Method for aligning and testing device having fine pitch

Abstract

The present invention relates to a method for aligning and testing a device in which multiple semiconductor chips are stacked and singulated, wherein after a device such as a high bandwidth memory (HBM) having a small bump size, a narrow pitch, and a large number of signal buses is manufactured, the device can be precisely aligned while being suctioned onto a picker before being loaded onto a vacuum chuck, and then loaded onto the vacuum chuck. To this end, the present invention comprises the steps of: preparing a vacuum chuck (20) having a plurality of vacuum holes (21); detecting, by an upper vision system (50), the pattern and bump position of a device (30) located at a loading position, thereby notifying a control unit of the detected information; suctioning, by a picker (40), the device (30) located at the loading position; reading, by a lower vision system (60), edge information of the device (30) from the bottom side thereof while the device (30) is suctioned onto the picker (40), thereby notifying the control unit of the edge information; computing, by the control unit, the pattern, bump position, and edge information of the device (30) detected by the upper and lower vision systems (50, 60), thereby adjusting the position of the picker (40) in the X, Y, and θ directions to align the device (30); and loading the device (30), after alignment of the device (30) suctioned onto the picker (40) is completed, onto the vacuum holes (21) formed in the vacuum chuck (20) and suctioning the device (30).

Description

Alignment method and testing method for devices with fine pitch

[0001] The present invention relates to an alignment method and a test method for a device in which a plurality of semiconductor chips are stacked and singulated, and more specifically, to an alignment method and a test method for a device having a fine pitch, which enables a device such as an HBM (High Bandwidth Memory) having a small bump size, a narrow pitch, and a large number of signal buses to be precisely aligned while being absorbed by a picker before being loaded onto a vacuum chuck and then loaded onto a vacuum chuck.

[0002] The recent trend in the electronics industry is to manufacture lightweight, miniaturized, high-speed, multi-functional, and high-performance products at low prices. Furthermore, to enhance the performance of integrated circuits, three-dimensional structures such as multi-chip stacked packages are being developed.

[0003] Among these multi-chip stacked packages, HBM is a high-performance (RAM) interface for three-dimensional stacked dynamic RAM (DRAM).

[0004] The above HBM is made by sequentially stacking multiple chips on a wafer, then molding them as a single piece and then separating them into individual pieces through a sawing process.

[0005] Figure 1 is a bottom view showing a bump of a typical HBM. The HBM (10) has countless bumps (11) with a size of 60 to 80 ㎛ and a very narrow pitch (p) of 125 to 170 ㎛, so that ultra-precision alignment technology is basically required even in the wafer state for testing.

[0006] Here, since the die is cut and separated in the sawing process, process errors inevitably occur, which leads to a problem in that the distance (s) between the center of the bump placed on the edge of the die and the edge border is not constant.

[0007] Therefore, in the case of HBMs with this structure that have been produced, they are being shipped without being tested because there is no technology to precisely align the bumps with small size (outer diameter) and narrow pitch with the terminals of the tester.

[0008] Accordingly, when a GPU (Graphical Processing Unit) was configured by mounting a defective HBM component, a major problem occurred in which the entire GPU became defective.

[0009]

[0010] (Prior art literature)

[0011] (Patent Document 0001) Republic of Korea Patent Publication No. 10-1149759 (registered on May 18, 2012)

[0012] (Patent Document 0002) Republic of Korea Patent Publication No. 10-1464990 (registered on November 19, 2014)

[0013] The present invention has been devised to solve the above-mentioned problems of the past, and its purpose is to produce a device having a small bump size (outer diameter) and a narrow pitch, such as HBM, and then load the device by accurately aligning the position of the device before loading the device absorbed by the picker into a vacuum chuck.

[0014] Another object of the present invention is to enable performance testing of a device by loading the device so that alignment is accurately achieved on a vacuum chuck and the bumps of the device are accurately aligned with the test terminals.

[0015] Another object of the present invention is to enable a device sucked on a picker to be accurately aligned and then loaded onto a vacuum chuck for suction even if the distance between the center of a bump placed on the edge of the device and the edge border is not constant.

[0016] According to an aspect of the present invention for achieving the above object, a method for aligning a device having a fine pitch is provided, characterized by comprising the steps of: preparing a vacuum chuck having a plurality of vacuum holes; detecting, by an upper vision, a pattern and a bump position of a device positioned at a loading position and notifying the information to a control unit; a step of allowing a picker to adsorb the device positioned at the loading position; a step of allowing a lower vision to read edge information of the device from a bottom surface of the device adsorbed to the picker and notifying the information to the control unit; a step of allowing the control unit to calculate the pattern and bump position of the device detected by the upper and lower visions and the edge information and then adjust the position of the picker in the X, Y, and θ directions to align it; and a step of loading the device into a vacuum hole formed in the vacuum chuck and suctioning the device after the alignment of the device adsorbed to the picker is completed.

[0017] According to another aspect of the present invention, there is provided a method for manufacturing a vacuum chuck, comprising: a step of preparing a vacuum chuck having a plurality of vacuum holes; a step of detecting a pattern and a position of a bump of a device positioned at a loading position by an upper vision and notifying the information to a control unit; a step of allowing a picker to adsorb a device positioned at a loading position; a step of allowing a lower vision to read edge information of a device from a bottom surface of the device adsorbed to the picker and notifying the information to the control unit; a step of allowing the control unit to calculate the pattern and the bump position of the device detected by the upper and lower visions and the edge information and then adjust the position of the picker in the X, Y, and θ directions to align the device; a step of loading the device into a vacuum hole formed in the vacuum chuck and suctioning the device after the alignment of the device adsorbed to the picker is completed; a step of continuing to perform the above-described steps so that all devices to be tested are loaded into the vacuum holes formed in the vacuum chuck; a step of moving the vacuum chuck with the plurality of devices suctioned to a contact point of a tester; and a step of moving the vacuum chuck toward the tester so that the bump of the device is in contact with a terminal of the tester. A method for testing a device having a fine pitch is provided, characterized by comprising a step of making contact and conducting a test for a set period of time.

[0018] The present invention has the following several advantages over the prior art.

[0019] First, with the device to be tested positioned at the loading position, the upper vision reads the position of the pattern and bump and notifies the control unit. With the picker sucking the device, the lower vision reads the edge information of the device and notifies the control unit. The picker aligns the device and loads it onto the vacuum chuck. This significantly reduces the alignment time of the device, thereby maximizing the operating rate of expensive equipment.

[0020] Second, before loading the device for alignment on the upper surface of the vacuum chuck, the temperature of the vacuum chuck is maintained at room temperature according to the test conditions, or the device is loaded in an expanded or contracted state according to the expansion coefficient of the vacuum chuck by heating or cooling, thereby minimizing the alignment tolerance.

[0021] Third, after all devices are loaded onto the vacuum chuck, the spacing between the aligned devices is checked once more with an upper or other vision, thereby further maximizing alignment reliability.

[0022] Fourth, the chuck, whose alignment of the device is completed, is moved to the tester side, and the X, Y, and θ values ​​of the chuck are corrected with another upper and lower vision, thereby preventing contact defects.

[0023] Figure 1 is a bottom view showing a device having a fine pitch.

[0024] Figure 2 is a cross-sectional view showing a state in which a device is loaded into a vacuum chuck of the present invention.

[0025] Figure 3 is a schematic diagram of the picker of the present invention installed.

[0026] Figure 4 is a schematic diagram of the state in which the lower vision is installed in the present invention.

[0027] Figure 5 is a configuration diagram showing the tester in the present invention.

[0028] Figure 6 is a flowchart for explaining the method of the present invention.

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily practice the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein. It should be noted that the drawings are schematic and not drawn to scale. The relative dimensions and proportions of parts in the drawings are exaggerated or reduced in size for clarity and convenience in the drawings, and any dimensions are merely illustrative and not limiting. In addition, the same reference numerals are used for the same structures, elements, or parts appearing in two or more drawings to indicate similar features.

[0030] FIG. 2 is a cross-sectional view showing a state in which a device is loaded into a vacuum chuck of the present invention, FIG. 3 is a schematic diagram showing a state in which a picker of the present invention is installed, and FIG. 4 is a schematic diagram showing a state in which a lower vision is installed in the present invention. In the present invention, a heater or a cooling pipe (not shown) is built into a vacuum chuck (20) having a plurality of vacuum holes (21), and before loading a device (30) to be tested onto the upper surface of the vacuum chuck (20), the device (30) is maintained at room temperature, heated to about 50 to 170°C, or cooled to about 0 to -55°C depending on the test conditions of the device (30) (S100).

[0031] This is to minimize errors due to expansion or shrinkage of the vacuum chuck (20) within a range of about 0.3 mm depending on heating or cooling, assuming that the size of the vacuum chuck (20) is 300 × 300 mm, even if the vacuum chuck (20) is made of a material having a minimum expansion coefficient (e.g., ceramic, etc.).

[0032] The shape of the vacuum chuck (20) applied to the present invention can be applied in various shapes such as circular or square, so there is no need to specifically limit it.

[0033] As described above, after the vacuum chuck (20) is maintained at a temperature suitable for the test conditions of the device (30), before the picker (40) picks up the device (30) positioned at the loading position, the upper vision (50) installed on the picker (40) detects the pattern and bump positions of the device (30) and reports the information to the control unit (not shown) (S200).

[0034] The device to be tested (30) can be placed in a loading position in a sawed state in a wafer state so that the upper vision (50) can detect the positions of the pattern and bumps, or the device to be tested can be placed in a tray (not shown) so that the upper vision (50) can detect the positions of the pattern and bumps of the device (30).

[0035] Alternatively, a device (30) that has been sawn in a wafer state or a device (30) contained in a tray may be picked up by a separate picker and transferred to a buffer (not shown), and the upper vision (50) may detect the position of the pattern and bump of the device (30) and notify the control unit of the information.

[0036] As described above, when the upper vision (50) reads the upper information of the device (30) to be tested and notifies the control unit, the information of the device (30) that the picker (40) is adsorbing may be read, but considering the operating rate of expensive equipment, it is more preferable to read all information of the entire device sawed in the wafer state or the entire device contained in the tray at once and notify the control unit.

[0037] After the upper vision (50) reads the information of the device (30) and notifies the control unit, multiple pickers (40) installed in the picker block (41) sequentially pick up the device (30) to be tested (S300).

[0038] At this time, by providing multiple pickers (40) (about 4 to 8) and having the pickers (40) sequentially pick up and handle the device (30), the cycle time according to the test can be reduced.

[0039] After the above picker (40) has absorbed the device (30) to be tested, as the picker (40) moves to the point where the lower vision (60) is installed in Fig. 4, the lower vision (60) reads the edge information of the device (30) from the bottom surface of the device (30) and notifies the control unit (S400).

[0040] With the above-described operation, the upper vision (50) and the lower vision (60) read the information of the device (30), and the control unit calculates the correction value of the device (30) according to the notification to the control unit. Then, the picker block (41) installed so as to be able to move along the X, Y guide rails (42) (43) moves to align the X, Y directions of the device (30), and the picker (40) installed so as to be able to adjust the θ direction rotates at a predetermined angle, thereby aligning the position of the device (30) (S500).

[0041] The timing for aligning the device (30) absorbed on the picker (40) may be performed immediately after the lower vision (60) notifies the control unit of the edge information on the bottom surface of the device (30), or during the process in which the picker (40) moves to the vacuum chuck (20), or at the top of the vacuum chuck (20) where the device (30) to be tested is loaded. However, in order to minimize the cycle time, it is more preferable to perform the alignment step while the picker (40) is moving.

[0042] As described above, the alignment step of the device (30) absorbed into the picker (40) is performed in the same manner when there are multiple pickers (40), so a detailed description thereof will be omitted.

[0043] Accordingly, after the alignment step of the device (30) adsorbed on a plurality of pickers (40) is completed, the picker (40) on which the device (30) is adsorbed is transferred to the upper part of the vacuum chuck (20) to load the adsorbed device (30) into the vacuum hole (21) of the vacuum chuck (20) (S600).

[0044] When loading the device (30) adsorbed on the picker (40) into the vacuum hole (21) of the vacuum chuck (20), the alignment of the device (30) may be misaligned, so the vacuum pressure applied to the vacuum hole (21) is lower than the adsorption pressure of the picker (40) by 5 to 50 mmHg or less, and the device (30) adsorbed on the picker (40) is loaded into the vacuum hole (21). After the loading of the device (30) is completed, the device (30) is suctioned by a secondary vacuum pressure of about 50 to 100 mmHg, and the vacuum pressure applied to the picker (40) is released, thereby completing the loading of the device.

[0045] The reason for suctioning the above device (30) with a secondary vacuum pressure of about 50 to 100 mmHg is to prevent the device (30) from moving in the vacuum chuck (20) during the next step due to vibration occurring during the movement of the vacuum chuck (20) or when the bump or terminal comes into contact with the test pin of the tester (70) during the test step.

[0046] After the device (30) is loaded into the vacuum hole (21) of the vacuum chuck (20) by being aligned by the above picker (40), the alignment state of the device (30) loaded into the vacuum chuck (20) is re-inspected with an upper or other vision, and if the alignment matches, the next step is performed, and if the alignment does not match, a re-alignment operation is performed (S700).

[0047] If the device (30) loaded on the vacuum chuck (20) is re-examined and the alignment is not correct, the vacuum pressure applied to the vacuum chuck (20) is released, and then the picker (40) re-absorbs the device (30) from the vacuum chuck (20) and re-aligns and loads it using the same method as described above.

[0048] After all the devices (30) are aligned and loaded into the vacuum holes (21) formed in the vacuum chuck (20) by the above-described operation, the vacuum chuck (20) is moved to the contact point of the tester (70) (S800).

[0049] After the vacuum chuck (20) is moved to the contact point of the tester (70), the posture of the vacuum chuck (20) is checked with another upper vision (71) and a lower vision (omitted from the drawing) fixed to the chuck, and a step of correcting the X, Y, Z, and θ values ​​of the vacuum chuck (20) is further performed (S900).

[0050] This is to inspect the flatness of the contact part and the position of the contact pin, etc., with the lower vision fixed to the vacuum chuck (20) as the standard for the tester (70) and report it to the control unit, and inspect the flatness and thickness, etc., of the device (30) with the upper vision (71) as the standard for the vacuum chuck (20) and report it to the control unit so that the control unit calculates the related information and corrects the X, Y, Z, and θ values ​​according to the report so that the bump of the device can make accurate contact with the contact pin of the tester and perform a test.

[0051] If the vacuum chuck (20) is moved toward the tester (70) while the X, Y, Z, and θ values ​​of the vacuum chuck (20) are variable so that the bump of the device (30) comes into contact with the terminal of the tester (70), even if the alignment of the device (30) is performed accurately, a fatal defect occurs in which the bump of the device (30) does not come into contact with the terminal of the tester (70).

[0052] That is, some bumps come into contact with the terminals of the tester (70), but since the X, Y, Z, and θ values ​​of the vacuum chuck (20) are variable, the remaining bumps do not come into contact with the terminals of the tester (70), which results in a fatal error of judging a good device (30) as defective.

[0053] After correcting the X, Y, Z, and θ values ​​of the above vacuum chuck (20), the bump of the device (30) is brought into contact with the terminal of the tester (70) to perform a test for a set period of time (S1000).

[0054] It is understandable that after testing the performance of the device (30) mounted on the above vacuum chuck (20), the results are classified into good and bad products at the unloading position (not shown), and the good products are loaded onto trays to be shipped, while the bad products are retested or disposed of.

[0055] Although the embodiments of the present invention have been described with reference to the attached drawings, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features.

[0056] Therefore, the embodiments described above should be understood as being exemplary and not restrictive in all respects, and the scope of the present invention described in the detailed description above is indicated by the claims described below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. A step of preparing a vacuum chuck (20) having a plurality of vacuum holes (21), a step of detecting the pattern and bump positions of a device (30) positioned at a loading position by an upper vision (50) and notifying the control unit of the information, a step of allowing a picker (40) to adsorb the device (30) positioned at the loading position, a step of allowing a lower vision (60) to read the edge information of the device (30) from the bottom surface of the device (30) adsorbed to the picker (40) and notifying the control unit of the information, a step of allowing the control unit to calculate the pattern and bump positions of the device (30) detected by the upper and lower visions (50) (60) and the edge information and then adjust the position of the picker (40) in the X, Y, and θ directions to align, and after the alignment of the device (30) adsorbed to the picker (40) is completed, the device (30) is loaded into a vacuum hole (21) formed in the vacuum chuck (20) to load the device (30) A method for aligning a device having a fine pitch, characterized by comprising a suction step.

2. In claim 1, A method for aligning a device having a fine pitch, characterized in that a device (30) sawed from a wafer is positioned at the above loading position and is absorbed by a picker (40).

3. In claim 1, A method for aligning a device having a fine pitch, characterized in that a tray filled with a device (30) is positioned at the above loading position and a picker (40) adsorbs the device (30) from the tray.

4. In claim 1, A method for aligning a device having a fine pitch, characterized in that the loading position is a buffer in which a picker (40) is sucked from a tray filled with devices (30) and then transferred and waits.

5. In claim 2 or claim 3, A method for aligning a device having a fine pitch, characterized in that when the upper vision (50) reads the information of the device (30) located at the loading position, the information of the device (30) contained in the wafer or tray is read all at once and the information is reported to the control unit.

6. In claim 1, A method for aligning a device having a fine pitch, characterized in that the device (30) absorbed by the picker (40) is read by the lower vision (60) from the bottom surface and notifies the control unit of the edge information of the device (30).

7. In claim 1, A method for aligning a device having a fine pitch, characterized in that, in the step of loading a device (30) adsorbed on the picker (40) into a vacuum hole (21) formed in a vacuum chuck (20), the vacuum pressure applied to the vacuum hole (21) is lower than the vacuum pressure applied to the picker (40).

8. In claim 1, A method for aligning a device having a fine pitch, characterized in that after the device (30) is loaded into the vacuum hole (21) of the vacuum chuck (20), the alignment state is re-examined, and if the alignment matches, the next step is performed, and if the alignment does not match, the device (30) is re-aligned.

9. In claim 8, A method for aligning a device having a fine pitch, characterized in that when the alignment of the above device (30) is not correct, the picker (40) absorbs the device (30) in the vacuum hole (21), then rises to readjust the position of the picker (40) in the X, Y, and θ directions to align it, and then loads it into the vacuum hole (21) of the vacuum chuck (20).

10. In claim 1, A method for aligning a device having a fine pitch, characterized in that the device (30) is aligned by adjusting the position of the picker (40) in the X, Y, and θ directions each time the picker (40) adsorbs the device (30) at the loading position, and then sequentially loads the device (30) into the vacuum hole (21) of the vacuum chuck (20).

11. In claim 10, A method for aligning a device having a fine pitch, characterized in that a picker block (41) is installed so as to be movable along X, Y guide rails (42)(43), and a plurality of pickers (40) that rotate in the θ direction are installed on the picker block (41), so that the device (30) is adjusted along the X, Y directions by the movement of the picker block (41), and the device (30) is adjusted in the θ direction by the rotation of the picker (40).

12. A step of preparing a vacuum chuck (20) having a plurality of vacuum holes (21), a step of detecting the pattern and bump positions of a device (30) positioned at a loading position by an upper vision (50) and notifying the control unit of the information, a step of allowing a picker (40) to adsorb the device (30) positioned at the loading position, a step of allowing a lower vision (60) to read the edge information of the device (30) from the bottom surface of the device (30) adsorbed on the picker (40) and notifying the control unit of the information, a step of allowing the control unit to calculate the pattern and bump positions of the device (30) detected by the upper and lower visions (50) (60) and the edge information and then adjust the position of the picker (40) in the X, Y, and θ directions to align, and after the alignment of the device (30) adsorbed on the picker (40) is completed, the device (30) is loaded into the vacuum hole (21) formed in the vacuum chuck (20). A method for testing a device having a fine pitch, characterized by comprising: a step of suctioning a device (30); a step of moving a vacuum chuck (20) in which a plurality of devices (30) are suctioned after all devices (30) to be tested are loaded into vacuum holes (21) formed in a vacuum chuck (20) by continuously performing the above-described steps; a step of moving the vacuum chuck (20) in which a plurality of devices (30) are suctioned to a contact point of a tester (70); and a step of moving the vacuum chuck (20) toward the tester to bring the bumps of the devices (30) into contact with the terminals of the tester (70) and performing a test for a set period of time.

13. In claim 12, A test method for a device having a fine pitch, characterized in that after the vacuum chuck (20) with the aligned position of the above device (30) moves to the contact point of the tester (70), the posture of the vacuum chuck (20) is checked with another upper vision (71) and lower vision, and the step of correcting the X, Y, Z, and θ values ​​of the vacuum chuck (20) is further performed.

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