height, and the hot plate 20 is controlled to heat the target wafer 40 for a second preset time; wherein the first preset height is greater than the second height; and the first preset time is less than the second preset time.

[0062] In some embodiments, the first preset height is greater than 0 mm. Thus, in step S10, the upper end surface of the wafer ejector pin 30 is controlled to rise and fall to the first preset height, and the hot plate 20 is controlled to heat the target wafer 40 for the first preset time. At this time, the target wafer 40 located at the wafer ejector pin 30 is at least spaced apart from the hot plate 20 by the first preset height. Since the wafer heating device 10 in the above-mentioned embodiment is used to heat the target wafer 40 in the embodiment of the present application, the wafer heating device 10 can effectively improve the overheating of the contact portion between the top cap 32 and the target wafer 40 by lengthening the length of the top cap 32, thereby improving the problem of uneven wafer heating. Moreover, the heating process of the target wafer 40 can be completed in two steps, thereby simplifying the process flow, shortening the process time, and improving the processing efficiency.

[0063] In some embodiments, the first preset time is less than 10s. By way of example, the range of the first preset time includes 5s to 10s. For example, the range of the first preset time is 5s, 6s, 7s, 8s, 9s or 10s, etc. In the conventional wafer heating method, the ejector pin is usually raised to a certain height first, and the target wafer 40 is heated for more than 10s. At this time, due to the long heating time, the temperature of the wafer ejector pin 30 will directly act on the target wafer 40 through heat conduction, resulting in the problem of overheating of the contact portion between the target wafer 40 and the wafer ejector pin 30. However, in the wafer heating method of the embodiment of the present application, the first preset time is less than 10s, which can shorten the heating time of the target wafer 40 in step S10, thereby improving the overheating problem of a partial area of ​​the target wafer 40.

[0064] In some embodiments, the first preset time is equal to 5 seconds. In this way, the time during which the target wafer 40 is heated by the hot plate 20 under the support of the wafer ejector pins 30 can be minimized, thereby effectively improving the overheating problem of a partial area of ​​the target wafer 40 .

[0065] In some embodiments, the first preset height is not less than 10 mm. For example, the first preset height is 10 mm. In this way, process damage caused by the hot plate 20 being too close to the target wafer 40 in step S10 can be avoided.

[0066] In some embodiments, the second preset time is no more than 360 seconds. For example, the second preset time is 360 seconds. In this way, while ensuring the heating effect of the target wafer 40, overheating of the target wafer 40 can be avoided.

[0067] In some embodiments, the second preset height is equal to 0 mm. In the embodiment where the second preset height is equal to 0 mm, step S30, controlling the upper end surface of the wafer ejector pin 30 to rise and fall to the second preset height, and controlling the hot plate 20 to heat for a second preset time, includes:

[0068] Step S31 , controlling the upper end surface of the wafer ejector pin 30 to descend to be flush with the top surface of the hot plate 20 , so that the upper surface of the hot plate 20 contacts the bottom surface of the wafer.

[0069] In the above embodiment, by setting the second preset height equal to 0 mm, in step S31, the upper end surface of the wafer ejector pin 30 drops to be flush with the top surface of the hot plate 20, and the upper surface of the hot plate 20 is in direct contact with the bottom surface of the wafer. The target wafer 40 is directly heated by the hot plate 20, thereby avoiding the influence of heat conduction of the wafer ejector pin 30 on the heating of the target wafer 40, so that the target wafer 40 is heated more evenly.

[0070] Table 1 shows the steps of the conventional wafer heating method. Please understand in conjunction with Table 1 that in the conventional wafer heating method, three steps are usually used to heat the wafer. In step 1, the baking distance, i.e., the distance between the wafer and the heat source, is 10 mm, and the wafer is heated for 10 seconds; in step 2, the baking distance, i.e., the distance between the wafer and the heat source, is 5 mm, and the wafer is heated for 60 seconds; in step 3, the baking distance, i.e., the distance between the wafer and the heat source, is 2 mm, and the wafer is heated for 360 seconds. In this way, under the premise of a certain baking distance, the wafer is heated for a long time, especially in steps 2 and 3 of the traditional wafer heating method, the wafer is heated for 60s and 360s respectively. At this time, under the heat conduction of the ejector pin, the contact part between the wafer and the ejector pin is extremely prone to overheating, resulting in uneven heating of the entire wafer, and further causing the key dimensions of this part and the surrounding area after photolithography to be smaller. After undergoing the corresponding electroplating process, the structural dimensions of this area will also be smaller and cannot meet the design requirements.

[0071] Table 1

[0072] step 1 2 3 Step time(s) 10.0 60.0 360.0 Baking time(s) 0.0 0.0 0.0 Baking distance (mm) 10.0 5.0 2.0 Ejector speed Speed ​​1 Speed ​​1 Speed ​​2

[0073] Table 2 shows the steps of a wafer heating method in one embodiment of the present application. Figure 2 It is understood that the wafer heating method of the embodiment of the present application only needs to take two steps to complete the heating of the target wafer 40. In step 1, that is, in step S10 described above, the baking distance, that is, the interval between the wafer ejector pin 30 and the hot plate 20 is set to 10mm, and the target wafer 40 is heated for 10s. In step 2, that is, in step S30 described above, the baking distance, that is, the interval between the wafer ejector pin 30 and the hot plate 20 is set to 0mm, and the target wafer 40 is heated for 360s. That is to say, in step 2, there is no spacing between the wafer ejector pin 30 and the hot plate 20, the target wafer 40 is in direct contact with the hot plate 20, and the hot plate 20 directly heats the target wafer 40 for 360s without the action of the wafer ejector pin 30, thereby avoiding overheating of the contact portion of the wafer ejector pin 30 with the target wafer 40 by direct heat conduction. In the wafer heating method of the embodiment of the present application, the heating time at a certain baking distance is greatly shortened, which can effectively improve the influence of the heat conduction effect of the wafer ejector pin 30 on the heating process of the target wafer 40, thereby effectively improving the problem of uneven heating of the target wafer 40.

[0074] Table 2

[0075] step 1 2 Step time(s) 10.0 360.0 Baking time(s) 0.0 0.0 Baking distance (mm) 10.0 0.0 Ejector speed Speed ​​1 Speed ​​2

[0076] Please combine Table 2 and Figure 5It is understood that the applicant has experimentally concluded that after the target wafer 40 is heated by the wafer heating method of the embodiment of the present application, the target wafer 40 is heated evenly, the surface morphology of the target wafer 40 is good, and the key dimensions of the structure on the target wafer 40 can meet the design requirements. In this way, the wafer heating method of the embodiment of the present application can effectively avoid defects caused by overheating of the target wafer 40.

[0077] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0078] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A wafer heating device, It is characterized in that include: A hot plate, used for heating the target wafer, wherein the hot plate is provided with a through hole; A wafer ejector pin is disposed below the hot plate and rises and falls in a direction perpendicular to the hot plate to connect the target wafer and the hot plate; the wafer ejector pin comprises a main body and a top cap disposed on the top of the main body, the top cap is at least partially located in the through hole, and the upper end surface of the top cap contacts the bottom surface of the target wafer; wherein the length of the top cap is greater than a preset length.

2. The wafer heating device according to claim 1, It is characterized in that The top cap comprises a first heat-resistant member and a second heat-resistant member which are vertically connected, and the upper end surface of the second heat-resistant member contacts the bottom surface of the target wafer; The length of the first heat-resistant member is equal to a preset length.

3. The wafer heating device according to claim 2, It is characterized in that The length of the second heat-resistant member is not less than the preset length.

4. The wafer heating device according to claim 2 or 3, It is characterized in that The first heat-resistant component and the second heat-resistant component are integrally formed.

5. The wafer heating device according to claim 1, It is characterized in that The material of the top cap is polyetheretherketone.

6. The wafer heating device according to claim 1, It is characterized in that There are multiple through holes and multiple wafer ejector pins, and the number of the through holes is the same as that of the wafer ejector pins; the upper end surfaces of the multiple wafer ejector pins are flush; The top caps are correspondingly located in the plurality of through holes and are synchronously lifted and lowered in a direction perpendicular to the hot plate.

7. A wafer heating method, It is characterized in that The target wafer is heated using the wafer heating device according to any one of claims 1 to 6; the method further comprising: Controlling the upper end surface of the wafer ejector pin to rise and fall to a first preset height, and controlling the hot plate to heat the target wafer for a first preset time; Controlling the upper end surface of the wafer ejector pin to rise and fall to a second preset height, and controlling the hot plate to heat the target wafer for a second preset time; Among them, the first preset height is greater than the second height; the first preset time is less than the second preset time.

8. The wafer heating method according to claim 7, Features: The first preset time is less than 10 seconds; and / or The second preset time is no greater than 360 seconds.

9. The wafer heating method according to claim 7, It is characterized in that The second preset height is equal to 0 mm; The controlling the upper end surface of the wafer ejector pin to rise and fall to a second preset height, and controlling the hot plate to heat for a second preset time, comprises: The upper end surface of the wafer ejector pin is controlled to descend to be flush with the top surface of the hot plate, so that the upper surface of the hot plate contacts the bottom surface of the wafer.

10. The wafer heating method according to any one of claims 7 to 9, It is characterized in that The first preset time is equal to 5s.

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