Cleaning method and cleaning device for packaged structure

Abstract

Provided in the present application are a cleaning method and cleaning device for a packaged structure. The cleaning method comprises the steps of: spraying a cleaning liquid to a packaged structure; and evacuating air from a cavity where the packaged structure is located such that the pressure in the cavity reaches a preset pressure which is a negative pressure, and keeping the packaged structure stationary for a preset period of time to allow the cleaning liquid to enter gaps of the packaged structure to clean the packaged structure. In the present application, the cleaning liquid is firstly sprayed to the packaged structure, then air evacuation is performed, and the residual air sealed in the packaged structure by the cleaning liquid in the packaged structure is evacuated out of the packaged structure, such that each gap of the packaged structure is filled with the cleaning liquid, and the cleaning effect of the packaged structure is ensured. Moreover, after the cleaning liquid is sprayed, the cleaning environment of the packaged structure is set under a negative pressure condition, such that the surface tension of the cleaning liquid can be reduced, the diffusion capacity of the cleaning liquid is improved, the cleaning liquid can enter the gaps of the packaged structure more smoothly and diffuse uniformly, and the cleaning effect is further improved.

Description

A cleaning method and cleaning apparatus for a packaging structure Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a cleaning method and cleaning apparatus for a package structure. Background Technology

[0002] A system-on-chip (SoC) integrates a complex, large system onto a single large chip. In contrast, heterogeneous chip design proposes breaking down a large system into several smaller systems, fabricating each of these smaller systems into individual chips, or even standard chips, and then re-integrating these chips onto a single carrier using soldering processes in packaging technology. Each chip is stably connected to the carrier via bumps, achieving performance that may even surpass that of a single large chip in the larger system. During chip packaging, flux (such as rosin) is used to improve the reliability of the soldering between the chip and the carrier. After soldering, the packaged structure needs to be cleaned to remove residual flux, preventing it from adversely affecting subsequent packaging processes and thus impacting product yield.

[0003] As packaging density continues to increase and package size shrinks, the gaps between the chip and carrier, as well as between bumps, become smaller. This makes it more difficult for cleaning fluid to penetrate the tiny gaps between the chip and carrier, rendering traditional high-pressure water flushing at atmospheric pressure inapplicable. Therefore, a method is urgently needed that allows liquid to flow within extremely confined spaces to completely remove flux residue from the package structure within a reasonable timeframe. Summary of the Invention

[0004] To improve the cleaning quality and efficiency of packaging structures, this application proposes a cleaning method and apparatus for packaging structures.

[0005] In a first aspect, this application proposes a cleaning method for a packaging structure, comprising the following steps:

[0006] Spray cleaning solution onto the packaging structure;

[0007] The chamber containing the packaging structure is evacuated to bring the pressure inside the chamber to a predetermined pressure, wherein the predetermined pressure is a negative pressure.

[0008] Keep the packaged structure still for a predetermined time to allow the cleaning fluid to enter the gaps in the packaged structure and clean it.

[0009] Secondly, this application proposes a cleaning device for a packaging structure, including a control device and a cleaning module, wherein the cleaning module includes:

[0010] Chamber;

[0011] A package structure holding device is configured to hold the package structure to be cleaned;

[0012] A fluid supply device is configured to spray cleaning fluid onto the encapsulation structure;

[0013] A pressure regulating device is configured to regulate the pressure in the chamber;

[0014] A control device is configured to control the cleaning module to perform the cleaning method for the encapsulation structure described above.

[0015] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description and the accompanying drawings.

[0016] Overview of the attached figures

[0017] The features and performance of this application are further described by the following embodiments and accompanying drawings.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 shows an exemplary packaging structure;

[0020] Figure 2 shows a flowchart of the cleaning method for the encapsulation structure in Embodiment 1 of this application;

[0021] Figure 3 shows a schematic diagram of the cleaning device structure of the encapsulation structure in Embodiment 1 of this application; and

[0022] Figure 4 shows a flowchart of the cleaning method for the encapsulation structure in Embodiment 2 of this application.

[0023] Preferred embodiments of this application

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] During chip packaging, flux (such as rosin) is used to improve the reliability of the soldering between the chip and the carrier. Taking a flip chip as an example, please refer to Figure 1, which shows an exemplary packaging structure. The packaging structure 10 includes a carrier 11 and at least one chiplet 12, which is flip-chip bonded to the carrier 11 via bumps 13. As described in the background art, when the chiplet 12 is flip-chip bonded to the carrier 11, some flux and other contaminants may remain in the gaps between the chiplet 12 and the carrier 11, as well as in the gaps between the bumps 13. To avoid the contaminants in the gaps affecting subsequent packaging processes, the residual contaminants need to be cleaned.

[0026] This application aims to provide a cleaning method and apparatus for a package structure, which removes residual flux and other contaminants from the package structure. Specifically, the method includes: spraying cleaning fluid onto the package structure; evacuating the chamber containing the package structure to achieve a predetermined pressure, wherein the predetermined pressure is a negative pressure; and keeping the package structure stationary for a predetermined time to allow the cleaning fluid to enter the gaps in the package structure and clean it.

[0027] Example 1

[0028] Please refer to Figure 2, which shows a flowchart of the cleaning method for the packaging structure in Embodiment 1 of this application. As shown in Figure 2, the cleaning method for the packaging structure includes:

[0029] Step S1100: Place the package structure to be cleaned into the cavity.

[0030] Specifically, the encapsulation structure to be cleaned is held in the chamber using an encapsulation structure holding device, at which time the air pressure in the chamber is at atmospheric pressure.

[0031] Step S1200: Spray a cleaning solution with a predetermined temperature onto the packaging structure.

[0032] Specifically, under normal atmospheric pressure within the chamber, a cleaning solution is sprayed onto the encapsulation structure located within the chamber using a fluid supply device. The cleaning solution includes, but is not limited to, deionized water and liquids containing saponifying agents; the composition of the cleaning solution can be selected according to the actual process. The temperature of the cleaning solution is controlled by a temperature regulating device. For example, in this embodiment, deionized water is selected as the cleaning solution, and the predetermined temperature is set between 25°C and 80°C. Before the deionized water, used as the cleaning solution, is delivered to the chamber, it is heated to a predetermined temperature, such as 25°C to 80°C, using the temperature regulating device. The fluid supply device then delivers the deionized water to the chamber at the predetermined temperature and sprays it onto the encapsulation structure to be cleaned.

[0033] Furthermore, during the spraying of cleaning fluid onto the encapsulation structure, the encapsulation structure can be either kept stationary or rotated at a predetermined speed. It should be understood that the predetermined speed in this document can be a relatively low speed; for example, a predetermined speed of less than or equal to 600 rpm. Selecting a stationary state or rotating at a low speed effectively prevents the cleaning fluid from being directly ejected from the encapsulation structure due to the greater centrifugal force at high speeds, effectively avoiding the situation where the cleaning fluid is ejected from the encapsulation structure before effectively entering the gaps for cleaning. It is worth noting that when the encapsulation structure remains stationary, the outlet of the fluid supply device can move relative to the encapsulation structure, or the outlet can be large enough to cover the encapsulation structure.

[0034] Step S1300: Evacuate the chamber containing the packaging structure to bring the pressure inside the chamber to a predetermined pressure, which is a negative pressure.

[0035] Step S1400: Keep the package structure still for a predetermined time to allow the cleaning fluid to enter the gaps in the package structure and clean it.

[0036] Specifically, after the cleaning fluid is sprayed onto the packaging structure, the pressure regulating device evacuates the chamber to bring the pressure inside the chamber to a predetermined pressure. In this embodiment, the predetermined pressure is 5 torr to 400 torr. After evacuating the chamber to the predetermined pressure, the packaging structure is kept stationary for a predetermined time, which in this embodiment is less than or equal to 600 seconds. It is worth noting that during the period when the packaging structure remains stationary, it is possible to choose to stop spraying the cleaning fluid onto the packaging structure or to continue spraying the cleaning fluid onto the packaging structure. When the packaging structure remains stationary for a longer period, it is preferable to continue spraying the cleaning fluid onto the packaging structure to prevent the cleaning fluid from flowing away. It should be understood that the method of continuing to spray the cleaning fluid onto the packaging structure can be continuous spraying or spraying the cleaning fluid onto the packaging structure at a certain frequency.

[0037] In this application, a cleaning solution is first sprayed onto the packaging structure, followed by evacuation. This process removes residual gas from the packaging structure, ensuring that every crevice is filled with the cleaning solution, thus guaranteeing effective cleaning. Simultaneously, after spraying the cleaning solution, the cleaning environment is set to negative pressure. This reduces the surface tension of the cleaning solution, improves its diffusion capacity, and allows it to penetrate more easily into the crevice of the packaging structure, spreading evenly between bumps and between the chip and the carrier. This further prevents residual gas in the crevice of the packaging structure from affecting the cleaning effect. Furthermore, after evacuation, the pressure inside the chamber reaches a predetermined level. Maintaining the packaging structure in a negative pressure environment for a predetermined time allows sufficient time for air bubbles to escape from the packaging structure and for the cleaning solution to penetrate, resulting in a better cleaning effect.

[0038] Furthermore, in order to facilitate the next process flow of the packaging structure, the cleaning method for the packaging structure also includes: step S1500: drying process.

[0039] In one embodiment, the drying process includes: introducing gas into the chamber to break the vacuum environment and bring the pressure inside the chamber to atmospheric pressure; rotating the packaging structure under atmospheric pressure; and controlling the rotation speed of the packaging structure to use the centrifugal force generated by the rotation to dislodge the cleaning liquid from the packaging structure, thereby achieving the drying purpose. In this embodiment, the rotation speed of the packaging structure is generally selected to be relatively high. For example, the rotation speed range of the packaging structure in the drying process is 600-1000 rpm, and preferably, for example, 800-1000 rpm.

[0040] In another embodiment, the drying process includes: introducing gas into the chamber to break the vacuum environment and bring the pressure inside the chamber to atmospheric pressure; and then, under atmospheric pressure, blowing the drying gas onto the packaging structure. By blowing the drying gas onto the surface of the packaging structure, the cleaning liquid on the surface of the packaging structure is blown outside the packaging structure and then collected and discharged. In this embodiment, the drying gas is nitrogen or an inert gas. It should be understood that in this embodiment, the packaging structure can remain stationary or rotate.

[0041] In another embodiment, the drying process includes: introducing gas into the chamber to break the vacuum environment and bring the pressure inside the chamber to atmospheric pressure; rotating the packaging structure under atmospheric pressure; controlling the rotation speed of the packaging structure to use the centrifugal force generated by the rotation to fling the cleaning fluid off the packaging structure; and simultaneously blowing drying gas onto the packaging structure to blow the cleaning fluid from the surface of the packaging structure to the outside of the packaging structure, thereby achieving rapid drying. This drying process removes the cleaning fluid from the surface of the packaging structure, facilitating its entry into the next process while preventing the cleaning fluid from contaminating the process environment of the next process, thus improving process safety and stability.

[0042] It should be understood that, in order to further ensure the cleaning effect, steps S1200 to S1500 can be repeated during the actual cleaning process to achieve the purpose of cleaning the packaged structure multiple times and ensure the cleaning effect. The number of repetitions can be selected according to the process requirements.

[0043] It is worth noting that this application does not specifically limit the order of steps S1200 and S1300. In actual process, after step S1100 is completed, step S1300 can be performed first and then step S1200; or step S1200 can be performed first and then step S1300.

[0044] When step S1200 is performed first, followed by step S1300, the specific process flow is as described above. When step S1300 is performed first, followed by step S1200, the specific process flow is: Step S1100 → Step S1300 → Step S1200 → Step S1400 → Step S1500. The chamber containing the packaging structure is evacuated from atmospheric pressure to negative pressure, and then cleaning fluid is sprayed onto the packaging structure. After spraying the cleaning fluid, the packaging structure is kept still for a predetermined time, allowing the cleaning fluid to enter the gaps in the packaging structure and soak the contaminants in the gaps, which helps to completely clean the residual contaminants. Especially when steps S1300 to S1500 are repeated, the packaging structure, after soaking and being cleaned again with the cleaning fluid, achieves even better cleaning results for the softened contaminants.

[0045] This application also proposes a cleaning apparatus for a packaged structure, which can perform the cleaning method described above. Referring to Figure 3, the cleaning apparatus for the packaged structure includes a control device and a cleaning module 100. The cleaning module 100 includes a chamber 101, a packaged structure holding device 102, a fluid supply device 103, a pressure regulating device 104, a temperature regulating device 105, etc.

[0046] The chamber 101 provides a sealed space to accommodate the package structure 10. The package structure holding device 102 is placed within the chamber 101 to hold the package structure 10.

[0047] A fluid supply device 103 is used to spray cleaning fluid onto the surface of the encapsulation structure 10. In one example, the fluid supply device 103 includes a supply source 1031, a supply line 1032, and a nozzle 1033. The supply source 1031 is used to store the cleaning fluid. The nozzle 1033 is disposed in the chamber 101 and connected to the supply source 1031 via the supply line 1032 for spraying the cleaning fluid onto the encapsulation structure 10. In one example, the cleaning fluid includes at least one of deionized water and a liquid containing a saponifying agent. The liquid containing the saponifying agent is, for example, an aqueous solution of a saponifying agent with a mass fraction of 5% to 10%, and the main component of the saponifying agent includes, for example, 2-amino-2-methyl-1-propanol.

[0048] The pressure regulating device 104 is used to regulate the pressure in the chamber 101.

[0049] In one example, the pressure regulating device 104 includes a vacuum pump 1041 and a vacuum breaking valve 1042. The vacuum pump 1041 is located on a pressure reducing line L1 communicating with the chamber 101. The vacuum pump 1041 is configured to evacuate the chamber 101, bringing the pressure inside the chamber 101 to a predetermined pressure. During the cleaning process, the predetermined pressure of the chamber 101 is set between 5 torr and 400 torr. The vacuum breaking valve 1042 is located on a vacuum breaking line L2 communicating with the chamber 101. The vacuum breaking valve 1042 is configured to open or close the gas flowing through the vacuum breaking line L2. After the cleaning process in the chamber 101 is completed, the control device can open the vacuum breaking valve 1042 to allow air to enter the chamber 101, breaking the vacuum in the chamber 101 and restoring the chamber 101 to normal pressure, facilitating operations such as removing the packaged structure 10 from the chamber 101.

[0050] Furthermore, the cleaning module 100 also includes a temperature regulating device 105. The temperature regulating device 105 is configured to regulate the temperature of the cleaning fluid sprayed onto the packaging structure 10. In this example, the control device controls the temperature regulating device 105 to heat the cleaning fluid before it is supplied to the nozzle 1033, so that the nozzle 1033 sprays the cleaning fluid at a predetermined temperature onto the packaging structure 10. During the cleaning process, the predetermined temperature of the cleaning fluid is set between 25°C and 80°C. Heating the cleaning fluid improves its solubility, thus enhancing the cleaning effect. In one example, the temperature regulating device 105 includes temperature control components such as a heater 1051 and a temperature sensor 1052 disposed on the supply line 1032. For example, the control device controls the heating power of the heater 1051 based on the temperature of the cleaning fluid in the supply line 1032 detected by the temperature sensor 1052, so that the temperature of the cleaning fluid reaches the predetermined temperature. In some examples, the temperature regulating device 105 may also be disposed on the supply source 1031. By setting the temperature regulation device 105, the cleaning fluid can be prevented from vaporizing before entering the gaps of the packaging structure 10. It should be understood that during the cleaning process, the predetermined pressure of the chamber 101 where the packaging structure 10 is located should be higher than the vaporization pressure of the cleaning fluid sprayed onto the packaging structure 10 at a predetermined temperature, so that the cleaning fluid remains in a liquid state at the predetermined pressure, which is beneficial to achieving a better cleaning effect.

[0051] Furthermore, the cleaning module 100 also includes a rotating device 106 for driving the packaging structure holding device 102 to rotate, so that the packaging structure 10 can rotate accordingly. During the spraying of cleaning fluid onto the packaging structure, the control device can control the rotational speed of the packaging structure holding device 102 via the rotating device 106, for example, controlling the rotational speed of the packaging structure holding device 102 between 0 and 600 rpm. When in the drying process, if it is necessary to keep the packaging structure 10 rotating, the control device can control the rotational speed of the packaging structure holding device 102 via the rotating device 106, for example, controlling the rotational speed of the packaging structure holding device 102 between 600 and 1000 rpm.

[0052] Example 2

[0053] This embodiment provides a cleaning device for the packaging structure that is the same as in Embodiment 1, and the cleaning method for the packaging structure in this embodiment is basically the same as in Embodiment 1. The difference is that, as shown in Figure 4, which illustrates a flowchart of the cleaning method for the packaging structure in Embodiment 2 of this application, the cleaning method in this embodiment further includes step S2500. Step S2500 is performed before step S2600 (drying process). Steps S2100, S2200, S2300, S2400, and S2600 in this embodiment correspond to steps S1100, S1200, S1300, S1400, and S1500 in Embodiment 1, respectively, and will not be described in detail here.

[0054] Step S2500 in this embodiment includes:

[0055] The cleaning fluid at a predetermined temperature is sprayed onto the packaging structure again, and the pressure inside the chamber is changed at least once during the spraying process.

[0056] After the pressure stops changing, keep the packaged structure still for a predetermined time.

[0057] Specifically, after steps S2100, S2200, S2300, and S2400 are completed, i.e., after the control device controls the pressure regulating device 104 to adjust the environment inside the chamber 101 to a predetermined pressure and maintain the encapsulation structure in a static state for a predetermined time, the control device controls the fluid supply device 103 to continuously spray cleaning fluid with a predetermined temperature onto the encapsulation structure 10. During the spraying of the cleaning fluid, the control device controls the vacuum pump 1041 or the vacuum breaking valve 1042 of the pressure regulating device 104 to change the pressure inside the chamber 101 by reducing or increasing the pressure, so as to form a pressure difference between the pressure inside the chamber 101 after the change and before the change. The pressure inside the chamber 101 is in a negative pressure state both after and before the change. During the formation of the pressure difference, a pulling or pushing force is generated, which changes the force on the cleaning fluid, thereby changing its position, making it easier for the cleaning fluid to enter the gaps in the encapsulation structure, dissolve the contaminants, and thus facilitate the cleaning fluid to completely clean the contaminants, further improving the cleaning effect. It is worth noting that the pressure inside chamber 101 is changed at least once. The specific number of changes can be selected based on actual process requirements, and this application does not impose a specific limitation. It should be understood that, in order to improve cleaning efficiency, the number of pressure changes can be as many as possible, so that the rate at which the cleaning fluid enters the gaps in the packaging structure 10 is accelerated during the continuous change of environmental pressure inside chamber 101. After the cleaning fluid has completely dissolved the contaminants, it is then accelerated to discharge the cleaning fluid from the packaging structure 10.

[0058] Each time the pressure inside chamber 101 is changed and a pressure difference is formed, the encapsulation structure 10 is kept still for a predetermined time, so that the cleaning fluid has enough time to enter the gaps of the encapsulation structure 10 and clean the contaminants remaining in the gaps of the encapsulation structure 10, thereby further improving the cleaning quality.

[0059] To further ensure the cleaning effect, in the actual cleaning process, steps S2200 to S2600 can be repeated to achieve the purpose of cleaning the package structure multiple times and ensure the cleaning effect.

[0060] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A cleaning method for a packaging structure, characterized in that, include: Spray cleaning solution onto the packaging structure; The chamber containing the packaging structure is evacuated to bring the pressure inside the chamber to a predetermined pressure, wherein the predetermined pressure is a negative pressure. Keep the packaged structure still for a predetermined time to allow the cleaning fluid to enter the gaps in the packaged structure and clean it.

2. The cleaning method for the encapsulation structure according to claim 1, characterized in that, During the process of spraying cleaning fluid onto the packaging structure, the packaging structure remains stationary or rotates at a predetermined speed.

3. The cleaning method for the packaging structure according to claim 1, characterized in that, Also includes: The cleaning fluid at a predetermined temperature is sprayed onto the packaging structure again, and the pressure inside the chamber is changed at least once during the spraying process. After the pressure stops changing, the encapsulation structure remains stationary for a predetermined time.

4. The cleaning method for the packaging structure according to claim 3, characterized in that, The pressure inside the chamber was negative both before and after the change.

5. The cleaning method for the packaging structure according to claim 1, characterized in that, It also includes a drying process, which includes: Gas is introduced into the chamber to bring the pressure inside the chamber to atmospheric pressure. Under atmospheric pressure, Rotate the packaging structure; And / or, Dry gas is blown into the packaging structure.

6. The cleaning method for the packaging structure according to claim 1, characterized in that, The predetermined time for keeping the packaged structure stationary is less than or equal to 600 seconds.

7. The cleaning method for the packaging structure according to claim 1, characterized in that, The predetermined pressure is 5 torr to 400 torr.

8. A cleaning device with a packaged structure, characterized in that, It includes a control device and a cleaning module, the cleaning module comprising: Chamber; A package structure holding device is configured to hold the package structure to be cleaned; A fluid supply device is configured to spray cleaning fluid onto the encapsulation structure; A pressure regulating device is configured to regulate the pressure in the chamber; A control device is configured to control the cleaning module to perform a cleaning method for the packaging structure according to any one of claims 1 to 7.

9. The cleaning device for the packaging structure according to claim 8, characterized in that, The pressure regulating device includes a vacuum pump and a vacuum breaking valve; The vacuum pump is located on a pressure-reducing pipeline connected to the chamber, and the vacuum pump is configured to evacuate the chamber to bring the pressure inside the chamber to a predetermined pressure. The vacuum breaking valve is installed on the vacuum breaking pipeline that communicates with the chamber, and the vacuum breaking valve is configured to open or close the gas flowing through the vacuum breaking pipeline.

10. The cleaning apparatus for the packaging structure according to claim 8, characterized in that, Also includes: A temperature regulating device is configured to regulate the temperature of the cleaning fluid supplied to the packaging structure.

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