CN102034684A - Device and method for introducing multi-gradient temperature field in laser annealing process of silicon wafer - Google Patents

Abstract

The invention discloses a laser annealing device and a laser annealing method for forming a multi-gradient temperature field in a semiconductor wafer and belongs to semiconductor manufacturing equipment and technique range. The device comprises an annealing laser light source, an annealing laser beam processing system, an auxiliarily heating light source and a moveable slide glass platform with the auxiliarily heating light source. The processing method comprises the following steps of: placing a wafer to be annealed on the slide glass platform and performing scanning heating by using annealing laser beams; acting the slide glass platform and auxiliarily heating light beams on the surface of a substrate wafer at the same time so as to preheat the surface of the substrate wafer; and forming a secondary high-temperature temperature field with buffer function, so that the on chip multi-gradient temperature field is introduced and undesirable influence on the annealing effect and the surface appearance of the wafer caused by high temperature and large thermal stress in the laser annealing process is improved. The preheating process finished under the sharing and collaboration of a plurality of heat source units, so the respective realizing difficulty of each unit is greatly reduced, the whole machine operates stably and reliably, and the process is flexible and convenient in operation and control.

Description

Translated fromChinese

硅片激光退火中多梯度温度场的装置和方法Device and method for multi-gradient temperature field in silicon wafer laser annealing

技术领域technical field

本发明属于半导体制造技术范围，特别涉及在半导体晶圆片进行激光退火过程中引入多梯度温度场的一种硅片激光退火中多梯度温度场的装置和方法。The invention belongs to the technical scope of semiconductor manufacturing, and in particular relates to a device and method for introducing multiple gradient temperature fields in the laser annealing of silicon wafers, which introduce multiple gradient temperature fields in the laser annealing process of semiconductor wafers.

背景技术Background technique

在半导体制造过程中，为了调节硅片表面局部区域的导电特性，广泛采用离子注入技术，对硅片表面的特定区域进行杂质掺杂。离子注入之后，由于所掺杂杂质原子处于硅晶格中缺陷的状态，一般需要进行退火的处理，一方面消除掺杂对于半导体材料晶格造成的损伤，另一方面能够有效地激活掺杂杂质。In the semiconductor manufacturing process, in order to adjust the conductivity of the local area of the silicon wafer surface, ion implantation technology is widely used to do impurity doping on a specific area of the silicon wafer surface. After ion implantation, because the doped impurity atoms are in the state of defects in the silicon lattice, annealing treatment is generally required. On the one hand, it can eliminate the damage caused by doping to the semiconductor material lattice, and on the other hand, it can effectively activate the doped impurities. .

传统的退火采用热作用的方式进行，例如将待退火的硅片放置于高温炉管中的常规热退火方式。热退火工艺的一项缺点在于杂质在高温下的再扩散；为了限制掺杂杂质的再扩散，一般会采用限制热作用时间的退火技术；图1列出了几种常见的快速热退火的实现方案，分别是短时间的快速热退火1，更短作用时间的热冲击退火2，激光脉冲退火3，和进行辅助性加热的激光退火4。不同的快速退火技术，在硅片中造成的温度分布是不同的，其中快速热退火1和热冲击退火2，在硅片中造成比较均匀的温度分布5，激光脉冲退火3可在硅片中造成温度分布6，特点为，表面很浅的局部温度很高，但离开表面进入到硅片深处，则温度维持在比较低的水平，热辅助激光退火4，在硅片中造成温度分布7，与温度分布6相比较而言，硅片内部的温度并不是太低，因而改善了硅片整体的温度梯度状况。比较上述几种退火可以看出，过高的温度差所带来的主要的问题，是它能够破坏硅片表面的形貌，使得硅片表面出现微小的裂纹、表面微观的起伏/不平整等。Traditional annealing is carried out by means of thermal action, such as the conventional thermal annealing method in which the silicon wafer to be annealed is placed in a high-temperature furnace tube. One of the disadvantages of the thermal annealing process is the re-diffusion of impurities at high temperatures; in order to limit the re-diffusion of doped impurities, annealing techniques that limit the time of thermal action are generally used; Figure 1 lists several common implementations of rapid thermal annealing The schemes are short-time rapid thermal annealing 1, thermal shock annealing with shorter action time 2, laser pulse annealing 3, and laser annealing with auxiliary heating 4. Different rapid annealing techniques cause different temperature distributions in silicon wafers. Among them, rapid thermal annealing 1 and thermal shock annealing 2 cause relatively uniform temperature distribution in silicon wafers 5, and laser pulse annealing 3 can be used in silicon wafers. Resulting in temperature distribution 6, the characteristic is that the local temperature on the surface is very shallow, but when it leaves the surface and enters the depth of the silicon wafer, the temperature is maintained at a relatively low level. Heat-assisted laser annealing 4 causes temperature distribution in the silicon wafer 7 , compared with the temperature distribution 6, the temperature inside the silicon wafer is not too low, thus improving the overall temperature gradient of the silicon wafer. Comparing the above several annealings, it can be seen that the main problem caused by excessive temperature difference is that it can destroy the surface morphology of the silicon wafer, causing tiny cracks and microscopic fluctuations/unevenness on the surface of the silicon wafer, etc. .

与本发明申请有关的另一项技术背景内容，涉及到半导体材料对于退火激光的光吸收特性；该特性不仅会影响“激光-半导体材料作用的模式”，也会进一步导致激光器、退火装置光路、机械部件等方面的不同方案选择，以及工艺效果的不同，所以需要在此提及。Another technical background content related to the application of the present invention involves the optical absorption characteristics of semiconductor materials for annealing lasers; this characteristic will not only affect the "mode of laser-semiconductor material interaction", but will also further cause lasers, annealing device optical paths, Different options for mechanical parts and other aspects, as well as different process effects, need to be mentioned here.

图2描绘出了典型半导体材料的光吸收系数曲线。由图2可见，当入射光波长小于红外吸收限9时，存在较大的吸收。对于硅材料来说，红外吸收限在1.1μm波长附近，对应于载流子从价带向导带的跃迁。在波长10μm附近的远红外区域，也存在一个吸收峰，它对应于光学支声子的吸收。Figure 2 depicts light absorption coefficient curves for typical semiconductor materials. It can be seen from Figure 2 that when the wavelength of the incident light is smaller than the infrared absorption limit 9, there is greater absorption. For silicon materials, the infrared absorption limit is around 1.1 μm wavelength, which corresponds to the transition of carriers from the valence band to the conduction band. In the far-infrared region near the wavelength of 10 μm, there is also an absorption peak, which corresponds to the absorption of optical branch phonons.

随着半导体电子器件尺寸的不断缩小，器件的有源区域逐渐地更靠近于硅片的浅表面或者极浅表面，对于这样的器件的退火处理，要求在掺杂杂质有效激活的同时，尽可能地降低热效应的影响，尽可能地减小掺杂杂质在热驱动下的扩散和再分布，因此希望采用激光退火技术3或者热辅助的激光退火技术4，并在硅片中造成曲线6或者曲线7那样的温度分布，也就是令激光能量在硅片的浅表面处就被完全吸收，在激光辐照到硅片表面的短时间内，热量和高温区仅限制在硅片的浅表面，有效地退火和激活掺杂杂质。至于硅片表面以下的更深处，并不希望从入射的激光束中吸取能量，因为此处无掺杂杂质，不需要退火的处理。With the continuous shrinking of the size of semiconductor electronic devices, the active region of the device is gradually closer to the shallow or extremely shallow surface of the silicon wafer. For the annealing treatment of such devices, it is required to activate the doped impurities as much as possible while effectively activating the doped impurities. Minimize the influence of thermal effects, and minimize the diffusion and redistribution of dopant impurities under thermal driving. Therefore, it is hoped to use laser annealing technology 3 or heat-assisted laser annealing technology 4, and cause curve 6 or curve 7 The temperature distribution means that the laser energy is completely absorbed at the shallow surface of the silicon wafer. In the short time when the laser irradiates the surface of the silicon wafer, the heat and high temperature area are only limited to the shallow surface of the silicon wafer, effectively ground annealing and activation of doped impurities. As for the depth below the surface of the silicon wafer, it is not desirable to absorb energy from the incident laser beam, because there are no doping impurities and no annealing treatment is required.

结合图2半导体材料的吸收特性可见，本发明针对小尺寸半导体器件中的浅结和超浅结进行退火处理，具体地说，源漏或其他PN结的结深均要小于100nm，这样条件下的激光退火处理，需要利用到波长小于半导体材料红外吸收限的短波长、高能量的激光光束，因为只有这样的光束作用，才能够提供较大的吸收系数，使得激光能量能够在圆片的极浅表面处被完全吸收。具体而言，本发明所涉及的激光波长均小于1.1μm，根据具体器件中PN结的结深，可选择可见光波段，紫外、深紫外波段的激光光束等。In conjunction with the absorption characteristics of semiconductor materials in Figure 2, it can be seen that the present invention performs annealing treatment for shallow junctions and ultra-shallow junctions in small-scale semiconductor devices. Specifically, the junction depths of source-drain or other PN junctions are all less than 100nm. Laser annealing treatment requires the use of a short-wavelength, high-energy laser beam with a wavelength smaller than the infrared absorption limit of the semiconductor material, because only such a beam effect can provide a large absorption coefficient, so that the laser energy can be absorbed at the extreme end of the wafer. Absorbs completely on shallow surfaces. Specifically, the laser wavelengths involved in the present invention are all less than 1.1 μm. According to the junction depth of the PN junction in a specific device, laser beams in the visible light band, ultraviolet, and deep ultraviolet bands can be selected.

在一些传统的激光退火方案中，采用二氧化碳连续波激光器作为主退火作用的激光，波长在10.6μm附近的中、远红外波段。由于考虑吸收机制，吸收效率，退火或者热处理作用的目标及最终的工艺效果，本发明与采用到二氧化碳激光器的技术均存在着较大的差异，因此本发明的内容将不会与此类传统技术相冲突。In some traditional laser annealing schemes, a carbon dioxide continuous wave laser is used as the main annealing laser, and the wavelength is in the middle and far infrared bands near 10.6 μm. Considering the absorption mechanism, absorption efficiency, annealing or heat treatment goals and the final process effect, the present invention is quite different from the technology that adopts carbon dioxide laser, so the content of the present invention will not be different from such traditional technology. Conflict.

本发明申请，与激光退火有关，并且着重于处理和进一步改善硅片作为一个整体的片内的温度梯度分布，使得在硅片的极浅表面处相对于硅片内部不存在过高的温度差，从而可以改善退火的效果。本发明所说的激光退火，除了在激光波长方面有一定的范围限定之外，在激光光束方面，专指光束截面或者束斑为矩形的激光，对于矩形的激光光斑内，要求光场分布均匀。本发明所说明的内容，不与已有的采用线形光束的激光退火技术相冲突。所说的矩形束斑，系指矩形形状，宽长比大于1/7，一般而言，至少是矩形的长度要与硅片上分布的芯片尺寸相当，在厘米量级。所说的线形光束，举例来说，长度在几毫米量级或更长，宽度在1毫米以下，至少是宽度值，远远小于芯片的尺寸。The application of the present invention is related to laser annealing, and focuses on processing and further improving the temperature gradient distribution within the silicon wafer as a whole, so that there is no excessive temperature difference at the extremely shallow surface of the silicon wafer relative to the inside of the silicon wafer , which can improve the effect of annealing. The laser annealing mentioned in the present invention, in addition to the limited range of the laser wavelength, specifically refers to the laser beam with a rectangular beam cross section or beam spot in terms of the laser beam. For the rectangular laser spot, uniform distribution of the light field is required. . The content described in the present invention does not conflict with the existing laser annealing technology using linear beams. The so-called rectangular beam spot refers to a rectangular shape with a width-to-length ratio greater than 1/7. Generally speaking, the length of the rectangle should be at least equivalent to the size of the chips distributed on the silicon wafer, on the order of centimeters. The linear beam, for example, has a length of several millimeters or more and a width of less than 1 millimeter, at least the width is much smaller than the size of the chip.

鉴于当前主流的硅片尺寸为200毫米，300毫米，将来还可能会更大，但退火的激光光束，特别是本发明所涉及的紫外、深紫外光束，由于扩束很困难，目前技术还无法做到形成大光场，光束的束斑很难覆盖整个的硅片，所以激光对于硅片的退火，只能是一个局部、一个局部地进行，采用扫描或者步进的方式。In view of the fact that the current mainstream silicon wafer size is 200 mm and 300 mm, it may be larger in the future, but the annealed laser beam, especially the ultraviolet and deep ultraviolet beams involved in the present invention, is difficult to expand the beam, and the current technology cannot To form a large light field, the beam spot of the beam is difficult to cover the entire silicon wafer, so the annealing of the silicon wafer by the laser can only be carried out in a local, one local, scanning or stepping manner.

普通的激光退火技术3，采用高强度的激光，对圆片表面进行瞬时的作用，这将会在衬底材料表面处引起较大的热应力，对于加工质量产生不良的影响，所以人们也采用对衬底材料预加热的热辅助激光退火4，来减轻热应力的影响。对衬底材料进行辅助性加热，一般采用电炉加热的方式，从圆片的背面进行，对圆片整片进行加热。Ordinary laser annealing technology 3 uses a high-intensity laser to act instantaneously on the surface of the wafer, which will cause a large thermal stress on the surface of the substrate material, which will have a negative impact on the processing quality, so people also use Heat-assisted laser annealing 4 preheating the substrate material to mitigate the effects of thermal stress. Auxiliary heating of the substrate material is generally carried out by means of electric furnace heating, which is carried out from the back of the wafer to heat the entire wafer.

发明内容Contents of the invention

本发明的目的是提供一种硅片激光退火中多梯度温度场的装置和方法，该激光退火的装置在光学处理系统14的两边分别水平放置退火激光源13和全反射镜，衬底圆片16载于承片台15上，全反射镜将经过光学处理系统14处理形成大束斑的退火激光束19反射后，垂直入射到承片台15上面的衬底圆片16之上，另外采用一个辅助性加热的光源20产生辅助性加热光束17斜入射到衬底圆片16的表面，载片台15内部装置的加热源18用于形成晶圆片本底温度区域，载片台15内部安装用于形成晶圆片本底温度区域的辅助加热源18以及装置自动化运行的计算机控制系统；其特征在于，由退火激光束19、斜入射到衬底圆片16表面的辅助性加热光束17和载片台15内部安装的辅助加热源18在半导体晶圆片激光退火过程中形成多梯度温度场；The object of the present invention is to provide a device and method for multi-gradient temperature field in laser annealing of silicon wafers. The device for laser annealing is respectively horizontally placed annealinglaser source 13 and total reflection mirror on both sides ofoptical processing system 14, andsubstrate wafer 16 is carried on thewafer stage 15, and the total reflection mirror reflects the annealing laser beam 19 which has been processed by theoptical processing system 14 to form a large beam spot, and then vertically incident on the substrate wafer 16 above thewafer stage 15. The auxiliaryheating light source 20 produces anauxiliary heating beam 17 obliquely incident on the surface of thesubstrate wafer 16, and theheating source 18 installed inside the loading table 15 is used to form the background temperature area of the wafer, and the inside of the loading table 15 is installed Theauxiliary heating source 18 used to form the background temperature zone of the wafer and the computer control system for the automatic operation of the device; it is characterized in that the annealing laser beam 19, theauxiliary heating beam 17 obliquely incident on the surface of thesubstrate wafer 16 and the Theauxiliary heating source 18 installed inside the loading table 15 forms a multi-gradient temperature field during the laser annealing process of the semiconductor wafer;

所述的退火激光光源13，波长至少在材料的红外吸收限以内，对于超浅结制作，波长限定为在400nm以下；The annealinglaser light source 13 has a wavelength at least within the infrared absorption limit of the material, and for ultra-shallow junction fabrication, the wavelength is limited to below 400nm;

所述的光束处理系统14，主要的功能是将激光器13出射的光束进行扩束、对光束整形、光场均匀化，最终得到作用于半导体晶圆片16表面之上的大束斑的退火激光光束19；The main function of thebeam processing system 14 is to expand the beam emitted by thelaser 13, shape the beam, and homogenize the light field, and finally obtain an annealing laser beam that acts on the large beam spot on the surface of thesemiconductor wafer 16 19;

所述的半导体晶圆片16，放置于载片台15之上，并且随载片台15相对于退火激光束19进行扫描或者步进方式的移动。Thesemiconductor wafer 16 is placed on theloading stage 15 and moves in a scanning or stepping manner with theloading stage 15 relative to the annealing laser beam 19 .

所述的多梯度温度场为在半导体晶圆片中造成3个不同温度区域，这三个温度区域分别由不同的能量源提供升温热量，其中退火激光光束19用于形成硅片浅表面处的高温区域10，辅助加热光束17用于形成包含高温区域10在内的次高温区域11，载片台15内部安装的辅助加热源18用于形成晶圆片本底温度区域12；随着晶圆片相对于退火激光束19的扫描或者步进式的移动，激光束19和辅助加热光束17将移动通过晶圆片的整个表面，因此高温区域10和次高温区域11，在不同的时间是处于晶圆片表面不同的局部位置的。The multi-gradient temperature field is to cause 3 different temperature regions in the semiconductor wafer, and these three temperature regions are respectively provided with heating heat by different energy sources, wherein the annealing laser beam 19 is used to form the silicon wafer at the shallow surface. In the high-temperature area 10, theauxiliary heating beam 17 is used to form a secondary high-temperature area 11 including the high-temperature area 10, and theauxiliary heating source 18 installed inside the slide table 15 is used to form the background temperature area 12 of the wafer; The scanning or stepping movement of the wafer relative to the annealing laser beam 19, the laser beam 19 and theauxiliary heating beam 17 will move through the entire surface of the wafer, so thehigh temperature region 10 and the sub-high temperature region 11 are at different times different local locations on the wafer surface.

所述的退火激光束19，其作用在于对晶圆片掺杂杂质进行退火，即便是不附加其他辅助性的措施，该光束也能够独立完成退火的作用。The annealing laser beam 19 is used to anneal the doped impurities on the wafer, even if no other auxiliary measures are added, the beam can independently complete the annealing function.

所述的辅助加热光束17为普通光源或激光光束，对于半导体材料晶圆片的透入深度大于退火激光光束19，并且具备一定的功率，能够在扫描通过晶圆片表面特定区域的短时间内，令该区域获得一定量的温度提升。Theauxiliary heating beam 17 is an ordinary light source or a laser beam, the penetration depth of the semiconductor material wafer is greater than that of the annealing laser beam 19, and has a certain power, and can scan through a specific area of the wafer surface within a short time , so that the area gets a certain amount of temperature increase.

所述的辅助加热光束17和辅助加热源18，分担和协同地完成总的辅助加热温升目标。The auxiliaryheating light beam 17 and theauxiliary heating source 18 share and cooperate to complete the total auxiliary heating temperature rise target.

所述退火激光光源19和辅助加热光源17，采取但不限于退火激光束正入射、辅助加热光束斜入射到晶圆片表面的方式。The annealing laser light source 19 and the auxiliaryheating light source 17 adopt, but are not limited to, the manner in which the annealing laser beam is normally incident and the auxiliary heating beam is obliquely incident on the wafer surface.

所述片内多温度场的激光退火方法能够减小晶圆片所承受的热梯度应力，具有更好的退火效果，该方法的具体步骤如下：The laser annealing method with multiple temperature fields in the chip can reduce the thermal gradient stress suffered by the wafer, and has a better annealing effect. The specific steps of the method are as follows:

1)将衬底圆片16载于承片台15上，被加热源18所加热；1) Loading thesubstrate wafer 16 on thewafer stage 15 and being heated by theheating source 18;

2)调整辅助加热光束17，使光束斜入射到衬底圆片的表面，总的辅助加热量是要令晶圆片表面的局部区域11的温度控制在200～600℃；总的升温量，由辅助加热光束17和加热源18分担，例如辅助加热光束造成200℃的升温，而加热源18造成250℃的升温，二者共同造成450℃的升温；2) Adjust theauxiliary heating beam 17 so that the beam is obliquely incident on the surface of the substrate wafer. The total auxiliary heating amount is to control the temperature of the local area 11 on the wafer surface at 200-600° C.; the total temperature rise is, Shared by theauxiliary heating beam 17 and theheating source 18, for example, the auxiliary heating beam causes a temperature rise of 200°C, while theheating source 18 causes a temperature rise of 250°C, and the two together cause a temperature rise of 450°C;

3)调整光束处理系统，改变激光束19的矩形束斑的大小，使其长度等于或略大于一个或若干个芯片的面积，而宽度至少取为长度的1/7；3) Adjust the beam processing system to change the size of the rectangular beam spot of the laser beam 19 so that its length is equal to or slightly larger than the area of one or several chips, and the width is at least 1/7 of the length;

4)承片台15在退火激光19所形成矩形束斑的宽度方向上扫描，如果矩形束斑的宽度刚好能够覆盖一个或若干个芯片宽度，则片台15取步进的方式移动；4) Thewafer stage 15 scans in the width direction of the rectangular beam spot formed by the annealing laser 19, if the width of the rectangular beam spot can just cover one or several chip widths, then thewafer stage 15 moves in a step-by-step manner;

5)无论是扫描方式还是步进方式的移动，平均而言，单位面积的晶圆片，其实现良好退火的激光辐照剂量在250～700mJ/cm²范围内，因而可根据工艺上对于剂量的要求，又根据光场均匀化处理后退火激光束19的功率密度，确定片台15的扫描或者步进移动的速度；在另一方面，根据片台15平均的移动速度，又根据辅助加热升温的需求，对于辅助加热光束的加热能力要求是要在10-200毫秒内，造成晶圆片表面200℃的升温；5) Regardless of the movement in the scanning mode or the stepping mode, on average, the laser irradiation dose for a unit area of wafer to achieve good annealing is in the range of 250-700mJ/^cm2 , so the dose can be adjusted according to the process requirements, and according to the power density of the annealing laser beam 19 after the light field homogenization treatment, determine the scanning or stepping speed of thefilm stage 15; on the other hand, according to the average moving speed of thefilm stage 15, and according to the auxiliary heating The demand for heating, the heating capacity of the auxiliary heating beam is required to be within 10-200 milliseconds, resulting in a 200°C temperature rise on the wafer surface;

6)以上控制或参数调整的过程，均通过计算机自动控制系统操作执行。6) The above control or parameter adjustment processes are all executed through the computer automatic control system.

本发明的有益效果是，通过不同能量源的配置使用，在硅片内部引入多个温度场，使得温度的变化逐级递减，变化相对和缓，因而能够更为有效地降低因温度分布不均匀而引起的热应力对于激光退火工艺效果的影响。由于在辅助性加热环节采用了多个热源协同作用，极大降低了其中任一加热源的加热负担，不仅加热源的设计与实现更为便捷，整机的结构组成中也省去了若干热与非热部件的隔离与保护环节，技术上可以做到更加稳定可靠。采用多热源辅助加热，同时还能够带来更多工艺过程控制的灵活性。The beneficial effect of the present invention is that through the configuration and use of different energy sources, a plurality of temperature fields are introduced inside the silicon chip, so that the change of temperature decreases step by step, and the change is relatively gentle, so it can more effectively reduce the temperature caused by uneven temperature distribution. The effect of the induced thermal stress on the effect of the laser annealing process. Due to the synergistic effect of multiple heat sources in the auxiliary heating link, the heating burden of any one of the heating sources is greatly reduced. The isolation and protection of non-thermal components can be technically more stable and reliable. The use of multiple heat sources for auxiliary heating can also bring more flexibility in process control.

附图说明Description of drawings

图1为几种现有的，半导体晶圆片快速热处理技术中，热源升温曲线和圆片内温度分布的情况示意图。FIG. 1 is a schematic diagram of the heating curve of the heat source and the temperature distribution in the wafer in several existing rapid thermal processing technologies for semiconductor wafers.

图2为典型半导体材料的光吸收曲线示意图。FIG. 2 is a schematic diagram of light absorption curves of typical semiconductor materials.

图3是在半导体晶圆片中引入多个不同温度分布区域的情况示意图。FIG. 3 is a schematic diagram of introducing multiple regions with different temperature distributions into a semiconductor wafer.

图4是多温度场激光退火装置的示意图。Fig. 4 is a schematic diagram of a multi-temperature field laser annealing device.

图中，In the figure,

1是快速热退火热源温度随时间变化的示意；2是热冲击退火热源温度随时间变化的示意；3是激光退火中，等效的热源温度随时间变化的示意；4是热辅助激光退火中，等效的热源温度随时间变化的示意；5是快速热退火和热冲击退火作用下，晶圆片内部温度分布的情况；6是激光退火作用下，晶圆片内部温度分布的情况；7是热辅助激光退火作用下，晶圆片内部温度分布的情况；8是波长在远红外波段的声子吸收峰；9是波长在红外吸收限以内，载流子跨能带跃迁而引起吸收系数极大增加的情况；10是由退火激光造成的圆片表面局部的高温区域；11是含区域10在内的，由辅助加热光束造成的圆片内部的次高温区域；12是由衬底加热源造成的晶圆片本底温度区域；13是退火激光源；14是退火激光的光束处理系统；15是可移动载片台；16是半导体晶圆片；17是辅助加热光束；18是辅助加热的衬底热源；19是经过扩束、整形、匀束处理后的退火激光光束；20是产生辅助加热光束的光源。1 is the schematic diagram of the heat source temperature changing with time in rapid thermal annealing; 2 is the schematic diagram of the heat source temperature changing with time in thermal shock annealing; 3 is the schematic diagram of the equivalent heat source temperature changing with time in laser annealing; 4 is the thermal assisted laser annealing , the equivalent heat source temperature changes with time; 5 is the temperature distribution inside the wafer under the action of rapid thermal annealing and thermal shock annealing; 6 is the temperature distribution inside the wafer under the action of laser annealing; 7 8 is the temperature distribution inside the wafer under the action of heat-assisted laser annealing; 8 is the phonon absorption peak with a wavelength in the far-infrared band; 9 is the absorption coefficient caused by the carrier transition across the energy band when the wavelength is within the infrared absorption limit 10 is the local high temperature area on the surface of the wafer caused by the annealing laser; 11 is the sub-high temperature area inside the wafer caused by the auxiliary heating beam including area 10; 12 is the substrate heating 13 is the annealing laser source; 14 is the beam processing system of the annealing laser; 15 is the movable stage; 16 is the semiconductor wafer; 17 is the auxiliary heating beam; 18 is the auxiliary Heated substrate heat source; 19 is the annealing laser beam after beam expansion, shaping and uniform beam treatment; 20 is the light source for generating auxiliary heating beam.

具体实施方式Detailed ways

本发明提供一种在片内引入多梯度温度场的激光退火装置和退火方法。下面结合附图予以进一步说明。激光退火装置的具体结构如图4所示。在图4中，退火激光源13出射的激光束，经过光学处理系统14的扩束，匀束，边沿整形的处理，形成矩形束斑的退火激光束19，经放置在光路上的全反射镜反射后，垂直入射到承片台15上面的衬底圆片16之上，对衬底圆片进行退火的处理。衬底圆片16随承片台15在纵、横两个方向上进行扫描，因而整个衬底圆片都可以被激光光束的作用所覆盖，完成所要求的激光退火。在图4中，另外采用一个辅助性加热的光源20，所产生辅助性加热光束17斜入射到衬底圆片16的表面，辅助加热光束的束斑面积大于退火激光束束斑，退火激光束波长为150nm～400nm，并将后者包含在内部。辅助光源20的光束，波长较退火激光束长，因而透入深度更深一些，在上百微米的范围，辅助加热光源所产生的次高温区域11将退火激光束所产生的高温区域10包含在内部。三个不同的热源所造成的片内的多温度区域分布，如图3所示；其中对应于最高温度的区域10，处在硅片的极浅表面处，是由退火激光束造成的；对应于次高温度的区域11，完全包围着激光退火的作用区域10，可采用加热光束造成；对于辅助加热光束的加热能力要求是要在10-200毫秒内，造成晶圆片表面200℃的升温；而晶圆片衬底的本底温度区12，由载片台15内部安装的辅助加热源18(电阻性加热炉等热源)从硅片背面对硅片进行均匀的加热造成。The invention provides a laser annealing device and an annealing method for introducing multi-gradient temperature fields in a chip. Further description will be given below in conjunction with the accompanying drawings. The specific structure of the laser annealing device is shown in Figure 4. In Fig. 4, the laser beam emitted by theannealing laser source 13, through the beam expansion of theoptical processing system 14, the uniform beam, and the processing of edge shaping, the annealing laser beam 19 forming a rectangular beam spot passes through the total reflection mirror placed on the optical path After reflection, it is incident vertically on thesubstrate wafer 16 above thewafer stage 15, and the substrate wafer is annealed. Thesubstrate wafer 16 scans along with thewafer stage 15 in the vertical and horizontal directions, so that the entire substrate wafer can be covered by the action of the laser beam to complete the required laser annealing. In Fig. 4, an auxiliaryheating light source 20 is adopted in addition, and the generatedauxiliary heating beam 17 is obliquely incident on the surface of thesubstrate wafer 16, and the beam spot area of the auxiliary heating beam is larger than the annealing laser beam spot, and the annealing laser beam The wavelength ranges from 150nm to 400nm, and the latter is included inside. The beam of the auxiliarylight source 20 has a longer wavelength than the annealing laser beam, so the penetration depth is deeper. In the range of hundreds of microns, the sub-high temperature region 11 generated by the auxiliary heating light source includes thehigh temperature region 10 generated by the annealing laser beam. . The distribution of multiple temperature regions in the chip caused by three different heat sources is shown in Figure 3; theregion 10 corresponding to the highest temperature is located at the very shallow surface of the silicon chip, which is caused by the annealing laser beam; the corresponding The sub-highest temperature area 11 completely surrounds theactive area 10 of the laser annealing, which can be formed by heating beams; the heating capacity of the auxiliary heating beam is required to be within 10-200 milliseconds, resulting in a 200°C temperature rise on the wafer surface and the background temperature zone 12 of the wafer substrate is caused by the uniform heating of the silicon wafer from the silicon wafer back side by the auxiliary heating source 18 (heat sources such as resistive heating furnaces) installed in the loading table 15.

上述用于形成次高温度区11的光束加热源，可以是激光束，也可以是普通光源；上述多梯度温度场，系指硅片内存在3个或3个以上的温度区域。The above-mentioned beam heating source for forming the subhighest temperature zone 11 can be a laser beam or an ordinary light source; the above-mentioned multi-gradient temperature field means that there are 3 or more temperature zones in the silicon wafer.

具体的退火过程，举例说明如下：The specific annealing process is illustrated as follows:

1)载片台置于初始位置，该初始位置位于退火激光束19和辅助加热光束17的光束路径之外；1) The slide stage is placed in an initial position, which is located outside the beam paths of the annealing laser beam 19 and theauxiliary heating beam 17;

2)将衬底圆片16放置于承片台15上；2) placing thesubstrate wafer 16 on thewafer stage 15;

3)调整衬底加热源的加热功率，对衬底圆片进行预热，例如衬底圆片的本底温度为200℃；3) Adjust the heating power of the substrate heating source to preheat the substrate wafer, for example, the background temperature of the substrate wafer is 200°C;

4)调节辅助加热光源20的功率，准备用于对衬底圆片表面的某处进行快速加热，例如所造成的局部温升为250℃；4) Adjusting the power of the auxiliaryheating light source 20 to prepare for rapid heating of a certain place on the surface of the substrate wafer, for example, the resulting local temperature rise is 250°C;

5)承片台15移动至退火激光束19和加热光束17的光束路径附近，并且开始执行扫描，令得衬底圆片的整个表面，都逐渐随着片台的扫描动作而接受光束的辐照作用；5) Thewafer stage 15 moves to the vicinity of the beam path of the annealing laser beam 19 and theheating beam 17, and starts scanning, so that the entire surface of the substrate wafer gradually receives the radiation of the beam along with the scanning action of the wafer stage. According to the role;

6)承片台的扫描速度，根据激光辐射的剂量要求，例如平均值处在250～700mJ/cm²之间，而计算出来，并且用于片台的运行控制。令v表示承片台的扫描速度，退火激光束的功率密度为I，单位是mW/cm²，工艺中要求的退火激光剂量为D，单位为mJ/cm²，退火束斑的宽度为L，单位为cm，则扫描速度服从下式所定义的关系：6) The scanning speed of the film stage is calculated according to the dose requirements of laser radiation, for example, the average value is between 250 and 700mJ/cm² , and is used for the operation control of the film stage. Let v represent the scanning speed of the wafer table, the power density of the annealing laser beam is I, the unit is mW/cm² , the annealing laser dose required in the process is D, the unit is mJ/cm² , and the width of the annealing beam spot is L , the unit is cm, then the scanning speed obeys the relationship defined by the following formula:

V＝(I×L)/D  (cm/s)V＝(I×L)/D (cm/s)

举例来说，如果通过实验，确定对于某项特定的应用，激光退火的剂量要求为500mJ/cm²，当退火束斑的宽度为0.2cm，退火激光束的功率密度是25W/cm²时，扫描速度根据上式求出为10cm/s。For example, if it is determined through experiments that the dose requirement for laser annealing is 500mJ/cm² for a specific application, when the width of the annealing beam spot is 0.2cm and the power density of the annealing laser beam is 25W/cm² , The scanning speed was obtained from the above formula to be 10 cm/s.

7)圆片完成扫描退火后，承片台退至初始位置，可换上另一片圆片，继续进行后续晶圆片的激光退火。7) After the scanning and annealing of the wafer is completed, the wafer carrier returns to the initial position, and another wafer can be replaced to continue the laser annealing of the subsequent wafer.

本发明相对于已有技术的有益效果在于：The beneficial effect of the present invention relative to prior art is:

(1)硅片内存在多个温度场分布，使得温度变化逐级递减，变化相对和缓，因而能够更有效地降低因温度分布不均匀而引起的热应力对于激光退火的影响。(1) There are multiple temperature field distributions in the silicon wafer, which makes the temperature change gradually decrease and the change is relatively gentle, so the influence of thermal stress caused by uneven temperature distribution on laser annealing can be more effectively reduced.

(2)激光退火是用很强的激光能量，作用到硅片浅表面的局部面积上，瞬间的能量投送造成的温升，在极端情况下可达1000摄氏度以上。此时如果硅片整体的温度水平处在室温，或者相对较低的200～300摄氏度的范围，则热应力将会对已加工硅片的表面形貌造成损伤。由于这个原因，为了保护硅片表面的形貌，需要引入辅助性加热措施来减小温度梯度，并且辅助加热所提供的温升还要相当地大。(2) Laser annealing uses strong laser energy to act on the local area of the shallow surface of the silicon wafer. The temperature rise caused by the instantaneous energy delivery can reach more than 1000 degrees Celsius in extreme cases. At this time, if the overall temperature of the silicon wafer is at room temperature, or a relatively low range of 200-300 degrees Celsius, the thermal stress will cause damage to the surface morphology of the processed silicon wafer. For this reason, in order to protect the topography of the silicon wafer surface, it is necessary to introduce auxiliary heating measures to reduce the temperature gradient, and the temperature rise provided by the auxiliary heating is also quite large.

如果采用单一热源的辅助性加热，通过辅助加热令硅片整体的温度处在400摄氏度或更高水平之上，则实现高温片台的材料方面，以及防止高温片台向加工设备四周的强烈的热扩散方面，都会面临技术上很难处理的问题。前述背景技术也提到，由于光束相对于硅片尺寸很小，对于硅片的退火只能是一个局部一个局部地进行，因此如果载片台进行扫描或者步进，则如何在较高温度的前提下，还要保证片台的扫描或者步进的运行精度，也成为一项难题。If the auxiliary heating of a single heat source is used, the temperature of the silicon wafer as a whole is kept above 400 degrees Celsius or higher through auxiliary heating, so as to realize the material aspect of the high-temperature wafer stage and prevent the high-temperature wafer stage from being strongly forced to the surroundings of the processing equipment. In terms of thermal diffusion, there will be technically difficult problems to deal with. The aforementioned background technology also mentions that since the beam is relatively small in size relative to the silicon wafer, the annealing of the silicon wafer can only be performed locally one by one. Under the premise, it has also become a difficult problem to ensure the scanning or stepping operation accuracy of the film stage.

在此情形下，一个较好的技术方案选择就是要采用本发明所提出的多梯度温度场方案了。此时，在片台加热和光束加热之间可以进行温升量的平衡折衷，例如，总温升量如果需要是500摄氏度，那么片台可以负责200摄氏度的温升，而加热光束可以负责剩下300摄氏度的温升。片台加热的温升是全局性的，但因为温升的总量被控制住，在实现难度上，包括选择热稳定性的材料，提供热屏蔽保护等，都要容易许多。辅助性加热光束的加热仅限于硅片表面某个局部，此时对热量扩散的屏蔽并不是主要的问题，以现有技术能力同样是方便实现的。In this case, a better technical solution choice is to adopt the multi-gradient temperature field solution proposed by the present invention. At this time, a balance compromise can be made between the stage heating and the beam heating. For example, if the total temperature rise needs to be 500 degrees Celsius, then the stage can be responsible for the temperature rise of 200 degrees Celsius, and the heating beam can be responsible for the remaining temperature. under 300°C temperature rise. The temperature rise of the stage heating is global, but because the total temperature rise is controlled, it is much easier to realize the difficulty, including selecting thermally stable materials and providing thermal shielding protection. The heating of the auxiliary heating beam is limited to a certain part of the surface of the silicon wafer. At this time, the shielding of heat diffusion is not the main problem, and it is also convenient to realize with the existing technical capabilities.

(3)在另一方面，如果仍旧使用单一的辅助加热源，但是将加热源换成局部性加热的光源，那么相对于这种仅仅采用光束做辅助性加热的技术来说，本发明方案亦存在明显的优点。前述背景技术提到，为了减少掺杂杂质在退火处理期间的再扩散分布，当前的主要的技术趋势，都是要减少退火作用的时间，以使掺杂杂质没有时间来进行深度的扩散，例如图1所描绘的快速退火，冲击退火，激光脉冲退火等等。这就表明，采用激光进行硅片退火时，退火激光光束相对于硅片是做较快速的扫描或者步进式移动的，不可能作用很长的时间。当光束从硅片上甲处移向片上乙处时，如果要预先令乙处的温度能够在短时间内迅速地上升至所设定的预加热温度，就要求有足够大能量随加热光束在短时间内投送硅片的表面，这实际上极大地增加了辅助加热光源的实现难度。(3) On the other hand, if a single auxiliary heating source is still used, but the heating source is replaced by a localized heating light source, then compared to this technology that only uses light beams for auxiliary heating, the solution of the present invention is also There are clear advantages. As mentioned in the aforementioned background art, in order to reduce the re-diffusion distribution of dopant impurities during annealing treatment, the current main technical trend is to reduce the annealing time so that dopant impurities do not have time to diffuse deeply, for example Figure 1 depicts rapid annealing, shock annealing, laser pulse annealing, etc. This shows that when using a laser to anneal a silicon wafer, the annealing laser beam scans or moves in steps relative to the silicon wafer, and it is impossible to act for a long time. When the light beam moves from point A on the silicon wafer to point B on the chip, if the temperature at point B can be rapidly raised to the set preheating temperature in a short time in advance, it is required to have enough energy to move with the heating beam. The surface of the silicon wafer is projected in a short time, which actually greatly increases the difficulty of realizing the auxiliary heating light source.

但是对于本发明，由于采用多温度场的方案，硅片背面的加热源分担了一部分的加热量，相应地，对加热光束的要求就降低了很多，加热光束只需要负责少量的温升即可。However, for the present invention, due to the adoption of the multi-temperature field scheme, the heating source on the back of the silicon wafer shares a part of the heating amount, and accordingly, the requirements for the heating beam are greatly reduced, and the heating beam only needs to be responsible for a small amount of temperature rise. .

综上所述，本发明所提出多梯度温度场的方案，可更好地减轻热应力对于硅片的影响，对于辅助性加热部件，热隔离部件等的要求降低，也能够增加工艺过程控制的灵活性，技术上更加稳定可靠，易于实现，设备成本降低。In summary, the multi-gradient temperature field scheme proposed by the present invention can better reduce the influence of thermal stress on silicon wafers, reduce the requirements for auxiliary heating components, thermal isolation components, etc., and can also increase the efficiency of process control. Flexibility, technically more stable and reliable, easy to implement, and lower equipment costs.

Claims (10)

Translated fromChinese

1.一种硅片激光退火中多梯度温度场的装置，该激光退火装置由在光学处理系统(14)的两边分别水平放置退火激光源(13)和全反射镜，衬底圆片(16)载于承片台(15)上，全反射镜将经过光学处理系统(14)处理形成大束斑的退火激光束(19)反射后，垂直入射到承片台(15)上面的衬底圆片(16)之上，另外采用一个辅助性加热的光源(20)产生辅助性加热光束(17)斜入射到衬底圆片(16)的表面，载片台(15)内部装置的加热源(18)用于形成晶圆片本底温度区域，载片台(15)内部安装用于形成晶圆片本底温度区域的辅助加热源(18)以及装置自动化运行的计算机控制系统；其特征在于，由退火激光束(19)、斜入射到衬底圆片(16)表面的辅助性加热光束(17)和载片台(15)内部安装的辅助加热源(18)在半导体晶圆片激光退火过程中形成多梯度温度场；1. a kind of device of multi-gradient temperature field in the laser annealing of silicon chip, this laser annealing device is by placing annealing laser source (13) and total reflection mirror horizontally respectively on both sides of optical processing system (14), substrate wafer (16 ) on the wafer stage (15), the total reflection mirror will reflect the annealing laser beam (19) which is processed by the optical processing system (14) to form a large beam spot, and then vertically incident on the substrate circle above the wafer stage (15). On the sheet (16), an auxiliary heating light source (20) is used to generate an auxiliary heating beam (17) obliquely incident on the surface of the substrate wafer (16), and the heating source of the internal device of the loading table (15) (18) For forming the background temperature area of the wafer, the auxiliary heating source (18) for forming the background temperature area of the wafer and the computer control system for automatic operation of the device are installed inside the loading table (15); its characteristics Be that, by the annealing laser beam (19), the auxiliary heating beam (17) obliquely incident on the surface of the substrate wafer (16) and the auxiliary heating source (18) installed inside the loading table (15) on the semiconductor wafer A multi-gradient temperature field is formed during laser annealing;所述的退火激光光源(13)，波长至少在材料的红外吸收限以内，对于超浅结制作，波长限定为在400nm以下；The annealing laser light source (13) has a wavelength at least within the infrared absorption limit of the material, and for ultra-shallow junction fabrication, the wavelength is limited to below 400nm;所述的光束处理系统(14)，主要的功能是将激光器(13)出射的光束进行扩束、对光束整形、光场均匀化，最终得到作用于半导体晶圆片(16)表面之上的大束斑的退火激光光束(19)；The main function of the beam processing system (14) is to expand the beam emitted by the laser (13), reshape the beam, and homogenize the light field, and finally obtain the beam that acts on the surface of the semiconductor wafer (16). An annealing laser beam (19) with a large beam spot;所述的半导体晶圆片(16)，放置于载片台(15)之上，并且随载片台(15)相对于退火激光束(19)进行扫描或者步进方式的移动。The semiconductor wafer (16) is placed on the loading stage (15), and moves in a scanning or stepping manner with the loading stage (15) relative to the annealing laser beam (19).2.根据权利要求1所述硅片激光退火中多梯度温度场的装置，其特征在于，所述的多梯度温度场为在半导体晶圆片中造成3个不同温度区域，这三个温度区域分别由不同的能量源提供升温热量，其中退火激光光束(19)用于形成硅片浅表面处的高温区域(10)，辅助加热光束(17)用于形成包含高温区域(10)在内的次高温区域(11)，载片台(15)内部安装的辅助加热源(18)用于形成晶圆片本底温度区域(12)；随着晶圆片相对于退火激光束(19)的扫描或者步进式的移动，激光束(19)和辅助加热光束(17)将移动通过晶圆片的整个表面，因此高温区域(10)和次高温区域(11)，在不同的时间是处于晶圆片表面不同的局部位置的。2. according to the device of multi-gradient temperature field in the described silicon chip laser annealing of claim 1, it is characterized in that, described multi-gradient temperature field is to cause 3 different temperature regions in semiconductor wafer, these three temperature regions The heating heat is provided by different energy sources respectively, wherein the annealing laser beam (19) is used to form the high temperature region (10) at the shallow surface of the silicon wafer, and the auxiliary heating beam (17) is used to form the high temperature region (10) including the Sub-high temperature zone (11), the auxiliary heating source (18) installed inside the slide table (15) is used to form the background temperature zone (12) of the wafer; Scanning or step-by-step movement, the laser beam (19) and the auxiliary heating beam (17) will move through the entire surface of the wafer, so the high temperature area (10) and the sub-high temperature area (11) are at different times different local locations on the wafer surface.3.根据权利要求1所述硅片激光退火中多梯度温度场的装置，其特征在于，所述退火激光束(19)，其作用在于对晶圆片掺杂杂质进行退火，即便是不附加其他辅助性的措施，该光束也能够独立完成退火的作用。3. according to the device of multi-gradient temperature field in the described silicon wafer laser annealing of claim 1, it is characterized in that, described annealing laser beam (19), its effect is to carry out annealing to wafer doped impurity, even without additional As other auxiliary measures, the light beam can also independently complete the annealing function.4.根据权利要求1所述硅片激光退火中多梯度温度场的装置，其特征在于，所述辅助加热光束(17)为普通光源或激光光束，对于半导体材料晶圆片的透入深度大于退火激光光束(19)，并且具备一定的功率，能够在扫描通过晶圆片表面特定区域的短时间内，令该区域获得一定量的温度提升；在所述的辅助加热光束(17)和辅助加热源(18)之间，分担和协同完成总的辅助加热温升目标。4. according to the device of multi-gradient temperature field in the described silicon chip laser annealing of claim 1, it is characterized in that, described auxiliary heating beam (17) is common light source or laser beam, for the penetration depth of semiconductor material wafer greater than The annealing laser beam (19) has a certain power, which can make the area obtain a certain amount of temperature increase within a short time of scanning through a specific area on the wafer surface; in the auxiliary heating beam (17) and auxiliary The heating sources (18) share and cooperate to complete the total auxiliary heating temperature rise target.5.根据权利要求1所述硅片激光退火中多梯度温度场的装置，其特征在于，所述退火激光光源(19)和辅助加热光源(17)，采取但不限于退火激光束正入射、辅助加热光束斜入射到晶圆片表面的方式。5. according to the device of multi-gradient temperature field in the described silicon chip laser annealing of claim 1, it is characterized in that, described annealing laser light source (19) and auxiliary heating light source (17), take but not limited to annealing laser beam normal incidence, The way in which the auxiliary heating beam is obliquely incident on the wafer surface.6.根据权利要求1所述硅片激光退火中多梯度温度场的装置，其特征在于，当采用光束作为辅助加热源时，光束为单色光或多色光合成的；或采用激光；当采用激光束进行辅助性加热时，辅助加热光束的束斑包含退火激光的束斑，并且二者同时在晶圆片表面移动；辅助加热的激光束，波长要大于退火激光束的波长，这是因为要求辅助加热透入半导体晶圆片的深度要大于退火光束作用深度的缘故。6. according to the device of multi-gradient temperature field in the described silicon wafer laser annealing of claim 1, it is characterized in that, when adopting light beam as auxiliary heating source, light beam is monochromatic light or polychromatic light synthesis; Or adopt laser; When adopting When the laser beam performs auxiliary heating, the beam spot of the auxiliary heating beam includes the beam spot of the annealing laser, and both of them move on the wafer surface at the same time; the wavelength of the auxiliary heating laser beam is greater than the wavelength of the annealing laser beam, because The reason why it is required that the depth of the auxiliary heating penetrating into the semiconductor wafer is greater than the action depth of the annealing beam.7.根据权利要求1所述硅片激光退火中多梯度温度场的装置，其特征在于，所述衬底圆片载于承片台上，随承片台在纵、横两个方向上进行扫描或者步进移动，因而退火激光光束能够作用到退火晶圆片的整个表面。7. The device of multi-gradient temperature field in the laser annealing of silicon wafers according to claim 1, characterized in that, the substrate wafer is carried on the wafer stage, and is carried out along with the wafer stage in both vertical and horizontal directions. Scanning or stepping movement, whereby the annealing laser beam can be applied to the entire surface of the annealed wafer.8.根据权利要求1所述硅片激光退火中多梯度温度场的装置，其特征在于，所述退火激光的光束处理系统，对于退火激光进行扩束，匀束，整形的处理，使得辐照到半导体晶圆片表面的激光光束束斑为矩形，矩形的长、宽值在几毫米至几厘米量级。8. according to the device of multi-gradient temperature field in the described silicon chip laser annealing of claim 1, it is characterized in that, the beam processing system of described annealing laser, carries out beam expansion for annealing laser, uniform beam, the processing of shaping, makes irradiation The laser beam spot on the surface of the semiconductor wafer is rectangular, and the length and width of the rectangle are on the order of several millimeters to several centimeters.9.根据权利要求7所述硅片激光退火中多梯度温度场的装置的激光退火方法，其特征在于，承片台的扫描速度，根据激光辐射的剂量要求而计算出来，并用于片台的运行控制，令v表示承片台的扫描速度，退火激光束的功率密度为I，单位是mW/cm²，工艺中要求的退火的激光剂量为D，单位为mJ/cm²，退火束斑的宽度为L，单位为cm，则扫描速度服从下式所定义的关系：9. according to the laser annealing method of the device of multi-gradient temperature field in the described silicon chip laser annealing of claim 7, it is characterized in that, the scanning speed of the wafer stage is calculated according to the dose requirement of laser radiation, and is used for the scanning speed of the wafer stage Operation control, let v represent the scanning speed of the substrate, the power density of the annealing laser beam is I, the unit is mW/cm² , the annealing laser dose required in the process is D, the unit is mJ/cm² , the annealing beam spot The width is L, and the unit is cm, then the scanning speed obeys the relationship defined by the following formula:V＝(I×L)/D  (cm/s)。V=(I×L)/D (cm/s).10.一种采用权利要求1所述硅片激光退火中多梯度温度场的装置的激光退火方法，其特征在于，片内多温度场的激光退火方法能够减小晶圆片所承受的热梯度应力，具有更好的退火效果，该方法的具体步骤如下：10. A laser annealing method adopting the device of multi-gradient temperature field in the silicon wafer laser annealing of claim 1, is characterized in that, the laser annealing method of multi-temperature field in the chip can reduce the thermal gradient that wafer is borne Stress has a better annealing effect, the specific steps of the method are as follows:1)将衬底圆片(16)载于承片台(15)上，被加热源(18)所加热；1) Loading the substrate wafer (16) on the wafer carrier (15) and being heated by the heating source (18);2)调整辅助加热光束(17)，使光束斜入射到衬底圆片的表面，总的辅助加热量是要令晶圆片表面的局部区域(11)的温度控制在200～600℃；总的升温量，由辅助加热光束(17)和加热源(18)分担，其中，当辅助加热光束造成200℃的升温，而加热源(18)造成250℃的升温，二者共同造成450℃的升温；2) Adjust the auxiliary heating beam (17) so that the beam is obliquely incident on the surface of the substrate wafer, and the total auxiliary heating amount is to control the temperature of the local area (11) on the wafer surface at 200-600° C.; The amount of temperature rise is shared by the auxiliary heating beam (17) and the heating source (18), wherein, when the auxiliary heating beam causes a temperature rise of 200°C, and the heating source (18) causes a temperature rise of 250°C, the two together cause a temperature rise of 450°C heat up;3)调整光束处理系统，改变激光束(19)的矩形束斑的大小，使其长度等于或略大于一个或若干个芯片的面积，而宽度至少取为长度的1/7；3) Adjusting the beam processing system, changing the size of the rectangular beam spot of the laser beam (19) so that its length is equal to or slightly greater than the area of one or several chips, and the width is at least 1/7 of the length;4)承片台(15)在退火激光(19)所形成矩形束斑的宽度方向上扫描，如果矩形束斑的宽度刚好能够覆盖一个或若干个芯片宽度，则片台(15)取步进的方式移动；台移动至退火激光束及加热光束的光束路径附近，并且开始执行扫描，令得衬底圆片的整个表面，都逐渐随着片台的扫描动作而接受光束的辐照作用；4) The wafer stage (15) scans in the width direction of the rectangular beam spot formed by the annealing laser (19). If the width of the rectangular beam spot is just enough to cover one or several chip widths, the wafer stage (15) takes stepping The stage moves to the vicinity of the beam path of the annealing laser beam and the heating beam, and starts to scan, so that the entire surface of the substrate wafer is gradually irradiated by the beam along with the scanning action of the stage;5)无论是扫描方式还是步进方式的移动，平均而言，单位面积的晶圆片，其实现良好退火的激光辐照剂量在250～700mJ/cm²范围内，因而可根据工艺上对于剂量的要求，又根据光场均匀化处理后退火激光束(19)的功率密度，确定片台(15)的扫描或者步进移动的速度；在另一方面，根据片台(15)平均的移动速度，又根据辅助加热升温的需求，对于辅助加热光束的加热能力要求是要在10-200毫秒内，造成晶圆片表面200℃的升温；5) Regardless of the movement in the scanning mode or the stepping mode, on average, the laser irradiation dose for a unit area of wafer to achieve good annealing is in the range of 250-700mJ/^cm2 , so the dose can be adjusted according to the process requirements, and according to the power density of the annealing laser beam (19) after the light field homogenization treatment, determine the scanning or stepping speed of the film stage (15); on the other hand, according to the average moving speed of the film stage (15) Speed, and according to the demand for auxiliary heating, the heating capacity of the auxiliary heating beam is required to be within 10-200 milliseconds, resulting in a 200°C temperature rise on the wafer surface;6)以上控制或参数调整的过程，均通过计算机自动控制系统操作执行；6) The above control or parameter adjustment processes are all executed through the operation of the computer automatic control system;7)圆片完成扫描退火后，承片台退至初始位置，可换上另一片圆片，继续进行后续晶圆片的激光退火。7) After the scanning and annealing of the wafer is completed, the wafer carrier returns to the initial position, and another wafer can be replaced to continue the laser annealing of the subsequent wafer.

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