Colloidal testing methods before chip packaging

Abstract

This invention provides a method for detecting adhesive residues before chip packaging, comprising the following steps: S1, etching a dispensing pattern on a stepless platform; S2, using a suction cup to attach a glass cover plate to a ceramic carrier via dispensing, and observing the adhesive coverage under the glass cover plate; S3, when voids are formed in the adhesive on the stepless platform, improving the dispensing pattern, and repeating steps S1 and S2 until no voids are formed in the adhesive on the stepless platform; S4, retaining the dispensing pattern without voids; S5, after determining the dispensing pattern, adjusting parameters, calculating the area covered by the adhesive after spreading using the characteristic dimensions of the ceramic carrier, and calculating the thickness and tilt angle of the adhesive after mounting. This invention allows for intuitive observation of the adhesive coverage and timely adjustment and improvement of the dispensing pattern, shortening the detection time, and calculating the area covered by the adhesive, the thickness and tilt angle of the adhesive after mounting, adjusting certain parameters to ensure that the pixel area of ​​the image sensor is completely covered by the adhesive.

Description

Technical Field

[0001] This invention relates to the field of semiconductor chip packaging manufacturing technology, and in particular to a method for colloidal detection before chip packaging. Background Technology

[0002] Packaging, as a crucial component of chip manufacturing, plays a pivotal role in the chip manufacturing industry. Chip mounting is an indispensable part of the packaging process, and the quality of the colloid coating directly affects the quality of the packaged product. This is especially true for chips with high photosensitive requirements, where the quality of the colloid coating directly impacts light reflection and imaging. Traditional testing methods require sending the mounted chips for ultrasonic or near-infrared light testing. Both of these methods have long testing cycles, making it difficult to quickly modify process conditions, thus increasing production and R&D cycles, leading to increased production costs and waste. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a method for detecting colloids before chip packaging. This method allows for direct observation of colloid coverage and timely adjustment and improvement of the dispensing pattern, thereby shortening the detection time and reducing R&D and production costs.

[0004] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0005] This invention provides a method for colloidal detection before chip packaging, comprising the following steps:

[0006] Step S1: Draw a dotted pattern on the stepless platform;

[0007] Step S2: Use a suction cup to attach the glass cover to the ceramic carrier by applying adhesive, and observe the coverage of the adhesive under the glass cover.

[0008] Step S3: When the colloid produces voids on the stepless platform, improve the dispensing pattern and repeat steps S1 and S2 until the colloid does not produce voids on the stepless platform.

[0009] Step S4: Preserve the adhesive dotting pattern so that no voids are created;

[0010] Step S5: After determining the dispensing pattern, adjust the dispensing pattern mounting pressure, dispensing pattern scaling ratio, and dispensing speed. Calculate the area covered by the adhesive after it spreads through the characteristic dimensions of the ceramic carrier, and calculate the thickness and tilt angle of the adhesive after mounting.

[0011] Preferably, the ceramic carrier is quadrilateral in shape, with a length and width of 20 to 25 mm.

[0012] Preferably, the glass cover is polygonal in shape, with a length and width 1 to 1.2 mm less than the length and width of the ceramic carrier.

[0013] Preferably, the ceramic carrier is a non-pin-insertion type ceramic carrier.

[0014] Preferably, the suction cup is quadrilateral, and the area of ​​the suction cup is smaller than the area of ​​the chip.

[0015] Preferably, the suction cup is made of a flexible material.

[0016] Preferably, the flexible material is plastic or rubber.

[0017] The present invention can achieve the following technical effects:

[0018] 1. As the object to be mounted, the glass cover allows for direct observation of the coverage of the adhesive under the glass cover.

[0019] 2. The dispensing pattern can be adjusted and improved directly after testing, saving the time of waiting for test results, shortening the process development cycle, and reducing the production cost of R&D.

[0020] 3. Based on the characteristic dimensions of the ceramic carrier to be bonded, the area covered by the adhesive is calculated. The thickness and tilt angle of the adhesive after bonding are calculated using the Z-axis descent height of the equipment. The dispensing needle diameter, bonding pressure, graphic scaling ratio, and dispensing speed are then adjusted to ensure that the pixel area of ​​the image sensor is completely covered by the adhesive without air bubbles. This meets the requirements for adhesive thickness and tilt angle after product bonding, thereby satisfying the overall device's photosensitive focal length and image contrast requirements, ensuring that the image sensor chip is more sensitive and efficient in photosensitive operation. Attached Figure Description

[0021] Figure 1 This is a flowchart of a colloidal detection method for chip packaging pre-processing according to an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the colloid non-compliance coverage effect of the colloid detection method before chip packaging provided by an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram illustrating the effect of the cross-shaped adhesive pattern provided in an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram illustrating the effect of a snowflake-shaped adhesive pattern provided in an embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram illustrating the qualified coverage effect of the colloid in the pre-packaging colloid detection method provided by an embodiment of the present invention.

[0026] Figure 6 It is a schematic diagram of the characteristic dimensions of a ceramic carrier provided according to an embodiment of the present invention.

[0027] Figure 7 It is a schematic diagram of the detection effect after dispensing provided according to an embodiment of the present invention.

[0028] Figure 8 It is a schematic diagram of a suction cup structure provided according to an embodiment of the present invention.

[0029] The reference numerals therein include: ceramic carrier 1, stepped-free tabletop 11, glass cover plate 2, colloid 3, cavity 4, suction cup 5, and suction cup inner cavity 51. Detailed implementation manners

[0030] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, their detailed descriptions will not be repeated.

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0032] Figure 1 It shows the flow of the colloid detection method for the pre-sequence of chip packaging provided by an embodiment of the present invention.

[0033] Figure 3 It shows the effect of the cross-shaped dispensing pattern provided by an embodiment of the present invention.

[0034] Figure 4 It shows the effect of the snowflake-shaped dispensing pattern provided according to an embodiment of the present invention.

[0035] Figure 8 It shows the structure of the suction cup provided according to an embodiment of the present invention.

[0036] Such as Figure 1 , Figures 3-4 , Figure 8 As shown, an embodiment of the present invention provides a colloid detection method for the pre-sequence of chip packaging, including the following steps:

[0037] Step S1: Engrave a cross-shaped dispensing pattern on the stepped-free tabletop .

[0038] Step S2: Use the suction cup to mount the glass cover plate on the ceramic carrier by dispensing, and observe the coverage of the colloid under the glass cover plate .

[0039] The suction cup 5 is preferably quadrilateral in shape, and a suction cup cavity 51 for forming a negative pressure is provided on the suction cup 5.

[0040] The calculation process for determining the suction cup size is as follows:

[0041] The glass cover weighs 30-50g (note: the chip weighs 3-5g), and the machine vacuum pressure P... 机 The bar is 0.1–0.13 bar, and the gravitational acceleration g is 10 N / kg;

[0042] Therefore, the minimum pressure required to remove the glass cover plate 2 can be calculated as follows:

[0043] F = m * g = 50 * 10 -3 kg * 10 N / kg = 0.5 N

[0044] The minimum area required for the suction cup cavity 51 is:

[0045] S = F / P 机 =0.5N / (0.1*10 5 Pa) = 5 * 10 ﹣5 m 2 =50mm 2

[0046] The minimum required dimensions for the suction cup cavity 51 are:

[0047] L=√50mm 2 ≈7.1mm

[0048] In addition, to prevent the suction cup 5 from scratching the glass cover 2 and the chip, it should be made of plastic and the contact area with the glass cover should be minimized. At the same time, it should be ensured that there is no vacuum leakage during the suction process. Considering the processing tolerance range of 0.2mm, the length and width of the suction cup 5 are determined to be 0.3 to 0.5mm smaller than the chip, and the inner diameter width d is 1.5 to 2mm, so that the best mounting effect can be achieved.

[0049] Step S3: When the colloid 3 produces a void 4 on the stepless surface 11, there are two possible reasons: First, by observing the glass cover, it is found that the void exists in the middle and edge of the colloid, indicating that the distance between the glue lines is set too large. When the colloid extends, it cannot completely cover the glue area, resulting in the void.

[0050] To avoid the above phenomenon, the extension of colloid 3 was measured and calculated, and a reasonable pattern spacing was set. The specific calculation process is as follows:

[0051] First, draw a 5-7 mm long adhesive line on the ceramic carrier 1, and measure its width using a measuring microscope; the width of the adhesive line is 0.68 mm. Second, attach the ceramic carrier 1 with a glass cover plate 2. After attachment, the adhesive line extends, and the width of the extended adhesive line is measured using a measuring microscope; the width is 4 mm. Third, to ensure that the adhesive completely fills the coated area after the adhesive line extends, the distance between the drawn adhesive lines should be between 0.5 and 0.7 times the width of the extended adhesive line on one side. Therefore, the spacing between the drawn adhesive lines is:

[0052] (4-0.68) / 2*0.5~0.7=0.83~1.162mm

[0053] Figure 3-4 Each square in the grid measures 1mm in length and 1mm in width.

[0054] Secondly, the presence of air bubbles observed on the glass cover indicates an unreasonable graphic design. During the application process, the air bubbles had not yet dissipated, and the pathway to the outside had already closed. The adhesive pattern was improved to a "snowflake" shape. Steps S1 and S2 were repeated until the adhesive 3 did not produce voids 4 on the stepless surface 11.

[0055] Step S4: Retain the dispensing pattern of colloid 3 without creating voids. The "snowflake" dispensing pattern represents the qualified coverage effect of colloid 3 without voids or bubbles, and the successfully tested dispensing pattern can then be used for dispensing production. Figure 2 The invention illustrates the effect of colloid non-compliance coverage in the colloid detection method provided in the chip packaging pre-packaging process according to an embodiment of the present invention.

[0056] Step S5: After determining the dispensing pattern, adjust the dispensing needle diameter, dispensing pattern mounting pressure, dispensing pattern scaling ratio, and dispensing speed. Calculate the area covered by the adhesive after spreading using the characteristic dimensions of the ceramic carrier, and calculate the thickness and tilt angle of the adhesive after mounting using the Z-axis descent height of the equipment.

[0057] Figure 5 The colloid quality coverage effect of the colloid detection method before chip packaging provided in the embodiment of the present invention is shown.

[0058] like Figures 2-5 As shown, the ceramic carrier 1 is quadrilateral in shape, with a length and width of 20-25 mm. The glass cover 2 is quadrilateral in shape, with a length and width 1-1.2 mm smaller than the length and width of the ceramic carrier 1. The ceramic carrier 1 is a non-pin-insertion type. The presence of the glass cover 2 allows direct observation of the colloid coverage on the stepless surface 11. After observation, the pattern on the stepless surface 11 can be re-etched based on the observation results, shortening the overall process development cycle and reducing development costs.

[0059] Figure 6A schematic diagram of the characteristic dimensions of the ceramic carrier provided in an embodiment of the present invention is shown.

[0060] like Figure 6 As shown, the area covered by the extended colloid is calculated based on the characteristic dimensions of ceramic carrier 1. Specifically, the minimum coverage area length is: (6 + 0.6 + 0.2) * 2 = 13.6 mm.

[0061] Minimum coverage area width: [6 + 0.6 * 1 / 2 + (1 - 0.6)] * 2 = 13.4 mm

[0062] Pixel area length (Note: including positional deviation): 12.8 + 0.075 = 12.875 mm

[0063] Colloidal coverage area: 13.6mm * 13.4mm = 182.24mm 2 >Pixel area: 12.875mm * 12.875mm = 165.77mm 2 Ensure that the mounting requirements for this image sensor chip are met.

[0064] The thickness and tilt angle of the adhesive 3 after mounting are calculated using the Z-axis descent height of the equipment and the characteristic dimensions of the ceramic carrier 1. The specific calculation process is as follows:

[0065] First, measure the height H of four points on the plane where the ceramic outer shell 1 is located. 1～4 The values ​​are 59212.24um, 59222.25um, 59221.73um, and 59217.47um;

[0066] Second, measure the height H of four points on the same plane as the glass cover plate 2 after installation. 1’～4’ The values ​​are 58456.65um, 58480.37um, 58476.84um, and 58456.62um;

[0067] Third, the thickness THK of glass cover 2 is 700um, and the thickness H of colloid 3 is:

[0068] (H 1～4 -H 1’～4’ ) / 4-THK=(P1+P2+P3+P4) / 4-700=(59212.24-58456.65+59222.25-58480.37+59221.73-58476.84+59217.47-58456.62) / 4-700=50.8um;

[0069] Fourth, the distance L between measurement points 点 The value is 12500um, and the diagonal spacing L 对The value is 18000um, and the tilt angle T is:

[0070] T = max{X and Y direction tilt angles T1, diagonal tilt angle T2} = 0.07°

[0071] T1=arcsin{(max{P1-P2, P3-P4, P1-P4, P2-P3} / 12500)*180 / π}=0.07°

[0072] T2=arcsin{(max{P1-P3, P2-P4} / 18000)*180 / π}=0.06°

[0073] The image sensor chip mounting requires that the adhesive, after spreading, should not contact the outer wall of the ceramic carrier 1, corresponding to the outermost edge of the feature size of the ceramic carrier 1. The thickness of the adhesive 3 is 30-70um, the tilt angle is ≤0.1°, and the final confirmed dispensing needle diameter is 0.33mm, the mounting pressure is 400g-600g, the graphic scaling ratio is 50%-60%, and the dispensing speed is 2mm / s-3mm / s, which meets the mounting requirements.

[0074] Figure 7 This diagram illustrates the effect of testing after dispensing, as provided in an embodiment of the present invention.

[0075] like Figure 7 As shown, the product after dispensing with adjusted parameters was imaged under 1064nm infrared light to verify its effectiveness. The results showed that there were no abnormalities in the final infrared imaging, indicating that the method is effective.

[0076] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0077] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

[0078] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for detecting colloidal substances before chip packaging, characterized in that, Includes the following steps: S1. Draw a dot pattern on the stepless platform (11); S2. Use a suction cup (5) to attach the glass cover plate (2) to the ceramic carrier (1) by dispensing adhesive. The length and width of the suction cup (5) are 0.3 to 0.5 mm smaller than the chip, and the inner diameter width d is 1.5 to 2 mm. Observe the coverage of the colloid (3) under the glass cover plate (2). S3. When the colloid (3) creates a void (4) on the stepless platform (11), the dispensing pattern is improved, including: measuring and calculating the extension of the colloid (3) to set a reasonable spacing between the dispensing lines. The specific calculation process is as follows: First, draw a 5mm to 7mm long dispensing line on the ceramic carrier (1), and measure the width of the dispensing line with a measuring microscope to be 0.68mm; Second, attach the ceramic carrier (1) with a glass cover plate (2), and after attachment, the dispensing line extends. Measure the width of the extended dispensing line with a measuring microscope to be 4mm; Third, to ensure that the colloid completely fills the dispensing area after the dispensing line extends, the distance between the dispensing lines should be between 0.5 and 0.7 times the width of the extended dispensing line on one side. Therefore, the spacing between the dispensing lines is: Repeat steps S1 and S2 until the colloid (3) does not produce voids (4) on the stepless platform (11). S4. Retain the dispensing pattern of the colloid (3) without producing voids (4); S5. After determining the dispensing pattern, adjust the dispensing pattern mounting pressure, the dispensing pattern scaling ratio, and the dispensing speed. Calculate the area covered by the extended adhesive after dispensing using the characteristic dimensions of the ceramic carrier (1), and calculate the thickness and tilt angle of the adhesive (3) after mounting. The adhesive should not contact the outer wall of the ceramic carrier (1) after extension. The thickness of the adhesive (3) should be 30-70 μm, the tilt angle ≤ 0.1°, the dispensing needle diameter 0.33 mm, the mounting pressure 400 g-600 g, the pattern scaling ratio 50%-60%, and the dispensing speed 2 mm / s-3 mm / s, meeting the mounting requirements. Dispensing is performed using the adjusted parameters.

2. The colloidal detection method before chip packaging as described in claim 1, characterized in that, The ceramic carrier (1) is quadrilateral in shape, with a length and width of 20-25 mm.

3. The colloidal detection method before chip packaging as described in claim 1 or 2, characterized in that, The glass cover plate (2) is quadrilateral in shape, and its length and width are 1 to 1.2 mm shorter than the length and width of the ceramic carrier (1).

4. The colloidal detection method before chip packaging as described in claim 1, characterized in that, The ceramic carrier (1) is a non-pin-insertion type ceramic carrier (1).

5. The colloidal detection method before chip packaging as described in claim 1, characterized in that, The suction cup (5) is polygonal, and the area of ​​the suction cup (5) is smaller than the area of ​​the chip.

6. The colloidal detection method before chip packaging as described in claim 1 or 5, characterized in that, The suction cup (5) is made of a flexible material.

7. The colloidal detection method before chip packaging as described in claim 6, characterized in that, The flexible material is either plastic or rubber.

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