Crystal dislocation testing device and method

Abstract

The present invention belongs to the technical field of crystallization performance evaluation of semiconductor crystals, and specifically relates to a wafer dislocation testing device and method, the device comprising: an upper mask plate, on which a plurality of observation lenses for optical magnification are arranged; a lower mask plate, arranged on the opposite side of the upper mask plate; and observation of the wafer surface dislocation between the upper mask plate and the lower mask plate through the observation lens. By arranging the observation lens on the upper mask plate, the magnification effect of the lens is utilized, and real-time observation can be performed without the aid of a metallographic microscope or an electron microscope, thereby improving the convenience of operation; by arranging magnetic blocks on both the upper and lower mask plates, the upper mask plate can rotate freely relative to the lower mask plate, and under the magnetic effect between the upper and lower mask plate magnetic blocks, the fixed limit wafer reduces position deviation, improves the wafer fixing stability, and makes the specific crystal orientation identification more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of crystallization performance evaluation of semiconductor crystals, and in particular to a crystal dislocation testing device and method. Background Art

[0002] At present, with the rapid development of information technology, semiconductor materials are widely used in many fields such as integrated circuits, power devices and optoelectronic devices. Devices made of semiconductor materials support electronic information industries such as computers, networks, and communications, while semiconductor wafer materials are the foundation of the entire industry chain. The level of lattice defect control of semiconductor single crystal materials can affect the quality and performance parameters of epitaxial thin film growth.

[0003] The dislocation density index of the chip is used to evaluate the level of lattice defect control. The conventional practice is to take the cut wafers from the head and tail of the ingot, grind and polish them, and then use chemical reagents to corrode the surface to expose the dislocations. Then, under the field of view of a metallographic microscope or an electron microscope, observe the morphology of the dislocation corrosion pits, and calculate the dislocation density by counting the number. In the current inspection method, microscope observation is mostly required. In addition, based on the visual results of the corrosion pit morphology, the orientation information of a specific crystal direction can be identified on the chip. In the subsequent crystal rod rolling process, the identification information is used as a reference to find the specific crystal direction and process the positioning edge reference surface. In the process of manually identifying the orientation of a specific crystal direction, the accuracy may decrease due to the movement of the chip, and there is room for improvement in accuracy.

[0004] Therefore, there is a need for a solution to solve the problems in the prior art. Summary of the invention

[0005] To solve the above technical problems, according to one aspect of the present invention, the present invention provides a technical solution: utilizing the magnifying effect of a lens, real-time observation can be performed without the aid of a metallographic microscope or an electron microscope; reducing chip position deviation by fixed limiting, and more accurate identification of specific crystal orientations, which can at least solve some of the problems existing in the prior art.

[0006] A crystal dislocation testing device comprises: an upper mask plate, on which a plurality of observation lenses for optical magnification are arranged; a lower mask plate, arranged on the opposite side of the upper mask plate; and observation of the surface dislocation of the wafer between the upper mask plate and the lower mask plate through the observation lenses.

[0007] As a preferred solution of the wafer dislocation testing device described in the present invention, wherein: the observation lens array is distributed on the upper mask plate.

[0008] As a preferred solution of the wafer dislocation testing device described in the present invention, a marking area is provided on the upper mask plate for marking a specific crystal orientation of the wafer.

[0009] As a preferred solution of a chip dislocation testing device described in the present invention, wherein: the marking area is arranged at the edge of the upper mask plate and penetrates the upper mask plate in the shape of a long groove; when marking a specific crystal orientation, the specific crystal orientation of the chip is kept parallel to the long groove direction of the marking area, so as to draw a line on the chip to mark the specific crystal orientation.

[0010] As a preferred solution of a wafer dislocation testing device described in the present invention, an upper mask magnetic block is arranged on the upper mask plate, and a lower mask magnetic block is arranged on the lower mask plate, and the upper mask plate and the lower mask plate are rotatably fixed by the magnetic force between the upper mask magnetic block and the lower mask magnetic block, and the center of the upper mask plate is kept always coincident with the center of the lower mask plate during the rotation process.

[0011] As a preferred solution of the wafer dislocation testing device described in the present invention, the upper mask magnetic block and the lower mask magnetic block are respectively arranged at the center of the upper mask and the lower mask.

[0012] As a preferred solution of the wafer dislocation testing device described in the present invention, wherein: the lower mask is provided with a fixing groove for placing and limiting the wafer, and the size of the fixing groove matches the diameter of the wafer to be tested.

[0013] As a preferred solution of a wafer dislocation testing device described in the present invention, wherein: the lower mask is provided with a wafer placing groove, which is arranged at the circumferential edge of the lower mask and communicated with the fixing groove.

[0014] According to another aspect of the present invention, the present invention provides a technical solution: a method for testing using the above-mentioned crystal dislocation testing device, comprising the following steps:

[0015] S1: Processing and chemically etching the wafer surface to form dislocation corrosion pits;

[0016] S2: placing the wafer processed in step S1 in the lower mask fixing groove to limit the position, and placing the upper mask cover on the wafer;

[0017] S3: Visually observe wafer dislocation through the observation lens on the upper mask.

[0018] As a preferred embodiment of the method for testing using the above-mentioned crystal dislocation testing device described in the present invention, the method includes: before processing the surface of the wafer, when cutting the test wafer, making alignment marks before separating it from the crystal rod; observing the wafer dislocation, counting the dislocation density, identifying specific crystal orientation information, and transferring the specific crystal orientation information to the single crystal rod.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) The crystal dislocation testing device provided by the present invention can realize real-time observation without the aid of a metallographic microscope or an electron microscope by arranging an observation lens on the upper mask plate and utilizing the magnifying effect of the lens, thereby improving the convenience of operation.

[0021] (2) The crystal dislocation testing device provided by the present invention has magnetic blocks on both the upper and lower mask plates, so that the upper mask plate can rotate freely relative to the lower mask plate. Under the magnetic effect between the upper and lower mask plate magnetic blocks, the fixed limit wafer reduces position deviation, improves the wafer fixing stability, and makes the specific crystal orientation identification more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the structure of the device of the present invention;

[0024] Figure 2 This is a schematic diagram of the morphology of the (100) crystal orientation dislocation corrosion pit of the present invention;

[0025] Figure 3 This is the physical morphology of the dislocation corrosion pit with off-angle in a specific crystal orientation of the present invention;

[0026] Figure 4 This is a schematic diagram of the corresponding dislocation morphology and positioning edge of the (100) crystal orientation GaAs of the present invention.

[0027] Description of Figure Numbers:

[0028] 100-upper mask, 101-marking area, 102-upper mask magnetic block, 103-observation lens, 200-lower mask, 201-lower mask magnetic block, 202-fixing groove, 203-pick-and-place groove, 300-wafer, 400-corrosion pit

[0029] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0032] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0033] Example 1

[0034] As attached Figure 1 As shown, a crystal dislocation testing device is used for the crystallization performance evaluation process of semiconductor crystals, and the device comprises: an upper mask 100, on which a plurality of observation lenses 103 for optical magnification are provided; a lower mask 200, which is arranged on the side of a wafer 300 away from the upper mask 100, that is, the lower mask 200 is arranged on the side opposite to the upper mask 100; the upper mask 100 is freely rotatable relative to the lower mask 200, and the dislocation corrosion pits on the surface of the wafer 300 are observed through the observation lenses 103.

[0035] The upper mask plate 100 of the device is provided with a small hole for installing an observation lens 103. The observation lens 103 is installed on the small hole of the upper mask plate 100, and the observation lenses 103 are distributed in an array on the upper mask plate 100. Through the optical magnification effect of the observation lenses 103, visual observation of the dislocation corrosion pits on the surface of the wafer 300 can be performed. The upper mask plate 100 is provided with an identification area 101 for identifying a specific crystal orientation of the wafer. Specifically, the identification area 101 is provided at the edge of the upper mask plate 100 and penetrates the upper mask plate 100 in the shape of a long groove. The upper mask plate 100 of the device can rotate freely. When identifying a specific crystal orientation, the specific crystal orientation of the wafer is kept parallel to the long groove direction of the identification area 101, so as to mark the specific crystal orientation on the wafer. Here, the specific crystal orientation refers to the distribution orientation of a specific crystal plane. The upper mask 100 and the lower mask 200 of the device are provided with magnetic blocks at the center positions. Specifically, the upper mask 100 is provided with an upper mask magnetic block, and the lower mask 100 is provided with a lower mask magnetic block. The upper mask 100 and the lower mask 200 are rotatably fixed and the center of the upper mask 100 is kept always coincident with the center of the lower mask 200 during the rotation process, that is, the upper mask 100 is kept always coincident with the center of the wafer 300 during the rotation process, and no center deviation occurs. The lower mask 200 of the device is provided with a fixing groove 202 for placing and limiting the wafer, and its size matches the diameter of the wafer 300 to be tested, and can be used to fix and limit the test wafer 300. The lower mask plate 200 of the device has a wafer 300 access channel, which is configured as a wafer access groove 203. The access groove 203 is arranged at the circumferential edge of the lower mask plate 200 and communicates with the fixing groove 202 to facilitate the wafer 300 clamping tool to enter and exit the operation.

[0036] By opening a small hole on the upper mask 100 for installing the observation lens 103, the magnifying effect of the lens is utilized, so that real-time observation can be performed without the aid of a metallographic microscope or an electron microscope, thereby improving the convenience of operation.

[0037] By arranging magnetic blocks on both the upper and lower mask plates 200, the upper mask plate 100 can rotate freely relative to the lower mask plate 200. Under the magnetic effect between the upper mask plate magnetic block 102 and the lower mask plate magnetic block 201, the fixed limiting wafer 300 reduces position deviation, improves the fixing stability of the wafer 300, and makes the specific crystal orientation identification more accurate.

[0038] At the same time, the present invention provides a method for testing using the above crystal dislocation testing device, comprising the following steps:

[0039] S1: Processing and chemically etching the surface of the wafer 300 to form dislocation etching pits;

[0040] S2: placing the wafer 300 processed in step S1 in the lower mask fixing groove 202 to limit the position, and placing the upper mask cover on the wafer;

[0041] S3: Visually observe wafer dislocation through the observation lens 103 on the upper mask.

[0042] Wherein, when processing the test device as described above;

[0043] It is necessary to ensure that the array of small holes for installing the observation lens 103 is distributed on the upper mask 100, and the spacing between the small holes meets the observation conditions, so that visual observation of the dislocation corrosion pits on the surface of the wafer 300 is convenient and comfortable; on the one hand, it is necessary to pay attention to the fit of the assembled wafer 300 between the upper mask 100 and the lower mask 200, so that no asynchronism occurs during free rotation, and on the other hand, it is also necessary to ensure the matching accuracy of the fixed groove 202 and the wafer 300 to be tested.

[0044] At the same time, during assembly, it is necessary to ensure that the assembly environment is in a clean state and that the test device after processing and assembly can be observed reliably.

[0045] Before processing the surface of the wafer 300 , the test wafer 300 is cut and a position mark is made before separation from the crystal rod; the cutting of the test wafer 300 is completed by a conventional cutting method, and a position mark needs to be made when separating from the crystal rod.

[0046] After the wafer 300 is placed in the fixing groove 202 and limited, the lower mask 200 is rotated to the best observation position. The best observation position means that the long side of the dislocation corrosion pit is placed horizontally or vertically to meet the observation accuracy requirements.

[0047] After visually observing the dislocations through the observation lens 103, the dislocations can be counted to identify specific crystal plane orientation information; and the crystal plane orientation information can be transferred to the single crystal rod.

[0048] Example 2

[0049] Taking the crystal orientation GaAs wafer 300 as an example, the above test device is used to perform the test, and the test process is as follows:

[0050] After being polished and etched, the (100) crystal orientation GaAs wafer 300 is placed in the fixing groove 202 of the lower mask 200, and then the upper mask 100 is placed on the surface of the test wafer 300. The magnetic force is generated between the magnetic blocks of the upper mask 100 and the magnetic blocks of the lower mask 200, and the wafer 300 is fixed in place. The morphology of the dislocation corrosion pit is observed through the lens observation hole. The morphology of the (100) crystal orientation dislocation corrosion pit is shown in the attached figure. Figure 2 As shown, the upper mask 100 is rotated to the best observation position, such as keeping the long side of the dislocation pit parallel to the observation direction, and making a mark related to the specific crystal plane orientation information in the marking area 101. After the dislocation density statistics are completed, the test wafer 300 is taken out, and the position before cutting is restored according to the original mark on the wafer 300, and the marked specific crystal plane orientation information is transferred to the single crystal rod.

[0051] Example 3

[0052] Taking the InAs wafer 300 with a crystal orientation angle as an example, the above-mentioned testing device is used to perform the test, and the test process is as follows:

[0053] After polishing and etching, the InAs wafer 300 with a deflection angle in the crystal direction is placed in the fixing groove 202 of the lower mask 200, and then the upper mask 100 is placed on the surface of the test wafer 300. The magnetic force is generated between the magnetic blocks of the upper mask 100 and the magnetic blocks of the lower mask 200, and the wafer 300 is fixed in position. The morphology of the dislocation corrosion pit is observed through the lens observation hole. The actual morphology of the dislocation corrosion pit with a specific crystal direction angle is shown in the attached figure. Figure 3 As shown, the lower mask 200 is rotated to the best observation position, such as keeping the side length of the dislocation pit parallel to the observation direction, and making a mark related to the specific crystal plane orientation information in the marking area 101. The corresponding schematic diagram of the (100) crystal orientation GaAs dislocation morphology and positioning edge is shown in the attached figure. Figure 4 As shown, the etching pit 400 is shown in the figure. After the dislocation density statistics are completed, the test wafer 300 is taken out, and the position before cutting is restored according to the original mark on the wafer 300, and the marked specific crystal plane orientation information is transferred to the single crystal rod.

[0054] The above-mentioned embodiment results show that the crystal dislocation testing device and method provided by the present invention utilize the lens magnification effect to enable real-time observation without the aid of a metallographic microscope or an electron microscope, and are easy to operate; at the same time, they can improve the fixation stability of the wafer 300, making the identification of specific crystal orientation more accurate.

[0055] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A wafer dislocation testing device, characterized in that: The device comprises: an upper mask plate, on which a plurality of observation lenses for optical magnification are arranged; a lower mask plate, which is arranged on the opposite side of the upper mask plate; the surface dislocation of the wafer between the upper mask plate and the lower mask plate is observed through the observation lenses; an upper mask plate magnetic block is arranged on the upper mask plate, and a lower mask plate magnetic block is arranged on the lower mask plate, and the upper mask plate and the lower mask plate are rotatably fixed by the magnetic force between the upper mask plate magnetic block and the lower mask plate magnetic block, and the center of the upper mask plate is kept to always coincide with the center of the lower mask plate during the rotation process.

2. A wafer dislocation testing device according to claim 1, characterized in that: The observation lens array is distributed on the upper mask plate.

3. A wafer dislocation testing device according to claim 1, characterized in that: The upper mask is provided with a marking area for marking a specific crystal orientation of the wafer.

4. A wafer dislocation testing device according to claim 3, characterized in that: The marking area is arranged at the edge of the upper mask plate and penetrates the upper mask plate in the shape of a long groove; when marking a specific crystal orientation, the specific crystal orientation of the wafer is kept parallel to the long groove direction of the marking area, so as to mark the specific crystal orientation on the wafer.

5. The wafer dislocation testing device according to claim 1, characterized in that: The upper cover plate magnetic block and the lower cover plate magnetic block are respectively arranged at the center of the upper cover plate and the lower cover plate.

6. The wafer dislocation testing device according to claim 1, characterized in that: The lower mask plate is provided with a fixing groove for placing and limiting the wafer, and the size of the fixing groove matches the diameter of the wafer to be tested.

7. A wafer dislocation testing device according to claim 6, characterized in that: The lower mask plate is provided with a wafer placing and taking groove, which is arranged at the circumferential edge of the lower mask plate and communicated with the fixing groove.

8. A method for testing using a wafer dislocation testing device according to any one of claims 1 to 7, comprising the following steps: S1: Processing and chemically etching the wafer surface to form dislocation corrosion pits; S2: placing the wafer processed in step S1 in the lower mask fixing groove to limit the position, and placing the upper mask cover on the wafer; S3: Visually observe wafer dislocation through the observation lens on the upper mask.

9. The method according to claim 8, characterized in that: Before processing the wafer surface, when cutting the test wafer, make alignment marks before separating it from the crystal rod; observe the wafer dislocation, count the dislocation density, identify the specific crystal orientation information, and transfer the specific crystal orientation information to the single crystal rod.

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