A method for simultaneously taping a plurality of substrates

Abstract

The application relates to a method for simultaneously pasting multiple substrates in the field of semiconductors, which comprises the following steps: screening a plurality of substrates to be processed; manufacturing a first ceramic through-hole plate, wherein the through holes on the first ceramic through-hole plate correspond to required points on a PCB plate; carrying out reflow soldering and pasting on the first ceramic through-hole plate and the plurality of substrates; manufacturing a second ceramic through-hole plate; manufacturing a glass mask; manufacturing actual required metal pads on the substrates according to the glass mask; and carrying out reflow soldering and pasting on the second ceramic through-hole plate and the substrates. The application provides a method for simultaneously pasting multiple substrates, which can effectively solve the problems of poor relative position degree and poor levelness after multiple substrates are simultaneously pasted by reflow.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing research and development, and specifically to a method for simultaneously mounting multiple substrates. Background Technology

[0002] The semiconductor industry is developing rapidly, and a large number of chips need to be tested before packaging. This process requires probe cards, and the substrate (adapter board) is the main component of the probe card. The substrate is connected to the PCB by reflow soldering. Each substrate often corresponds to one die of the chip being tested. To improve testing efficiency and reduce testing costs, some probe cards need to use multiple substrates to reflow onto the PCB simultaneously to test multiple dies at the same time. This approach places very high demands on the substrate and the reflow process. First, the relative positional accuracy of the substrates must be within ±5µm. Second, the height difference of the C4 (Controlled Collapse Chip Connection) area of ​​all substrates must not exceed 25µm. Finally, the height difference of the surfaces of all substrates must not exceed 60µm. However, during the reflow soldering process, due to the different coefficients of thermal expansion between the substrate and the PCB, the fluidity of the molten solder, and many other factors, it is difficult to control the relative position and levelness. To address this problem, this invention proposes a method for simultaneously mounting multiple substrates to solve the above-mentioned issues. Summary of the Invention

[0003] This invention overcomes the shortcomings of existing technologies and provides a method for simultaneously mounting multiple substrates, which can effectively solve the problems of relative positional and horizontal inaccuracies that occur after simultaneous reflow mounting of multiple substrates. It also improves the accuracy and stability of substrate mounting and positioning, as well as the convenience of subsequent processing.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a method for simultaneously mounting multiple substrates, comprising the following steps;

[0005] Step S1: Select several substrates to be processed;

[0006] Step S2: Fabricate the first ceramic through-hole board. The through holes on the first ceramic through-hole board correspond to the required points on the PCB board. The through holes on the first ceramic through-hole board are pre-loaded with a metal layer, and the metal layer is solderable.

[0007] Step S3: The first ceramic through-hole plate is reflow soldered onto several substrates.

[0008] Step S4: Fabricate a second ceramic through-hole plate. The through holes on the second ceramic through-hole plate are consistent with the C4Pad positions of the multiple substrates actually required. Here, C4 is the controllable collapse chip connection solder joint, and Pad is the solder pad.

[0009] Step S5: Fabricate a glass mask;

[0010] Step S6: Fabricate the required metal pads on the substrate according to the glass mask;

[0011] Step S7: The second ceramic through-hole plate is reflow soldered onto the substrate.

[0012] In a preferred embodiment of the present invention, the actual C4 point position on the substrate is compared with the pre-designed C4 point position to generate an updated C4 point drawing; a glass mask is then fabricated based on the updated C4 point drawing.

[0013] In a preferred embodiment of the present invention, the positions of C4 points on several substrates on the first ceramic through-hole plate are measured and a C4 point pattern is generated; the generated C4 point pattern is compared with the actual required C4 point pattern; the generated C4 point pattern is offset to coincide with the actual required C4 point pattern, and then an updated C4 point pattern is generated, and a glass mask is fabricated based on the updated C4 point pattern.

[0014] In a preferred embodiment of the present invention, the horizontal flatness of the C4 region of each substrate is within 25 μm; and the horizontal flatness of the entire substrate is within 60 μm; when multiple substrates are simultaneously mounted on the same plane of the PCB board, the thickness difference between the multiple substrates is less than 20 μm.

[0015] In a preferred embodiment of the present invention, the second ceramic through-hole plate or the first ceramic through-hole plate is polished on both sides to ensure that the surface flatness of the second ceramic through-hole plate or the first ceramic through-hole plate is less than 2 μm.

[0016] In a preferred embodiment of the present invention, the step of fabricating the required metal pads on the substrate according to the glass mask includes:

[0017] Step 6-1: Align and expose the pattern on the glass mask with the pads on the substrate.

[0018] Step 6-2: Use the developer corresponding to the photoresist to transfer the pattern on the glass mask onto the photoresist film on the substrate; perform photolithography and development to solidify the pattern on the developed photoresist film; and then transfer the pattern on the glass mask onto the photoresist film on the substrate.

[0019] Step 6-3: Electroplating copper, with a copper layer thickness of 15-20µm;

[0020] Step 6-4: Remove the photoresist and perform organic cleaning to completely remove the photoresist from the surface.

[0021] Step 6-5: Ion beam etching to clean the seed layer;

[0022] Step 6-6: Cover the substrate with PI adhesive and perform photolithography to cure it, exposing the actual metal pads, while other metals are covered by PI adhesive.

[0023] In a preferred embodiment of the present invention, the step of making an adhesive film on a substrate includes: spreading the adhesive evenly on the substrate surface; achieving uniform adhesive application by applying adhesive and rotating and spinning the adhesive; and the adhesive thickness is 15um~25um.

[0024] In a preferred embodiment of the present invention, after step S7, the final finished PCB board is subjected to electrical performance measurement and inspection.

[0025] This invention addresses the shortcomings of the prior art, and its beneficial effects are as follows:

[0026] This invention provides a method for simultaneously mounting multiple substrates, which can effectively solve the problems of relative positional and horizontal inaccuracies that occur after simultaneous reflow mounting of multiple substrates. This method also improves the accuracy and stability of substrate mounting and positioning, as well as the convenience of subsequent processing. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Figure 1 This is a schematic diagram of a PCB board with a ball grid array pad in a preferred embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the substrate (with the ball grid array surface of the substrate facing upwards) in a preferred embodiment of the present invention. Figure 1 ;

[0030] Figure 3 This is a schematic diagram of the structure of two substrates (with the C4 pad of the substrate facing upwards) in a preferred embodiment of the present invention. Figure 2 ;

[0031] Figure 4 This is a schematic diagram of the structure of the first ceramic through-hole plate in a preferred embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of the second ceramic through-hole plate in a preferred embodiment of the present invention;

[0033] Among them, 1-PCB board, 11-ball grid array pad, 2-substrate, 21-substrate ball grid array surface, 22-pad surface of C4 point, 3-first ceramic through hole plate, 31-first through hole, 4-second ceramic through hole plate, 41-second through hole. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention and therefore only show the components relevant to the present invention. Example 1

[0035] like Figures 1-5 As shown, a method for simultaneously mounting multiple substrates 2 includes the following steps;

[0036] Step S1: Select several substrates 2 to be processed. The horizontal flatness of the C4 region of each substrate 2 is within 25um; and the horizontal flatness of the entire substrate 2 is within 60um; when multiple substrates 2 are simultaneously mounted on the same plane of the PCB board 1, the thickness difference of the multiple substrates 2 is less than 20um. One side of the substrate 2 is provided with a substrate ball grid array surface 21, and the other side of the substrate 2 is the pad surface 22 of the C4 point.

[0037] Step S2: Fabricate the first ceramic through-hole plate 3. The first through-hole 31 on the first ceramic through-hole plate 3 corresponds to the required points (ball grid array pads 11) on the PCB board 1, and a metal layer is pre-installed on the first through-hole 31 of the first ceramic through-hole plate 3, and the metal layer is solderable. The first ceramic through-hole plate 3 is polished on both sides to ensure that the surface flatness of the first ceramic through-hole plate 3 is less than 2um.

[0038] Step S3: The first ceramic through-hole plate 3 and several substrates 2 are reflow soldered together.

[0039] Step S4: Fabricate the second ceramic through-hole plate 4. The second through-hole 41 on the second ceramic through-hole plate 4 corresponds to the C4 Pad positions of the multiple substrates 2 required in practice. The second ceramic through-hole plate 4 has two sides, a front and a back. The side corresponding to the pad surface 22 of the C4 point on the substrate 2 is defined as the back side. A metal seed layer is sputtered on the back side of the second ceramic through-hole plate 4. The second ceramic through-hole plate 4 is then polished on both sides to ensure that the surface flatness of the second ceramic through-hole plate 4 is less than 2µm.

[0040] Step S5: Fabricate the glass mask. Compare the actual C4 point pad positions 22 on the substrate 2 with the pre-designed C4 point positions to generate an updated C4 point drawing; fabricate the glass mask based on the updated C4 point drawing; specifically, measure the C4 point positions on several substrates 2 on the first ceramic through-hole plate 3 and generate C4 point drawings; compare the generated C4 point drawings with the actual required C4 point drawings; offset the generated C4 point drawings to coincide with the actual required C4 point drawings, then generate an updated C4 point drawing, and fabricate the glass mask based on the updated C4 point drawing.

[0041] Step S6: Fabricate the required metal pads on the substrate 2 according to the glass mask.

[0042] The specific steps for creating the required metal pads include:

[0043] Step 6-1: Align and expose the pattern on the glass mask with the pad surface 22 of C4 point on the substrate 2.

[0044] Step 6-2: Transfer the pattern on the glass mask to the photoresist film on substrate 2 using the developer corresponding to the photoresist; perform photolithography and development to solidify the pattern on the developed photoresist film; and then fabricate the pattern on the glass mask onto the photoresist film on substrate 2. Specifically, the steps for fabricating the photoresist film on substrate 2 include: uniformly spreading the photoresist onto the surface of substrate 2; achieving uniform photoresist application through smearing and spinning; and ensuring the photoresist thickness is between 15µm and 25µm.

[0045] Step 6-3: Electroplating copper, with a copper layer thickness of 15-20µm;

[0046] Step 6-4: Remove the photoresist and perform organic cleaning to completely remove the photoresist from the surface.

[0047] Step 6-5: Ion beam etching to clean the seed layer;

[0048] Step 6-6: Cover substrate 2 with PI adhesive and perform photolithography to cure it, exposing the actual metal pads, while other metals are covered by PI adhesive.

[0049] Step S7: The second ceramic through-hole plate 4 is reflow soldered onto the substrate 2.

[0050] Step S9: Perform electrical performance measurement and inspection on the final finished PCB board 1.

[0051] Further, the electrical performance measurement and inspection mainly involves using a flying probe tester to perform continuity tests to check for any non-conductive or short-circuited points after reflow soldering. Example 2

[0052] Step S1: Select two substrates 2 to be processed. The horizontal flatness of the C4 region of each substrate 2 is within 25um; and the horizontal flatness of the entire substrate 2 is within 60um; when the two substrates 2 are simultaneously mounted on the same plane of the PCB board 1, the thickness difference of the multiple substrates 2 is less than 20um.

[0053] Step S2: Fabricate the first ceramic through-hole plate 3. The first through-hole 31 on the first ceramic through-hole plate 3 corresponds to the required points on the PCB board 1, and a metal layer is pre-installed on the through-hole of the first ceramic through-hole plate 3, and the metal layer is solderable. The first ceramic through-hole plate 3 is polished on both sides to ensure that the surface flatness of the first ceramic through-hole plate 3 is less than 2um.

[0054] Step S3: The first ceramic through-hole plate 3 and several substrates 2 are reflow soldered together.

[0055] Step S4: Fabricate the second ceramic through-hole plate 4. The second through-hole 41 on the second ceramic through-hole plate 4 corresponds to the C4Pad position of the multiple substrates 2 required in practice. The second ceramic through-hole plate 4 has two sides, a front and a back. The side corresponding to the C4 point of the substrate 2 is defined as the back side. A metal seed layer is sputtered on the back side of the second ceramic through-hole plate 4. The second ceramic through-hole plate 4 is then polished on both sides to ensure that the surface flatness of the second ceramic through-hole plate 4 is less than 2µm.

[0056] Step S5: Fabricate the glass mask. Compare the actual C4 point positions on substrate 2 with the pre-designed C4 point positions to generate an updated C4 point pattern; fabricate the glass mask based on the updated C4 point pattern; specifically, measure the C4 point positions on the two substrates 2 on the first ceramic through-hole plate 3 and generate C4 point patterns; compare the generated C4 point patterns with the actual required C4 point patterns; offset the generated C4 point patterns to match the actual required C4 point patterns, then generate an updated C4 point pattern, and fabricate the glass mask based on the updated C4 point pattern. Further, use an OGP device to measure the C4 point positions on all substrates 2 and generate patterns; compare the OGP-generated patterns with the actual required patterns, then modify the patterns, offset the OGP-generated patterns to match the actual required patterns, and then generate a new pattern; fabricate the glass mask according to the newly generated pattern.

[0057] Step S6: Fabricate the required metal pads on the substrate 2 according to the glass mask.

[0058] The specific steps for creating the required metal pads include:

[0059] Step 6-1: Align and expose the pattern on the glass mask with the pads on the substrate 2.

[0060] Step 6-2: Transfer the pattern on the glass mask to the photoresist film on substrate 2 using the developer corresponding to the photoresist; perform photolithography and development to solidify the pattern on the developed photoresist film; and then fabricate the pattern on the glass mask onto the photoresist film on substrate 2. Specifically, the steps for fabricating the photoresist film on substrate 2 include: uniformly spreading the photoresist onto the surface of substrate 2; achieving uniform photoresist application through smearing and spinning; and ensuring the photoresist thickness is 20µm.

[0061] Step 6-3: Electroplating copper, with a copper layer thickness of 17.5um.

[0062] Step 6-4: Remove the photoresist and perform organic cleaning to completely remove the photoresist from the surface.

[0063] Step 6-5: Ion beam etching to cleanly etch the seed layer.

[0064] Step 6-6: Cover substrate 2 with PI adhesive and perform photolithography to cure it, exposing the actual metal pads, while other metals are covered by PI adhesive.

[0065] Step S7: The second ceramic through-hole plate 4 is reflow soldered onto the substrate 2.

[0066] Step S8: Perform electrical performance measurement and inspection on the final finished PCB board 1.

[0067] Working principle:

[0068] First, multiple substrates 2 to be processed are selected. The horizontal flatness of the C4 region of each substrate 2 is within 25µm; and the horizontal flatness of the entire substrate 2 is within 60µm; when multiple substrates 2 are simultaneously mounted on the same plane of the PCB board 1, the thickness difference of the multiple substrates 2 is less than 20µm. Then, a first ceramic through-hole plate 3 and a second ceramic through-hole plate 4 are fabricated. The first through-hole 31 on the first ceramic through-hole plate 3 corresponds to the required point on the PCB board 1, and a metal layer is pre-installed on the through-hole of the first ceramic through-hole plate 3, and the metal layer is solderable. The first ceramic through-hole plate 3 is reflow soldered onto several substrates 2. Then, the second ceramic through-hole plate 4 is fabricated, and the second through-hole 41 on the second ceramic through-hole plate 4 is consistent with the C4Pad position of the actual required multiple substrates 2. The second ceramic through-hole plate 4 has two sides, and a metal seed layer is sputtered on the surface corresponding to the C4 point of the substrate 2. Finally, a glass mask is fabricated. The C4 point positions on several substrates 2 on the first ceramic through-hole plate 3 are measured, and a C4 point pattern is generated. The generated C4 point pattern is compared with the actual required C4 point pattern. The generated C4 point pattern is offset to coincide with the actual required C4 point pattern, and then an updated C4 point pattern is generated. A glass mask is fabricated based on the updated C4 point pattern. A metal seed layer is fabricated on the second ceramic through-hole plate 4 based on the glass mask. The pattern on the glass mask is aligned with the pad points on the substrate 2 and exposed. The pattern on the glass mask is transferred to the photoresist film on the substrate 2 using the developer corresponding to the photoresist. Photolithography and development are performed to cure the pattern on the developed photoresist film. The pattern on the glass mask is then transferred to the photoresist film on the substrate 2. Copper is then electroplated. The photoresist is removed, and organic cleaning is performed to completely remove the surface photoresist. Ion beam etching is performed to clean the seed layer. The substrate 2 is covered with PI adhesive and photolithography is performed to cure it, exposing the actual required metal pads while other metals are covered by PI adhesive. PI adhesive is applied to substrate 2 and photolithographically cured, exposing the necessary metal pads while other metals are covered by the PI adhesive. A second ceramic through-hole plate 4 is then reflow soldered onto substrate 2. The final finished PCB board 1 undergoes electrical performance measurements and checks.

[0069] This invention first involves bonding multiple substrates 2 to be mounted onto a first ceramic through-hole plate 3. The first through-hole 31 on the first ceramic through-hole plate 3 corresponds to the points to be set on the PCB board 1, which is the initial bonding and positioning. Then, the second through-hole 41 set on the second ceramic through-hole plate 4 is consistent with the C4Pad position of the multiple substrates 2 that are actually needed. Then, a glass mask is used as an intermediate transfer method to align and expose the pattern on the glass mask with the pad points on the substrate 2. The pattern on the glass mask is transferred to the photoresist film on the substrate 2 using a developer corresponding to the photoresist. Photolithography and development are performed to cure the pattern on the developed photoresist film. The pattern on the glass mask is then applied to the photoresist film on the substrate 2. Precise positioning is performed, and then copper electroplating, photoresist removal, and organic cleaning are used to completely remove the surface photoresist. Ion beam etching is used to etch the seed layer on the surface. The substrate 2 is covered with PI adhesive and photolithography is performed to cure it, exposing the actual metal pads that are needed, while other metals are covered by PI adhesive. The relative accuracy of substrate 2 mounting is improved by simultaneously positioning the first ceramic through-hole plate 3 and the second ceramic through-hole plate 4 on both sides of substrate 2. The mounting method of this invention, which involves simultaneously mounting multiple substrates 2, effectively solves the problems of relative positional and horizontal differences that occur after simultaneous Reflow mounting of multiple substrates 2. This method also improves the mounting accuracy and stability of substrate 2, as well as the convenience of subsequent processing. After mounting, the positional deviation of multiple substrates 2 can be controlled within 15µm, and the horizontality of the C4 region of multiple substrates 2 can be controlled within 25µm.

[0070] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for simultaneously mounting multiple substrates, characterized in that: Includes the following steps; Step S1: Select several substrates to be processed; Step S2: Fabricate the first ceramic through-hole board. The through holes on the first ceramic through-hole board correspond to the required points on the PCB board. The through holes on the first ceramic through-hole board are pre-loaded with a metal layer, and the metal layer is solderable. Step S3: The first ceramic through-hole plate is reflow soldered onto several substrates. Step S4: Fabricate a second ceramic through-hole board. The through holes on the second ceramic through-hole board are consistent with the C4Pad positions of the multiple substrates actually required. Here, C4 is the controllable collapse chip connection solder joint, and Pad is the solder pad. Step S5: Fabricate a glass mask; compare the actual C4 point positions on the substrate with the pre-designed C4 point positions to generate an updated C4 point drawing; fabricate the glass mask based on the updated C4 point drawing. Step S6: Fabricate the required metal pads on the substrate according to the glass mask; Step S7: The second ceramic through-hole plate is reflow soldered onto the substrate.

2. The method for simultaneously mounting multiple substrates according to claim 1, characterized in that: The positions of C4 points on several substrates on the first ceramic through-hole plate are measured and C4 point pattern is generated; the generated C4 point pattern is compared with the actual required C4 point pattern; the generated C4 point pattern is offset to coincide with the actual required C4 point pattern, and then an updated C4 point pattern is generated, and a glass mask is made according to the updated C4 point pattern.

3. The method for simultaneously mounting multiple substrates according to claim 1, characterized in that: The horizontal flatness of the C4 region of each substrate is within 25um; and the horizontal flatness of the entire substrate is within 60um; when multiple substrates are simultaneously mounted on the same plane of the PCB board, the thickness difference between the multiple substrates is less than 20um.

4. The method for simultaneously mounting multiple substrates according to claim 1, characterized in that: The second ceramic through-hole plate or the first ceramic through-hole plate is polished on both sides to ensure that the surface flatness of the second ceramic through-hole plate or the first ceramic through-hole plate is less than 2um.

5. The method for simultaneously mounting multiple substrates according to claim 1, characterized in that: The steps for fabricating the required metal pads on the substrate based on the glass mask include: Step 6-1: Align and expose the pattern on the glass mask with the pads on the substrate. Step 6-2: Use the developer corresponding to the photoresist to transfer the pattern on the glass mask onto the photoresist film on the substrate; perform photolithography and development to solidify the pattern on the developed photoresist film; and then transfer the pattern on the glass mask onto the photoresist film on the substrate. Step 6-3: Electroplating copper, with a copper layer thickness of 15-20µm; Step 6-4: Remove the photoresist and perform organic cleaning to completely remove the photoresist from the surface. Step 6-5: Ion beam etching to clean the seed layer; Step 6-6: Cover the substrate with PI adhesive and perform photolithography to cure it, exposing the actual metal pads, while other metals are covered by PI adhesive.

6. The method for simultaneously mounting multiple substrates according to claim 5, characterized in that: The steps for fabricating an adhesive film on a substrate include: spreading the adhesive evenly onto the substrate surface; achieving uniform adhesive application by applying and rotating the adhesive; and ensuring the adhesive thickness is between 15µm and 25µm.

7. The method for simultaneously mounting multiple substrates according to claim 1, characterized in that: After step S7, the final finished PCB board is subjected to electrical performance measurement and inspection.

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